This work includes the establishment of a Photovoltaic system connected to the grid by means of an inverter. The fundamental goal of the work is to incorporate an advanced active power flow management scheme in order to adopt load at any weather condition along with the advantage of maximum active power flow and zero harmonics from PV inverter to the grid. The outcome of analysis and control design of grid connected PV inverter using a Proportional-Integral (PI) control technique is based on synchronous dq rotating reference frame so as to achieve maximum output voltage and record the active power. It has been observed that the model provides a better rate of stability as compared to the existing topology.
Direct current (DC) electronic load is a useful equipment for testing the electrical system. It can emulate various load at a high rating. The electronic load requires a power converter to operate and a linear regulator is a common option. Nonetheless, it is hard to control due to the temperature variation. This paper proposed a DC electronic load using the boost converter. The proposed electronic load operates in the continuous current mode and control using the integral controller. The electronic load using the boost converter is compared with the electronic load using the linear regulator. The results show that the boost converter able to operate as an electronic load with an error lower than 0.5% and response time lower than 13 ms.
This paper presents simulation and experimental results of anti-windup PI controller to improve induction machine speed control based on direct torque control (DTC) strategy. Problems like rollover can arise in conventional PI controller due to saturation effect. In order to avoid such problems anti-windup PI controller is presented. This controller is simple for implementation in practice. The proposed anti-windup PI controller demonstrates better dynamic step changes response in speed in terms of overshoots. All simulation work was done using Simulink in the MATLAB software. The experimental results were obtained by practical implementation on a dSPACE 1104 board for a 1.5 KW induction machine. Simulation and experimental results have proven a good performance and verified the validity of the presented control strategy.
A hybrid DC/DC/AC converter connected to the grid without a three-phase transformer is controlled. The decentralized control method is applied to the hybrid DC-DC converter such that the maximum power of PV flows to the grid side. This controller must charge and discharge the battery at the proper time. It must also regulate DC-link voltage. An additional advantage of the proposed control is that the three-phase inverter does not need a separate controller such as PWM and SPWM. A simple technique is used for creating the desired phase shift in the three-phase inverter, which makes the active and reactive power of the inverter controllable. A new configuration is also proposed to transmit and manage the generation power of PV. In this scheme, the battery and fuel cell are employed as an auxiliary source to manage the generation power of PV. Finally, a real-time simulation is performed to verify the effectiveness of the proposed controller and system by considering the real characteristics of PV and FC.
The inverter is the principal part of the photovoltaic (PV) systems that assures the direct current/alternating current (DC/AC) conversion (PV array is connected directly to an inverter that converts the DC energy produced by the PV array into AC energy that is directly connected to the electric utility). In this paper, we present a simple method for detecting faults that occurred during the operation of the inverter. These types of faults or faults affect the efficiency and cost-effectiveness of the photovoltaic system, especially the inverter, which is the main component responsible for the conversion. Hence, we have shown first the faults obtained in the case of the short circuit. Second, the open circuit failure is studied. The results demonstrate the efficacy of the proposed method. Good monitoring and detection of faults in the inverter can increase the system's reliability and decrease the undesirable faults that appeared in the PV system. The system behavior is tested under variable parameters and conditions using MATLAB/Simulink.
Alternating current (AC) electrical drives mainly require smaller current (or torque) ripples and lower total harmonic distortion (THD) of voltage for excellent drive performances. Normally, in practice, to achieve these requirements, the inverter needs to be operated at high switching frequency. By operating at high switching frequency, the size of filter can be reduced. However, the inverter which oftenly employs insulated gate bipolar transistor (IGBT) for high power applications cannot be operated at high switching frequency. This is because, the IGBT switching frequency cannot be operated above 50 kHz due to its thermal restrictions. This paper proposes an alternate switching strategy to enable the use of IGBT for operating the inverter at high switching frequency to improve THD performances. In this strategy, each IGBT in a group of switches in the modified inverter circuit will operate the switching frequency at one-fourth of the inverter switching frequency. The alternate switching is implemented using simple analog and digital integrated circuits.
Direct current (DC) electronic load is a useful equipment for testing the electrical system. It can emulate various load at a high rating. The electronic load requires a power converter to operate and a linear regulator is a common option. Nonetheless, it is hard to control due to the temperature variation. This paper proposed a DC electronic load using the boost converter. The proposed electronic load operates in the continuous current mode and control using the integral controller. The electronic load using the boost converter is compared with the electronic load using the linear regulator. The results show that the boost converter able to operate as an electronic load with an error lower than 0.5% and response time lower than 13 ms.
This paper presents simulation and experimental results of anti-windup PI controller to improve induction machine speed control based on direct torque control (DTC) strategy. Problems like rollover can arise in conventional PI controller due to saturation effect. In order to avoid such problems anti-windup PI controller is presented. This controller is simple for implementation in practice. The proposed anti-windup PI controller demonstrates better dynamic step changes response in speed in terms of overshoots. All simulation work was done using Simulink in the MATLAB software. The experimental results were obtained by practical implementation on a dSPACE 1104 board for a 1.5 KW induction machine. Simulation and experimental results have proven a good performance and verified the validity of the presented control strategy.
A hybrid DC/DC/AC converter connected to the grid without a three-phase transformer is controlled. The decentralized control method is applied to the hybrid DC-DC converter such that the maximum power of PV flows to the grid side. This controller must charge and discharge the battery at the proper time. It must also regulate DC-link voltage. An additional advantage of the proposed control is that the three-phase inverter does not need a separate controller such as PWM and SPWM. A simple technique is used for creating the desired phase shift in the three-phase inverter, which makes the active and reactive power of the inverter controllable. A new configuration is also proposed to transmit and manage the generation power of PV. In this scheme, the battery and fuel cell are employed as an auxiliary source to manage the generation power of PV. Finally, a real-time simulation is performed to verify the effectiveness of the proposed controller and system by considering the real characteristics of PV and FC.
The inverter is the principal part of the photovoltaic (PV) systems that assures the direct current/alternating current (DC/AC) conversion (PV array is connected directly to an inverter that converts the DC energy produced by the PV array into AC energy that is directly connected to the electric utility). In this paper, we present a simple method for detecting faults that occurred during the operation of the inverter. These types of faults or faults affect the efficiency and cost-effectiveness of the photovoltaic system, especially the inverter, which is the main component responsible for the conversion. Hence, we have shown first the faults obtained in the case of the short circuit. Second, the open circuit failure is studied. The results demonstrate the efficacy of the proposed method. Good monitoring and detection of faults in the inverter can increase the system's reliability and decrease the undesirable faults that appeared in the PV system. The system behavior is tested under variable parameters and conditions using MATLAB/Simulink.
Alternating current (AC) electrical drives mainly require smaller current (or torque) ripples and lower total harmonic distortion (THD) of voltage for excellent drive performances. Normally, in practice, to achieve these requirements, the inverter needs to be operated at high switching frequency. By operating at high switching frequency, the size of filter can be reduced. However, the inverter which oftenly employs insulated gate bipolar transistor (IGBT) for high power applications cannot be operated at high switching frequency. This is because, the IGBT switching frequency cannot be operated above 50 kHz due to its thermal restrictions. This paper proposes an alternate switching strategy to enable the use of IGBT for operating the inverter at high switching frequency to improve THD performances. In this strategy, each IGBT in a group of switches in the modified inverter circuit will operate the switching frequency at one-fourth of the inverter switching frequency. The alternate switching is implemented using simple analog and digital integrated circuits.
In this paper, using a neural controller and a genetic optimization algorithm to control the voltage as well as, control the frequency of the grid along with the management of the reactive power of the micro-grid to control the output power during islanding using Simultaneous bilateral power converters with voltage/frequency droop strategy and optimization of PI coefficients of parallel power converters by genetic-neural micro-grid algorithm to suppress AC side-current flow that increases stability and improvement of conditions frequency and voltage are discussed. Given the performance of the micro-grid in two simulation scenarios, namely transition from on-grid to off-grid, the occurrence of a step change in load in island mode as well as return to working mode is connected. The ability to detect the robust performance and proper performance of two-level neural controller. The controller performance time was also very good, indicating the appropriate features of the method used to design the controller, namely two-level neural, genetics. The main advantage of this method is its simplicity of design. The method used is also efficient and resistant to changes in the system, which results from the simulations.
Improved Power Quality by using STATCOM Under Various Loading ConditionsIJMTST Journal
A Power quality problem is an occurrence manifested as a nonstandard voltage, current or frequency that
results in a failure or a mis-operation of end user equipment’s. Utility distribution networks, sensitive
industrial loads and critical commercial operations suffer from various types of outages and service
interruptions which can cost significant financial losses. With the restructuring of power systems and with
shifting trend towards distributed and dispersed generation, the issue of power quality is going to take
newer dimensions. Injection of the wind power into an electric grid affects the power quality. The
performance of the wind turbine and thereby power quality are determined on the basis of measurements
and the norms followed according to the guideline specified in International Electro-technical Commission
standard, IEC-61400. The influence of the wind turbine in the grid system concerning the power quality
measurements are-the active power, reactive power, variation of voltage, flicker, harmonics, and electrical
behavior of switching operation and these are measured according to national/international guidelines.
Static Compensator (STATCOM) is connected at a point of common coupling with a battery energy storage
system (BESS) to mitigate the power quality issues. The battery energy storage is integrated to sustain the
real power source under fluctuating wind power. Here two control schemes for STATCOM are Fuzzy logic
controller and hybrid Fuzzy logic controller. We can better response for hybrid fuzzy compare to fuzzy logic
controller. The STATCOM control scheme for the grid connected wind energy generation system for power
quality improvement is simulated using MATLAB/SIMULINK in power system block set. Finally the proposed
scheme is applied for both balanced and unbalanced linear nonlinear loads.
The growing demand for electricity and the increasing integration of clean energies into the electrical grids requires the multiplication and reinforcement of high-voltage direct current (HVDC) projects throughout the world and demonstrates the interest in this electricity transmission technology. The transmitting system of the voltage source converter-high-voltage direct current (VSC-HVDC) consists primarily of two converter stations that are connected by a dc cable. In this paper, a nonlinear control based on the backstepping approach is proposed to improve the dynamic performance of a VSC-HVDC transmission system, these transport systems are characterized by different complexities such as parametric uncertainties, coupled state variables, neglected dynamics, presents a very interesting research topic. Our contribution through adaptive control based on the backstepping approach allows regulating the direct current (DC) bus voltage and the active and reactive powers of the converter stations. Finally, the validity of the proposed control has been verified under various operating conditions by simulation in the MATLAB/Simulink environment.
Comparison of upqc and dvr in wind turbine fed fsig under asymmetric faultselelijjournal
This paper presents the mitigation of faults in wind turbine connected fixed speed induction generator using unified power quality conditioner and static compensator. The UPQC consists of shunt and series converters connected back-to-back through a dc-to-dc step up converter. The presence of the dc-to-dc step converter permits the UPQC to compensate faults for long duration. The series converter is connected to the supply side whereas the shunt converter is connected to the load side. The control system of the proposed UPQC is based on Id-Iq theory. The DVR consists of shunt and series converters connected back-to-back through a dc-to-dc step up converter. The presence of the dc-to-dc step converter permits the DVR to compensate faults for long duration. The series converter is connected to the supply side whereas the shunt converter is connected to the load side. The control system of the proposed DVR is based on
hysteresis voltage controlThe proposed wind turbine fed fixed speed induction generator is evaluated and simulated using MATLAB/SIMULINK environment with UPQC and DVR under asymmetric faults
Impact of hybrid FACTS devices on the stability of the Kenyan power system IJECEIAES
Flexible alternating current transmission system (FACTS) devices are deployed for improving power system’s stability either singly or as a combination. This research investigates hybrid FACTS devices and studies their impact on voltage, small-signal and transient stability simultaneously under various system disturbances. The simulations were done using five FACTS devices-static var compensator (SVC), static synchronous compensator (STATCOM), static synchronous series compensators (SSSC), thyristor controlled series compensator (TCSC) and unified power flow controller (UPFC) in MATLAB’s power system analysis toolbox (PSAT). These five devices were grouped into ten pairs and tested on Kenya’s transmission network under specific contingencies: the loss of a major generating machine and/or transmission line. The UPFC-STATCOM pair performed the best in all the three aspects under study. The settling times were 3 seconds and 3.05 seconds respectively for voltage and rotor angle improvement on the loss of a major generator at normal operation. The same pair gave settling times of 2.11 seconds and 3.12 seconds for voltage and rotor angle stability improvement respectively on the loss of a major transmission line at 140% system loading. From the study, two novel techniques were developed: A performance-based ranking system and classification for FACTS devices.
In a distributed generation system, divers renewable agents are connected to the low voltage 3 phase utility grid by an inverter which is used as power condition and must assurance the higher efficiency of the renewable agent. To achieve this level of efficiency, a unitary power factor between the utility grid voltages and the inverter currents is necessary, and a synchronization algorithm is required for the perfect synchronization between the 3-phase utility grid and the renewable agent. The aim of this paper is to present the optimization of the performance of a Synchronization controller for a 3-phase photovoltaic grid-connected system, assessing its accuracy under different conditions and studying their drawbacks and advantages. A grid connected photovoltaic system with a nominal power of 5 kW is used so as to assess the behavior of the synchronization algorithm when the 3 phase utility grid is affected by some disturbances such as voltage unbalances.
Autonomous microgrid based parallel inverters using droop controller for impr...journalBEEI
The existing microgrid has become a challenge to the sustainable energy source to provide a better quality of power to the consumer. To build a reliable and efficient microgrid, designing a droop controller for the microgrid is of utmost importance. In this paper, multiple voltage source inverters connected in parallel using an active power-frequency/reactive power-voltage droop scheme. The proposed method connected to two distributed generators local controllers, where each unit consists of a droop controller with an inner voltage-current controller and a virtual droop controller. By adding this controller to the microgrid reliability and load adaptability of an islanded system can be improved. This concept applied without any real-time communication to the microgrid. Thus, simulated using MATLAB/Simulink, the obtained results prove the effectiveness of the autonomous operation's microgrid model.
Mainly the DC motors are employed in most of the application. The main objective is to Regulate the DC motor system. A motor which displays the appearances of a DC motor but there is no commutator and brushes is called as brushless DC motor. These motors are widespread to their compensations than other motors in relationships of dependability, sound, efficiency, preliminary torque and longevity. To achieve the operation more reliable and less noisy, brushless dc motors are employed. In the proposed work, dissimilar methods of speed control are analysed. In real time submission of speed control of BLDC motor, numerous strategies are executed for the speed control singularity. The modified approaches are the employment of PI controller, use of PID controller and proposed current controller.
Control of Two Stage PV Power System under the Unbalanced Three Phase Grid Vo...ijtsrd
This paper proposes a dynamic power decoupling DPD strategy for the three phase grid tied PV power system without increasing the dc link capacitance. Under normal condition, the interleaved boost converter will extract the maximum power point MPP from the PV array and the three phase inverter will inject the power to the grid. During the unbalanced grid fault scenario, the input power and current of the interleaved boost converter will be controlled by the proposed DPD to achieve the power decoupling capability as well as to eliminate the dc link voltage oscillation. The proposed work has been carried out in MATLAB, and the results are presented. Manasa | Nirmaladevi ""Control of Two Stage PV Power System under the Unbalanced Three-Phase Grid Voltages"" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-4 | Issue-2 , February 2020,
URL: https://www.ijtsrd.com/papers/ijtsrd30091.pdf
Paper Url : https://www.ijtsrd.com/engineering/electrical-engineering/30091/control-of-two-stage-pv-power-system-under-the-unbalanced-three-phase-grid-voltages/manasa
Design and Analysis of PID and Fuzzy-PID Controller for Voltage Control of DC...Francisco Gonzalez-Longatt
DC microgrids are desired to provide the electricity for the remote areas which are far from the main grid. The microgrid creates the open horizontal environment to interconnect the distributed generation especially photovoltaic (PV). The stochastic nature of the PV output power introduces the large fluctuations of the power and voltage in the microgrid and forced to introduce the controller for voltage stability. There are many control strategies to control the voltage of a DC microgrid in the literature. In this paper the proportional-integral-derivative (PID) and fuzzy logic PID (FL-PID) controller has been designed and compared in term of performance. Performance measures like maximum overshoot and settling time of FL-PID compared with the PID proved that the former is better controller. The controllers are designed and simulated in the MATLAB programming environment. The controllers has been tested for the real time data obtained from Pecan Street Project, University of Texas at Austin USA.
This paper presents a thorough control structure of the distributed generators inside the microgrid during both grid-connected and islanded operation modes. These control structures of the DGs voltage source inverters are implemented in synchronous reference frame (SRF) and controlled using linear PI controllers. By implementing the control structures, the desired real and reactive power can be efficiently transferred to the local loads and the utility load by the microgrid generating units. A modified droop control technique is introduced to facilitate the microgrid performance during both modes of operation. The active and reactive power sharing of the load demand between the utility grid and the microgrid can be performed by this drop control technique during the islanded mode. The system performance during intentional islanding event and utility load increase is investigated. The effectiveness of the offered control structures is confirmed through simulation results during both modes of operation.
Adaptive Fuzzy PI Current Control of Grid Interact PV Inverter IJECEIAES
Now a day‟s, Photo Voltaic (PV) power generation rapidly increasing. This power generation highly depending on the temperature and irradiation. When this power interface with grid through the voltage source inverter with PI controller. Its gains should be updated due to the parametric changes for the better performance. In This Work Fuzzy Controller updates the gains of the proportional integral (PI)s Controller under variable parametric conditions. the gaines of the PI Controller are updated based on the error current and change in error current through the fuzzy controller. The error current in direct and quadrature frame are the Inputs to the PI controller. The PI Controller generates the reference voltage to the pulse width modulation technique. Here reference voltage is compared with the carrier signal to generate the pulses to the 3-Ph Inverter connected to the grid. This controller has given well dynamic response with less steady state error and also given The less THD of the grid current compared to the PI and Fuzzy controller.It Is implemented and verified in MATLAB Simulink.
Modeling and simulation of three phases cascaded H-bridge grid-tied PV inverterjournalBEEI
In this paper a control scheme for three phase seven level cascaded H-bridge inverter for grid tied PV system is presented. As power generation from PV depends on varing environmental conditions, for extractraction of maximum power from PV array, fuzzy MPPT controller is incorporated with each PV array. It gives fast and accurate response. To maintain the grid current
sinusoidal under varying conditions, a digital PI controller scheme is adopted. A MATLAB/Simulink model is developed for this purpose and results are presented. At last THD analysis is carried out in order to validate the performance of the overall system. As discussed, with this control strategy the balanced grid current is obtained keeping THD values with in the specified range of IEEE-519 standard.
In this paper, using a neural controller and a genetic optimization algorithm to control the voltage as well as, control the frequency of the grid along with the management of the reactive power of the micro-grid to control the output power during islanding using Simultaneous bilateral power converters with voltage/frequency droop strategy and optimization of PI coefficients of parallel power converters by genetic-neural micro-grid algorithm to suppress AC side-current flow that increases stability and improvement of conditions frequency and voltage are discussed. Given the performance of the micro-grid in two simulation scenarios, namely transition from on-grid to off-grid, the occurrence of a step change in load in island mode as well as return to working mode is connected. The ability to detect the robust performance and proper performance of two-level neural controller. The controller performance time was also very good, indicating the appropriate features of the method used to design the controller, namely two-level neural, genetics. The main advantage of this method is its simplicity of design. The method used is also efficient and resistant to changes in the system, which results from the simulations.
Improved Power Quality by using STATCOM Under Various Loading ConditionsIJMTST Journal
A Power quality problem is an occurrence manifested as a nonstandard voltage, current or frequency that
results in a failure or a mis-operation of end user equipment’s. Utility distribution networks, sensitive
industrial loads and critical commercial operations suffer from various types of outages and service
interruptions which can cost significant financial losses. With the restructuring of power systems and with
shifting trend towards distributed and dispersed generation, the issue of power quality is going to take
newer dimensions. Injection of the wind power into an electric grid affects the power quality. The
performance of the wind turbine and thereby power quality are determined on the basis of measurements
and the norms followed according to the guideline specified in International Electro-technical Commission
standard, IEC-61400. The influence of the wind turbine in the grid system concerning the power quality
measurements are-the active power, reactive power, variation of voltage, flicker, harmonics, and electrical
behavior of switching operation and these are measured according to national/international guidelines.
Static Compensator (STATCOM) is connected at a point of common coupling with a battery energy storage
system (BESS) to mitigate the power quality issues. The battery energy storage is integrated to sustain the
real power source under fluctuating wind power. Here two control schemes for STATCOM are Fuzzy logic
controller and hybrid Fuzzy logic controller. We can better response for hybrid fuzzy compare to fuzzy logic
controller. The STATCOM control scheme for the grid connected wind energy generation system for power
quality improvement is simulated using MATLAB/SIMULINK in power system block set. Finally the proposed
scheme is applied for both balanced and unbalanced linear nonlinear loads.
The growing demand for electricity and the increasing integration of clean energies into the electrical grids requires the multiplication and reinforcement of high-voltage direct current (HVDC) projects throughout the world and demonstrates the interest in this electricity transmission technology. The transmitting system of the voltage source converter-high-voltage direct current (VSC-HVDC) consists primarily of two converter stations that are connected by a dc cable. In this paper, a nonlinear control based on the backstepping approach is proposed to improve the dynamic performance of a VSC-HVDC transmission system, these transport systems are characterized by different complexities such as parametric uncertainties, coupled state variables, neglected dynamics, presents a very interesting research topic. Our contribution through adaptive control based on the backstepping approach allows regulating the direct current (DC) bus voltage and the active and reactive powers of the converter stations. Finally, the validity of the proposed control has been verified under various operating conditions by simulation in the MATLAB/Simulink environment.
Comparison of upqc and dvr in wind turbine fed fsig under asymmetric faultselelijjournal
This paper presents the mitigation of faults in wind turbine connected fixed speed induction generator using unified power quality conditioner and static compensator. The UPQC consists of shunt and series converters connected back-to-back through a dc-to-dc step up converter. The presence of the dc-to-dc step converter permits the UPQC to compensate faults for long duration. The series converter is connected to the supply side whereas the shunt converter is connected to the load side. The control system of the proposed UPQC is based on Id-Iq theory. The DVR consists of shunt and series converters connected back-to-back through a dc-to-dc step up converter. The presence of the dc-to-dc step converter permits the DVR to compensate faults for long duration. The series converter is connected to the supply side whereas the shunt converter is connected to the load side. The control system of the proposed DVR is based on
hysteresis voltage controlThe proposed wind turbine fed fixed speed induction generator is evaluated and simulated using MATLAB/SIMULINK environment with UPQC and DVR under asymmetric faults
Impact of hybrid FACTS devices on the stability of the Kenyan power system IJECEIAES
Flexible alternating current transmission system (FACTS) devices are deployed for improving power system’s stability either singly or as a combination. This research investigates hybrid FACTS devices and studies their impact on voltage, small-signal and transient stability simultaneously under various system disturbances. The simulations were done using five FACTS devices-static var compensator (SVC), static synchronous compensator (STATCOM), static synchronous series compensators (SSSC), thyristor controlled series compensator (TCSC) and unified power flow controller (UPFC) in MATLAB’s power system analysis toolbox (PSAT). These five devices were grouped into ten pairs and tested on Kenya’s transmission network under specific contingencies: the loss of a major generating machine and/or transmission line. The UPFC-STATCOM pair performed the best in all the three aspects under study. The settling times were 3 seconds and 3.05 seconds respectively for voltage and rotor angle improvement on the loss of a major generator at normal operation. The same pair gave settling times of 2.11 seconds and 3.12 seconds for voltage and rotor angle stability improvement respectively on the loss of a major transmission line at 140% system loading. From the study, two novel techniques were developed: A performance-based ranking system and classification for FACTS devices.
In a distributed generation system, divers renewable agents are connected to the low voltage 3 phase utility grid by an inverter which is used as power condition and must assurance the higher efficiency of the renewable agent. To achieve this level of efficiency, a unitary power factor between the utility grid voltages and the inverter currents is necessary, and a synchronization algorithm is required for the perfect synchronization between the 3-phase utility grid and the renewable agent. The aim of this paper is to present the optimization of the performance of a Synchronization controller for a 3-phase photovoltaic grid-connected system, assessing its accuracy under different conditions and studying their drawbacks and advantages. A grid connected photovoltaic system with a nominal power of 5 kW is used so as to assess the behavior of the synchronization algorithm when the 3 phase utility grid is affected by some disturbances such as voltage unbalances.
Autonomous microgrid based parallel inverters using droop controller for impr...journalBEEI
The existing microgrid has become a challenge to the sustainable energy source to provide a better quality of power to the consumer. To build a reliable and efficient microgrid, designing a droop controller for the microgrid is of utmost importance. In this paper, multiple voltage source inverters connected in parallel using an active power-frequency/reactive power-voltage droop scheme. The proposed method connected to two distributed generators local controllers, where each unit consists of a droop controller with an inner voltage-current controller and a virtual droop controller. By adding this controller to the microgrid reliability and load adaptability of an islanded system can be improved. This concept applied without any real-time communication to the microgrid. Thus, simulated using MATLAB/Simulink, the obtained results prove the effectiveness of the autonomous operation's microgrid model.
Mainly the DC motors are employed in most of the application. The main objective is to Regulate the DC motor system. A motor which displays the appearances of a DC motor but there is no commutator and brushes is called as brushless DC motor. These motors are widespread to their compensations than other motors in relationships of dependability, sound, efficiency, preliminary torque and longevity. To achieve the operation more reliable and less noisy, brushless dc motors are employed. In the proposed work, dissimilar methods of speed control are analysed. In real time submission of speed control of BLDC motor, numerous strategies are executed for the speed control singularity. The modified approaches are the employment of PI controller, use of PID controller and proposed current controller.
Control of Two Stage PV Power System under the Unbalanced Three Phase Grid Vo...ijtsrd
This paper proposes a dynamic power decoupling DPD strategy for the three phase grid tied PV power system without increasing the dc link capacitance. Under normal condition, the interleaved boost converter will extract the maximum power point MPP from the PV array and the three phase inverter will inject the power to the grid. During the unbalanced grid fault scenario, the input power and current of the interleaved boost converter will be controlled by the proposed DPD to achieve the power decoupling capability as well as to eliminate the dc link voltage oscillation. The proposed work has been carried out in MATLAB, and the results are presented. Manasa | Nirmaladevi ""Control of Two Stage PV Power System under the Unbalanced Three-Phase Grid Voltages"" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-4 | Issue-2 , February 2020,
URL: https://www.ijtsrd.com/papers/ijtsrd30091.pdf
Paper Url : https://www.ijtsrd.com/engineering/electrical-engineering/30091/control-of-two-stage-pv-power-system-under-the-unbalanced-three-phase-grid-voltages/manasa
Design and Analysis of PID and Fuzzy-PID Controller for Voltage Control of DC...Francisco Gonzalez-Longatt
DC microgrids are desired to provide the electricity for the remote areas which are far from the main grid. The microgrid creates the open horizontal environment to interconnect the distributed generation especially photovoltaic (PV). The stochastic nature of the PV output power introduces the large fluctuations of the power and voltage in the microgrid and forced to introduce the controller for voltage stability. There are many control strategies to control the voltage of a DC microgrid in the literature. In this paper the proportional-integral-derivative (PID) and fuzzy logic PID (FL-PID) controller has been designed and compared in term of performance. Performance measures like maximum overshoot and settling time of FL-PID compared with the PID proved that the former is better controller. The controllers are designed and simulated in the MATLAB programming environment. The controllers has been tested for the real time data obtained from Pecan Street Project, University of Texas at Austin USA.
This paper presents a thorough control structure of the distributed generators inside the microgrid during both grid-connected and islanded operation modes. These control structures of the DGs voltage source inverters are implemented in synchronous reference frame (SRF) and controlled using linear PI controllers. By implementing the control structures, the desired real and reactive power can be efficiently transferred to the local loads and the utility load by the microgrid generating units. A modified droop control technique is introduced to facilitate the microgrid performance during both modes of operation. The active and reactive power sharing of the load demand between the utility grid and the microgrid can be performed by this drop control technique during the islanded mode. The system performance during intentional islanding event and utility load increase is investigated. The effectiveness of the offered control structures is confirmed through simulation results during both modes of operation.
Adaptive Fuzzy PI Current Control of Grid Interact PV Inverter IJECEIAES
Now a day‟s, Photo Voltaic (PV) power generation rapidly increasing. This power generation highly depending on the temperature and irradiation. When this power interface with grid through the voltage source inverter with PI controller. Its gains should be updated due to the parametric changes for the better performance. In This Work Fuzzy Controller updates the gains of the proportional integral (PI)s Controller under variable parametric conditions. the gaines of the PI Controller are updated based on the error current and change in error current through the fuzzy controller. The error current in direct and quadrature frame are the Inputs to the PI controller. The PI Controller generates the reference voltage to the pulse width modulation technique. Here reference voltage is compared with the carrier signal to generate the pulses to the 3-Ph Inverter connected to the grid. This controller has given well dynamic response with less steady state error and also given The less THD of the grid current compared to the PI and Fuzzy controller.It Is implemented and verified in MATLAB Simulink.
Modeling and simulation of three phases cascaded H-bridge grid-tied PV inverterjournalBEEI
In this paper a control scheme for three phase seven level cascaded H-bridge inverter for grid tied PV system is presented. As power generation from PV depends on varing environmental conditions, for extractraction of maximum power from PV array, fuzzy MPPT controller is incorporated with each PV array. It gives fast and accurate response. To maintain the grid current
sinusoidal under varying conditions, a digital PI controller scheme is adopted. A MATLAB/Simulink model is developed for this purpose and results are presented. At last THD analysis is carried out in order to validate the performance of the overall system. As discussed, with this control strategy the balanced grid current is obtained keeping THD values with in the specified range of IEEE-519 standard.
Control strategies for seamless transfer between the grid-connected and isla...IJECEIAES
Design of control strategies for Distributed generation systems is very important to achieve smoother transition between the grid connected and islanding modes of operation. The transition between these two modes of operation should be seamless, without any severe transients during the changeover. In this paper, two different control strategies namely inverter output current control and indirect grid current control for the seamless transfer between the modes of operation has been explored for the suitability. The design and analysis of the cascaded control loops based on Proportional Integral (PI) controller has been dealt in detail for both inverter output current control and indirect grid current control strategy. Control parameters are designed using the control system toolbox in MATLAB. A 10kW grid connected microgrid system has been designed and simulated in MATLAB/Simulink and the results are presented under grid connected operation, islanding operation and the transition between the modes considering fault condition in the grid side. The simulation studies are carried out using both the control strategies and the results are presented to validate the design methodology.
An inverter system applied with the PV source typically has a problem of lower input voltage due to constraint in the PV strings connection. As a countermeasure a DC-DC boost converter is placed in between to achieve a higher voltage at the inverter DC link for connection to the grid and to realize the MPPT operation. This additional stage contributes to losses and complexity in control thus reducing the overall system efficiency. This work discussed on the design and development of a grid-connected quasi-Z-source PV inverter which has different topology and control method compared to the conventional voltage source inverter and able to overcome the above disadvantages. Modelling and performance analysis of the voltage and current controller to achieve a good power transfer from the PV source, as well sycnchronization with the grid are presented in detail. Results from both simulation and experimental verification demonstrate the designed and developed grid-connected qZSI PV inverter works successfully equivalent to the conventional voltage source inverter system.
Two fuzzy logic controllers are proposed in this paper to control a three phase inverter for grid connected photovoltaic system. The first controller was used to predict the DC voltage that allows the three phase inverter to track the maximum power point of photovoltaic array under different environmental conditions such as irradiances and temperature. The second was used to control the active power and reactive power injected into the grid in order to inject the maximum active power produced by photovoltaic systems into grid with high efficiency and low total harmonic distortion using the same three phase inverter. The system components are photovoltaic array, DC link voltage, three-phase inverter, inverter control, LC filter, transformer and grid. To verify the effectivnesse of the introdueced system, modeling and simulation are verified in Matlab/Simulink due to its frequent use and its effectiveness.
Improvement of Power Quality using Fuzzy Logic Controller in Grid Connected P...IAES-IJPEDS
In this paper, the design of combined operation of UPQC and PV-ARRAY is designed. The proposed system is composed of series and shunt inverters connected back to back by a dc-link to which pv-array is connected. This system is able to compensate voltage and current related problems both in inter-connected mode and islanding mode by injecting active power to grid. The fundamental aspect is that the power electronic devices (PE) and sensitive equipments (SE) are normally designed to work in non-polluted power system, so they would suffer from malfunctions when supply voltage is not pure sinusoidal. Thus this proposed operating strategy with flexible operation mode improves the power quality of the grid system combining photovoltaic array with a control of unified power quality conditioner. Pulse Width Modulation (PWM) is used in both three phase four leg inverters. A Proportional Integral (PI) and Fuzzy Logic Controllers are used for power quality improvement by reducing the distortions in the output power. The simulated results were compared among the two controller’s strategies With pi controller and fuzzy logic controller
The power generation using solar photovoltaic (PV) system in microgrid requires energy storage system due to their dilute and intermittent nature. The system requires efficient control techniques to ensure the reliable operation of the microgrid. This work presents dynamic power management using a decentralized approach. The control techniques in microgrid including droop controllers in cascade with proportional-integral (PI) controllers for voltage stability and power balance have few limitations. PI controllers alone will not ensure microgrid’s stability. Their parameters cannot be optimized for varying demand and have a slow transient response which increases the settling time. The droop controllers have lower efficiency. The load power variation and steady-state voltage error make the droop control ineffective. This paper presents a control scheme for dynamic power management by incorporating the combined PI and hysteresis controller (CPIHC) technique. The system becomes robust, performs well under varying demand conditions, and shows a faster dynamic response. The proposed DC microgrid has solar PV as an energy source, a lead-acid battery as the energy storage system, constant and dynamic loads. The simulation results show the proposed CPIHC technique efficiently manages the dynamic power, regulates DC link voltage and battery’s state of charge (SoC) compared to conventional combined PI and droop controller (CPIDC).
Modeling and simulation of three phases cascaded H-bridge grid-tied PV inverterjournalBEEI
In this paper a control scheme for three phase seven level cascaded H-bridge inverter for grid tied PV system is presented. As power generation from PV depends on varing environmental conditions, for extractraction of maximum power from PV array, fuzzy MPPT controller is incorporated with each PV array. It gives fast and accurate response. To maintain the grid current sinusoidal under varying conditions, a digital PI controller scheme is adopted. A MATLAB/Simulink model is developed for this purpose and results are presented. At last THD analysis is carried out in order to validate the performance of the overall system. As discussed, with this control strategy the balanced grid current is obtained keeping THD values with in the specified range of IEEE-519 standard.
Power quality optimization using a novel backstepping control of a three-phas...IJECEIAES
A novel nonlinear backstepping controller based on direct current (DC) link voltage control is proposed in three-phase grid-connected solar photovoltaic (PV) systems to control the active and reactive power flow between the PV system and the grid with improved power quality in terms of pure sinusoidal current injection with lower total harmonic distortion (THD), as well as to ensure unity power factor, or to compensate for reactive power required by the load, i.e., the electrical grid. The output power of the PV array is supplied to the grid through a boost converter with maximum power point tracking (MPPT) control and an inverter. Simulation results of the proposed controller show good robustness under nominal conditions, parameter variations, and load disturbances, which presents the main advantage of this controller as compared to an existing controller. The performance of this work was evaluated using a MATLAB/Simulink environment.
This paper presents the analysis, modeling and control of a grid connected photovoltaic generation system. The model contains a detailed representation of the solar array, grid side multilevel neutral point clamped voltage source inverter. Fuzzy logic controller for the maximum power point tracking of a photovoltaic system under variable temperature and insulation conditions is discussed. The PQ control approach has been presented for the multilevel inverter. One of the most common control strategies structures applied to decentralized power generator is based on power direct control employing a controller for the dc link voltage and a controller to regulate the injected current to the utility network. The proposed models were implemented in Matlab/Simulink.
Solar energy based impedance-source inverter for grid systemIJECEIAES
In this work, the fickleness of solar energy can be overcome by using Maximum Power Point Tracking algorithm (MPPT). Perturb and Observation (P&O) MPPT algorithm accomplish fast the maximum power point for rapid change of environmental conditions such as irradiance intensity and temperature. The MPPT algorithm applied to solar PV system keep the boost converter output constant. Output from boost converter is taken to three phase impedance-source inverter with RL load and grid system. Impedance-source inverter performs the transformation of variable DC output of the solar PV system in to near sinusoidal AC output. This near sinusoidal AC output consecutively is served to the RL load first and then to grid system. The simulation is carried out in matlab/simulink platform both for RL load and grid system and the simulation results are experimentally validated for RL load arrangement only.
This paper describes the Grid connected solar photovoltaique system using DC-DC boost converter and the DC/AC inverter (VSC) to supplies electric power to the utility grid. The model contains a representation of the main components of the system that are two solar arrays of 100 kW, boost converter and the grid side inverter. The paper starts with a system description, in this part we have given a definition and a short overview of every component used in this system and they are taken separately. The PV cell model is easy, accurate, and takes external temperature and solar radiation into consideration. It also proposes a maximum power point tracking (MPPT) algorithm. The algorithm incorporated in a DC/DC converter is used to track the maximum power of PV cell. Finally, the DC/AC inverter (VSC) of three- level is used to regulate the ouput voltage of DC/DC converter and connects the PV cell to the grid. Simulation results show how a solar radiation’s change can affect the power output of any PV system, also they show the control performance and dynamic behavior of the grid connected photovoltaic system.
This paper proposes an improvement of the direct power control (DPC) scheme of a grid connected three phase voltage source inverter based on artificial neural networks (ANN) and fuzzy logic (FL) techniques for the renewable energy applications. This advanced control strategy is based on two intelligent operations, the first one is the replacement of the conventional switching table of a three phase voltage source inverter (VSI) by a selector based on artificial neural networks approach, and the second one is the replacement of the hysteresis comparators by fuzzy logic controllers for the instantaneous active and reactive power errors. These operations enable to reduce the power ripples, the harmonic disturbances and increase the response time period of the system. Finally, the simulation results were obtained by Matlab/Simulink environment, under a unity power factor (UPF). These results verify the transient performances, the validity and the efficiency of the proposed DPC scheme.
In this paper the harmonic stability is investigated for multi paralleled three-phase photovoltaic inverters connected to grid. The causes to harmonically stabilize/destabilize the multi-paralleled PV inverters when tied to the grid isanalysed by the impedance-based stability criterion (IBSC). In this paper stability of the system is investigated by varying the grid inductance with constant grid resistance and also by varying load impedance while maintaining grid inductance constant. Stability of the multiple three phase inverters tied to the grid with different grid impedance, inductance value inparticular are analyzed. Overall system is stable up to grid inductance of5mH even though there is change in load admittance. It is concluded that system stability depends only on grid impedance. It is verified with Matlab Simulations.
4.power quality improvement in dg system using shunt active filterEditorJST
Injection of power generated by the wind turbine system into an electric grid mainly effects the power quality. The performance of this wind turbine and its power quality is determined on the basis of its measurement of power ratings as per IEEE standards. The influence of the wind turbine in the grid system concerning the power quality measurements are the active power, reactive power, variation of voltage, flicker, harmonics, and electrical behavior of switching operation. To mitigate the power quality problems this paper proposes the shunt compensator techniques. Here, the proposed system is verified experimentally using both STATCOM and TSC compensators. This control schemes for grid connected wind energy system is simulated using Matlab/Simulink.
The aim of this research is the speed tracking of the permanent magnet synchronous motor (PMSM) using an intelligent Neural-Network based adapative backstepping control. First, the model of PMSM in the Park synchronous frame is derived. Then, the PMSM speed regulation is investigated using the classical method utilizing the field oriented control theory. Thereafter, a robust nonlinear controller employing an adaptive backstepping strategy is investigated in order to achieve a good performance tracking objective under motor parameters changing and external load torque application. In the final step, a neural network estimator is integrated with the adaptive controller to estimate the motor parameters values and the load disturbance value for enhancing the effectiveness of the adaptive backstepping controller. The robsutness of the presented control algorithm is demonstrated using simulation tests. The obtained results clearly demonstrate that the presented NN-adaptive control algorithm can provide good trackingperformances for the speed trackingin the presence of motor parameter variation and load application.
This paper presents a fast and accurate fault detection, classification and direction discrimination algorithm of transmission lines using one-dimensional convolutional neural networks (1D-CNNs) that have ingrained adaptive model to avoid the feature extraction difficulties and fault classification into one learning algorithm. A proposed algorithm is directly usable with raw data and this deletes the need of a discrete feature extraction method resulting in more effective protective system. The proposed approach based on the three-phase voltages and currents signals of one end at the relay location in the transmission line system are taken as input to the proposed 1D-CNN algorithm. A 132kV power transmission line is simulated by Matlab simulink to prepare the training and testing data for the proposed 1D- CNN algorithm. The testing accuracy of the proposed algorithm is compared with other two conventional methods which are neural network and fuzzy neural network. The results of test explain that the new proposed detection system is efficient and fast for classifying and direction discrimination of fault in transmission line with high accuracy as compared with other conventional methods under various conditions of faults.
Among the most widespread renewable energy sources is solar energy; Solar panels offer a green, clean, and environmentally friendly source of energy. In the presence of several advantages of the use of photovoltaic systems, the random operation of the photovoltaic generator presents a great challenge, in the presence of a critical load. Among the most used solutions to overcome this problem is the combination of solar panels with generators or with the public grid or both. In this paper, an energy management strategy is proposed with a safety aspect by using artificial neural networks (ANNs), in order to ensure a continuous supply of electricity to consumers with a maximum solicitation of renewable energy.
In this paper, the artificial neural network (ANN) has been utilized for rotating machinery faults detection and classification. First, experiments were performed to measure the lateral vibration signals of laboratory test rigs for rotor-disk-blade when the blades are defective. A rotor-disk-blade system with 6 regular blades and 5 blades with various defects was constructed. Second, the ANN was applied to classify the different x- and y-axis lateral vibrations due to different blade faults. The results based on training and testing with different data samples of the fault types indicate that the ANN is robust and can effectively identify and distinguish different blade faults caused by lateral vibrations in a rotor. As compared to the literature, the present paper presents a novel work of identifying and classifying various rotating blade faults commonly encountered in rotating machines using ANN. Experimental data of lateral vibrations of the rotor-disk-blade system in both x- and y-directions are used for the training and testing of the network.
This paper focuses on the artificial bee colony (ABC) algorithm, which is a nonlinear optimization problem. is proposed to find the optimal power flow (OPF). To solve this problem, we will apply the ABC algorithm to a power system incorporating wind power. The proposed approach is applied on a standard IEEE-30 system with wind farms located on different buses and with different penetration levels to show the impact of wind farms on the system in order to obtain the optimal settings of control variables of the OPF problem. Based on technical results obtained, the ABC algorithm is shown to achieve a lower cost and losses than the other methods applied, while incorporating wind power into the system, high performance would be gained.
The significance of the solar energy is to intensify the effectiveness of the Solar Panel with the use of a primordial solar tracking system. Here we propounded a solar positioning system with the use of the global positioning system (GPS) , artificial neural network (ANN) and image processing (IP) . The azimuth angle of the sun is evaluated using GPS which provide latitude, date, longitude and time. The image processing used to find sun image through which centroid of sun is calculated and finally by comparing the centroid of sun with GPS quadrate to achieve optimum tracking point. Weather conditions and situation observed through AI decision making with the help of IP algorithms. The presented advance adaptation is analyzed and established via experimental effects which might be made available on the memory of the cloud carrier for systematization. The proposed system improve power gain by 59.21% and 10.32% compare to stable system (SS) and two-axis solar following system (TASF) respectively. The reduced tracking error of IoT based Two-axis solar following system (IoT-TASF) reduces their azimuth angle error by 0.20 degree.
Kosovo has limited renewable energy resources and its power generation sector is based on fossil fuels. Such a situation emphasizes the importance of active research and efficient use of renewable energy potential. According to the analysis of meteorological data for Kosovo, it can be concluded that among the most attractive potential wind power sites are the locations known as Kitka (42° 29' 41" N and 21° 36' 45" E) and Koznica (42° 39′ 32″ N, 21° 22′30″E). The two terrains in which the analysis was carried out are mountain areas, with altitudes of 1142 m (Kitka) and 1230 m (Koznica). the same measuring height, about 84 m above the ground, is obtained for these average wind speeds: Kitka 6,667 m/s and Koznica 6,16 m/s. Since the difference in wind speed is quite large versus a difference in altitude that is not being very large, analyses are made regarding the terrain characteristics including the terrain relief features. In this paper it will be studied how much the roughness of the terrain influences the output energy. Also, that the assumption to be taken the same as to how much they will affect the annual energy produced.
Large-scale grid-tied photovoltaic (PV) station are increasing rapidly. However, this large penetration of PV system creates frequency fluctuation in the grid due to the intermittency of solar irradiance. Therefore, in this paper, a robust droop control mechanism of the battery energy storage system (BESS) is developed in order to damp the frequency fluctuation of the multi-machine grid system due to variable active power injected from the PV panel. The proposed droop control strategy incorporates frequency error signal and dead-band for effective minimization of frequency fluctuation. The BESS system is used to consume/inject an effective amount of active power based upon the frequency oscillation of the grid system. The simulation analysis is carried out using PSCAD/EMTDC software to prove the effectiveness of the proposed droop control-based BESS system. The simulation result implies that the proposed scheme can efficiently curtail the frequency oscillation.
This study investigates experimentally the performance of two-dimensional solar tracking systems with reflector using commercial silicon based photovoltaic module, with open and closed loop control systems. Different reflector materials were also investigated. The experiments were performed at the Hashemite University campus in Zarqa at a latitude of 32⁰, in February and March. Photovoltaic output power and performance were analyzed. It was found that the modified photovoltaic module with mirror reflector generated the highest value of power, while the temperature reached a maximum value of 53 ̊ C. The modified module suggested in this study produced 5% more PV power than the two-dimensional solar tracking systems without reflector and produced 12.5% more PV power than the fixed PV module with 26⁰ tilt angle.
This paper focuses on the modeling and control of a wind energy conversion chain using a permanent magnet synchronous machine. This system behaves a turbine, a generator, DC/DC and DC/AC power converters. These are connected on both sides to the DC bus, where the inverter is followed by a filter which is connected to the grid. In this paper, we have been used two types of controllers. For the stator side converter, we consider the Takagi-Sugeno approach where the parameters of controller have been computed by the theory of linear matrix inequalities. The stability synthesis has been checked using the Lyapunov theory. According to the grid side converter, the proportional integral controller is exploited to keep a constant voltage on the DC bus and control both types of powers. The simulation results demonstrate the robustness of the approach used.
The development of modeling wind speed plays a very important in helping to obtain the actual wind speed data for the benefit of the power plant planning in the future. The wind speed in this paper is obtained from a PCE-FWS 20 type measuring instrument with a duration of 30 minutes which is accumulated into monthly data for one year (2019). Despite the many wind speed modeling that has been done by researchers. Modeling wind speeds proposed in this study were obtained from the modified Rayleigh distribution. In this study, the Rayleigh scale factor (Cr) and modified Rayleigh scale factor (Cm) were calculated. The observed wind speed is compared with the predicted wind characteristics. The data fit test used correlation coefficient (R2), root means square error (RMSE), and mean absolute percentage error (MAPE). The results of the proposed modified Rayleigh model provide very good results for users.
This paper deals with an advanced design for a pump powered by solar energyto supply agricultural lands with water and also the maximum power point is used to extract the maximum value of the energy available inside the solar panels and comparing between techniques MPPT such as Incremental conductance, perturb & observe, fractional short current circuit, and fractional open voltage circuit to find the best technique among these. The solar system is designed with main parts: photovoltaic (PV) panel, direct current/direct current (DC/DC) converter, inverter, filter, and in addition, the battery is used to save energy in the event that there is an increased demand for energy and not to provide solar radiation, as well as saving energy in the case of generation more than demand. This work was done using the matrix laboratory (MATLAB) simulink program.
The objective of this paper is to provide an overview of the current state of renewable energy resources in Bangladesh, as well as to examine various forms of renewable energies in order to gain a comprehensive understanding of how to address Bangladesh's power crisis issues in a sustainable manner. Electricity is currently the most useful kind of energy in Bangladesh. It has a substantial influence on a country's socioeconomic standing and living standards. Maintaining a stable source of energy at a cost that is affordable to everyone has been a constant battle for decades. Bangladesh is blessed with a wealth of natural resources. Bangladesh has a huge opportunity to accelerate its economic development while increasing energy access, livelihoods, and health for millions of people in a sustainable way due to the renewable energy system.
When the irradiance distribution over the photovoltaic panels is uniform, the pursuit of the maximum power point is not reached, which has allowed several researchers to use traditional MPPT techniques to solve this problem Among these techniques a PSO algorithm is used to have the maximum global power point (GMPPT) under partial shading. On the other hand, this one is not reliable vis-à-vis the pursuit of the MPPT. Therefore, in this paper we have treated another technique based on a new modified PSO algorithm so that the power can reach its maximum point. The PSO algorithm is based on the heuristic method which guarantees not only the obtaining of MPPT but also the simplicity of control and less expensive of the system. The results are obtained using MATLAB show that the proposed modified PSO algorithm performs better than conventional PSO and is robust to different partial shading models.
A stable operation of wind turbines connected to the grid is an essential requirement to ensure the reliability and stability of the power system. To achieve such operational objective, installing static synchronous compensator static synchronous compensator (STATCOM) as a main compensation device guarantees the voltage stability enhancement of the wind farm connected to distribution network at different operating scenarios. STATCOM either supplies or absorbs reactive power in order to ensure the voltage profile within the standard-margins and to avoid turbine tripping, accordingly. This paper present new study that investigates the most suitable-location to install STATCOM in a distribution system connected wind farm to maintain the voltage-levels within the stability margins. For a large-scale squirrel cage induction generator squirrel-cage induction generator (SCIG-based) wind turbine system, the impact of STATCOM installation was tested in different places and voltage-levels in the distribution system. The proposed method effectiveness in enhancing the voltage profile and balancing the reactive power is validated, the results were repeated for different scenarios of expected contingencies. The voltage profile, power flow, and reactive power balance of the distribution system are observed using MATLAB/Simulink software.
The electrical and environmental parameters of polymer solar cells (PSC) provide important information on their performance. In the present article we study the influence of temperature on the voltage-current (I-V) characteristic at different temperatures from 10 °C to 90 °C, and important parameters like bandgap energy Eg, and the energy conversion efficiency η. The one-diode electrical model, normally used for semiconductor cells, has been tested and validated for the polemeral junction. The PSC used in our study are formed by the poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl C61-butyric acid methyl ester (PCBM). Our technique is based on the combination of two steps; the first use the Least Mean Squares (LMS) method while the second use the Newton-Raphson algorithm. The found results are compared to other recently published works, they show that the developed approach is very accurate. This precision is proved by the minimal values of statistical errors (RMSE) and the good agreement between both the experimental data and the I-V simulated curves. The obtained results show a clear and a monotonic dependence of the cell efficiency on the studied parameters.
The electrical distribution network is undergoing tremendous modifications with the introduction of distributed generation technologies which have led to an increase in fault current levels in the distribution network. Fault current limiters have been developed as a promising technology to limit fault current levels in power systems. Though, quite a number of fault current limiters have been developed; the most common are the superconducting fault current limiters, solid-state fault current limiters, and saturated core fault current limiters. These fault current limiters present potential fault current limiting solutions in power systems. Nevertheless, they encounter various challenges hindering their deployment and commercialization. This research aimed at designing a bridge-type nonsuperconducting fault current limiter with a novel topology for distribution network applications. The proposed bridge-type nonsuperconducting fault current limiter was designed and simulated using PSCAD/EMTDC. Simulation results showed the effectiveness of the proposed design in fault current limiting, voltage sag compensation during fault conditions, and its ability not to affect the load voltage and current during normal conditions as well as in suppressing the source powers during fault conditions. Simulation results also showed very minimal power loss by the fault current limiter during normal conditions.
This paper provides a new approach to reducing high-order harmonics in 400 Hz inverter using a three-level neutral-point clamped (NPC) converter. A voltage control loop using the harmonic compensation combined with NPC clamping diode control technology. The capacitor voltage imbalance also causes harmonics in the output voltage. For 400 Hz inverter, maintain a balanced voltage between the two input (direct current) (DC) capacitors is difficult because the pulse width modulation (PWM) modulation frequency ratio is low compared to the frequency of the output voltage. A method of determining the current flowing into the capacitor to control the voltage on the two balanced capacitors to ensure fast response reversal is also given in this paper. The combination of a high-harmonic resonator controller and a neutral-point voltage controller working together on the 400 Hz NPC inverter structure is given in this paper.
This paper presents a new simplified cascade multiphase DC-DC buck power converter suitable for low voltage and large current applications. Cascade connection enables very low voltage ratio without using very small duty cycles nor transformers. Large current with very low ripple content is achieved by using the multiphase technique. The proposed converter needs smaller number of components compared to conventional cascade multiphase DC-DC buck power converters. This paper also presents useful analysis of the proposed DC-DC buck power converter with a method to optimize the phase and cascade number. Simulation and experimental results are included to verify the basic performance of the proposed DC-DC buck power converter.
A new bidirectional multilevel inverter topology with a high number of voltage levels with a very reduced number of power components is proposed in this paper. Only TEN power switches and four asymmetric DC voltage sources are used to generate 25 voltage levels in this new topology. The proposed multilevel converter is more suitable for e-mobility and photovoltaic applications where the overall energy source can be composed of a few units/associations of several basic source modules. Several benefits are provided by this new topology: Highly sinusoidal current and voltage waveforms, low Total Harmonic Distortion, very low switching losses, and minimum cost and size of the device. For optimum control of this 25-level voltage inverter, a special Modified Hybrid Modulation technique is performed. The proposed 25-level inverter is compared to various topologies published recently in terms of cost, the number of active power switches, clamped diodes, flying capacitors, DC floating capacitors, and the number of DC voltage sources. This comparison clearly shows that the proposed topology is cost-effective, compact, and very efficient. The effectiveness and the good performance of the proposed multilevel power converter (with and without PWM control) are verified and checked by computational simulations.
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Final project report on grocery store management system..pdfKamal Acharya
In today’s fast-changing business environment, it’s extremely important to be able to respond to client needs in the most effective and timely manner. If your customers wish to see your business online and have instant access to your products or services.
Online Grocery Store is an e-commerce website, which retails various grocery products. This project allows viewing various products available enables registered users to purchase desired products instantly using Paytm, UPI payment processor (Instant Pay) and also can place order by using Cash on Delivery (Pay Later) option. This project provides an easy access to Administrators and Managers to view orders placed using Pay Later and Instant Pay options.
In order to develop an e-commerce website, a number of Technologies must be studied and understood. These include multi-tiered architecture, server and client-side scripting techniques, implementation technologies, programming language (such as PHP, HTML, CSS, JavaScript) and MySQL relational databases. This is a project with the objective to develop a basic website where a consumer is provided with a shopping cart website and also to know about the technologies used to develop such a website.
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CFD Simulation of By-pass Flow in a HRSG module by R&R Consult.pptxR&R Consult
CFD analysis is incredibly effective at solving mysteries and improving the performance of complex systems!
Here's a great example: At a large natural gas-fired power plant, where they use waste heat to generate steam and energy, they were puzzled that their boiler wasn't producing as much steam as expected.
R&R and Tetra Engineering Group Inc. were asked to solve the issue with reduced steam production.
An inspection had shown that a significant amount of hot flue gas was bypassing the boiler tubes, where the heat was supposed to be transferred.
R&R Consult conducted a CFD analysis, which revealed that 6.3% of the flue gas was bypassing the boiler tubes without transferring heat. The analysis also showed that the flue gas was instead being directed along the sides of the boiler and between the modules that were supposed to capture the heat. This was the cause of the reduced performance.
Based on our results, Tetra Engineering installed covering plates to reduce the bypass flow. This improved the boiler's performance and increased electricity production.
It is always satisfying when we can help solve complex challenges like this. Do your systems also need a check-up or optimization? Give us a call!
Work done in cooperation with James Malloy and David Moelling from Tetra Engineering.
More examples of our work https://www.r-r-consult.dk/en/cases-en/
Overview of the fundamental roles in Hydropower generation and the components involved in wider Electrical Engineering.
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Author: Robbie Edward Sayers
Collaborators and co editors: Charlie Sims and Connor Healey.
(C) 2024 Robbie E. Sayers
Cosmetic shop management system project report.pdfKamal Acharya
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Data file handling has been effectively used in the program.
The automated cosmetic shop management system should deal with the automation of general workflow and administration process of the shop. The main processes of the system focus on customer's request where the system is able to search the most appropriate products and deliver it to the customers. It should help the employees to quickly identify the list of cosmetic product that have reached the minimum quantity and also keep a track of expired date for each cosmetic product. It should help the employees to find the rack number in which the product is placed.It is also Faster and more efficient way.
Hybrid optimization of pumped hydro system and solar- Engr. Abdul-Azeez.pdffxintegritypublishin
Advancements in technology unveil a myriad of electrical and electronic breakthroughs geared towards efficiently harnessing limited resources to meet human energy demands. The optimization of hybrid solar PV panels and pumped hydro energy supply systems plays a pivotal role in utilizing natural resources effectively. This initiative not only benefits humanity but also fosters environmental sustainability. The study investigated the design optimization of these hybrid systems, focusing on understanding solar radiation patterns, identifying geographical influences on solar radiation, formulating a mathematical model for system optimization, and determining the optimal configuration of PV panels and pumped hydro storage. Through a comparative analysis approach and eight weeks of data collection, the study addressed key research questions related to solar radiation patterns and optimal system design. The findings highlighted regions with heightened solar radiation levels, showcasing substantial potential for power generation and emphasizing the system's efficiency. Optimizing system design significantly boosted power generation, promoted renewable energy utilization, and enhanced energy storage capacity. The study underscored the benefits of optimizing hybrid solar PV panels and pumped hydro energy supply systems for sustainable energy usage. Optimizing the design of solar PV panels and pumped hydro energy supply systems as examined across diverse climatic conditions in a developing country, not only enhances power generation but also improves the integration of renewable energy sources and boosts energy storage capacities, particularly beneficial for less economically prosperous regions. Additionally, the study provides valuable insights for advancing energy research in economically viable areas. Recommendations included conducting site-specific assessments, utilizing advanced modeling tools, implementing regular maintenance protocols, and enhancing communication among system components.
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This presentation is about the working procedure of Shahjalal Fertilizer Company Limited (SFCL). A Govt. owned Company of Bangladesh Chemical Industries Corporation under Ministry of Industries.
About
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Stability analysis of photovoltaic system under grid faults
1. International Journal of Power Electronics and Drive System (IJPEDS)
Vol. 11, No. 2, June 2020, pp. 931~941
ISSN: 2088-8694, DOI: 10.11591/ijpeds.v11.i2.pp931-941 931
Journal homepage: http://ijpeds.iaescore.com
Stability analysis of photovoltaic system under grid faults
Nivedita Pati1
, Babita Panda2
, Bhagabat Panda3
1,2 School of Electrical Engineering, KIIT University, India
1 Department of Electrical and Electronics Engineering, SIT Bhubaneswar, India
3 Department of Electrical Engineering, PMEC, India
Article Info ABSTRACT
Article history:
Received May 26, 2019
Revised Oct 22, 2019
Accepted Dec 5, 2019
This work includes the establishment of a Photovoltaic system connected to
the grid by means of an inverter. The fundamental goal of the work is to
incorporate an advanced active power flow management scheme in order to
adopt load at any weather condition along with the advantage of maximum
active power flow and zero harmonics from PV inverter to the grid. The
outcome of analysis and control design of grid connected PV inverter using a
Proportional-Integral (PI) control technique is based on synchronous dq
rotating reference frame so as to achieve maximum output voltage and record
the active power. It has been observed that the model provides a better rate of
stability as compared to the existing topology.
Keywords:
Boost converter
MPPT
Photovoltaic model
Proportional-integral controller
Pulse width modulation (PWM) This is an open access article under the CC BY-SA license.
Corresponding Author:
Nivedita Pati,
School of Electrical Engineering, KIIT University,
Bhubanewsar, 751024, India.
Email: nivedita.pati@silicon.ac.in
1. INTRODUCTION
As fossil fuels are depleting day by day, more research is going on harvesting electrical energy from
renewable energy. Among all other renewable energy sources, Solar and wind energies, are the maximum
accessible and dispersed all over the universe. Utilization of photovoltaic (PV) has been rising notably by
virtue of the fast advancement of power electronic techniques. Here the objective of the study is to get the
maximum energy efficiency under the different operating condition and to approach the design of a robust
controller having the ability to reject the noises. The main objective of the study is to coordinate the voltage,
the power injected into the utility. Many earlier works have inspected different control aspects of Inverter
that are connected to the grid. Most of the analysis is done to reduce the THD of the system. But very few of
them focus on stability issues of grid coonected PV system. Different Power quality issues of the grid
connected PV system are described by Vikas khare [1]. The author herself explained about the different types
of fault analysis in grid connected photovoltaic system [2]. M. G. Molina and L. E. Juanico explained the
designing of the photovoltaic structure connected to the grid [3]. The dynamic behavior of grid connected
Photovoltaic system is studied under the LLLG fault by author K. Manohar [4] and [5]. The proposed work
gives the information about a three-phase Pulse Width Modulated inverter modeling and its control strategy.
The single staged grid connected inverter gets its input from a dc-dc converter fed through a photovoltaic
input [6]. Particularly, the control design of grid connected inverter using the PI control technique has been
proposed in the dq rotating frame in order to achieve maximum output voltage and maximum active power.
A current control PWM technique has been suggested to provide the pulse for voltage source inverter.
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932
By virtue of the huge amount of interconnection of dispersed power generation to the grid in some
regions, uncertainty and fluctuation of a different parameter of the power system may appear which requires
proper design of controllers for stability analysis under variable conditions [7]. more importance is put on the
capability of a Distributed Power Generation System (DPGS) to overcome sharp grid disruptions such as
variations in voltage and frequency. This paper focuses on some desirable control techniques that DPGS can
follow during damaged grid circumstances. First, a grouping of different kinds of grid faults is illustrated,
and it ensured by some applications of the control technique during damaged grid circumstances. A. V.
Timbus [8] and [9]analyzed some possible control techniques that DPGS can follow during faulty grid
conditions followed by the grouping of different kinds of grid faults in this paper .The primary objective of
the control technique is reproduction of power, and also the generation of the currents referred which can
meet the grid power requirement. M.Cai [10] adopted a shunt controller for voltage dip compensation when a
fault is introduced in the grid. In [11, 12] dynamic stability of a Photovoltaic structure connected with a
distribution system is analyzed. Reference [13] and [14] has adopted a control technique to analyze the
dynamic stability of the PV System.
2. PROPOSED ACTIVE POWER FLOW CONTROL SCHEME FOR STABILITY ANALYSIS
This section describes the internal structure proposed control design which consists of an external
voltage circuit and an internal current circuit [15]. The proposed model is discussed in Figure 1. It consists of
a Solar (PV) system, step up converter, which is then interfaced with an inverter (VSI), a distribution
network, load and grid with a power flow controller. Figure 1 describes the circuit diagram of the
proposed structure.
Figure 1. Block diagram of Grid connected PV system
The suggested structure is built to control the various parameters like current, voltage and power
injected into the utility [16]. The 305 Solar Panel is being selected for designing of PV system using
MATLAB. MPPT approach is employed for enhancing the efficiency of the solar panel. The Perturb &
Observe (P&O) method is selected as the MPPT tracker whose primary goal is to obtain rapid and correct
tracking act and reduces oscillations with respect to changeable weather conditions. P&O method
implementation is quite cheap. The output of the boost converter which is1200 V DC is converted into 800V
AC by a voltage source inverter, then that voltage is increased to 11 KV by a step-up delta/star transformer.
2.1 Internal structure of control system
Figure 2 represents the circuit diagram representation of the control structure. It includes the abc-dq
transformation block, PLL block, PI controller and the PWM generator. The step-up converter to steps up the
voltage of the solar MPPT system while the MPPT generates the pulse for the converter. The PV system and
boost converters are connected to the voltage source converter.
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Stability analysis of photovoltaic system under grid faults (Nivedita Pati)
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Figure 2. Block diagram of internal control structure
The speed of the control loop depends on the bandwidth of the loop. So by varying the cut-off
frequency of open loop transfer function (transfer function of inner loop multiplies with PI transfer function),
the differential speeds can be achieved. Since some of the state variables are multiplied with the control
inputs, the mathematical model of the converter becomes nonlinear.
2.2. DC-link voltage control scheme
The active power is restrained by the voltage at the DC-link with its desired value. Figure 3 shows
the internal structure of the dc-link voltage management strategy. It has six components: MPPT, voltage
compensator, limiter, current components, and integrator. Here dref
u
is a reference DC voltage recorded by
the maximum power point technique [17]. dref
u
correlates with the dc
u and the output signal is fed to the PI
compensator. The compensator sets up dref
i
which is the ref. the current value of the d-axis component. The
current controller sets up actual d-axis current d
i from ref. current value dref
i
and then
)
( d
pv i
i
is passed
through an integrator which generates dc
u .
Figure 3. Inside structure of DC link voltage control scheme
(1)
(2)
(3)
(4)
(5)
Modulation
and
PWM
Generator
abc
dq
abc
dq
PLL
DC LINK PI
CONTROLLER
CURRENT PI
CONTROLLER
CURRENT PI
CONTROLLER
wl
‐wl
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934
Where C is the capacitor, ic is current through the capacitor, ipv is the PV current, udc is the voltage
across DC link, udref the DC voltage reference, id is d-axis component of grid current, idref is it's a
reference value.
2.3. Internal current loop
The d−q transformation matrix is used for the conversion of three-axis grid voltage and current to
the dq reference frame. The AC grid voltage and current are converted into DC values with the help of abc →
dq transformation matrix, by regulating the variables. The phase angle is calculated with the help of PLL
(Phase Lock Loop) [18] which is further required for synchronization of grid voltage with controlled current.
To get the unity power factor, iqref*(reference reactive current) is set to zero. The Proportional-Integral
controllers provide the voltage outputs (Vd*, Vq*) which fed to the PWM generator to generates the pulses
used to for Inverter [19].
Iୢ
I୯
I
ൌ ට
ଶ
ଷ
ൈ T ൈ
Iୟ
Iୠ
Iୡ
൩ (6)
By using the above formula given in (6), the abc-dq transformation is made where T is the
transformation matrix.
As the voltage of grid is cannot be managed, the ultimate desirable choice of governing the action of
the arrangement is by regulating the Id and Iq that is injecting to the grid. Figure 4 depicts output of a
compensator (Ud),is the control signal focusing on minimizing error as:
(7)
Correspondingly, the error signal that another regulator processes,
(8)
The error commands are fed to a PI regulator. The PI regulator constants are selected so that,
(9)
(10)
where is the time constant of the circuit. The internal control structure of the system is shown
in Figure 4.
Figure 4. Basic structure of pulse generation scheme
The PWM modulating commands are,
5. Int J Pow Elec & Dri Syst ISSN: 2088-8694
Stability analysis of photovoltaic system under grid faults (Nivedita Pati)
935
(11)
(12)
Where are d-axis and q-axis factors of modulating commands, Vdc is the voltage at DC
link, are control signals of d-axis and q-axis, Usd, Usq are refined voltage of VSI, is the grid
frequency. The pulses are developed by conversion of d and q signals into a,b,c signals. By regulating md
and mq, the id and iq quickly follow their corresponding reference signals idref and iqref [20]. Then active
and reactive power of Photovoltaic arrangement are given as:
(13)
(14)
As the voltage at the grid is unmanageable, the ultimate practicable approach of monitoring the
arrangement is by regulating grid currents Id and Iq. As active power flow is reliant on the current Id, and
reactive power inserted to the grid is dependent on the current Iq and thus Iqref = 0 is set forcefully to make
zero reactive power [21, 22].
2.4. Simulink environment
The validity of the system is checked with the help of computer simulations. The
MATLAB/SIMULINK software is used to simulate the final system and for unusual circumstances, the
analysis is done. The symmetrical and unsymmetrical faults are created on the distribution network, for the
analysis of system behavior under fault [23].
3. SIMULATION OUTCOMES OF FAULT ANALYSIS
The simulation is conducted in order to achieve stability of the photovoltaic system under different
conditions of grid faults. The transient state stability of the system may be analyzed by many methods; here
some aspects are taken into account. The faults on the grid can be divided into two main groups.
a) Symmetrical fault: When an equal decrease in the magnitude of the grid voltage occurs in all three
phases whereas the system remains balanced. Symmetrical faults are not uncommon (they do happen
often: bus faults, lightning strikes in substations etc).
b) Unsymmetrical fault: When an unequal decrease in grid voltage occurs with alternation in phase in
between. This category of fault arises as more than one phase is shorted to ground or to one another.
The effectiveness of the control system is checked by considering three cases of grid faults. In each
of the cases, the result analysis is carried out that has been recorded for stability analysis [24].
case-1: Three phase to ground fault (LLLG fault): Three phases to ground fault is a familiar fault in the
industrial climate. The outcome of the PV circuit with a LLLG fault of 0.3 sec to 0.4 sec is analyzed in this
section.
case-2: LLG fault in distribution network: In this case, a double line to ground fault is simulated from 0.3
sec to 0.4 sec. When this type of fault occurs a sudden power surge is experienced in the converter. The
voltage of the converter rises rapidly and then recovers with an oscillation that lasts for a few cycles. This
response is generated with the PI controller.
case-3: LG fault in distribution network: In this case, a single line to ground fault is simulated.
The Figure 5 illustrates the Simulation model of the grid connected PV system. The sub-system of
the PV source includes a PV block, MPPT controller along with step up converter interfaced to the grid via
voltage source inverter. Table 1 gives system parameters data and specifications [25]. Here the system is
certified under the least fault circumstances.
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Int J Pow Elec & Dri Syst, Vol. 11, No. 2, June 2020 : 931 – 941
936
Figure 5. Simulation model of the proposed system
Table 1. System Parameter and Specifications
Parameter Values Parameter Values
The voltage at the Grid 11KV Vdc 1200V
Supply frequency 50 Hz Fsw_inv 2 kHz
Filter Inductor 10 mH Filter Capacitor 100µF
Inverter voltage 1200V Inverter output voltage after filtering 800V
Three phase line 15 km length Load 5MW,100VAR
3.1. Three phase to ground fault (LLLG fault)
The output waveforms of proposed structure with a LLLG fault are illustrated below. At t=0.3 sec to
0.4 sec, LLLG fault is inserted into the system. Figure 6(a) shows the waveform of DC voltage generated by
the boost converter. Figures 6(b) and 6(c) depict with LLLG fault the nature of 3-phase current and voltage at
the grid. Figures 6(d) and 6(e) show the variation of powers fed to the grid.
Figure 6(a) illustrates the waveform of the DC voltage produced by the step-up converter. Before
the application of the fault, DC voltage attains a value of 1200V. During the fault, DC voltage increases
suddenly from 1200 to 1600V. Just after 0.42 sec, 1200V is achieved.
Figure 6(b) depicts the response of a three-phase current in the course of the three-phase fault.
Ahead of the introduction of fault, current is settled at 5 A. When a fault is introduced at 0.3 sec the current
rises nearly to 180A (max) and certainly the current recovers its steady value of 5 A after the fault period.
Figure 6(c) indicates the nature of three-phase voltages at the time of LLLG fault. Ahead of the
application of fault, voltage is kept at 8KV (max). At the time of application of fault, the voltage at the grid is
zero from 0.3 to 0.4 sec. Later 0.4 sec, voltage settles to its constant value.
Figure 6(d) shows the waveform of active power fed to the grid at the time of the fault period from
0.3 sec to 0.4 sec. In the course of the fault period, both active, as well as reactive power, remains zero. At
0.45 sec power settles to its normal value.
In Figure, 6(e) it is observed that there is a very slight change in reactive power just after 0.4
seconds. Then after some time, it settles to its steady-state value.
7. Int J Pow Elec & Dri Syst ISSN: 2088-8694
Stability analysis of photovoltaic system under grid faults (Nivedita Pati)
937
(a) (b)
(c) (d)
(e)
Figure 6. (a) DC voltage generated vs.time, (b) 3-phase current vs.time at grid, (c) 3-phase voltage vs .time at
grid, (d) Active power at grid, (e) Reactive power vs. time at the grid with LLLG fault
3.2. LLG fault at distribution network
The Figure 7(a) shows the DC voltage generated by the Step up converter along LLG fault.
Figures 7(b) and 7(c) depict 3-phase current and voltages at the grid along with LLG fault. Figures 7(d) and
7(e) illustrate the changes in active and reactive power. Figure 7(a) shows the DC voltage generated by the
boost converter is disrupted more than LLLG fault. With 0.3 sec DC voltage oscillates between 1200 to
1600V and then decreases to 1200V after the fault. Later at 0.41 sec, voltage settles to its steady-state value.
Figure 7(b) indicates the nature of three-phase voltages during LLG fault. The voltage at the grid is
disturbed from 0.3 to 0.4 sec. After 0.4-sec voltage settles to its regular value.
When a fault is introduced at 0.3 sec the current rises nearly to 100A (max) which is shown in
Figure 7(c). At 0.42 sec, current attains its original value. From Figure 7(d) it is observed that the real and
reactive power inserted to the grid is highly disrupted at the time of the LLG fault of 0.3 sec to 0.4 sec. At
0.43 sec power attains its steady-state value.
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8
-200
-150
-100
-50
0
50
100
150
200
Time (s)
L
in
e
C
urre
nt
(A)
A
B
C
8. ISSN: 2088-8694
Int J Pow Elec & Dri Syst, Vol. 11, No. 2, June 2020 : 931 – 941
938
Figure 7(e) shows the changes in the reactive power in the course of the fault period. The output
waveform depicts that the reactive power is negative during the fault period. Just after the clearance of fault,
growth is seen, then after some time, it settles to its normal value.
(a) (b)
(c) (d)
(e)
Figure 7. (a) Converter voltage vs. time with LLLG fault, (b) Grid voltage vs. time with LLLG fault
(c) Grid current with LLG fault, (d) Active power at the grid with LLG fault, (e) Reactive power vs. time at
the grid with LLG fault
3.3. LG Fault at distribution network
Figure 8(a) shows the voltage generated by the converter with LG fault. Figures 8(b) and 8(c) show
3-phase current and voltages at the grid with LG fault. Figures 8(d) and 8(e) show changes in active and
reactive power fed to the grid.
Figure 8(a) shows the voltage generated by the converter with LG fault is disturbed less than LLG
fault during the LG fault of 0.3 sec to 0.4 sec. At 0.42 sec the voltage reaches its regular value that is 1200V.
With 0.3 sec DC voltage oscillates between 1200 to 1400V and then decreases to 1200V after the clearance
of fault. After 0.42 sec voltage settles to its regular value. In Figure 8(b), it is shown that in the course of the
LG fault the grid voltage is disturbed from 0.3 to 0.4 sec. After 0.4 sec voltage settles to its regular value.
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8
0
200
400
600
800
1000
1200
1400
1600
1800
2000
Time (s)
Voltage
(V)
0 0.1 0.2 0.3 0.4 0.5 0.6
-10
-8
-6
-4
-2
0
2
4
6
8
10
Time (s)
Phase
Voltage
(kV)
A
B
C
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8
-200
-150
-100
-50
0
50
100
150
200
Time (s)
Line
C
urrent
(A)
A
B
C
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8
-0.2
-0.1
0
0.1
0.2
0.3
0.4
Time (s)
A
ctive
Po
w
er
(M
W
))
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8
-0.2
-0.15
-0.1
-0.05
0
0.05
0.1
0.15
0.2
Time (s)
Reactive
Power
(MVAR))
9. Int J Pow Elec & Dri Syst ISSN: 2088-8694
Stability analysis of photovoltaic system under grid faults (Nivedita Pati)
939
Figure 8(c) depicts the current response for the SLG fault. The current rises from 5 A to 100 A
instantly during the fault. The fault is cleaned 1 sec later and the current grasp the normal value at t = 0.42 s.
Figure 8(d) shows the waveform of active power fed to the grid. It is visible that the power injected
to the grid is less disrupted during the LG fault than the LLG fault from 0.3 sec to 0.4 sec. At 0.42 sec power
attains its steady state value because of the action of a robust controller. Figure 8(e) shows the changes in
reactive power in the course of the fault period. It is less disrupted than LLG fault.
(a) (b)
(c) (d)
(e)
Figure 8. (a) Converter voltage with LG fault, (b), Grid voltage with SLG fault, (c) Grid current with SLG
fault, (d) Active power at the grid with SLG fault, (e) Reactive power at the grid with SLG fault
4. CONCLUSION
Initially, the system is simulated without any fault. The three types of faults are presented and the
impact on the system is studied under the presence of different types of faults. The simulation result is given
below for all types of faults. Nevertheless, there are countless processes to analyze the dynamic stability of
the structure, only important aspects are taken into consideration. This paper describes the effective
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8
0
200
400
600
800
1000
1200
1400
1600
1800
2000
Time (s)
Voltage
(V)
0 0.1 0.2 0.3 0.4 0.5 0.6
-10
-8
-6
-4
-2
0
2
4
6
8
10
Time (s)
Phase
Voltage
(kV)
A
B
C
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8
-200
-150
-100
-50
0
50
100
150
200
Time (s)
Line
Current
(A)
A
B
C
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8
-0.2
-0.1
0
0.1
0.2
0.3
0.4
Time (s)
Active
Power
(MW))
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8
-0.2
-0.15
-0.1
-0.05
0
0.05
0.1
0.15
0.2
Time (s)
R
eactive
Power
(MVAR))
10. ISSN: 2088-8694
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940
achievement of the system. In this paper, the structure is certified under the least damaged circumstances i.e.
the symmetrical as well as unsymmetrical fault. Just after the fault, system parameters retain their original
values because of the robustness of the controller. The correctness of the current control scheme is
demonstrated by the result analysis. The output waveform compiled the validity of the used control
techniques since the delivered powers pursue the regular values, provided by the MPPT controller of the PV
system, both in a normal and abnormal condition.
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BIOGRAPHIES OF AUTHORS
Nivedita Pati, received the M.Tech degree from National Institute of Technology, Rourkela,
Odisha, India with a specialization in Control and Automation.
She is currently persuing her PhD in KIIT University and is working as an Assitant Professor
in Silicon Institute of Technology, Bhubaneswar,Odisha, India from 2012.
Her research interest includes Control Systems and Renewable Energy She is a member in
IEEE since last 7 years and has 5 IEEE conference and one journal publication.
Babita Panda received the B.Tech. degree in electrical engineering from the BIET, Bhadrak,
M.Tech and Ph D degree from Kalinga Institute of Industrial Techonology deemed to be
University. She is working as an Assistant Professor in the department of Electrical
Engineering at KIIT university since 16th August 2012.Her research interests include
distributed generation, renewable energy and power Electronics.
Dr. Bhagabat Panda received the Ph.D degree from Utkal University,M.Tech degree from and
B.Tech degree in Electrical Engg from VSSUT Burla, Sambalpur, Odisha. He is working as an
Associate Professor in the department of Electrical Engineering at PME College,
Barhampur.His research interests include distributed generation, renewable energy and power
System.