An electronic system of measuring and processing surface voltage potentials distributed along the grounding grid was developed. The electronic system is composed of several parts, an embedded computer, signal conditioning circuits and computational routines. The adopted processor was a low-power open-source single-board computer that allows the implementation of routines based on the finite-difference method. It was possible to create two real time dimensional plots using the fall-of-potential method. The electronic system was able to make a correct diagnosis of the aging state of the grounding grid. The results allowed evaluation of the potential behaviour of the ground surface voltage in a consistent manner in a steady state operation. The results obtained from measurements in high voltage substations using the developed embedded system were satisfactory when compared to other measuring devices. This system was capable of easily locating problematic zones, such as high potential concentrations, allowing efficient and fast grounding grid diagnosis.
These slides presents an overall discussion on fault location techniques generally used in present power transmission and distribution system. Later of the class we will discuss about the implementation principles and mathematical formulations.
This document summarizes a research paper that proposes a network-based coordination control technique for synchronizing a microgrid with the main electric power system during reconnection. A microgrid contains multiple distributed generators that must be controlled cooperatively to satisfy synchronization criteria. The proposed method uses a microgrid central controller that communicates with distributed generator controllers over a communication network. The controller calculates frequency, voltage, and phase offset commands to minimize differences between the microgrid and main grid. Simulation results using Matlab/Simulink show the technique can reliably synchronize the microgrid for network delays up to 200ms but not for delays of 500ms or greater.
This slide presents the control aspects of Energy Storage System in Microgrid. Later I will discuss about the control strategy with integration to DGs and EVs.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
These slides focus on preliminary discussions about wide area monitoring, protection and control in future smart grid. Later in the class i will show its application through simulation and case study results.
A Matlab/Simulink Model for the control scheme utilized to improve power qual...AM Publications
the wind energy generation, utilization and its grid penetration in electrical grid are increasing worldwide. The
integration of wind energy into the power system is to minimize the environmental impact on conventional plant but the injection
of the wind power into an electric grid affects the power quality. The wind generated power is always fluctuating due to its time
varying nature and causing stability problem. The power quality is 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. The project demonstrates the power quality problem due to installation of wind turbine with
the grid. In this proposed scheme Static Compensator (STATCOM) is connected at a point of common coupling with a battery
energy storage system (BESS) to mitigate the harmonics. The battery energy storage is integrated to sustain the real power
source under fluctuating wind power. 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. The effectiveness of the
proposed scheme relives the main supply source from the reactive power demand of the load and the induction generator. The
development of the grid co-ordination rule and the scheme for improvement in power quality norms as per IEC-standard on the grid has been presented.
The document discusses various maximum power point tracking (MPPT) algorithms for wind energy systems. It describes three main MPPT control methods: tip speed ratio control, power signal feedback control, and hill-climb search control. For each control method, it provides the basic principles, block diagrams, and examples of implementations for different types of wind turbine generators including permanent magnet synchronous generators, squirrel cage induction generators, and doubly fed induction generators.
These slides present an introduction to load flow analysis for distribution system. Later the detail algorithm, matlab coding and application to IEEE radial distribution system will be subsequently provided.
These slides presents an overall discussion on fault location techniques generally used in present power transmission and distribution system. Later of the class we will discuss about the implementation principles and mathematical formulations.
This document summarizes a research paper that proposes a network-based coordination control technique for synchronizing a microgrid with the main electric power system during reconnection. A microgrid contains multiple distributed generators that must be controlled cooperatively to satisfy synchronization criteria. The proposed method uses a microgrid central controller that communicates with distributed generator controllers over a communication network. The controller calculates frequency, voltage, and phase offset commands to minimize differences between the microgrid and main grid. Simulation results using Matlab/Simulink show the technique can reliably synchronize the microgrid for network delays up to 200ms but not for delays of 500ms or greater.
This slide presents the control aspects of Energy Storage System in Microgrid. Later I will discuss about the control strategy with integration to DGs and EVs.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
These slides focus on preliminary discussions about wide area monitoring, protection and control in future smart grid. Later in the class i will show its application through simulation and case study results.
A Matlab/Simulink Model for the control scheme utilized to improve power qual...AM Publications
the wind energy generation, utilization and its grid penetration in electrical grid are increasing worldwide. The
integration of wind energy into the power system is to minimize the environmental impact on conventional plant but the injection
of the wind power into an electric grid affects the power quality. The wind generated power is always fluctuating due to its time
varying nature and causing stability problem. The power quality is 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. The project demonstrates the power quality problem due to installation of wind turbine with
the grid. In this proposed scheme Static Compensator (STATCOM) is connected at a point of common coupling with a battery
energy storage system (BESS) to mitigate the harmonics. The battery energy storage is integrated to sustain the real power
source under fluctuating wind power. 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. The effectiveness of the
proposed scheme relives the main supply source from the reactive power demand of the load and the induction generator. The
development of the grid co-ordination rule and the scheme for improvement in power quality norms as per IEC-standard on the grid has been presented.
The document discusses various maximum power point tracking (MPPT) algorithms for wind energy systems. It describes three main MPPT control methods: tip speed ratio control, power signal feedback control, and hill-climb search control. For each control method, it provides the basic principles, block diagrams, and examples of implementations for different types of wind turbine generators including permanent magnet synchronous generators, squirrel cage induction generators, and doubly fed induction generators.
These slides present an introduction to load flow analysis for distribution system. Later the detail algorithm, matlab coding and application to IEEE radial distribution system will be subsequently provided.
Three main microgrid control strategies are described:
1. Master-slave mode where one DG acts as the voltage/frequency master and others follow as slaves under P/Q control.
2. Peer-to-peer mode where all DGs use droop control to cooperatively regulate voltage and frequency without a master.
3. Combined mode using aspects of both by assigning control roles based on DG type.
These slides present the introduction to FACTS devices. Later we will discuss about its modelling and control aspect applications. This comes under the topic on power electronics application in smart and microgrid systems.
Series of blackouts encountered in recent years in power system have been occurred because either of voltage or angle instability or both together was not detected within time and progressive voltage or angle instability further degraded the system condition, because of increase in loading. This paper presents the real-time assessment methodology of voltage stability using Phasor Measurement Unit (PMU) with observability of load buses only in power network. PMUs are placed at strategically obtained location such that minimum number of PMU’s can make all load buses observable. Data obtained by PMU’s are used for voltage stability assessment with the help of successive change in the angle of bus voltage with respect to incremental load, which is used as on-line voltage stability predictor (VSP). The real-time voltage phasors obtained by PMU’s are used as real time voltage stability indicator. The case study has been carried out on IEEE-14 bus system and IEEE-30 bus systems to demonstrate the results.
This document discusses energy efficiency in wireless sensor networks. It describes how sensor nodes consist of an RF transceiver, microcontroller, sensors, and memory. Radio transceivers are the largest energy consumer. The document measures energy usage for different components and transmitting data. It also discusses using lithium-ion batteries for their discharge characteristics and the ability to model remaining capacity. A measurement setup is used to test batteries at different temperatures and loads, developing a linear model to calculate residual energy as a function of temperature directly on sensor nodes.
ANN Based SVC Switching at Distribution Level for Minimal Injected HarmonicsYateesh Yadav
1) The document discusses using an artificial neural network (ANN) controller for a static VAR compensator (SVC) at the distribution level to minimize reactive power drawn from the supply and injected harmonics.
2) An SVC consists of a thyristor controlled reactor and thyristor switched capacitor to compensate loads through reactive power generation or absorption.
3) The ANN controller determines the optimal firing angles of the thyristor controlled reactor to control the SVC online and balance reactive power loads while keeping harmonic injection low.
Automatic load frequency control of two area power system with conventional a...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
Transmission line is one the important compnent in protection of electric power system because the transmission line connects the power station with load centers.
The fault includes storms, lightning, snow, damage to insulation, short circuit fault [1].
Fault needs to be predicted earlier in order to be prevented before it occur
An Under frequency Load Shedding Scheme forAjay Singh
This document presents an under frequency load shedding scheme for hybrid and multi-area power systems. It discusses the need for such a scheme to maintain frequency stability during faults or imbalances. The proposed scheme uses frequency first derivative to estimate power deficit independently of system parameters. It was tested through simulations of different scenarios involving islanding, variable generation, and inertia changes in hybrid systems as well as multi-area systems. The results demonstrated the scheme's ability to determine appropriate load shedding to regulate frequency.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Load Frequency Control of Multi Area System using Integral-Fuzzy ControllerIJERA Editor
The power system is interconnected to enhance the security and reliability. With large interconnected system, unexpected external disturbances, parameter uncertainties and the model uncertainties make big challenges for stability of system. Load Frequency Control (LFC) deals with the control of real power and frequency of the system. The LFC is used to reduce the transient deviations in the power system. It limits the frequency within limits and controls the tie-line exchange power. Various controllers are used for this purpose. Recently Artificial Intelligence Techniques such as Artificial Neural Network (ANN), fuzzy logic, Genetic Algorithm etc. are used for the designing of controllers. These controllers provide a faster response and are flexible to adjust according to system conditions. In this paper, I have designed integral controller which is conventional method for Load Frequency Control and Artificial Intelligence Technique based Fuzzy Logic controller to deal with the Load Frequency Control Problem for Multi-area System. The simulation of the system is done with MATLAB. These controllers provide a robust system which is more stable and reliable and helps the system to regain its normal state after any disturbance.
This document compares different state estimation methods for a smart distribution grid using synchrophasor technology. It analyzes how integrating phasor measurements from PMUs can improve state estimation accuracy compared to conventional measurements. The study examines different measurement configurations using conventional data, PMU data, or a hybrid approach. It models an 18-bus test grid using real load data from a 110kV distribution system. The results demonstrate that using PMUs can provide more accurate estimates of the system state by leveraging their precise, time-synchronized measurements.
Power transformer faults diagnosis using undestructive methods and ann for dg...Mellah Hacene
Power transformer faults diagnosis using undestructive methods (Roger and IEC) and artificial neural network for dissolved gas analysis applied on the functional transformer in the Algerian north-eastern: a comparative study
Bouchaoui Lahcene, Kamel Eddine Hemsas, Hacene Mellah, saad eddine benlahneche
Nowadays, power transformer aging and failures are viewed with great attention in power transmission industry. Dissolved gas analysis (DGA) is classified among the biggest widely used methods used within the context of asset management policy to detect the incipient faults in their earlier stage in power transformers. Up to now, several procedures have been employed for the lecture of DGA results. Among these useful means, we find Key Gases, Rogers Ratios, IEC Ratios, the historical technique less used today Doernenburg Ratios, the two types of Duval Pentagons methods, several versions of the Duval Triangles method and Logarithmic Nomograph. Problem. DGA data extracted from different units in service served to verify the ability and reliability of these methods in assessing the state of health of the power transformer. Aim. An improving the quality of diagnostics of electrical power transformer by artificial neural network tools based on two conventional methods in the case of a functional power transformer at Sétif province in East North of Algeria. Methodology. Design an inelegant tool for power transformer diagnosis using neural networks based on traditional methods IEC and Rogers, which allows to early detection faults, to increase the reliability, of the entire electrical energy system from transport to consumers and improve a continuity and quality of service. Results. The solution of the problem was carried out by using feed-forward back-propagation neural networks implemented in MATLAB-Simulink environment. Four real power transformers working under different environment and climate conditions such as: desert, humid, cold were taken into account. The practical results of the diagnosis of these power transformers by the DGA are presented. Practical value.....
Control of grid connected inverter system for sinusoidal current injection wi...ijiert bestjournal
The control strategy for the grid connected inverter (GCI) during abnormal conditions like voltage sag,swell and line to ground fault has been presented. The strategy adopted here operates even during faulty conditions,unlike the conventional controller which fails to operate during fault y conditions. The Multi-Reference Frame (MRF) PI Controller is used for this purpose. In order to study the D ynamic Performance of the system,it is simulated in Matlab Simulink environment. The overall system is simulated for normal condition that is without the presence of fault,and with the presence of fault. The performance is also studied during abnormal conditions of the grid and its results are analyzed. The simulat ion results exhibit improved performance of the system during normal as well as abnormal conditions.
In this paper, a detail design and description of a predictive current control scheme are adopted for three-phase grid-connected two-level inverter and its application in wind energy conversion systems. Despite its advantages, the predictive current controller is very sensitive to parameter variations which could eventually affected on system stability. To solve this problem, an estimation technique proposed to identify the value of harmonic filter parameter based on Model reference adaptive system (MRAS). Lyapunov stability theory is selected to guarantee a robust adaptation and stable response over large system parameter variation. The simulation results shows the efficiency of the proposed techniques to improve the current tracking performance.
1. Distribution systems were traditionally designed for unidirectional power flow but high renewable energy source (RES) penetration can cause bidirectional power flow and other challenges.
2. Maintaining minimum voltage drop was traditionally the main concern but RES integration affects voltage regulation.
3. Distributed RES integration increases vulnerability to overload conditions on small distribution feeders due to intermittent generation and changing network configurations.
This document discusses various topics related to analysis of wind and PV systems including:
- Standalone and grid-connected operation of fixed and variable speed wind energy conversion systems and solar photovoltaic systems.
- Grid integration issues for permanent magnet synchronous generator (PMSG) and squirrel-cage induction generator (SCIG) based wind energy conversion systems, as well as grid-integrated solar systems.
- Design of power converters such as AC-DC, DC-DC, and AC-AC converters for renewable energy sources and analysis of various operating modes of wind and solar systems.
- Design of hybrid renewable energy systems and factors affecting the plant economy of renewable power plants such as initial capital cost
Svpwm based 3 level statcom for reactive power management under line-lineIAEME Publication
This document summarizes a research paper that analyzes the performance of a 3-level STATCOM for reactive power management under a line-line fault in a transmission line. The paper tests a line-line fault in an IEEE 14 bus system incorporating nonlinear loads. A 2-level and 3-level STATCOM using SVPWM control are placed at bus 14 to regulate the voltage. Simulation results show the effectiveness of the SVPWM control strategy in managing reactive power and voltage stability during steady state and transient operation for both the 2-level and 3-level STATCOM configurations.
2.[6 13]investigation on d-statcom operation for power quality improvement in...Alexander Decker
1) The document presents a new control scheme for D-STATCOM that uses sinusoidal PWM signals based only on voltage measurements to regulate voltage in distribution systems.
2) Simulations using MATLAB/PLECS show the control scheme maintains constant voltage under disturbances by exchanging reactive power with the system through the D-STATCOM.
3) Results demonstrate the control scheme effectively regulates voltage, compensates for harmonics, and corrects power factor during system faults and load variations.
This document discusses Flexible AC Transmission Systems (FACTS). It provides 3 key points:
1. FACTS are power electronics-based devices used to improve transmission systems by enhancing controllability and increasing power transfer capability.
2. Benefits of FACTS include regulating power flows, reducing the need for new transmission infrastructure, improving transient stability, and controlling real and reactive power flows independently.
3. FACTS controllers can be series, shunt, or combined series-series/series-shunt configurations, with the appropriate choice depending on objectives like controlling power flows or damping oscillations.
1. The document discusses the computer-aided design of grounding systems for transformer stations to ensure low grounding resistance and safe touch and step voltages. It presents the design of grounding systems for three transformer stations in Croatia using CDEGS software.
2. The design process involves measuring soil resistivity on site, modeling the soil as multiple layers, designing the grounding grid geometry, and simulating fault conditions to analyze touch and step voltages.
3. For a sample 110x80m grounding grid, the analysis shows that touch voltages are highest in the station corners. Additional measures like an outer ring conductor are recommended to improve safety.
Permanent Fault Location in Distribution System Using Phasor Measurement Unit...IJECEIAES
This paper proposes a new method for locating high impedance fault in distribution systems using phasor measurement units (PMUs) installed at certain locations of the system. To implement this algorithm, at first a new method is suggested for the placement of PMUs. Taking information from the units, voltage and current of the entire distribution system are calculated. Then, the two buses in which the fault has been occurred is determined, and location and type of the fault are identified. The main characteristics of the proposed method are: the use of distributed parameter line model in phase domain, considering the presence of literals, and high precision in calculating the high impedance fault location. The results obtained from simulations in EMTP-RV and MATLAB software indicate high accuracy and independence of the proposed method from the fault type, fault location and fault resistance compared to previous methods, so that the maximum observed error was less than 0.15%.
Investigation of overvoltage on square, rectangular and L-shaped ground grid...IJECEIAES
Ground grid system is important for preventing the hazardous effects of overvoltage in high voltage substations due to fault current perhaps from lightning strike or device malfunction. Therefore, this study aimed to investigate the effects of overvoltage on square, rectangular and L-shaped ground grids with ground rods being distributed in mesh-pattern by using alternate transients program/electromagnetic transients program (ATP/EMTP) program. The models were simulated in the cases that 25 kAfault current being injected into the center or one of the corners of ground grids. The results showed that the highest level of overvoltage (6.3349 kV) was detected at the corner of rectangular ground grid when the fault current was injected into its corner. However, the lowest level of overvoltage was found when the fault current was injected into the center of square ground grid. The results from this study indicated that ATP/EMTP program was useful for preliminary investigation of overvoltage on ground grids of different shapes. The obtained knowledge could be beneficial for further designing of ground grid systems of high voltage substations to receive the minimal damages due to fault current.
Three main microgrid control strategies are described:
1. Master-slave mode where one DG acts as the voltage/frequency master and others follow as slaves under P/Q control.
2. Peer-to-peer mode where all DGs use droop control to cooperatively regulate voltage and frequency without a master.
3. Combined mode using aspects of both by assigning control roles based on DG type.
These slides present the introduction to FACTS devices. Later we will discuss about its modelling and control aspect applications. This comes under the topic on power electronics application in smart and microgrid systems.
Series of blackouts encountered in recent years in power system have been occurred because either of voltage or angle instability or both together was not detected within time and progressive voltage or angle instability further degraded the system condition, because of increase in loading. This paper presents the real-time assessment methodology of voltage stability using Phasor Measurement Unit (PMU) with observability of load buses only in power network. PMUs are placed at strategically obtained location such that minimum number of PMU’s can make all load buses observable. Data obtained by PMU’s are used for voltage stability assessment with the help of successive change in the angle of bus voltage with respect to incremental load, which is used as on-line voltage stability predictor (VSP). The real-time voltage phasors obtained by PMU’s are used as real time voltage stability indicator. The case study has been carried out on IEEE-14 bus system and IEEE-30 bus systems to demonstrate the results.
This document discusses energy efficiency in wireless sensor networks. It describes how sensor nodes consist of an RF transceiver, microcontroller, sensors, and memory. Radio transceivers are the largest energy consumer. The document measures energy usage for different components and transmitting data. It also discusses using lithium-ion batteries for their discharge characteristics and the ability to model remaining capacity. A measurement setup is used to test batteries at different temperatures and loads, developing a linear model to calculate residual energy as a function of temperature directly on sensor nodes.
ANN Based SVC Switching at Distribution Level for Minimal Injected HarmonicsYateesh Yadav
1) The document discusses using an artificial neural network (ANN) controller for a static VAR compensator (SVC) at the distribution level to minimize reactive power drawn from the supply and injected harmonics.
2) An SVC consists of a thyristor controlled reactor and thyristor switched capacitor to compensate loads through reactive power generation or absorption.
3) The ANN controller determines the optimal firing angles of the thyristor controlled reactor to control the SVC online and balance reactive power loads while keeping harmonic injection low.
Automatic load frequency control of two area power system with conventional a...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
Transmission line is one the important compnent in protection of electric power system because the transmission line connects the power station with load centers.
The fault includes storms, lightning, snow, damage to insulation, short circuit fault [1].
Fault needs to be predicted earlier in order to be prevented before it occur
An Under frequency Load Shedding Scheme forAjay Singh
This document presents an under frequency load shedding scheme for hybrid and multi-area power systems. It discusses the need for such a scheme to maintain frequency stability during faults or imbalances. The proposed scheme uses frequency first derivative to estimate power deficit independently of system parameters. It was tested through simulations of different scenarios involving islanding, variable generation, and inertia changes in hybrid systems as well as multi-area systems. The results demonstrated the scheme's ability to determine appropriate load shedding to regulate frequency.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Load Frequency Control of Multi Area System using Integral-Fuzzy ControllerIJERA Editor
The power system is interconnected to enhance the security and reliability. With large interconnected system, unexpected external disturbances, parameter uncertainties and the model uncertainties make big challenges for stability of system. Load Frequency Control (LFC) deals with the control of real power and frequency of the system. The LFC is used to reduce the transient deviations in the power system. It limits the frequency within limits and controls the tie-line exchange power. Various controllers are used for this purpose. Recently Artificial Intelligence Techniques such as Artificial Neural Network (ANN), fuzzy logic, Genetic Algorithm etc. are used for the designing of controllers. These controllers provide a faster response and are flexible to adjust according to system conditions. In this paper, I have designed integral controller which is conventional method for Load Frequency Control and Artificial Intelligence Technique based Fuzzy Logic controller to deal with the Load Frequency Control Problem for Multi-area System. The simulation of the system is done with MATLAB. These controllers provide a robust system which is more stable and reliable and helps the system to regain its normal state after any disturbance.
This document compares different state estimation methods for a smart distribution grid using synchrophasor technology. It analyzes how integrating phasor measurements from PMUs can improve state estimation accuracy compared to conventional measurements. The study examines different measurement configurations using conventional data, PMU data, or a hybrid approach. It models an 18-bus test grid using real load data from a 110kV distribution system. The results demonstrate that using PMUs can provide more accurate estimates of the system state by leveraging their precise, time-synchronized measurements.
Power transformer faults diagnosis using undestructive methods and ann for dg...Mellah Hacene
Power transformer faults diagnosis using undestructive methods (Roger and IEC) and artificial neural network for dissolved gas analysis applied on the functional transformer in the Algerian north-eastern: a comparative study
Bouchaoui Lahcene, Kamel Eddine Hemsas, Hacene Mellah, saad eddine benlahneche
Nowadays, power transformer aging and failures are viewed with great attention in power transmission industry. Dissolved gas analysis (DGA) is classified among the biggest widely used methods used within the context of asset management policy to detect the incipient faults in their earlier stage in power transformers. Up to now, several procedures have been employed for the lecture of DGA results. Among these useful means, we find Key Gases, Rogers Ratios, IEC Ratios, the historical technique less used today Doernenburg Ratios, the two types of Duval Pentagons methods, several versions of the Duval Triangles method and Logarithmic Nomograph. Problem. DGA data extracted from different units in service served to verify the ability and reliability of these methods in assessing the state of health of the power transformer. Aim. An improving the quality of diagnostics of electrical power transformer by artificial neural network tools based on two conventional methods in the case of a functional power transformer at Sétif province in East North of Algeria. Methodology. Design an inelegant tool for power transformer diagnosis using neural networks based on traditional methods IEC and Rogers, which allows to early detection faults, to increase the reliability, of the entire electrical energy system from transport to consumers and improve a continuity and quality of service. Results. The solution of the problem was carried out by using feed-forward back-propagation neural networks implemented in MATLAB-Simulink environment. Four real power transformers working under different environment and climate conditions such as: desert, humid, cold were taken into account. The practical results of the diagnosis of these power transformers by the DGA are presented. Practical value.....
Control of grid connected inverter system for sinusoidal current injection wi...ijiert bestjournal
The control strategy for the grid connected inverter (GCI) during abnormal conditions like voltage sag,swell and line to ground fault has been presented. The strategy adopted here operates even during faulty conditions,unlike the conventional controller which fails to operate during fault y conditions. The Multi-Reference Frame (MRF) PI Controller is used for this purpose. In order to study the D ynamic Performance of the system,it is simulated in Matlab Simulink environment. The overall system is simulated for normal condition that is without the presence of fault,and with the presence of fault. The performance is also studied during abnormal conditions of the grid and its results are analyzed. The simulat ion results exhibit improved performance of the system during normal as well as abnormal conditions.
In this paper, a detail design and description of a predictive current control scheme are adopted for three-phase grid-connected two-level inverter and its application in wind energy conversion systems. Despite its advantages, the predictive current controller is very sensitive to parameter variations which could eventually affected on system stability. To solve this problem, an estimation technique proposed to identify the value of harmonic filter parameter based on Model reference adaptive system (MRAS). Lyapunov stability theory is selected to guarantee a robust adaptation and stable response over large system parameter variation. The simulation results shows the efficiency of the proposed techniques to improve the current tracking performance.
1. Distribution systems were traditionally designed for unidirectional power flow but high renewable energy source (RES) penetration can cause bidirectional power flow and other challenges.
2. Maintaining minimum voltage drop was traditionally the main concern but RES integration affects voltage regulation.
3. Distributed RES integration increases vulnerability to overload conditions on small distribution feeders due to intermittent generation and changing network configurations.
This document discusses various topics related to analysis of wind and PV systems including:
- Standalone and grid-connected operation of fixed and variable speed wind energy conversion systems and solar photovoltaic systems.
- Grid integration issues for permanent magnet synchronous generator (PMSG) and squirrel-cage induction generator (SCIG) based wind energy conversion systems, as well as grid-integrated solar systems.
- Design of power converters such as AC-DC, DC-DC, and AC-AC converters for renewable energy sources and analysis of various operating modes of wind and solar systems.
- Design of hybrid renewable energy systems and factors affecting the plant economy of renewable power plants such as initial capital cost
Svpwm based 3 level statcom for reactive power management under line-lineIAEME Publication
This document summarizes a research paper that analyzes the performance of a 3-level STATCOM for reactive power management under a line-line fault in a transmission line. The paper tests a line-line fault in an IEEE 14 bus system incorporating nonlinear loads. A 2-level and 3-level STATCOM using SVPWM control are placed at bus 14 to regulate the voltage. Simulation results show the effectiveness of the SVPWM control strategy in managing reactive power and voltage stability during steady state and transient operation for both the 2-level and 3-level STATCOM configurations.
2.[6 13]investigation on d-statcom operation for power quality improvement in...Alexander Decker
1) The document presents a new control scheme for D-STATCOM that uses sinusoidal PWM signals based only on voltage measurements to regulate voltage in distribution systems.
2) Simulations using MATLAB/PLECS show the control scheme maintains constant voltage under disturbances by exchanging reactive power with the system through the D-STATCOM.
3) Results demonstrate the control scheme effectively regulates voltage, compensates for harmonics, and corrects power factor during system faults and load variations.
This document discusses Flexible AC Transmission Systems (FACTS). It provides 3 key points:
1. FACTS are power electronics-based devices used to improve transmission systems by enhancing controllability and increasing power transfer capability.
2. Benefits of FACTS include regulating power flows, reducing the need for new transmission infrastructure, improving transient stability, and controlling real and reactive power flows independently.
3. FACTS controllers can be series, shunt, or combined series-series/series-shunt configurations, with the appropriate choice depending on objectives like controlling power flows or damping oscillations.
1. The document discusses the computer-aided design of grounding systems for transformer stations to ensure low grounding resistance and safe touch and step voltages. It presents the design of grounding systems for three transformer stations in Croatia using CDEGS software.
2. The design process involves measuring soil resistivity on site, modeling the soil as multiple layers, designing the grounding grid geometry, and simulating fault conditions to analyze touch and step voltages.
3. For a sample 110x80m grounding grid, the analysis shows that touch voltages are highest in the station corners. Additional measures like an outer ring conductor are recommended to improve safety.
Permanent Fault Location in Distribution System Using Phasor Measurement Unit...IJECEIAES
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Failure Detection in Energized High Voltage Substation Grounding Grids - A Case Study
1. International Journal of Engineering Science Invention
ISSN (Online): 2319 – 6734, ISSN (Print): 2319 – 6726
www.ijesi.org ||Volume 5 Issue 7|| July 2016 || PP. 24-35
www.ijesi.org 24 | Page
Failure Detection in Energized High Voltage Substation
Grounding Grids - A Case Study
Luana Vasconcelos Gomes1
, Euler C. T. Macedo2
, Edson Guedes da Costa1
,
Raimundo Carlos Silvério Freire1
and Malone Soares de Castro1
1
(Postgraduate of Electrical Engineering/Federal University of Campina Grande, Brazil)
2
(Department of Electrical Engineering/Federal University of Paraiba, Brazil)
Abstract: An electronic system of measuring and processing surface voltage potentials distributed along the
grounding grid was developed. The electronic system is composed of several parts, an embedded computer,
signal conditioning circuits and computational routines. The adopted processor was a low-power open-source
single-board computer that allows the implementation of routines based on the finite-difference method. It was
possible to create two real time dimensional plots using the fall-of-potential method. The electronic system was
able to make a correct diagnosis of the aging state of the grounding grid. The results allowed evaluation of the
potential behaviour of the ground surface voltage in a consistent manner in a steady state operation. The results
obtained from measurements in high voltage substations using the developed embedded system were satisfactory
when compared to other measuring devices. This system was capable of easily locating problematic zones, such
as high potential concentrations, allowing efficient and fast grounding grid diagnosis.
Keywords: diagnostic, grounding grid degradation, high voltage grounding, substation, surface voltages
I. Introduction
The introduction most equipment found in a high voltage substation uses the ground connection as a reference
for all operational voltages in the system. From an operational safety point of view, the objective of a ground
grid is to allow safe equipotential surface voltage on the ground during a surge (e.g. atmospheric and switching
surges) and when an industrial frequency current is flowing to the grounding.
A poor grounding system not only results in unnecessary transient damage, but also causes data and equipment
loss, plant shutdown, and increases fire and personnel risk[1]. An efficientgrounding systemcan impacton
betterenergy qualityrate.A low ground resistance value is not a guarantee of safety, because there is no direct
relationship between the grounding resistance and the maximum electric current that that a person is capable of
surviving[2]; based on this, alongside the necessity of verifying ground resistance during inspections, it is
necessary to evaluate the grid conductor condition and its connection points. The difference of potential between
different substation positions must mitigate personal safety and the adequate operation of equipment installed in
high voltage substations.
Based on their importance in relation to the system‟s operational continuity, grounding grids require periodic
evaluation, not only based on conductor corrosion, but also on ground resistivity and soil imperfections (e.g.
rocks, soil composition, soil inclination, etc.).
Some analytical methods are now being implemented in computational routines. Most of these methods try to
simulate real situations in grounding systems, promoting an additional analysis to the practical measurement
method[3-8].Many papers deal with the monitoring and diagnosis of the operational conditions of grounding
grids[1], [9-16].
An indirect manner of evaluating the degradation level of a grounding grid is to analyze the potential surface
distribution in the substation area and its surroundings. Grids that possess a uniform potential distribution and
low ground resistance do not present degradation problems, however, an elevated potential concentration might
indicate degradation [9], or other problems, such as rocks, unsuitable soil composition, etc.
A methodology that allows the detection of failures in energized grounding grids in real time is presented.
Therefore, an electronic device was specially developed for this application, which measures and processes the
surface potentials of an energized high voltage substation. The device is capable of measuring several points of
surface potential distributed along the grounding grid, performing the surface potential mapping in order to
identify high resistivity and degradation zones, discontinuities in the grid or failure points. The measured data is
processed with the aid of embedded software based on the Finite Difference Method. The measurements are
performed at industrial frequency and use the substation transformer unbalance current as a reference for ground
potential elevation.
2. Failure Detection In Energized High Voltage Substation Grounding Grids - A Case Study
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II. Grounding System Theory
2.1 Grounding Grids
Grounding systems must be projected to allow the surface potential in a high voltage substation to stay under the
maximum potential limits allowed for safety. The surface potential values must be limited in steady state and
transient conditions. To satisfy the low ground resistance values and to obtain low touch and step potential
values, high voltage substations are normally projected with ground grids composed of horizontal cables that
connect all copper electrodes. The grounding grids are efficient and economic, and are adopted in all kinds of
substations.
The IEEE standard [17]defines some important concepts in relation to the electric potential distribution:
Step voltage: The difference in surface potential experienced by a person bridging a distance of 1 m with
their feet without contacting any other grounded object.
Touch voltage: The difference of potential between the ground potential rise (GPR) and the surface
potential at the point where a person is standing, while at the same time having their hands in contact with a
grounded structure.
Mesh voltage: The maximum touch voltage to be found within a mesh of a ground grid.
Transferred voltage: A special case of touch voltage where voltage is transferred into or out of the
substation.
In a grounding grid, the current flows preferentially through the edges. The typical equipotential distribution
lines inside and in the neighboring region of the ground grid are given in Error! Reference source not
found.1.
(a) (b)
Figure 1. Equipotential distributions lines: (a) Equipotential lines (b) Potentials inside and in the neighboring
regions of a ground grid.
2.2 Finite Difference Methods (FDM)
To determine the electric potential in a region when the potential Vis known only in certain points of the region
under analysis, either a Poisson Equation (1) or a Laplace equation (2) is used [18], [19]. [9] presents the
mathematical development and the computer simulation steps.
The surface potential mapping of a region of interest is obtained by performing the Laplace equation solution
using the Finite Difference Method. The solution is performed in four steps. The first step consists of dividing
the interest region into node grids, as seen in Error! Reference source not found. 2.
In the second step, the contour conditions are established, attributing nodes, called „fixed nodes‟ to the grid
extremity of the region. Internal nodes are termed „free nodes‟.
In the third step, it is necessary to obtain approximations by calculating the finite difference of the Poisson
differential equation. In case ρs = 0, the finite difference approximation of the Laplace Equation is obtained, as
illustrated by (1):
)(
4
1
1,1,,1,1,
jijijijiji
VVVVV (1)
3. Failure Detection In Energized High Voltage Substation Grounding Grids - A Case Study
www.ijesi.org 26 | Page
The Laplace finite difference equation is determined for each point of the discretized region for which it is
desired to calculate the problem solution.
The fourth step consists of iteratively calculating the potential values at all grid nodes.
Figure 2. Domain discretization [18].
III. Material And Methods
[9] presents the embedded system development with the several technologies employed. A block diagram of the
developed system is presented in Fig.3.In the sequence, each block of the measurement system is detailed.
Measurement
System
Embedded
Platform
Graphic
Analysis of
Surface
Potentials
Grounding
Grids
Diagnosis
Software
Figure 3.Embedded electronic system block diagram.
3.1 Measurement System
The measurement system procedure is composed of signal conditioning circuit plus protection; analog
multiplex; PIC microcontroller; serial/USB communication and a Beagle Board.
The conditioning circuit is composed of resistors and operational amplifiers and allows the attenuation of input
signals. The measurement system operates with eight different scales, and the correct scale selection is
performed automatically by the microcontroller. Initially, the scale is tested in its lower value and then is
automatically changed until the detection of the appropriated scale value. The PIC 18F452 microcontroller is
responsible for automatically controlling the scales using an analog multiplexer, performing the peak detection,
coordinating and executing the measurement process and transferring the measured data to the embedded
system (the Beagle Board, using the RS232/USB communication protocol). The functional block diagram of the
measurement system is presented in Error! Reference source not found. 4.
To perform the surface potential measurement efficiently, specific procedures were adopted in the process:
Automatically repeating the measurement and calculating the arithmetic mean of the obtained data, to avoid
incorrect values. If the calculated mean result is not consistent, the data is discarded and the procedure is
repeated.
Verifying whether the mean of the measured values is in the range of ± 10% of the fifth digit of the
measurement value, to filter harmonic components from the measurement data.
3.2 Embedded Platform
The Beagle Board is equipped with the basic functionalities of a computer [20]. It is employed in several
embedded system technologies. The descriptions of the technical characteristics of the Beagle Board used as a
4. Failure Detection In Energized High Voltage Substation Grounding Grids - A Case Study
www.ijesi.org 27 | Page
coordinator system are found in [9], but, with the objective of maintaining the low-cost development, an open-
source Linux® operational system was used, the Angstrom® distribution.
3.3 Grounding Grid Diagnosis Software
The software must be able to map the potential at the ground surface of the substation and itsneighborhoods.
The diagnosis enables possible field concentrations or eventual difficulties for current draining to be noted, such
as high resistivity zones in the grid area, corrosion or discontinuity in steady-state operation condition or in a
short-circuit occurrence.
The computational routine was developed by using a multiplatform tool, the Qt®, which is widely used for the
application development of graphical user interfaces (GUI), in embedded systems. The tools adopted were the
QT Creator platform, C++ language and the Qwt graphical library (Qt Widgets for Technical Applications). The
Qwt library possesses several types of data structures for bi-dimensional data plotting. These features include
curve plots, scatter plots, spectrograms, contour plots, histograms, dials, compasses, knobs, wheels, sliders,
thermos, etc.
In order to use the software, the specification of a domain, contour conditions and/or initial conditions are
necessary. Using these conditions associated with computational resources, it was possible to simulate the
behavior of the electric potential (V) in a determined region, in this case, the HV substation [9] - [16].
Fig. 5 shows the second software window when the user has selected the measurement point. With a virtual
keyboard, the user enters the coordinates of the measured point. The graphic is generated after the selection of
the Graphic button. The flowchart of the measurement procedure is presented in Fig. 6.
Perform
Measurement
Peak
Detector
Authomatic Scale
Adjustment
Measurements = 5?
Results at
BeagleBoard
Display
Arithimetic Mean
of the
Measurements
Mean is Ok?
Yes End of Measurement
Results at Display
Input Signals
Acquistion
Measurements
Begin
Yes
No
Figure 4. Block diagram of the measurement system.
5. Failure Detection In Energized High Voltage Substation Grounding Grids - A Case Study
www.ijesi.org 28 | Page
Figure 5. Measurement system user interface.
3.4 Graphic Analysis of Surface Potentials
The surface potential of the graphical analysis of three cases is shown in the results and discussion section. The
behavior of the grounding grid in normal steady-state operational conditions, analysis of the occurrence of a
fault in the grounding grid with a discontinuity, and the analyses and diagnoses of an energized 69/13.8 kV high
voltage substation will be shown.
Start
Windon is created and
shown
User clicks in a point of the
grid
Window is exhibited to get the coordinates
and measure the voltage
Storage?
New
measurement?
Spectrogram is show
MainWindow*w = new
MainWindow;
W->show();
onActionPerformed();
No
Yes
Yes
NoGraphic ();
Figure 6. Measurement procedure flowchart.
6. Failure Detection In Energized High Voltage Substation Grounding Grids - A Case Study
www.ijesi.org 29 | Page
IV. Results And Discussion
This section presents some results obtained using the developed system. The main results are the evaluation of
measurement data. The grounding grid surface potential measurements were performed on the patio of the High
Voltage Laboratory at the Federal University of Campina Grande, and at a 69/13.8 kV energized substation.
With the objective of evaluating the performance of the developed embedded system, several measurements
were initially taken in a ground grid composed of three copper rods of 1.2 m in length, placed in an equilateral
triangular configuration. The ground grid was installed in heterogeneous soil with a resistance equal to 8.46 Ω,
with 2.5 m side and the electrodes were buried 50 cm deep. The tests were performed using a Variable Voltage
Transformer (variac) that tries to simulate the unbalanced current injected.
The system was evaluated in three different cases:
A grounding grid under normal steady-state operational conditions (i.e. without surges and grid defects),
labelled Case 1.
The occurrence of a fault in the ground grid with a discontinuity was simulated in Case 2.
The third situation (Case 3) consisted of several measurements, analyses and diagnoses of an energized
69/13.8 kV high voltage substation.
4.1 Measurement System Evaluation
Initially, to verify the accuracy of the measurements made by the developed system, several measurements were
taken simultaneously using a Tektronix® digital oscilloscope TDS 2024B model. The comparison between the
two measurement systems is presented in Table 1. Data was obtained using the setup presented in Error!
Reference source not found.7.
Table 1 Comparison between the performed measurements using the developed embedded system and an
oscilloscope
Measurement
Points
Embedded
System
Oscilloscope Error
(%)
1 5.80 6.00 3.40
23 5.30 5.60 5.30
31 7.94 8.40 5.40
39 9.00 9.50 5.30
45 10.60 11.20 5.35
50 15.80 16.40 3.70
53 16.40 17.20 4.65
57 21.85 22.40 2.50
63 25,60 26.20 2.30
69 30.45 31.20 2.42
The error percentage was calculated in relation to the measured values arithmetic mean. It was confirmed that
sometimes the measurement results obtained using the oscilloscope presented variations (spikes, noise, etc.).The
results presented in Table I correspond to the arithmetic mean of five measurement results. The same procedure
was automatically adopted by the developed system.
As the obtained results were considered satisfactory, the experimental setup presented in Case 1 was performed:
the complete analysis of a grounding grid under normal operational steady-state conditions(without surges and
grid defects).
Case 2 was then analyzed. The same grounding grid presented in Case 1 was considered, but a discontinuity
zone was inserted.
In Case 3, several measurements were taken in an energized substation, with a special characteristic: the
measurements were taken at different periods of time, during the humid and dry seasons.
In the following sections, the results obtained in the three distinct situations are detailed.
4.2 Case 1 – Grounding Grid in Steady State
For adequate computational routine processing, the determination of the correct position of each measurement
point (geographic coordinates of the measurement point)is necessary to create a simplified scheme (sketch), as
presented in Error! Reference source not found.7. In this figure, for example, the number of measurement
points and their coordinates (x and y), the position where the electrodes are installed, and the grid dimensions,
etc., are presented.
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The potential surface measurements were performed in accordance with Section III. The main goal of this
procedure was to verify the functionality of the developed embedded system and to measure and map the
potential distribution on the ground to indirectly assess the degradation of the grounding grid.
During the experimental setup, 91 measurements were taken, spaced 1.5 m apart. The reference point was
positioned 48 m from the ground grid, and an unbalanced current of 5 A was injected into the ground.
Figure 7. Surface potential measurement points from a steady-state laboratory grounding grid (no defects).
The results obtained with the proposed embedded system, for steady state operation are presented in Figs. 8 and
9. In these figures, the surface potential distribution and the equipotential lines found on the ground are
presented, respectively. In Fig.10the combination of the two previous figures is presented.
Figure 8.Surface potentials levels of a grounding grid without defects.
The results obtained demonstrate that the surface potential distribution and the equipotential lines are uniform,
since elevated values of voltage were detected in the points near the grounding grid, where the 5A current was
Reference
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injected, and with an increase in distance the surface potential gradually decreased.This behavior demonstrates
the adequate current flow in the ground.
Figure 9. Equipotential lines of a grounding grid without defects.
Figure 10. Result obtained combining the surface potential levels and the equipotential lines of a grounding grid
without defects.
4.3 Case 2 – Grounding Grid with Discontinuity
In order to evaluate the performance of the developed embedded device in grounding grid with a discontinuity
zone, the same grounding grid configuration as presented in Case 1 was used. A defect zone was generated by
inserting an electrode with a 12 m distance from the grounding grid, where a 1.3 Acurrent was injected, as seen
in Fig.11.
The results obtained are presented in Figs.12, 13 and 14. In these figures the surface potential distribution, the
equipotential lines and the combination of the previous figures in a single graph are illustrated.
Analyzing the results from Case 2, it is possible to verify a region with elevated surface. A concentration of
equipotential lines was also verified. The results confirm that the developed device allows the identification of
areas with an elevation of surface potential in a grounding grid, thereby providing an efficient diagnosis.
4.4 Case 3 – Results obtained from an Energized High Voltage Substation
The surface potential measurements in an energized substation were taken using the same procedure presented
in Case 1 and 2, but in two distinct seasons, with an interval of about six months between the measurements.
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0 6 9 11 15 18 21
10
20
30
40
50
42 39 38 37
77 76 74 73
91 90 89
Ponto de
Referencia
X (m)
Y (m)
88
1,5 m
1,5 m
9,40 m
26,30m
I = 5A
14,50 m
24m
12,90 m
5,40 m
5
9 2 178
1,5 m
6 5 4 3
1,5m
111617 15 14 13 12
202526 24 23 22 21
293435 33 32 31 30
18
27
36
10
19
28
4041
51 505253
69 687071
63 626465
57 565859
45 444647 43
49
55
61
6772
66
60
54
48
75
78
83
79808182
84858687 I = 1,3A
Ponto de Falha
Fig.1. Surface potential measurement points from a steady-state laboratory grounding grid (with a discontinuity
zone defects).
Figure 11. Surface potential measurement points from a steady-state laboratory grounding grid (with a
discontinuity zone defects).
Figure 12. Surface potential levels of a grounding grid with a discontinuity zone.
Reference
Discontinuity zone
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The first measurement setup was carried out at the end of the rainy season and the second setup at the end of the
dry period with elevated ambient temperature.
During the first setup measurements were made at 70 different points arranged in the effective area of the
grounding grid and its surroundings. The test electrode was positioned in a 7x7 m mesh.
Following the same procedure used in the second setup, 118 different surface potential levels were measured in
the effective area of the grounding grid and its surroundings. With the objective of obtaining a more detailed
surface potential mapping, the test electrode was positioned following a 5x5 m mesh.
Figure 13. Equipotential lines of a grounding grid with a discontinuity zone.
Figure 14. Results obtained combining the surface potential levels and the equipotential lines of a grounding
grid with a discontinuity zone.
From the measured surface potential data, it was possible to map the ground surface potentials, indicating the
field concentrations, both in steady state and in short circuit conditions, generating 2D graphics for both
situations.
Error! Reference source not found. presents the 2D plots of the surface potential distribution generated by
the measurements after the rainy period.
Error! Reference source not found. presents the 2D plots with the surface potential distribution of the
energized substations in the end of the dry period.
Visual inspection showed that the surface potential mapping for the energized substation presented different
results, especially for a particular region. It was verified that the results obtained during the second setup
presented elevated surface potentials values in comparison to the first setup. The explanation for this is basically
the geological conditions and seasonality. It is possible to confirm from the results that during the grounding
grid mesh implantation, soil with lower resistivity was used, and a rock is probably located close to the surface.
Water evaporation is more intense in this region, and as a consequence, soil resistivity is greater, not allowing
the current to flow through the soil, and generating elevated surface potentials during the dry season.
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(a) (b)
Figure 15.Surface potential levels and equipotential lines of an energized high voltage substation grounding
after the rainy period: (a) steady state, (b) short circuit.
(a) (b)
Figure 16. Surface potential levels and equipotential lines of an energized high voltage substation grounding
after the dry period: (a) steady state, (b) short circuit.
V. Conclusion
Substation grounding systems require permanent monitoring due to corrosion, degradation caused by high
intensity current surges, seasonality, and mesh implantation conditions, such as chemical additives to reduce the
original resistivity, etc.
Predictive tests on substations are increasingly difficult to perform because it is not generally possible to shut
the substation down, and thus have monitoring systems that permit the real time evaluation of the operational
conditions of energized substations is relevant. On the other hand, the grounding grid evaluation and
determination of operational conditions is not a trivial task, because the conventional techniques of ground
resistance measurement do not highlight the real conditions of the grounding grid.
A low cost system (hardware and software) was presented, and its ability to localize high resistivity zones, grid
corrosion, and discontinuity zones in the grounding grid was verified. This system allows the measurement of
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surface potentials and data to be analyzed using embedded software, presenting the results in 2D plots. The
developed system was effective because it allowed the rapid determination of problematic zones with potential
concentration, allowing a precise diagnosis of an energized 69/13.8 kV substation.
With the objective of obtaining a more accurate diagnosis and reliable operating conditions for an energized
substation, several measurements were performed under different weather and humidity conditions, after dry
and rainy seasons. The system highlighted the seasonality effects and geological conditions where the grid was
installed, and the need for substation grounding system monitoring was demonstrated.
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