Zenergy Power has been developing an inductive-type of fault current limiter (FCL) for electric power grid applications. The FCL employs a magnetically saturating reactor concept which acts as a variable inductor in an electric circuit. In March 2009 Zenergy Power, with funding from the California Energy Commission and the U.S. Department of Energy (DOE), installed an FCL in the Avanti distribution circuit of Southern California Edison’s Shandin substation in San Bernardino, CA. Rated at 15 kV and 1,250 amperes steady-state, the “Avanti” device is the first superconductor FCL installed in a US utility. In January 2010, the “Avanti” device successfully limited its first series of real-world faults when the circuit experienced multiple single-phase and three-phase faults. After successfully validating the performance of a new “compact” saturated-core FCL, Zenergy Power received contracts to install a 12 kV, 1,250 amperes compact FCL in the CE Electric UK grid in early 2011 and a 138 kV, 1,300 amperes FCL at the Tidd substation of American Electric Power in late 2011.
New Hybrid Structure Based on Improved Switched Inductor Z-Source and Paralle...IJPEDS-IAES
Nowadays, more and more distributed generations and renewable energy
sources, such as wind, solar and tidal power, are connected to the public grid
by the means of power inverters. They often form microgrids before being
connected to the public grid. Due to the availability of high current power
electronic devices, it is inevitable to use several inverters in parallel for highpower
and/or low-cost applications. So, inverters should beconnected in
parallel to provide system redundancy and high reliability, which are
important for critical customers. In this paper, the modeling, designing and
stability analysis of parallel-connected three-phaseinverters are derived for
application in renewable energy systems. To enlarge voltage adjustability,
the proposed inverter employs an improved switched inductor Z-source
impedance network to couple the main circuit and the power source.
Compared with the classical Z-source inverter (ZSI) and switched inductor
Z-source inverter (SL-ZSI), the proposed inverter significantly increases the
voltage boost inversion ability and also can increase the power capacity and
the reliability of inverter systems. The proposed topology and its
performances are validated using simulation results which are obtained in
Matlab/Simulink.
The long established battery chargers are having many drawbacks such as prominent ripple charging current, less efficiency and bulky in size. To overcome these drawbacks of conventional battery charger, several charging circuits have been proposed and inevitability force to design a high-performance battery charger with small in size and improved efficiency. In this paper solar photovoltaic system based half-bridge series–parallel resonant converter (HBSPRC) charger is proposed for battery interface. The converter is designed to abolish low and high-frequency ripple currents and thus take full advantage of the life of secondary battery circuit. This is achieved by designing converter switches turn on at zero current and zero voltage with switching frequency greater than that of resonance frequency which leads to freewheeling diodes need not have very fast reverse-recovery characteristics. The performance of the power converters depends upon the control method adopted; in this work fuzzy logic controller is used for controlling the output voltage of HBSPRC. The fuzzy control scheme for the HBSPR converter has been designed and validated in hardware implementation of HBSPRC switching technique. From the results, it is found that the proposed battery charging system which reduces the switching loss and voltage stress across the power switches which increases the efficiency of the converter.
SIMULATION STUDY OF QZSI Z-SOURCE INVERTER FOR RESISTIVE AND INDUCTIVE LOADijiert bestjournal
This paper involves design and simulation of a step up dc/dc converter topology connected with the chopper circuit
intended for resistive and inductive load. The topology contains voltage fed qzsi Z Source Inverter (qzsi), a high
frequency isolation transformer with reduced turn’s ratio, a Voltage Doubler Rectifier (VDR). A carrier based PulseWidth
Modulation (PWM) which employs shoot through state strategy for qzsi is implemented which gives significantly
high voltage gain compared to traditional PWM techniques. To improve the power density of converter, three phase aclink
and three-phase VDR is implemented. The designed step up dc/dc converter is tested for various kinds of resistive
and inductive load in MATLAB/SIMULIKN platform.
New Hybrid Structure Based on Improved Switched Inductor Z-Source and Paralle...IJPEDS-IAES
Nowadays, more and more distributed generations and renewable energy
sources, such as wind, solar and tidal power, are connected to the public grid
by the means of power inverters. They often form microgrids before being
connected to the public grid. Due to the availability of high current power
electronic devices, it is inevitable to use several inverters in parallel for highpower
and/or low-cost applications. So, inverters should beconnected in
parallel to provide system redundancy and high reliability, which are
important for critical customers. In this paper, the modeling, designing and
stability analysis of parallel-connected three-phaseinverters are derived for
application in renewable energy systems. To enlarge voltage adjustability,
the proposed inverter employs an improved switched inductor Z-source
impedance network to couple the main circuit and the power source.
Compared with the classical Z-source inverter (ZSI) and switched inductor
Z-source inverter (SL-ZSI), the proposed inverter significantly increases the
voltage boost inversion ability and also can increase the power capacity and
the reliability of inverter systems. The proposed topology and its
performances are validated using simulation results which are obtained in
Matlab/Simulink.
The long established battery chargers are having many drawbacks such as prominent ripple charging current, less efficiency and bulky in size. To overcome these drawbacks of conventional battery charger, several charging circuits have been proposed and inevitability force to design a high-performance battery charger with small in size and improved efficiency. In this paper solar photovoltaic system based half-bridge series–parallel resonant converter (HBSPRC) charger is proposed for battery interface. The converter is designed to abolish low and high-frequency ripple currents and thus take full advantage of the life of secondary battery circuit. This is achieved by designing converter switches turn on at zero current and zero voltage with switching frequency greater than that of resonance frequency which leads to freewheeling diodes need not have very fast reverse-recovery characteristics. The performance of the power converters depends upon the control method adopted; in this work fuzzy logic controller is used for controlling the output voltage of HBSPRC. The fuzzy control scheme for the HBSPR converter has been designed and validated in hardware implementation of HBSPRC switching technique. From the results, it is found that the proposed battery charging system which reduces the switching loss and voltage stress across the power switches which increases the efficiency of the converter.
SIMULATION STUDY OF QZSI Z-SOURCE INVERTER FOR RESISTIVE AND INDUCTIVE LOADijiert bestjournal
This paper involves design and simulation of a step up dc/dc converter topology connected with the chopper circuit
intended for resistive and inductive load. The topology contains voltage fed qzsi Z Source Inverter (qzsi), a high
frequency isolation transformer with reduced turn’s ratio, a Voltage Doubler Rectifier (VDR). A carrier based PulseWidth
Modulation (PWM) which employs shoot through state strategy for qzsi is implemented which gives significantly
high voltage gain compared to traditional PWM techniques. To improve the power density of converter, three phase aclink
and three-phase VDR is implemented. The designed step up dc/dc converter is tested for various kinds of resistive
and inductive load in MATLAB/SIMULIKN platform.
A ZVS Interleaved Boost AC/DC Converter Using Super Capacitor Power for Hybri...IJMER
International Journal of Modern Engineering Research (IJMER) is Peer reviewed, online Journal. It serves as an international archival forum of scholarly research related to engineering and science education.
Assessment of the Static Stability Margin and Voltage Profile Improvement in ...Dr. Amarjeet Singh
The huge increase in the demand of electric power and the economic constraints to build new facilities, lead the power systems to operate near of their stability limits. Indeed, instability has become a major problem in the management of power systems. Unavoidable disturbances such as short circuits, momentary unavailability of transmission lines, generators as well as transformers can affect the stability of the power system at any time and bring it into a state of instability or collapse. These collapses become a major problem for energy consumers, because the lack of energy leads them to use backup energy sources that are relatively expensive and polluting. This situation lowers the productivity of the industry, and for the national electric company of the Congo, (SNEL), the time to get rid of the magnetization of the network and to take all the loads, can generate penalties, which is a loss of revenue for the company. This paper aims to assess the stability margin and to improve the quality of electrical energy in the south-SNEL transmission system.
Reactive Power Compensation in 132kv & 33kv Grid of Narsinghpur Areaijceronline
Power Sector is considered to be very important and priority sector as it leads to overall development of country. The cost of installation of new generating units is rising; hence generated electrical energy has to be utilized carefully and efficiently, which changes through each AC cycle. It is proposed to study the effect of group shunt compensation provided for the mix of rural and urban loads, catered from grid sub-stations in the district of Narsinghpur, to assess its adequacy and saving in transmission losses. An optimum combination of compensators which yields maximum benefits in the system shall be worked out. Load Flow Study for the effect of group shunt compensation provided on 132KV bus of 220KV sub-station Narsinghpur and on 33KV buses of 132KV sub stations Srinagar, Narsinghpur, Gadarwara and Burman sub-stations for the mix of rural and urban loads, catered from partial grid network in Narsinghpur district. If reactive power is supplied near the load, the line current can be reduced or minimized, reducing power losses and improving voltage regulation at the load terminals. The leading current drawn by the shunt capacitors compensates the lagging current drawn by the load. The selection of shunt capacitors depends on many factors, the most important of which is the amount of lagging reactive power taken by the load. Objective was to study the effect of group shunt compensation provided for the mix of rural and urban loads, catered from grid sub-stations in the district of Narsinghpur and to assess the adequacy and saving in transmission losses & to work out an optimum combination of compensators which yields maximum benefits in the system. Depending on the stages of 'ON' and 'OFF', operations to be carried out in various permutations and combinations of shunt compensators i.e. switchable capacitor banks provided on 132 KV bus of 220KV substation Narsinghpur and on 33KV buses of 132 KV substations
Power loss analysis of current-modules based multilevel current-source power ...TELKOMNIKA JOURNAL
A power loss analysis of multilevel current-source inverter (MCSI) circuits developed from two basic configurations of three-level current-source inverters, i.e. H-bridge and common-emitter inverter configurations is presented and discussed. The first circuit topology of the MCSI is developed by using DC current modules connected to the primary three-level H-bridge inverter. The second MCSI circuit is created by connecting the current-modules to a three-level common-emitter inverter. The DC current modules work generating the intermediate level waveform of the inverter circuits. Power loss analysis of the both topologies was carried out to explore the efficiency performance of the inverter circuits. The results showed that for the H-bridge and common-emitter MCSI using DC current modules, the amount of conduction losses in the inverter circuits could be diminished when the level number of AC output current increase. The measurement test results have also proved that using these MCSI topologies, the power conversion efficiency will also increase.
Universal demand for power increases due to continuous development to fulfil all these demand. Resources
are used with optimization. A high efficiency and high power factor converters are the major parts of energy
transfer system. This paper present a general review on single stage forward and flyback converter topologies to get
better its performance. This is paper presents a kind general idea of increasing efficiency and power factor of single
stage forward and fly back converter.
A DC Inrush Current Minimisation Method using Modified Z-Source Inverter in A...IAES-IJPEDS
The adjustable speed drives employ PWM converter-inverter system in order
to obtain unity power factor. The DC inrush current in DC link capacitors of
the rectifier limits the operation of power devices. Hence, this paper proposes
a new approach to reduce the DC inrush current by employing modified
Z-source inverter in a Adjustable Speed Drive system. The operating
principles, design procedure and simulation results are shown and compared
with the conventional Z-Source inverter.
This paper presents a combined operation of the Unified Power Quality Conditioner (UPQC) with Fuel cell system (FC). The proposed system consists of a series inverter, a shunt inverter and a Fuel cell that is connected with the DC link of UPQC through a back boost converter, where it is a SEPIC converter. The mean purpose for using the SEPIC converter is ensuring a constant DC link voltage value and to make the FC system intervening only in the case when the DC link energy is insufficient. Excepting this case, the FC system will be in the standby state. To validate the proposed topology, several sags of source voltage have been applied, at the point of common coupling (PCC).The simulation results from MATLAB/SIMULINK are discussed to verify the proposed topology.
Time Response enhancement utilizing photovoltaic based cascaded Landsman Converter (LC) structure is one of the soft strategies in the recent scenario. The prime function of a DC-DC Landsman converter is to optimize the output power of the photovoltaic array and reduce the output voltage ripples. This paper reveals the demonstration and simulation of the Cascaded Landsman Converter Inverter System (CLCIS) with a PV source. MATLAB Simulink-model for CLCIS has been created utilizing the components of Simulink and closed-loop examinations are performed with PI and Fractional-Order-PID (FOPID) Controllers. The present work deal with the comparison of transient and steady-state time responses of CLCIS with PI and FOPID controllers. The outcomes demonstrate that dynamic reaction is enhanced by utilizing FOPID controller.
Reactive Power Compensation and Control via Shunt Reactors and Under Ground P...IJERA Editor
In this paper we will cover the techniques used locally to accomplish the reactive power compensation. First, the importance of reactive power compensation is explained through defining the different types of electrical power and showing the effect of power compensation on the electric power network quality. The power under ground cable is the first technique used to compensate for the inductance of overhead transmission lines and power transformers during heavy loading of the network. Then, we explore the application of the two types of shunt reactors in different locations of the network to compensate for the capacitance of the network during light loading. Finally, a conclusion is presented.
Improving the Stability of Cascaded DC Power Supply System by Adaptive Active...IJMER
Abstract: When all links are changes in the cascade is the corner of the shape in the dc division
energy orbit (DEO). When resistances are intermission betwixt one by one stylish changes in that
would possibly end up so the cascaded orbits are unsteady. They are antecedent we can place in a
nearer to the useful in the cascaded orbit can be got in compelled to vary the supply they have load
changes in the internal structure of the same regions in the electrical device they can be opposed in
a quality of the characteristic of dc DEO. Throughout the Associate in nursing adaptation active
device in the (AACC) we can know another determined in the cascaded orbit. Therefore the AACC
was connected by side by side in the cascaded orbit’s they can mediate in between the carries and
completely a requirement of a notice then they carries the voltage with none modification in this
subsystems. Then it will have a stylish to the customary have basic units to measuring in the dc
DEO. When the AACC is additionally a similar bus device to cut back the output resistance of the
supply device, therefore averting in a interiority have their load changes in the input resistance, of
the cascaded orbit have their solutions then they becomes constant. We have important carrier
device it will computing in the AACC adaptation in line with they have output energy to the
cascaded orbit, they have energy vesting in the AACC that’s way they will reduced and therefore
they have a lot of energy in a reacting to the orbit so it is a best in the orbit of a submissive device.
What\'s many, since no capacitance have a requirement among an AACC, when the cascaded orbits
have their quantity of it slowly it will extend in time. They have activity fundamental truth to stop
their magnificence thought in the AACC are mentioned throughout of this project, it can have four
thousand eight hundred and zero watts cascaded orbit was contain a strive of process to move in a
full-bridge changes they can be styli shed and evaluated. So when the simulation solutions have to
clear the performance of the arrangement of AACC.
Voltage Control of Dual Active Bridge Converter for CO-Amorphous Core Materia...kuldeep12555
Solid-State Transformer (SST) provides versatile power system operation. In the smart world, there are technologies where everything is incorporated that reduce the size and eventually save time in delivering a fast process. It has been seen that solid-state transformer voltage begins to decrease during operation that needs to be regulated through some control strategy. In this paper, a Dual Active Bridge (DAB) converter has been used to control the voltage of SST that employs the Single-Phase Shift (SPS) technique. For further efficiency improvement Co73(Si, B)27 co-amorphous material has been used for the core of SST because co-amorphous alloy has much lower loss compared with Fe-amorphous cores and have limited saturation flux density. Real-time parameters of core have been used in the analysis. It has been evident from the results that DAB dc-dc converter-based SST with SPS control technique is simple and offers better performance compared to stand-alone SST. It improves the overall performance and efficiency of the system. This paper has been accomplished in Matlab® / Simulink environment.
Keywords: Co73 (Si, B)27 Amorphous Core Material; Solid-State transformer (SST); Dual Active Bridge (DAB); High
voltage (HV) Application.
International Journal of Engineering Research and Applications (IJERA) aims to cover the latest outstanding developments in the field of all Engineering Technologies & science.
International Journal of Engineering Research and Applications (IJERA) is a team of researchers not publication services or private publications running the journals for monetary benefits, we are association of scientists and academia who focus only on supporting authors who want to publish their work. The articles published in our journal can be accessed online, all the articles will be archived for real time access.
Our journal system primarily aims to bring out the research talent and the works done by sciaentists, academia, engineers, practitioners, scholars, post graduate students of engineering and science. This journal aims to cover the scientific research in a broader sense and not publishing a niche area of research facilitating researchers from various verticals to publish their papers. It is also aimed to provide a platform for the researchers to publish in a shorter of time, enabling them to continue further All articles published are freely available to scientific researchers in the Government agencies,educators and the general public. We are taking serious efforts to promote our journal across the globe in various ways, we are sure that our journal will act as a scientific platform for all researchers to publish their works online.
Single-Phase Inverter with Energy Buffer and DC-DC Conversion CircuitsAsoka Technologies
This paper proposes a new single-phase inverter topology and describes the control method for the proposed inverter. The inverter consists of an energy buffer circuit, a dc-dc conversion circuit and an H-bridge circuit. The energy buffer circuit and H-bridge circuit enable the proposed inverter to output a multilevel voltage according to the proposed pulse width modulation (PWM) technique. The dc-dc conversion circuit can charge the buffer capacitor continuously because the dc-dc conversion control cooperates with the PWM. Simulation results confirm that the proposed inverter can reduce the voltage harmonics in the output and the dc-dc conversion current in comparison to a conventional inverter consisting of a dc-dc conversion circuit and H-bridge circuit. Experiments demonstrate that the proposed inverter can output currents of low total harmonic distortion and have higher efficiency than the conventional inverter. In addition, it is confirmed that these features of the proposed inverter contribute to the suppression of the circuit volume in spite of the increase in the number of devices in the circuit.
Saturated core fault current limiter field experience at a distribution subst...Franco Moriconi
Zenergy Power has been developing an inductive-type of
fault current limiter (FCL) for electric power grid
applications. In March 2009 Zenergy Power installed a
FCL in the Avanti distribution circuit of Southern
California Edison’s Shandin substation in San Bernardino,
CA, rated at 15 kV and 1,200 amperes steady-state. In
January 2010, this device successfully limited its first series
of real-world faults when the circuit experienced multiple
single-phase and three-phase faults. Zenergy Power also
received contracts to deliver an 11 kV, 1,250 amperes FCL
for the CE Electric UK grid and a 138 kV, 1,300 amperes
FCL for the Tidd substation of American Electric Power.
Modeling and test validation of a 15 kV - 24 MVA superconducting fault curren...Franco Moriconi
High-power short-circuit test results and numerical simulations of a 15kV–24MVA distribution-class High Temperature Superconductor (HTS) Fault Current Limiters (FCL) are presented and compared in this paper. The FCL design was based on the nonlinear inductance model here described, and the device was tested at 13.1kV line-to-line voltage for prospective fault currents up to 23kArms, prior to its installation in the electric grid. Comparison between numerical simulations and fault test measurements show good agreement. Some simulations and field testing results are depicted. The FCL was energized in the Southern California Edison grid on March 9, 2009.
A ZVS Interleaved Boost AC/DC Converter Using Super Capacitor Power for Hybri...IJMER
International Journal of Modern Engineering Research (IJMER) is Peer reviewed, online Journal. It serves as an international archival forum of scholarly research related to engineering and science education.
Assessment of the Static Stability Margin and Voltage Profile Improvement in ...Dr. Amarjeet Singh
The huge increase in the demand of electric power and the economic constraints to build new facilities, lead the power systems to operate near of their stability limits. Indeed, instability has become a major problem in the management of power systems. Unavoidable disturbances such as short circuits, momentary unavailability of transmission lines, generators as well as transformers can affect the stability of the power system at any time and bring it into a state of instability or collapse. These collapses become a major problem for energy consumers, because the lack of energy leads them to use backup energy sources that are relatively expensive and polluting. This situation lowers the productivity of the industry, and for the national electric company of the Congo, (SNEL), the time to get rid of the magnetization of the network and to take all the loads, can generate penalties, which is a loss of revenue for the company. This paper aims to assess the stability margin and to improve the quality of electrical energy in the south-SNEL transmission system.
Reactive Power Compensation in 132kv & 33kv Grid of Narsinghpur Areaijceronline
Power Sector is considered to be very important and priority sector as it leads to overall development of country. The cost of installation of new generating units is rising; hence generated electrical energy has to be utilized carefully and efficiently, which changes through each AC cycle. It is proposed to study the effect of group shunt compensation provided for the mix of rural and urban loads, catered from grid sub-stations in the district of Narsinghpur, to assess its adequacy and saving in transmission losses. An optimum combination of compensators which yields maximum benefits in the system shall be worked out. Load Flow Study for the effect of group shunt compensation provided on 132KV bus of 220KV sub-station Narsinghpur and on 33KV buses of 132KV sub stations Srinagar, Narsinghpur, Gadarwara and Burman sub-stations for the mix of rural and urban loads, catered from partial grid network in Narsinghpur district. If reactive power is supplied near the load, the line current can be reduced or minimized, reducing power losses and improving voltage regulation at the load terminals. The leading current drawn by the shunt capacitors compensates the lagging current drawn by the load. The selection of shunt capacitors depends on many factors, the most important of which is the amount of lagging reactive power taken by the load. Objective was to study the effect of group shunt compensation provided for the mix of rural and urban loads, catered from grid sub-stations in the district of Narsinghpur and to assess the adequacy and saving in transmission losses & to work out an optimum combination of compensators which yields maximum benefits in the system. Depending on the stages of 'ON' and 'OFF', operations to be carried out in various permutations and combinations of shunt compensators i.e. switchable capacitor banks provided on 132 KV bus of 220KV substation Narsinghpur and on 33KV buses of 132 KV substations
Power loss analysis of current-modules based multilevel current-source power ...TELKOMNIKA JOURNAL
A power loss analysis of multilevel current-source inverter (MCSI) circuits developed from two basic configurations of three-level current-source inverters, i.e. H-bridge and common-emitter inverter configurations is presented and discussed. The first circuit topology of the MCSI is developed by using DC current modules connected to the primary three-level H-bridge inverter. The second MCSI circuit is created by connecting the current-modules to a three-level common-emitter inverter. The DC current modules work generating the intermediate level waveform of the inverter circuits. Power loss analysis of the both topologies was carried out to explore the efficiency performance of the inverter circuits. The results showed that for the H-bridge and common-emitter MCSI using DC current modules, the amount of conduction losses in the inverter circuits could be diminished when the level number of AC output current increase. The measurement test results have also proved that using these MCSI topologies, the power conversion efficiency will also increase.
Universal demand for power increases due to continuous development to fulfil all these demand. Resources
are used with optimization. A high efficiency and high power factor converters are the major parts of energy
transfer system. This paper present a general review on single stage forward and flyback converter topologies to get
better its performance. This is paper presents a kind general idea of increasing efficiency and power factor of single
stage forward and fly back converter.
A DC Inrush Current Minimisation Method using Modified Z-Source Inverter in A...IAES-IJPEDS
The adjustable speed drives employ PWM converter-inverter system in order
to obtain unity power factor. The DC inrush current in DC link capacitors of
the rectifier limits the operation of power devices. Hence, this paper proposes
a new approach to reduce the DC inrush current by employing modified
Z-source inverter in a Adjustable Speed Drive system. The operating
principles, design procedure and simulation results are shown and compared
with the conventional Z-Source inverter.
This paper presents a combined operation of the Unified Power Quality Conditioner (UPQC) with Fuel cell system (FC). The proposed system consists of a series inverter, a shunt inverter and a Fuel cell that is connected with the DC link of UPQC through a back boost converter, where it is a SEPIC converter. The mean purpose for using the SEPIC converter is ensuring a constant DC link voltage value and to make the FC system intervening only in the case when the DC link energy is insufficient. Excepting this case, the FC system will be in the standby state. To validate the proposed topology, several sags of source voltage have been applied, at the point of common coupling (PCC).The simulation results from MATLAB/SIMULINK are discussed to verify the proposed topology.
Time Response enhancement utilizing photovoltaic based cascaded Landsman Converter (LC) structure is one of the soft strategies in the recent scenario. The prime function of a DC-DC Landsman converter is to optimize the output power of the photovoltaic array and reduce the output voltage ripples. This paper reveals the demonstration and simulation of the Cascaded Landsman Converter Inverter System (CLCIS) with a PV source. MATLAB Simulink-model for CLCIS has been created utilizing the components of Simulink and closed-loop examinations are performed with PI and Fractional-Order-PID (FOPID) Controllers. The present work deal with the comparison of transient and steady-state time responses of CLCIS with PI and FOPID controllers. The outcomes demonstrate that dynamic reaction is enhanced by utilizing FOPID controller.
Reactive Power Compensation and Control via Shunt Reactors and Under Ground P...IJERA Editor
In this paper we will cover the techniques used locally to accomplish the reactive power compensation. First, the importance of reactive power compensation is explained through defining the different types of electrical power and showing the effect of power compensation on the electric power network quality. The power under ground cable is the first technique used to compensate for the inductance of overhead transmission lines and power transformers during heavy loading of the network. Then, we explore the application of the two types of shunt reactors in different locations of the network to compensate for the capacitance of the network during light loading. Finally, a conclusion is presented.
Improving the Stability of Cascaded DC Power Supply System by Adaptive Active...IJMER
Abstract: When all links are changes in the cascade is the corner of the shape in the dc division
energy orbit (DEO). When resistances are intermission betwixt one by one stylish changes in that
would possibly end up so the cascaded orbits are unsteady. They are antecedent we can place in a
nearer to the useful in the cascaded orbit can be got in compelled to vary the supply they have load
changes in the internal structure of the same regions in the electrical device they can be opposed in
a quality of the characteristic of dc DEO. Throughout the Associate in nursing adaptation active
device in the (AACC) we can know another determined in the cascaded orbit. Therefore the AACC
was connected by side by side in the cascaded orbit’s they can mediate in between the carries and
completely a requirement of a notice then they carries the voltage with none modification in this
subsystems. Then it will have a stylish to the customary have basic units to measuring in the dc
DEO. When the AACC is additionally a similar bus device to cut back the output resistance of the
supply device, therefore averting in a interiority have their load changes in the input resistance, of
the cascaded orbit have their solutions then they becomes constant. We have important carrier
device it will computing in the AACC adaptation in line with they have output energy to the
cascaded orbit, they have energy vesting in the AACC that’s way they will reduced and therefore
they have a lot of energy in a reacting to the orbit so it is a best in the orbit of a submissive device.
What\'s many, since no capacitance have a requirement among an AACC, when the cascaded orbits
have their quantity of it slowly it will extend in time. They have activity fundamental truth to stop
their magnificence thought in the AACC are mentioned throughout of this project, it can have four
thousand eight hundred and zero watts cascaded orbit was contain a strive of process to move in a
full-bridge changes they can be styli shed and evaluated. So when the simulation solutions have to
clear the performance of the arrangement of AACC.
Voltage Control of Dual Active Bridge Converter for CO-Amorphous Core Materia...kuldeep12555
Solid-State Transformer (SST) provides versatile power system operation. In the smart world, there are technologies where everything is incorporated that reduce the size and eventually save time in delivering a fast process. It has been seen that solid-state transformer voltage begins to decrease during operation that needs to be regulated through some control strategy. In this paper, a Dual Active Bridge (DAB) converter has been used to control the voltage of SST that employs the Single-Phase Shift (SPS) technique. For further efficiency improvement Co73(Si, B)27 co-amorphous material has been used for the core of SST because co-amorphous alloy has much lower loss compared with Fe-amorphous cores and have limited saturation flux density. Real-time parameters of core have been used in the analysis. It has been evident from the results that DAB dc-dc converter-based SST with SPS control technique is simple and offers better performance compared to stand-alone SST. It improves the overall performance and efficiency of the system. This paper has been accomplished in Matlab® / Simulink environment.
Keywords: Co73 (Si, B)27 Amorphous Core Material; Solid-State transformer (SST); Dual Active Bridge (DAB); High
voltage (HV) Application.
International Journal of Engineering Research and Applications (IJERA) aims to cover the latest outstanding developments in the field of all Engineering Technologies & science.
International Journal of Engineering Research and Applications (IJERA) is a team of researchers not publication services or private publications running the journals for monetary benefits, we are association of scientists and academia who focus only on supporting authors who want to publish their work. The articles published in our journal can be accessed online, all the articles will be archived for real time access.
Our journal system primarily aims to bring out the research talent and the works done by sciaentists, academia, engineers, practitioners, scholars, post graduate students of engineering and science. This journal aims to cover the scientific research in a broader sense and not publishing a niche area of research facilitating researchers from various verticals to publish their papers. It is also aimed to provide a platform for the researchers to publish in a shorter of time, enabling them to continue further All articles published are freely available to scientific researchers in the Government agencies,educators and the general public. We are taking serious efforts to promote our journal across the globe in various ways, we are sure that our journal will act as a scientific platform for all researchers to publish their works online.
Single-Phase Inverter with Energy Buffer and DC-DC Conversion CircuitsAsoka Technologies
This paper proposes a new single-phase inverter topology and describes the control method for the proposed inverter. The inverter consists of an energy buffer circuit, a dc-dc conversion circuit and an H-bridge circuit. The energy buffer circuit and H-bridge circuit enable the proposed inverter to output a multilevel voltage according to the proposed pulse width modulation (PWM) technique. The dc-dc conversion circuit can charge the buffer capacitor continuously because the dc-dc conversion control cooperates with the PWM. Simulation results confirm that the proposed inverter can reduce the voltage harmonics in the output and the dc-dc conversion current in comparison to a conventional inverter consisting of a dc-dc conversion circuit and H-bridge circuit. Experiments demonstrate that the proposed inverter can output currents of low total harmonic distortion and have higher efficiency than the conventional inverter. In addition, it is confirmed that these features of the proposed inverter contribute to the suppression of the circuit volume in spite of the increase in the number of devices in the circuit.
Saturated core fault current limiter field experience at a distribution subst...Franco Moriconi
Zenergy Power has been developing an inductive-type of
fault current limiter (FCL) for electric power grid
applications. In March 2009 Zenergy Power installed a
FCL in the Avanti distribution circuit of Southern
California Edison’s Shandin substation in San Bernardino,
CA, rated at 15 kV and 1,200 amperes steady-state. In
January 2010, this device successfully limited its first series
of real-world faults when the circuit experienced multiple
single-phase and three-phase faults. Zenergy Power also
received contracts to deliver an 11 kV, 1,250 amperes FCL
for the CE Electric UK grid and a 138 kV, 1,300 amperes
FCL for the Tidd substation of American Electric Power.
Modeling and test validation of a 15 kV - 24 MVA superconducting fault curren...Franco Moriconi
High-power short-circuit test results and numerical simulations of a 15kV–24MVA distribution-class High Temperature Superconductor (HTS) Fault Current Limiters (FCL) are presented and compared in this paper. The FCL design was based on the nonlinear inductance model here described, and the device was tested at 13.1kV line-to-line voltage for prospective fault currents up to 23kArms, prior to its installation in the electric grid. Comparison between numerical simulations and fault test measurements show good agreement. Some simulations and field testing results are depicted. The FCL was energized in the Southern California Edison grid on March 9, 2009.
Resonance of a distribution feeder with a saturable core fault current limiterFranco Moriconi
Simulations of a resonance event were performed based on actual field data of a commercially operating distribution feeder and a superconducting saturable core fault current limiter. The analysis was conducted from both the system's and the fault current limiter's perspectives. Agreement in the results of the two approaches showed that under certain values of reactive shunt compensation, full insertion of the limiter's reactance, and low load conditions, a sustained but damped resonance can occur. Resonance suppression preventive measures for these conditions are proposed.
Transient Recovery Voltage Test Results of a 25 MVA Saturable-Core Fault Curr...Franco Moriconi
Test results obtained during fault current interruption tests with an air-core reactor are compared to test results obtained using a saturating-core inductive HTS Fault Current Limiter in the same circuit under the same circumstances. These test results are further compared with analytical simulations developed using the PSCAD® software suite. The simulations exhibit good agreement with the test results and confirm that compared to an equivalent air-core reactor, the HTS FCL results in lower amplitude and significantly lower rate of rise of the Transient Recovery Voltage.
An innovative compact saturable-core HTS Fault Current Limiter - development,...Franco Moriconi
The development and testing of an innovative and compact saturating-reactor High Temperature Superconductor Fault Current Limiter (HTS FCL) is described. The development includes an initial dry-type magnetic core design with iron cores partially encircled by an HTS DC coil and a recently completed oil-immersed design with magnetic cores enclosed in a metallic tank placed inside the warm bore of a rectangular HTS DC magnet. The first 15 kV HTS FCL was installed in Southern California Edison’s grid in 2009 and the first transmission-class 138 kV Compact HTS FCL is planned to be in operation in American Electric Power’s grid in 2011.
Design, Test and Demonstration of Saturable Reactor High-Temperature Supercon...Franco Moriconi
Zenergy Power has successfully designed, built, tested, and installed in the US electrical grid a saturable reactor Fault Current Limiter. Beginning in 2007, first as SC Power Systems and from 2008 as Zenergy Power, Inc., ZP used DOE matching grant and ARRA funds to help refine the design of the saturated reactor fault current limiter.
International Journal of Engineering Research and Development (IJERD)IJERD Editor
journal publishing, how to publish research paper, Call For research paper, international journal, publishing a paper, IJERD, journal of science and technology, how to get a research paper published, publishing a paper, publishing of journal, publishing of research paper, reserach and review articles, IJERD Journal, How to publish your research paper, publish research paper, open access engineering journal, Engineering journal, Mathemetics journal, Physics journal, Chemistry journal, Computer Engineering, Computer Science journal, how to submit your paper, peer reviw journal, indexed journal, reserach and review articles, engineering journal, www.ijerd.com, research journals,
yahoo journals, bing journals, International Journal of Engineering Research and Development, google journals, hard copy of journal
PV Cell Fed High Step-up DC-DC Converter for PMSM Drive ApplicationsIJMTST Journal
In this concept novel high step-up dc–dc converter with an active coupled-inductor network is presented for
a sustainable energy system. The proposed converter contains two coupled inductors which can be
integrated into one magnetic core and two switches. The primary sides of coupled inductors are charged in
parallel by the input source, and both the coupled inductors are discharged in series with the input source to
achieve the high step-up voltage gain with appropriate duty ratio, respectively. In addition, the passive
lossless clamped circuit not only recycles leakage energies of the coupled inductor to improve efficiency but
also alleviates large voltage spike to limit the voltage stresses of the main switches. The reverse-recovery
problem of the output diode is also alleviated by the leakage inductor and the lower part count is needed;
therefore, the power conversion efficiency can be further upgraded. The voltage conversion ratios, the effect of
the leakage inductance and the parasitic parameters on the voltage gain are discussed. The voltage stress
and current stress on the power devices are illustrated and the comparisons between the proposed converter
and other converters are given. The simulation results are presented by using Mat lab/Simulink software.
Power factor correction the easiest, biggest, green initiativeRoss Welsh V.A.
Poor power factor costs our community in increased electricity charges and unnecessary
greenhouse gases. Incentives for customers to maintain the required power factor varies across
Australia fromthose that are charged a penaltyby wayofa kilovoltamperes(kVA) demand charge
to those that should comply with the local service rules, legislated or National Electricity Rules
requirements.
Single core configurations of saturated core fault current limiter performanc...IJECEIAES
Economic growth with industrialization and urbanization lead to an extensive increase in power demand. It forced the utilities to add power generating facilities to cause the necessary demand-generation balance. The bulk power generating stations, mostly interconnected, with the penetration of distributed generation result in an enormous rise in the fault level of power networks. It necessitates for electrical utilities to control the fault current so that the existing switchgear can continue its services without upgradation or replacement for reliable supply. The deployment of fault current limiter (FCL) at the distribution and transmission networks has been under investigation as a potential solution to the problem. A saturated core fault current limiter (SCFCL) technology is a smart, scalable, efficient, reliable, and commercially viable option to manage fault levels in existing and future MV/HV supply systems. This paper presents the comparative performance analysis of two single-core SCFCL topologies impressed with different core saturations. It has demonstrated that the single AC winding configuration needs more bias power for affecting the same current limiting performance with an acceptable steady-state voltage drop contribution. The fault state impedance has a transient nature, and the optimum bias selection is a critical design parameter in realizing the SCFCL applications.
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.
TCSC AND SVC OPTIMAL LOCATION TO IMPROVE THE PERFORMANCE OF POWER SYSTEM WITH...eeiej_journal
Wind generation connection to power system affects steady state and transient stability. Furthermore, this
effect increases with the increase of wind penetration in generation capacity. In this paper optimal location
of FACTS devices is carried out to solve the steady state problems of wind penetration. Two case studies
are carried out on modified IEEE39 bus system one with wind reduction to 20% and the second with wind
penetration increase by 50% in the two cases system suffer from outage of one generator with load at bus
39 decreases from 1104 MW to 900 MW.
APPENDICES California Energy Commission 500-2013-134-APPENDIXESFranco Moriconi
APPENDIX A: Zenergy Power HTS FCL Test Plan APPENDIX B: Zenergy Power HTS FCL Laboratory Test APPENDIX C: Zenergy Power HTS FCL Dielectric and HV Tests
APPENDIX D: Zenergy Power HTS FCL Normal State Temperature Rise Test
APPENDIX E: Zenergy Power HTS FCL Short Circuit Test APPENDIX F: Zenergy Power HTS FCL High Voltage Field Test
APPENDIX G: Zenergy Power HTS FCL Operation Manual APPENDIX H: Zenergy Power HTS FCL Cryostat Evacuation and Moisture Removal Procedure
APPENDIX I: Zenergy Power HTS FCL Liquid Nitrogen Fill Procedure
Inductive shielded superconducting fault current limiter: test results for sc...Franco Moriconi
Results of measurements with a downscaled model of a novel superconducting inductive Shielded Fault Current Limiter (iSFCL) based on 2nd generation HTS material are reported. Two different types of models were tested, one with an open iron core and one with a closed iron core. The operational characteristics of both systems with focus on the superconducting secondary modules in normal operation and in quenching mode with quench times of up to 500 ms are analyzed. The HTS modules are based on 40 mm wide YBCO coated conductors with a high-ohmic protection layer and an external shunt system. Further development/testing program includes a 3-phase-field trial, where a full scale technology demonstrator (15-MVA class) will be integrated in the distribution grid of the utility Stadtwerke Augsburg in Germany. This joint project of Schneider Electric, Bruker HTS, Bruker Advanced Supercon and Stadtwerke Augsburg is supported by the German Federal Ministry of Economics and Technology (BMWi)
GraphRAG is All You need? LLM & Knowledge GraphGuy Korland
Guy Korland, CEO and Co-founder of FalkorDB, will review two articles on the integration of language models with knowledge graphs.
1. Unifying Large Language Models and Knowledge Graphs: A Roadmap.
https://arxiv.org/abs/2306.08302
2. Microsoft Research's GraphRAG paper and a review paper on various uses of knowledge graphs:
https://www.microsoft.com/en-us/research/blog/graphrag-unlocking-llm-discovery-on-narrative-private-data/
Epistemic Interaction - tuning interfaces to provide information for AI supportAlan Dix
Paper presented at SYNERGY workshop at AVI 2024, Genoa, Italy. 3rd June 2024
https://alandix.com/academic/papers/synergy2024-epistemic/
As machine learning integrates deeper into human-computer interactions, the concept of epistemic interaction emerges, aiming to refine these interactions to enhance system adaptability. This approach encourages minor, intentional adjustments in user behaviour to enrich the data available for system learning. This paper introduces epistemic interaction within the context of human-system communication, illustrating how deliberate interaction design can improve system understanding and adaptation. Through concrete examples, we demonstrate the potential of epistemic interaction to significantly advance human-computer interaction by leveraging intuitive human communication strategies to inform system design and functionality, offering a novel pathway for enriching user-system engagements.
UiPath Test Automation using UiPath Test Suite series, part 4DianaGray10
Welcome to UiPath Test Automation using UiPath Test Suite series part 4. In this session, we will cover Test Manager overview along with SAP heatmap.
The UiPath Test Manager overview with SAP heatmap webinar offers a concise yet comprehensive exploration of the role of a Test Manager within SAP environments, coupled with the utilization of heatmaps for effective testing strategies.
Participants will gain insights into the responsibilities, challenges, and best practices associated with test management in SAP projects. Additionally, the webinar delves into the significance of heatmaps as a visual aid for identifying testing priorities, areas of risk, and resource allocation within SAP landscapes. Through this session, attendees can expect to enhance their understanding of test management principles while learning practical approaches to optimize testing processes in SAP environments using heatmap visualization techniques
What will you get from this session?
1. Insights into SAP testing best practices
2. Heatmap utilization for testing
3. Optimization of testing processes
4. Demo
Topics covered:
Execution from the test manager
Orchestrator execution result
Defect reporting
SAP heatmap example with demo
Speaker:
Deepak Rai, Automation Practice Lead, Boundaryless Group and UiPath MVP
PHP Frameworks: I want to break free (IPC Berlin 2024)Ralf Eggert
In this presentation, we examine the challenges and limitations of relying too heavily on PHP frameworks in web development. We discuss the history of PHP and its frameworks to understand how this dependence has evolved. The focus will be on providing concrete tips and strategies to reduce reliance on these frameworks, based on real-world examples and practical considerations. The goal is to equip developers with the skills and knowledge to create more flexible and future-proof web applications. We'll explore the importance of maintaining autonomy in a rapidly changing tech landscape and how to make informed decisions in PHP development.
This talk is aimed at encouraging a more independent approach to using PHP frameworks, moving towards a more flexible and future-proof approach to PHP development.
SAP Sapphire 2024 - ASUG301 building better apps with SAP Fiori.pdfPeter Spielvogel
Building better applications for business users with SAP Fiori.
• What is SAP Fiori and why it matters to you
• How a better user experience drives measurable business benefits
• How to get started with SAP Fiori today
• How SAP Fiori elements accelerates application development
• How SAP Build Code includes SAP Fiori tools and other generative artificial intelligence capabilities
• How SAP Fiori paves the way for using AI in SAP apps
Securing your Kubernetes cluster_ a step-by-step guide to success !KatiaHIMEUR1
Today, after several years of existence, an extremely active community and an ultra-dynamic ecosystem, Kubernetes has established itself as the de facto standard in container orchestration. Thanks to a wide range of managed services, it has never been so easy to set up a ready-to-use Kubernetes cluster.
However, this ease of use means that the subject of security in Kubernetes is often left for later, or even neglected. This exposes companies to significant risks.
In this talk, I'll show you step-by-step how to secure your Kubernetes cluster for greater peace of mind and reliability.
Welocme to ViralQR, your best QR code generator.ViralQR
Welcome to ViralQR, your best QR code generator available on the market!
At ViralQR, we design static and dynamic QR codes. Our mission is to make business operations easier and customer engagement more powerful through the use of QR technology. Be it a small-scale business or a huge enterprise, our easy-to-use platform provides multiple choices that can be tailored according to your company's branding and marketing strategies.
Our Vision
We are here to make the process of creating QR codes easy and smooth, thus enhancing customer interaction and making business more fluid. We very strongly believe in the ability of QR codes to change the world for businesses in their interaction with customers and are set on making that technology accessible and usable far and wide.
Our Achievements
Ever since its inception, we have successfully served many clients by offering QR codes in their marketing, service delivery, and collection of feedback across various industries. Our platform has been recognized for its ease of use and amazing features, which helped a business to make QR codes.
Our Services
At ViralQR, here is a comprehensive suite of services that caters to your very needs:
Static QR Codes: Create free static QR codes. These QR codes are able to store significant information such as URLs, vCards, plain text, emails and SMS, Wi-Fi credentials, and Bitcoin addresses.
Dynamic QR codes: These also have all the advanced features but are subscription-based. They can directly link to PDF files, images, micro-landing pages, social accounts, review forms, business pages, and applications. In addition, they can be branded with CTAs, frames, patterns, colors, and logos to enhance your branding.
Pricing and Packages
Additionally, there is a 14-day free offer to ViralQR, which is an exceptional opportunity for new users to take a feel of this platform. One can easily subscribe from there and experience the full dynamic of using QR codes. The subscription plans are not only meant for business; they are priced very flexibly so that literally every business could afford to benefit from our service.
Why choose us?
ViralQR will provide services for marketing, advertising, catering, retail, and the like. The QR codes can be posted on fliers, packaging, merchandise, and banners, as well as to substitute for cash and cards in a restaurant or coffee shop. With QR codes integrated into your business, improve customer engagement and streamline operations.
Comprehensive Analytics
Subscribers of ViralQR receive detailed analytics and tracking tools in light of having a view of the core values of QR code performance. Our analytics dashboard shows aggregate views and unique views, as well as detailed information about each impression, including time, device, browser, and estimated location by city and country.
So, thank you for choosing ViralQR; we have an offer of nothing but the best in terms of QR code services to meet business diversity!
UiPath Test Automation using UiPath Test Suite series, part 3DianaGray10
Welcome to UiPath Test Automation using UiPath Test Suite series part 3. In this session, we will cover desktop automation along with UI automation.
Topics covered:
UI automation Introduction,
UI automation Sample
Desktop automation flow
Pradeep Chinnala, Senior Consultant Automation Developer @WonderBotz and UiPath MVP
Deepak Rai, Automation Practice Lead, Boundaryless Group and UiPath MVP
DevOps and Testing slides at DASA ConnectKari Kakkonen
My and Rik Marselis slides at 30.5.2024 DASA Connect conference. We discuss about what is testing, then what is agile testing and finally what is Testing in DevOps. Finally we had lovely workshop with the participants trying to find out different ways to think about quality and testing in different parts of the DevOps infinity loop.
Assure Contact Center Experiences for Your Customers With ThousandEyes
Development and Deployment of Saturated-Core Fault Current Limiters in Distribution and Transmission Substations
1. ASC 2010 preprint 2LY-01 submitted to IEEE Transactions on Applied Superconductivity 1
Abstract—Zenergy Power has been developing an inductive-
type of fault current limiter (FCL) for electric power grid
applications. The FCL employs a magnetically saturating
reactor concept which acts as a variable inductor in an electric
circuit. In March 2009 Zenergy Power, with funding from the
California Energy Commission and the U.S. Department of
Energy (DOE), installed an FCL in the Avanti distribution
circuit of Southern California Edison’s Shandin substation in
San Bernardino, CA. Rated at 15 kV and 1,250 amperes steady-
state, the “Avanti” device is the first superconductor FCL
installed in a US utility. In January 2010, the “Avanti” device
successfully limited its first series of real-world faults when the
circuit experienced multiple single-phase and three-phase faults.
After successfully validating the performance of a new
“compact” saturated-core FCL, Zenergy Power received
contracts to install a 12 kV, 1,250 amperes compact FCL in the
CE Electric UK grid in early 2011 and a 138 kV, 1,300 amperes
FCL at the Tidd substation of American Electric Power in late
2011.
Index Terms—fault current limiters, high-temperature
superconductors, saturable cores, short circuit currents,
superconducting magnets
I. INTRODUCTION
INCE 2006, Zenergy Power, Inc. (ZEN) has been
developing an inductive type of high-temperature
superconductor (HTS) fault current limiter (FCL) for electric
power grid applications. The HTS FCL employs a
magnetically saturating reactor concept which acts as a
variable inductor in an electric circuit. The inductance of the
HTS FCL changes instantly in real-time in response to the
current in the electrical circuit being protected and varies from
a low steady-state value of inductance during normal
operating conditions to a high value of inductance during a
fault condition that is sufficient to limit the fault current to the
desired maximum value. HTS fault current limiting concepts
have been extensively reported to date [1-5].
Manuscript received 3 August 2010. This work was supported in part by
the California Energy Commission and the U.S. Department of Energy.
F. Moriconi, F. De La Rosa, A. Nelson, and L. Masur are with Zenergy
Power Inc., Burlingame, CA 94010 USA (650-259-5700; e-mail:
larry.masur@zenergypower.com).
F. Darmann is with Zenergy Power Pty Ltd., Wollongong, NSW 2500
Australia. (e-mail: frank.darmann@zenergypower.com).
II. BACKGROUND
Unlike resistive and shielded core FCLs that rely on the
quenching of superconductors to achieve increased
impedance, saturable core FCLs utilize the dynamic behavior
in the magnetic properties of iron to change the inductive
reactance on the ac line. Referring to Fig. 1, one can see that
there are two rectangular iron cores arranged side-by-side.
The iron cores are surrounded by a single HTS coil that
encircles the adjacent inner limbs of the iron cores in the
middle. A small DC power supply energizes the HTS coil
with a DC bias current to create a very strong DC magnetic
field that magnetically biases and saturates the iron cores.
Conventional copper AC coils are wound on the outer limbs of
the iron cores. The AC coils are connected in series to the
electrical circuit that is to be protected. These AC coils are
wound in opposite magnetic “sense,” so that using this
arrangement a single-phase device can be made in which each
of the rectangular iron cores acts independently during each
positive and negative half-cycle of the AC line current.
Fig. 1 – The Basic Saturating Reactor FCL Concept Diagram
When the AC circuit is energized and the AC line current is
flowing at normal values, the iron is highly saturated and has a
low relative permeability. To the ac coils, the iron acts like
air, so the ac impedance is small. When an AC fault occurs,
the AC amp-turns generated by the AC coils increase linearly
with the fault current to force the iron core out of saturation,
resulting in increased line impedance during part of each half-
cycle. The result is a considerable reduction in peak fault
current. Essentially, the saturable core type FCL is a variable-
inductance, iron-core reactor [6].
Fig. 2 shows the FCL equivalent inductance as a function of
the instantaneous line current. Around the bias point (at
Development and Deployment of Saturated-
Core Fault Current Limiters in Distribution and
Transmission Substations
Franco Moriconi, Francisco De La Rosa, Senior Member, IEEE, Frank Darmann, Albert Nelson,
Member, IEEE, and Larry Masur, Member, IEEE
S
2. ASC 2010 preprint 2LY-01 submitted to IEEE Transactions on Applied Superconductivity 2
current zero) the inductance is that of an air core reactor, and
therefore small. As the line current increases due to a fault,
the inductance increases substantially and instantaneously,
generating the desired limiting effect.
Fig. 3 compares a variable inductor FCL to a conventional
current limiting reactor. For equivalent impedance at nominal
rating, the FCL can achieve impedance gains of the order of 4
or 5 times that of a current limiting reactor. Similarly, an FCL
that has the equivalent limiting capability of a current limiting
reactor will have only 20% to 25% of the voltage losses as a
current limiting reactor at nominal rating.
-15.0 -10.0 -5.0 0.0 5.0 10.0 15.0
-0.0010
0.0000
0.0010
0.0020
0.0030
0.0040
0.0050
0.0060
+y
-y
-x +x
X Coordinate Y Coordinate
I_Limited L_cus
Equivalent Inductance [Henry]
Instantaneous AC Current [kA]
Fig. 2 – The FCL equivalent inductance illustrating low inductance at small
currents and non-linear increase of inductance at high currents.
Fig. 3 – Comparison of saturable-core FCL to conventional current limiting
reactor (CLR) illustrating impedance gain of 4 to 5 for the FCL.
From the simple schematic in Fig. 1, it is easy to envisin a
three-phase HTS FCL using a single HTS DC bias coil. Fig. 4
shows an arrangement in which three single-phase devices are
arranged radially with their corresponding inner core limbs
inside a single cryostat (silver cylinder) containing the HTS
DC bias magnet. The copper AC coils (red cylinders) are
located on the outer limbs of the iron cores and spaced
equidistantly. This arrangement constituted the basic design
for the ZEN FCL and was used to construct the FCL device
installed at Southern California Edison. A similar design is
employed in an installation in China by Innopower [7].
III. THE FCL AT SOUTHERN CALIFORNIA EDISON
With the support of the California Energy Commission
(CEC) and the U.S. Department of Energy (DOE), this device,
known as the CEC FCL, became the first HTS FCL in
commercial service in the United States on March 9, 2009
when it was placed in the Avanti Circuit (otherwise known as
the “Circuit of the Future”) in the Southern California Edison
(SCE) Company’s Shandin substation in San Bernardino,
California. The “Circuit of the Future” is an actual
commercial 12.47 kV distribution circuit with real residential,
commercial and light-industrial customers that has been
established by SCE, CEC and DOE to demonstrate innovative
technologies of potential value in the modern electric grid.
Fig. 4 – A three-phase saturating reactor HTS FCL with a single HTS DC bias
coil
The CEC FCL employs cast-epoxy AC coils and a closed-
loop cryogenic cooling system that uses sub-cooled liquid
nitrogen at approximately 68K to increase the Ic and the
working current of the DC HTS bias magnet coil to increase
the available DC amp-turns and the range of DC magnetic bias
flux. The basic design parameters of the CEC FCL are shown
in Table I. Because the Avanti Circuit is a newly constructed
distribution circuit with a low duty-cycle and no expected fault
issues, the CEC FCL was designed for only modest fault
current limiting capabilities and was intended to limit a 23 kA
RMS potential steady-state fault current by about 20%.
Instead of fault limiting performance, emphasis was placed on
accurately modeling and predicting the performance of the
FCL and its associated electrical waveforms.
TABLE I CEC FCL DESIGN PARAMETERS
Parameter Value
Line Voltage 12 kV
Maximum load current 800 A (3 phase, 60 Hz)
Voltage drop at max. load < 1% (70 V rms)
Prospective fault current 23 kA rms symmetrical
Asymmetry X/R = 21.6
Fault limiting capability 20%
Fault type 3 phase to ground
Fault duration 30 cycles
Recovery time instantaneous
The CEC FCL underwent extensive testing at Powertech
Laboratories in October 2008. In the absence of an industry
standard for HTS FCL testing, a comprehensive test plan that
incorporated IEEE standards [7-9] for series reactors and
transformers was prepared with input from SCE and the
National Electric Energy Testing, Research and Applications
Center (NEETRAC), a member-financed, non-profit research
laboratory of the Georgia Technical University (Georgia Tech)
in Atlanta, Georgia. Special emphasis was placed on
comparing the performance of the CEC FCL predicted by
3. ASC 2010 preprint 2LY-01 submitted to IEEE Transactions on Applied Superconductivity 3
ZEN’s design protocol with the measured performance of the
actual device, including AC steady-state current voltage drop
(insertion impedance), steady-state AC current temperature
rise, AC fault current limiting, and AC coil and DC HTS
electromagnetic coupling. The dielectric performance of the
CEC FCL was also tested including BIL, DC withstand
voltage, lightning impulse and chopped-wave testing as
required by the applicable IEEE standards [8-10]. Dielectric
testing was performed before fault testing, and then repeated
upon the conclusion of fault testing by SCE at their
Westminster, California test facility before installation in the
Avanti Circuit.
Fig. 5 – Design performance verification test for the CEC FCL showing 20%
fault current reduction at 23 kA prospective fault current.
Fig. 6 – 82-cycle endurance fault test of the CEC FCL
Fig. 7 – A double-fault sequence simulating re-closer operation on the CEC
FCL
In all more than 65 separate test events were performed on
the CEC FCL, including 32 fault tests. A typical fault test
sequence involved the application of full-load steady-state
current and voltage (1,250 amperes RMS at 13.1 kV), the
application of 30-cycles or more of fault current up to nearly
60 kA first-peak, and returning to the full-load conditions
upon clearance of the fault. The CEC FCL performed
extremely well and exceeded expectations by withstanding
more than an expected lifetime of actual faults during a week
of testing. Fig. 5 shows a typical fault sequence test in which
the AC fault current is limited by approximately the targeted
20% reduction level. Fig. 6 is an endurance test of the CEC
FCL in which it was subjected to an 82-cycle fault, and Fig. 7
is a double-fault sequence test, which was performed to
measure the CEC FCL performance under an automatic re-
closer scenario. Fig. 8 shows the CEC FCL in the Avanti
Circuit at SCE’s Shandin substation, where it will remain
through the end of 2010.
Fig. 8 – The CEC FCL installed at the SCE Shandin Substation in San
Bernardino, California.
IV. OPERATIONAL EXPERIENCE AT SCE
The FCL operates in San Bernardino, CA, where the
ambient temperature reached 108°F (or 42°C) in July 2009.
During the past 18 months, the refrigeration portion of the
device operated nearly 24/7. Only once, during a hot summer
week, did the device experience venting of the cryogenics
fluid and require replenishment of the liquid nitrogen. Once,
an unexpected loss of DC magnetic bias occurred, causing the
FCL to remain in-line in the unbiased condition for over one
hour. The results of this event were published in a recent
paper [11]. Following this event, the FCL was integrated with
an automatic bypass switch that removes the FCL from the
grid in case of a problem.
The FCL experienced three outages of substation power. It
was able to ride-through the outages without suffering any
downtime. It operated properly and safely by sending the
correct alarms and bypass commands to the host utility,
Southern California Edison. One of the three substation
power outages is illustrated in Fig. 9. This particular event
occurred June 27, 2010 at 1:30AM. An unexpected event on
the 115kV high-voltage side caused a voltage dip and an
outage at the 12kV substation side. The outage lasted more
than 2 minutes. The FCL is equipped with a DC UPS and
battery. As specified by the host utility, the FCL signaled the
condition and immediately issued a bypass command,
followed by a DC shut down. Fig. 9 shows how the DC
magnet was gracefully shutdown. Upon resuming AC power,
the cryogenic compressor was restarted, and cryogenic
4. ASC 2010 preprint 2LY-01 submitted to IEEE Transactions on Applied Superconductivity 4
conditions returned to normal, as shown in Fig. 10. At this
point, the HTS magnet was ready to be energized and the FCL
could have been switched in-line again. Note that a full ride-
through of the event could have been possible, without
bypassing the FCL, if the host utility had desired it.
Fig. 9 – Loss of substation power and subsequent command to perform a
controlled shut down of the DC magnet.
Fig. 10 – Cryogenics system returns to normal once substation power is
restored.
The FCL is installed with an industrial programmable logic
controller (PLC). The PLC allows Zenergy Power to fully
monitor the device and fully communicate with the protection
and control systems. The controller provides alarms, bypass
commands, and shutdown signals to the utility control room
via MODBUS communication. The controller also shares data
with the utility SCADA system for monitoring purposes.
Cyber security was essential for Southern California
Edison. To fulfill this requirement, Zenergy Power provided a
dual-Ethernet port connection with secure data transfer and
communication capabilities with two physically separate
channels for independent SCE and Zenergy Power
communications.
On January 14, 2010 the FCL experienced its first-ever in-
grid fault. Based on the voltage data located at the load side
of the FCL, as shown in Fig. 11, the event evolved from a
phase-to-phase fault, to a three-phase fault, to a temporary
recovery, to a phase-to-phase fault, to another three-phase
fault, ending with an open line and clearing. This very
unusual, mostly symmetrical, multi-fault event occurred over a
three-second period. Physically the event was initiated by the
overhead conductors of A and B phases slapping together
during high wind conditions near the end of the Avanti
Circuit. This phase-to-phase fault lasted about 250
milliseconds, when Phase C also faulted, thus evolving into a
three-phase fault, lasting about half a second. The air
insulation recovered its full strength for about one second, but
then the conductors of phases A and B again arced to each
other for about three quarters of a second. The arc was about
to be extinguished at this time; however, Phase C also arced,
becoming another three-phase fault. The event ended about a
quarter of a second later when Phase B conductor opened,
dropped to the ground, and the circuit was eventually cleared.
During this sequence of events the FCL operated as designed
and limited the fault current.
Fig. 11 – Multiphase sequence of fault events lasting over a three second
period. This was the first in-grid fault experienced by the CEC FCL. It
performed as designed and limited the fault current.
V. THE COMPACT FCL
In the course of building and testing the CEC FCL, ZEN
conceived a new concept for saturating reactor FLC design
that had the potential to considerably reduce the size and
weight of the device, while allowing the dielectric rating of the
FCL to be increased to transmission voltages of 100 kV and
higher. This concept became known as the “Compact FCL,”
and in order to test the concept and evaluate alternative
methods for implementing it, ZEN, with financial support
from the U.S. Department of Energy and the Consolidated
Edison Company of New York, built and tested four full-scale
prototypes using different internal designs.
All of the Compact FCL prototypes were built using
standard “oil-filled” liquid dielectric transformer construction
techniques. This allowed the required dielectric offset
distances within the FCL to be minimized, greatly reducing
the FCL prototypes’ size and weight for equivalent
performance. Another important design innovation was the
use of “dry-type” cryogenics to conductively cool the HTS
coil without the use of liquid cryogens. This allowed the
operating temperature of the HTS coils to be reduced below
the freezing temperature of liquid nitrogen, enabling further
increases in the Ic and working current of the 1G HTS wire
used in the DC bias magnet system and correspondingly
higher DC amp-turns to magnetically saturate the iron cores.
The use of conduction cooling also removes potential utility
concerns about having large volumes of liquid cryogens in
confined spaces and potential pressure vessel over-
pressurization, rupture and venting concerns.
Table II shows all four of the Compact HTS FCL
5. ASC 2010 preprint 2LY-01 submitted to IEEE Transactions on Applied Superconductivity 5
prototypes that were built and tested. These prototypes had
the same nominal 15 kV design voltage and 110 BIL rating,
but differed in their steady-state AC current ratings and
targeted AC steady-state current insertion impedance and AC
fault current limiting performance. The designed AC steady-
state current levels ranged from 1,250 amperes RMS to 2,500
amperes RMS, and the targeted AC fault current reduction
levels ranged from about 30% up to more than 50% of a 25 kA
RMS potential steady-state fault current with an asymmetry
factor yielding a first-peak fault current approaching 50 kA.
TABLE II COMPACT FCL DEVICES TESTED AT POWERTECH
LABS IN JULY 2009
Parameter Units FCL #
1
FCL #
2
FCL #
3
FCL #
4
Line-to-Line Voltage kV 12.47 12.47 12.47 13.8
Number of Phases # 3 3 1 1
Line Frequency Hz 60 60 60 60
Prospective Fault
Current
kA 35 46 80 25
Limited Peak Fault kA 27 30 40 18
Prospective Fault
Current RMS
Symmetrical
kA 20 20 40 11
Limited Symmetric
Fault Current
kA 15 11.5 18 6.5
Load Current Steady-
State RMS
kA 1.25 1.25 1.25 2.5 –
4.0
Voltage Drop Steady-
State Maximum
% 1 1 1 2
Line-to-Ground
Voltage
kV 6.9 6.9 6.9 8.0
Asymmetry Factor # 1.2 1.6 1.4 1.6
Source Fault
Impedance
Ohms 0.346 0.346 0.173 0.724
Fault Reduction % 25 43 55 41
The Compact FCL prototypes underwent full-power load
and fault testing at Powertech Laboratories in July 2009 using
essentially the same comprehensive test plan that was
employed for the CEC FCL. In all 118 separate tests were
performed on the four Compact FCL prototypes, including 55
calibration tests, 12 load current only tests, and 51 fault tests.
In many cases, the measured performance exceeded
expectations, and the test program completely validated both
the performance potential of the Compact FCL design and the
efficacy of ZEN’s design protocol.
Fig. 12 shows the results of a typical AC load current
voltage drop or insertion impedance test which displays good
agreement between the predicted and the measured
performance. Fig. 13 shows a fault current test in which the
Compact FCL prototype reduced a prospective 25 kA RMS
fault current by about 46%.
A particularly important result from the Compact FCL
testing program was the fact that the AC coils and the DC
HTS Coil exhibited very little electromagnetic coupling. Fig.
14 shows that the DC current in the HTS bias coil varied only
by 5% as the Compact FCL was subjected to up to a 30 kA
peak fault current. These results were very typical for all of
the Compact FCL devices during fault current testing. The
steady-state voltage drop of the Compact FCL typically
remained low with increasing AC currents and also exhibited
very “clean” AC power characteristics with Total Harmonic
Distortion levels well within the requirements of IEEE 519-
1992 [10].
Fig. 12 – Typical AC steady-state load current voltage drop measurements
illustrating good agreement between predicted and actual performance.
Fig. 13 – Compact FCL fault test showing a prospective 25 kA fault current
limited by 46%. The black curve is the prospective fault current, the red curve
is the limited fault current, and the blue curve is the voltage measured at the
FCL terminals
Fig. 14 – AC coil and DC HTS coil electromagnetic coupling during AC fault
current testing illustrating the minimal coupling between the two coils.
VI. ADDITIONAL FCL PROJECTS IN PROGRESS
As a result of the successful testing of the Compact FCL
prototype, ZEN has initiated the commercial sale of the
Compact FCL for medium-voltage applications. Through the
experiences of the CEC and DOE projects, ZEN has advanced
the product development as illustrated in Fig. 15.
In January 2010 ZEN received a contract for a 15 kV-class
Compact FCL, 1.25 kA nominal operating current, 50 Hz,
6. ASC 2010 preprint 2LY-01 submitted to IEEE Transactions on Applied Superconductivity 6
capable of limiting a 3-second fault and reducing it by at least
30%. It will be tested at KEMA USA late 2010 or early 2011
and delivered to the system integrator, Applied
Superconductor Ltd, in early 2011 for installation in a CE
Electric substation in the UK. A drawing illustrating its rough
design and layout is shown in Fig. 16.
In the UK, the distribution network operators such as CE
Electric, Energy North West, Scottish Power, E-On Central
Networks, and EDF Energy Networks have become intensely
interested in fault current limiters. All five of the above
DNOs have commitments to host a 15 kV-class FCL
sometime in the next 2-3 years. The reason for this
enthusiasm is that with some 15% of England’s distribution
network already at 85% of its fault level design capability,
there will be limited head room to allow for the connection of
renewable (and more specifically) distributed generation
which is required to support the UK Government’s Low
Carbon reduction targets. One of the solutions to freeing up
network capacity to allow the connection of this generation
will be the utilization of Fault Current Limiters.
Fig. 15 – The path to commercial product. On the left is the first generation
FCL that was tested, installed and operated in the grid to show performance
and reliability. In the middle is the rectangular prototype Compact, which was
built and tested to validate a smaller and more efficient FCL. And on the right
is our now-standard round Compact FCL for distribution-class applications
that takes advantage of all lessons learned throughout the process
15 kV Voltage Rating
3-Phase, 50 Hz
1.25 kA Nominal Current
Fig. 16 – Design and layout of commercial 15 kV-class FCL for installation in
a CE Electric substation in early 2011.
Also, ZEN has entered into an agreement with American
Electric Power (AEP), Columbus, Ohio, to partner for the
demonstration of a 138 kV three-phase Compact FCL as a part
of ZEN’s ongoing DOE-sponsored FCL development
program. A single-phase 138 kV Compact FCL prototype will
be built and tested in early 2011, and a three-phase Compact
FCL demonstration unit will be built, tested and installed in
AEP’s Tidd substation located near Steubenville, Ohio at the
end of 2011. This device will be designed to operate at 1.3 kA
steady state and reduce an approximate 20 kA prospective
fault by 43% and instantaneously recover under load. The
device will be installed on the low side of the 345 kV to
138 kV transformer and will protect the 138 kV feeder.
VII. SUMMARY
Zenergy Power has now had the experience of installing and
operating a fault current limiter in the Southern California
Edison electricity grid. As a result we can say that:
1. We successfully integrated a superconducting FCL
in the grid,
2. The operational experience has been a big success
for both ZEN and Southern California Edison,
3. Both parties gained invaluable experience by
operating through all four seasons,
4. Zenergy Power learned to address unplanned events
such as loss of station power, and
5. The host utility learned about preventive
maintenance and how the device responded to real
fault events.
As a result of this experience, Zenergy Power has received
contracts for the installation of a 15 kV-class device in the UK
and a 138 kV-class device in the US.
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