The Experts below are selected from a list of 2130 Experts worldwide ranked by ideXlab platform
Sohrab Mirsaeidi - One of the best experts on this subject based on the ideXlab platform.
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a controllable thyristor based Commutation Failure inhibitor for lcc hvdc transmission systems
IEEE Transactions on Power Electronics, 2021Co-Authors: Sohrab Mirsaeidi, Xinzhou Dong, Dalila Mat Said, Dimitrios Tzelepis, Campbell BoothAbstract:Commutation Failure is a serious malfunction in line-commutated high voltage direct current (HVdc) converters which is mainly caused by the inverter ac faults, and results in a temporary interruption of transmitted power and damage to the converter equipment. In this article, a controllable Commutation Failure inhibitor (CCFI) is developed which obviates the main drawbacks of the existing power electronic based and fault current limiting based strategies. Under normal circumstances, the developed CCFI improves the steady-state stability and the power transfer capability of the inverter ac lines, while it does not cause excessive voltage stress on the converter valves. In addition, it would reduce the risk of Commutation Failure occurrence, since it does not lead to any voltage drop in the Commutation circuit. When a fault occurs at one of the inverter ac systems, its corresponding CCFI limits the fault current depending on the reduced extinction angle. This would not only inhibit the successive Commutation Failures on the HVdc converter, but also extend the lifetime of components in the inverter ac systems. The practical feasibility of the developed CCFI is assessed through laboratory testing, using a real-time Opal-RT hardware prototyping platform. The obtained results indicate that the developed CCFI can reliably inhibit the Commutation Failures during various types of faults.
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An Enhanced Strategy to Inhibit Commutation Failure in Line-Commutated Converters
IEEE Transactions on Industrial Electronics, 2020Co-Authors: Sohrab Mirsaeidi, Xinzhou DongAbstract:Failure of the Commutation process is a serious malfunction in line-commutated high-voltage direct current (HVdc) converters, which mainly occurs due to inverter ac faults and may lead to outage of the HVdc system. In this paper, an improved strategy is developed that functions based on the SIEMENS HVdc control system under normal conditions and switches to a designed Commutation Failure inhibition module (CFIM) during an inverter ac fault. From the response speed point of view, since the designed CFIM does not require any proportional-integral controller, the inverter control system has a quick performance in prevention of the Commutation Failure. This is achieved by direct measurement of the overlap area using the waveforms of the valves anode–cathode and commuting voltages. In addition, from the accuracy aspect, the proposed method has a superior performance in comparison with the existing strategies. It is because of the fact that by direct measurement of the overlap area, variations of both direct current and the Commutation inductance are considered, and hence, the unnecessary increase of the inverter reactive power consumption during the fault and the repetitive Commutation Failures are prevented. The practical performance and feasibility of the proposed strategy is validated through the laboratory testing, using the real-time Opal-RT hardware prototyping platform. The experimental results demonstrate that the proposed strategy can effectively inhibit the Commutation Failure or repetitive Commutation Failures under different fault types by considering the lowest possible reactive power consumption.
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A Fault Current Limiting Approach for Commutation Failure Prevention in LCC-HVDC Transmission Systems
IEEE Transactions on Power Delivery, 2019Co-Authors: Sohrab Mirsaeidi, Xinzhou Dong, Dalila Mat SaidAbstract:Commutation Failure is one of the most frequent Failures in line-commutated converter based high-voltage direct-current (LCC-HVdc) systems which may lead to the outage of HVdc links, and thus affect the performance of the power system. Most Commutation Failures are caused by voltage reduction due to ac system faults. In this paper, a Commutation Failure prevention module (CFPM) is developed, which inserts the optimal value of resistance proportional to the reduced extinction angle in series with the fault current path using a simple switching method. When a fault occurs at the inverter ac side, a self turn- off switch starts switching with a pre-specified frequency and controlled modulation index, which limits the fault current to the desired value and inhibits Commutation Failure. The salient feature of the proposed CFPM is that it is fully controllable. In addition, despite the available controller modification methods which are not effective for low-impedance faults, the proposed CFPM can prevent Commutation Failure regardless of the fault severity. The practical performance and feasibility of the developed CFPM is validated through laboratory testing, using the real-time Opal-RT hardware prototyping platform. The experimental results demonstrate that the proposed strategy can effectively eliminate the Commutation Failure or repetitive Commutation Failures under different fault types.
Ehv Power - One of the best experts on this subject based on the ideXlab platform.
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ANALYSIS ON INFLUENCE OF AC SINGLE PHASE FAULTS ON HVDC Commutation Failure
High Voltage Engineering, 2004Co-Authors: Ehv PowerAbstract:The reasons of causing HVDC Commutation Failure and influence of AC single phase faults on Commutation Failure are investigated. A new method is presented for analyzing influence of single phase to ground fault on Commutation Failure according to the actual conditions of Tian Guang HVDC system, It is confirmed that normal single phase auto reclosing technique can be applied to AC transmission lines near Guangzhou inverter station.
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Research on Commutation Failure in Tian-Guang HVDC transmission system
2003Co-Authors: Jing Yong, Ehv PowerAbstract:Commutation Failure is one of the most common faults in inverter station.It would be affected by many factors,such as DC current,advance firing angle,DC dropping operation,full-load ratio,short circuit impedance and ratio of converter transformer.This paper analyzes the effects of these factors on the Commutation Failure in the inverter in Tian-Guang HVDC transmission system.What's more,the results are close to those of simulation study.The obtained general rule of Commutation Failure in the inverter in Tian-Guang HVDC transmission system is also helpful to its operation.
Shaobo Lin - One of the best experts on this subject based on the ideXlab platform.
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An Improved Commutation Prediction Algorithm to Mitigate Commutation Failure in High Voltage Direct Current
Energies, 2017Co-Authors: Shuyong Chen, Qiang Zou, Shaobo LinAbstract:Commutation Failure is a common fault for line-commutated converters in the inverter. To reduce the possibility of Commutation Failure, many prediction algorithms based on alternating current (AC) voltage detection have already been implemented in high voltage direct current (HVDC) control and protection systems. Nevertheless, there are currently no effective methods to prevent Commutation Failure due to transformer excitation surge current. In this paper, an improved Commutation Failure prediction algorithm based on the harmonic characteristics of the converter bus voltage during transformer charging is proposed. Meanwhile, a sliding-window iterative algorithm of discrete Fourier transformation (DFT) is developed for detecting the voltage harmonic in real time. This method is proved to be an effective solution, which prevents Commutation Failure in cases of excitation surge current, through experimental analysis. This method is already implemented into TianShan-ZhongZhou (TianZhong) ± 800 kV ultra high voltage direct current (UHVDC) system.
Xinzhou Dong - One of the best experts on this subject based on the ideXlab platform.
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a controllable thyristor based Commutation Failure inhibitor for lcc hvdc transmission systems
IEEE Transactions on Power Electronics, 2021Co-Authors: Sohrab Mirsaeidi, Xinzhou Dong, Dalila Mat Said, Dimitrios Tzelepis, Campbell BoothAbstract:Commutation Failure is a serious malfunction in line-commutated high voltage direct current (HVdc) converters which is mainly caused by the inverter ac faults, and results in a temporary interruption of transmitted power and damage to the converter equipment. In this article, a controllable Commutation Failure inhibitor (CCFI) is developed which obviates the main drawbacks of the existing power electronic based and fault current limiting based strategies. Under normal circumstances, the developed CCFI improves the steady-state stability and the power transfer capability of the inverter ac lines, while it does not cause excessive voltage stress on the converter valves. In addition, it would reduce the risk of Commutation Failure occurrence, since it does not lead to any voltage drop in the Commutation circuit. When a fault occurs at one of the inverter ac systems, its corresponding CCFI limits the fault current depending on the reduced extinction angle. This would not only inhibit the successive Commutation Failures on the HVdc converter, but also extend the lifetime of components in the inverter ac systems. The practical feasibility of the developed CCFI is assessed through laboratory testing, using a real-time Opal-RT hardware prototyping platform. The obtained results indicate that the developed CCFI can reliably inhibit the Commutation Failures during various types of faults.
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An Enhanced Strategy to Inhibit Commutation Failure in Line-Commutated Converters
IEEE Transactions on Industrial Electronics, 2020Co-Authors: Sohrab Mirsaeidi, Xinzhou DongAbstract:Failure of the Commutation process is a serious malfunction in line-commutated high-voltage direct current (HVdc) converters, which mainly occurs due to inverter ac faults and may lead to outage of the HVdc system. In this paper, an improved strategy is developed that functions based on the SIEMENS HVdc control system under normal conditions and switches to a designed Commutation Failure inhibition module (CFIM) during an inverter ac fault. From the response speed point of view, since the designed CFIM does not require any proportional-integral controller, the inverter control system has a quick performance in prevention of the Commutation Failure. This is achieved by direct measurement of the overlap area using the waveforms of the valves anode–cathode and commuting voltages. In addition, from the accuracy aspect, the proposed method has a superior performance in comparison with the existing strategies. It is because of the fact that by direct measurement of the overlap area, variations of both direct current and the Commutation inductance are considered, and hence, the unnecessary increase of the inverter reactive power consumption during the fault and the repetitive Commutation Failures are prevented. The practical performance and feasibility of the proposed strategy is validated through the laboratory testing, using the real-time Opal-RT hardware prototyping platform. The experimental results demonstrate that the proposed strategy can effectively inhibit the Commutation Failure or repetitive Commutation Failures under different fault types by considering the lowest possible reactive power consumption.
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A Fault Current Limiting Approach for Commutation Failure Prevention in LCC-HVDC Transmission Systems
IEEE Transactions on Power Delivery, 2019Co-Authors: Sohrab Mirsaeidi, Xinzhou Dong, Dalila Mat SaidAbstract:Commutation Failure is one of the most frequent Failures in line-commutated converter based high-voltage direct-current (LCC-HVdc) systems which may lead to the outage of HVdc links, and thus affect the performance of the power system. Most Commutation Failures are caused by voltage reduction due to ac system faults. In this paper, a Commutation Failure prevention module (CFPM) is developed, which inserts the optimal value of resistance proportional to the reduced extinction angle in series with the fault current path using a simple switching method. When a fault occurs at the inverter ac side, a self turn- off switch starts switching with a pre-specified frequency and controlled modulation index, which limits the fault current to the desired value and inhibits Commutation Failure. The salient feature of the proposed CFPM is that it is fully controllable. In addition, despite the available controller modification methods which are not effective for low-impedance faults, the proposed CFPM can prevent Commutation Failure regardless of the fault severity. The practical performance and feasibility of the developed CFPM is validated through laboratory testing, using the real-time Opal-RT hardware prototyping platform. The experimental results demonstrate that the proposed strategy can effectively eliminate the Commutation Failure or repetitive Commutation Failures under different fault types.
Campbell Booth - One of the best experts on this subject based on the ideXlab platform.
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a controllable thyristor based Commutation Failure inhibitor for lcc hvdc transmission systems
IEEE Transactions on Power Electronics, 2021Co-Authors: Sohrab Mirsaeidi, Xinzhou Dong, Dalila Mat Said, Dimitrios Tzelepis, Campbell BoothAbstract:Commutation Failure is a serious malfunction in line-commutated high voltage direct current (HVdc) converters which is mainly caused by the inverter ac faults, and results in a temporary interruption of transmitted power and damage to the converter equipment. In this article, a controllable Commutation Failure inhibitor (CCFI) is developed which obviates the main drawbacks of the existing power electronic based and fault current limiting based strategies. Under normal circumstances, the developed CCFI improves the steady-state stability and the power transfer capability of the inverter ac lines, while it does not cause excessive voltage stress on the converter valves. In addition, it would reduce the risk of Commutation Failure occurrence, since it does not lead to any voltage drop in the Commutation circuit. When a fault occurs at one of the inverter ac systems, its corresponding CCFI limits the fault current depending on the reduced extinction angle. This would not only inhibit the successive Commutation Failures on the HVdc converter, but also extend the lifetime of components in the inverter ac systems. The practical feasibility of the developed CCFI is assessed through laboratory testing, using a real-time Opal-RT hardware prototyping platform. The obtained results indicate that the developed CCFI can reliably inhibit the Commutation Failures during various types of faults.