This paper systematically analyzes the transfer characteristics of the Rogowski-coil Current Transformer and its effect on protective relaying through theoretical analysis, experiments and simulations. The frequency c...This paper systematically analyzes the transfer characteristics of the Rogowski-coil Current Transformer and its effect on protective relaying through theoretical analysis, experiments and simulations. The frequency characteristics and transient characteristics of Rogowski transducer and Rogowski-coil Current Transformer are deeply analyzed based on the physical structure of the transformer.?It is revealed that broad bandwidth of the transformer can improve the performance of protective relaying, and the bandwidth is determined mainly by the parameters of the Rogowski transducer and signal processing circuits. It is also discovered that the measurement errors of transient current mainly depend on the abilities for the current transformer to reproduce an accurate replica of the decaying dc components, which is mainly decided by the decay time constant of the aperiodic component of transient current and the parameters of the integral unit. Finally, some measures are proposed for the performance improvement of Rogowski-coil Current Transformer to meet the requirements of protective relaying system in terms of structural design and testing standards.展开更多
Reliable sampled value(SV)synchronization is used to ensure the reliability of protective relaying in a smart substation based on IEC 61850.In this paper,an SV synchronization method based on SV propagation delay meas...Reliable sampled value(SV)synchronization is used to ensure the reliability of protective relaying in a smart substation based on IEC 61850.In this paper,an SV synchronization method based on SV propagation delay measurement and compensation is proposed.The method does not depend on an external reference clock and has higher reliability than existing ones.The core issue in the proposed method is to measure the switching delay.The following steps are undertaken in this work:First,the composition of SV propagation delay in a smart substation is analyzed.Second,a new switch with the capability of switching delay measuring and recording is presented.Third,two laboratory tests are conducted to study the measurement accuracy of the switching delay.Finally,an SV synchronization method is presented and its application is tested on a busbar protection system to demonstrate that the proposed method can achieve SV synchronization effectively.Test results show that the measurement is sufficiently accurate for the SV propagation delay compensation.The proposed method also shows that the reliability of the protective relaying in a smart substation is significantly improved.展开更多
文摘This paper systematically analyzes the transfer characteristics of the Rogowski-coil Current Transformer and its effect on protective relaying through theoretical analysis, experiments and simulations. The frequency characteristics and transient characteristics of Rogowski transducer and Rogowski-coil Current Transformer are deeply analyzed based on the physical structure of the transformer.?It is revealed that broad bandwidth of the transformer can improve the performance of protective relaying, and the bandwidth is determined mainly by the parameters of the Rogowski transducer and signal processing circuits. It is also discovered that the measurement errors of transient current mainly depend on the abilities for the current transformer to reproduce an accurate replica of the decaying dc components, which is mainly decided by the decay time constant of the aperiodic component of transient current and the parameters of the integral unit. Finally, some measures are proposed for the performance improvement of Rogowski-coil Current Transformer to meet the requirements of protective relaying system in terms of structural design and testing standards.
基金supported by the National Natural Science Foundation of China under Grants 51577073 and 51377026.
文摘Reliable sampled value(SV)synchronization is used to ensure the reliability of protective relaying in a smart substation based on IEC 61850.In this paper,an SV synchronization method based on SV propagation delay measurement and compensation is proposed.The method does not depend on an external reference clock and has higher reliability than existing ones.The core issue in the proposed method is to measure the switching delay.The following steps are undertaken in this work:First,the composition of SV propagation delay in a smart substation is analyzed.Second,a new switch with the capability of switching delay measuring and recording is presented.Third,two laboratory tests are conducted to study the measurement accuracy of the switching delay.Finally,an SV synchronization method is presented and its application is tested on a busbar protection system to demonstrate that the proposed method can achieve SV synchronization effectively.Test results show that the measurement is sufficiently accurate for the SV propagation delay compensation.The proposed method also shows that the reliability of the protective relaying in a smart substation is significantly improved.
