Fault component integrated impedance-based pilot protection scheme for EHV/UHV transmission line with thyristor controlled series capacitor (TCSC) and controllable shunt reactor (CSR)

• Published in: Science China. Technological sciences Vol. 56; no. 2; pp. 342 - 350
• Main Authors: He, ShiEn, Suonan, JaLe, Kang, XiaoNing, Jiao, ZaiBin
• Format: Journal Article
• Language: English
• Published: Heidelberg SP Science China Press 01.02.2013
• Subjects: Capacitors; China; Dynamics; Engineering; Faults; Impedance; Phasors; Pilots; Transmission lines; pilot protection; EHV/UHV; controllable shunt reactor (CSR); thyristor controlled series capacitor (TCSC); fault component integrated impedance (FCII); transmission line
• ISSN: 1674-7321; 1869-1900
• DOI: 10.1007/s11431-012-5079-z

This paper analyzes the fundamental frequency impedance characteristic of a thyristor controlled series capacitor (TCSC) and presents a novel transmission line pilot protection scheme based on fault component integrated impedance (FCII) calculated for a transmission line with TCSC and controllable shunt reactor (CSR). The FCII is defined as the ratio of the sum of the fault component voltage phasors of a transmission line with TCSC and CSR to the sum of the fault component current phasors where all the phasors are determined at both line’s terminals. It can be used to distinguish internal faults occurring on the line from external ones. If the fault is an external one the FCII reflects the line’s capacitive impedance and has large value. If the fault is an internal one on the line the FCII reflects the impedance of the equivalent system and the line and is relatively small. The new pilot protection scheme can be easily set and has the fault phase selection ability and also it is not affected by the capacitive current and the fault transition resistance. It is not sensitive to compensation level and dynamics of TCSC and CSR. The effectiveness of the new scheme is validated against data obtained in ATP simulations and Northwest China 750 kV Project.