An Improved Pilot Relaying Scheme for Shunt Compensated Transmission Line Protection Based on Superimposed Reactive Power Coefficients

Abstract

The fault component power and energy based relaying schemes have limitation during double-phase to ground fault due to the mutual coupling effect. This article presents a superimposed reactive power coefficient (SRPC) based pilot relaying scheme for the protection of shunt compensated transmission line. SRPC of a phase is defined as the ratio of integrated superimposed reactive power (SRP) of that phase to the maximum magnitude of integrated SRPs among all three phases. If SRPC of any phase is found less than −0.5, an internal fault is detected and that phase is considered as a faulty phase. If no phase possesses SRPC less than −0.5, the fault is an external fault. The algorithm will start only if the superimposed differential current of any phase is found more than 50% of pre-fault differential current. The results are obtained using PSCAD/EMTDC software for different conditions, such as different fault resistances, fault locations, static VAR compensator locations, and source impedances. The proposed scheme is found robust and accurate for all the cases considered. The performance of the proposed scheme is superior to the recently proposed similar type of scheme and is unaffected from capacitive coupled voltage transformer and current transformer measurement errors and synchronization error.

Keywords::

• digital relaying
• fault classification
• fault detection
• power systems protection
• protection of compensated line
• static VAR compensator
• superimposed reactive power coefficient
• transmission line

Additional information

Notes on contributors

Om Hari Gupta

Om Hari Gupta received the M.Tech. degree in electrical engineering from the Department of Electrical Engineering, MN National Institute of Technology, Allahabad, India, in 2011 and the Ph.D. degree from the Department of Electrical Engineering, Indian Institute of Technology Roorkee, India, in 2017. He received the Queen Elizabeth-II scholarship for research visiting the Department of Electrical, Computer and Software Engineering, University of Ontario Institute of Technology (UOIT), Canada, in 2017. Currently, he is an Assistant Professor in the Department of Electrical Engineering, Dayalbagh Educational Institute, Agra, India. Dr. Gupta is also a reviewer for various international journals. His research interests include microgrid/smart-grid control and protection, power system compensation and protection, and control of drives.

Manoj Tripathy

Manoj Tripathy received the B.E. degree in electrical engineering from the Nagpur University, Nagpur, India, in 1999, the M.Tech. degree in instrumentation and control from the Aligarh Muslim University, Aligarh, India, in 2002, and the Ph.D. degree in electrical engineering from the Indian Institute of Technology Roorkee, Roorkee, India, in 2008. He is currently working as Associate Professor in the Department of Electrical Engineering, Indian Institute of Technology Roorkee, India. Dr. Tripathy is a reviewer for various international journals in the area of power systems and speech processing. His research interests include wavelets, neural network, optimization techniques, content-based image retrieval, digital instrumentation, digital protective relays, and digital speech processing.