Measurement of Line Impedance during Single Line-to-Ground Fault in Non-Homogeneous Transmission Line Network

Abstract

The measurement of the line impedance in long lines is adversely affected by fault and system parameters such as, the type and location of the fault, fault resistance, short circuit MVA of the source (presence of weak source), power transfer angle etc. This paper proposes a new technique to measure the line impedance during fault condition accurately, considering wide variations in the aforementioned variables. It is based on the mathematical analysis of the sequence network diagram of a non-homogeneous 400 kV, 50 Hz double infeed line, considering a single line-to-ground fault. Instead of using voltage and current vectors for the analysis, the impedance vectors are used to calculate the new impedance seen at the time of fault. The technique is verified using MATLAB/SIMULINK software. The simulation results conclude that the new measuring technique is precise, simple to understand, and rigid to the changes in all the system and fault parameters considered in this paper.

Keywords:

• distance protection
• impedance measurement
• non-homogeneous system
• single line-to-ground fault
• double infeed line
• short-circuit MVA of the source

Additional information

Notes on contributors

Abhishri Jani

Abhishri Jani received her B.Tech in Electrical Engineering from Nirma University, Ahmedabad, India in 2012 and M.Tech in Electrical Engineering (Power Systems) from Pandit Deendayal Energy University, Gandhinagar, India in 2016. Currently, she is pursuing Ph.D. in Electrical Engineering from Gujarat Technological University, Ahmedabad, India. She has published 5 papers in various international peer-reviewed journals. Her research interests include power system protection, power system modeling and simulation, reactive power compensation, and FACTS.

Vijay Makwana

Vijay H. Makwana received his BE (Electrical) and ME (Electrical Power System) from BVM Engineering College, Sardar Patel University, Vallabh Vidhyanagar, Gujarat, India in 1999 and 2002, respectively. He obtained PhD (Electrical) from Sardar Patel University, Vallabh Vidyanagar, India in 2013. He has more than 20 years of teaching experience. Currently he is working as a Professor in the Department of Electrical Engineering at the G H Patel College of Engineering and Technology, Vallabh Vidyanagar, India. He has published 20 papers in various international peer-reviewed journals. He has written a book on Power System Protection and Switchgear published by Tata Mc-Graw Hill, 2010, India. He has also written a monograph on Transmission Line Protection Using Digital Technology published by Springer in 2016. His research interests include power system protection, power system stability and control, power system modeling and simulation, reactive power compensation, and FACTS.