An Overview of High Impedance Differential Scheme, Design, Protection and Simulation for a 132 KV Double Bus Bar Single Breaker System

Abstract

This paper illustrates the common practical schematics used for high voltage bus bar protection. The schematic includes the detailed high impedance AC circuit including shunt and series resistors, nonlinear resistors (Metrosils), current transformers supervision relays circuit and overcurrent relay. The design criteria for each component that ensuring correct selectivity. The DC schematic includes the discriminative and check zones which determine the tripping criteria in which the protection will operate to protect the bus bar and how it is achieving optimal reliability. This paper demonstrates both primary and secondary circuit simulation during internal fault condition by OMICRON RelaySim Test and PSIM softwares with and without Metrosils approaches.