A new principle for high resistance earth fault detection during fast power swings for distance protection

TLDR

High‑impedance ground faults during fast power swings cause the apparent impedance seen by distance protection to vary widely, making detection and location difficult. The paper proposes a new principle for detecting high‑impedance faults during fast power swings that overcomes existing detection deficiencies. The principle is incorporated into a complete power swing relaying scheme and can be implemented on standard relaying hardware. Simulation studies on a typical 400 kV transmission system using EMTP demonstrate the effectiveness of the proposed method.

Abstract

The combined effects of a high impedance ground fault condition and a fast power swing condition cause the apparent impedance 'seen' by power system distance protection schemes to vary over a wide range. Previous research work has shown that the detection and location of high impedance faults during power swings is very difficult. A new principle for high impedance fault detection during fast power swings is presented which overcomes these deficiencies. This method forms a part of a complete power swing relaying scheme and can be implemented on standard relaying hardware. Results are presented based on extensive simulation studies carried out on a typical 400 kV transmission system, using the Electromagnetic Transient program (EMTP).