Improvement of single-phase grounding fault detection for small resistance grounding systems based on steady-state monitoring information in the substation

Abstract

In order to use the existing hardware sources to improve the line selection performance of single-phase grounding fault of small resistance grounding systems， a method for line selection of single-phase grounding fault based on the global steady-state monitoring information of the substation automation system is investigated. The zero-sequence voltage of the busbar and the zero-sequence current of each line in the case of single-phase grounding faults are deduced. The ratio of zero-sequence current of lines with single-phase grounding faults to that of non-fault lines under extreme conditions is analyzed. Moreover， the line selection method of single-phase grounding fault is proposed. The zero-sequence current is used as the starting criterion for line selection of single-phase grounding fault， and the setting principle of zero-sequence principle is introduced to calculate the maximum transition resistance that can be started under the setting value of zero-sequence current. An example is given to illustrate the proposed method， and the results show that the steady-state monitoring information of the substation automation system can remarkably improved the detection performance of single-phase grounding fault of small resistance grounding systems.

Keywords

• distribution networks
• small resistance grounding system
• line selection of single-phase grounding fault
• comprehensive telemetry error
• substation automation