Detection method of ground fault in neutral non-directly grounded system

Abstract

The invention discloses a detection method of a ground fault in a neutral non-directly grounded system and relates to the field of power grid fault detection technologies. According to the detection method, first, voltage and current data of a faulted phase and a healthy phase in a system with a single-phase ground fault is measured, and the voltage and current change law of a major loop is analyzed and determined; and in a system with a to-be-determined faulted phase, the faulted phase is determined through comparison with the determined voltage and current change law. Through the method, analysis is performed starting from a major loop current, a faulted line can be located quickly and accurately, and line protective setting is easier.

Description

technical field [0001] The invention relates to the technical field of grid fault detection, in particular to a detection method for a ground fault in a neutral point indirect grounding system. Background technique [0002] The 10-63kV power grid generally adopts neutral point non-effective grounding methods, including neutral point non-grounding, resistance grounding, arc suppression coil grounding, etc. When a single-phase ground fault occurs in the system, since the neutral point is not effectively grounded, the fault point will not generate a large short-circuit current, so the system is allowed to operate with faults for a short time. However, in recent years, the transformation of the two networks has greatly increased the capacitive current of the 10-63kV distribution network in small and medium-sized cities. The internal single-phase ground fault expands into an accident. If no effective measures are taken to eliminate the single-phase ground fault, the safe operati...

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Problems solved by technology

However, in recent years, the transformation of the two networks has greatly increased the capacitive current of the 10-63kV distribution network in small and medium-sized cities. If the internal single-phase ground fault is expanded into an accident, if effective measures are not taken to eliminate the single-phase ground fault, the safe operation of the power supply and distribution network will be endangered

[0003] The current traditional method for single-phase ground fault detection generally does not take into account the situation of the main current circuit, which leads to difficulties in protection setting and fault location, and cannot correctly and quickly locate and cut off the fault line

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