Single-phase grounding protection method and system

Abstract

The invention provides a single-phase grounding protection method which is used for judging and isolating a single-phase grounding fault of a small-current grounding system. The single-phase grounding protection method comprises the following steps of: 102, synchronously acquiring the power frequency voltage of a bus of the small-current grounding system and current traveling waves of all outgoing lines corresponding to the bus in real time; 104, when the small-current grounding system is disturbed, determining a disturbance outgoing line according to the current traveling waves of all the outgoing lines; 106, determining whether the small-current grounding system has the single-phase grounding fault according to the power frequency voltage; and 108, determining that the disturbance outgoing line is a faulted outgoing line if the small-current grounding system has the single-phase grounding fault, sending a tripping instruction and insolating the faulted outgoing line. Correspondingly, the invention also provides a single-phase grounding protection system. By the single-phase grounding protection method and the single-phase grounding protection system, a requirement for judging the single-phase grounding fault of the small-current grounding system and a requirement for quick, reliable, sensitive and selective isolation can be met.

Description

technical field [0001] The invention relates to the field of relay protection of power systems, in particular to a single-phase grounding protection method and system. Background technique [0002] The small current grounding system refers to the system with a small fault current when a single-phase grounding fault occurs, specifically refers to the neutral point not grounded, the neutral point through the arc suppression coil or the neutral point through the high resistance grounding system, commonly known as the small current system. When a single-phase ground fault occurs in a small current system, since no short circuit is formed and the fault current is small, the existing overcurrent protection cannot operate accurately to isolate the faulty line. However, according to statistics, single-phase ground faults account for more than 70% of all faults in the entire power distribution system. Once a single-phase grounding fault occurs, if the fault cannot be eliminated in t...

AI Technical Summary

Problems solved by technology

Once a single-phase grounding fault occurs, if the fault cannot be eliminated in time, the fault arc at the fault point may burn the equipment, cause a phase-to-phase fault, and expand the accident. Therefore, it is necessary to study the single-phase grounding protection technology of the small current grounding system

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