Handling method of small current grounding fault with line selection device and protection reclosing switch

Abstract

The invention provides a small current grounding fault processing method with a line selection device and a protection recloser cooperated and belongs to the field of power system relay protection. The method is characterized by including the following steps that a, fault lines are judged; b, a tripping instruction is sent in a delayed mode; c, whether faults exist or not is judged, the step d is executed if the faults exist, and the step f is executed if the faults disappear; d-e, the fault lines are reclosed; f, whether the faults reappear or not is judged, the step g is executed if the faults do not reappear, and the step h is executed if the faults reappear; g, the fault lines are restored to normal power supply; h, the tripping instruction and a recloser locking instruction are sent. By means of the small current grounding fault processing method with the line selection device and the protection recloser cooperated, fault lines which are wrongly judged and can be self-cured through tripping arc blowout are subjected to power supply again after being tripped and the fault lines with faults incapable of disappearing by themselves are isolated through the line selection device, so that power supply reliability is greatly improved.

Description

technical field [0001] The invention relates to a small current grounding fault handling method in which a line selection device cooperates with a protection reclosing switch, and belongs to the field of relay protection of electric power systems. Background technique [0002] After a single-phase ground fault occurs in a small current grounding system, the line insulation pressure increases due to the increase of the non-fault phase voltage. Arcing overvoltages can also cause equipment damage in the event of intermittent arcing ground faults. Long-term operation with faults is also likely to cause electric shock accidents for humans and animals. Therefore, after the small current ground fault line selection device selects the faulty line, it should trip after a period of delay to cut off the faulty line. Since the current line selection device cannot achieve 100% correct rate of line selection at the first time, and some small current grounding faults can be self-healed a...

AI Technical Summary

Problems solved by technology

This mode of operation cannot restore power supply to faults that can be self-healed by tripping and extinguishing the arc, resulting in reduced power supply reliability

When the line selection device selects the wrong line, the non-faulty line will be tripped by mistake and cannot be recovered, further reducing the reliability of power supply

[0004] Patent application number 201410109169.0 "A method for self-adaptive tripping of small current grounding faults" provides the conditions for self-adaptive tripping, and monitors the reliability of fault line selection results, line insulation conditions, and fault severity through online real-time monitoring, and comprehensively considers line types, According to the load's demand for power supply reliability, etc., adaptively select whether and when the faulty line trips, but the patent does not involve the implementation logic of tripping

[0005] Patent No. ZL201520271576.1 "A Small Current Grounding Line Selection Tripping and Reclosing Device" proposes the logic of tripping and closing through the circuit of the line selection device itself, but most of the current practical applications are that the line selection device passes through the line protection device and its reclosing The brake function realizes tripping and closing, or the line selection device directly controls the tripping operation circuit, and generally does not directly control the closing operation circuit. This patent does not provide the coordination logic and control method of the line selection device and the line protection device

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