High-accuracy arc extinguishing coil grounding system single-phase grounding wire selection method

Abstract

The invention discloses a high-accuracy arc extinguishing coil grounding system single-phase grounding wire selection method. The method comprises the steps of parallelly connecting a series loop which is composed of a grounding resistor and a circuit breaker with two ends of an arc extinguishing coil, wherein in normal operation, the circuit breaker is in an on state; additionally mounting a zero-sequence current transformer on each outlet wire of a transformer station without the zero-sequence current transformer; in single-phase grounding, acquiring the zero-sequence current of the zero-sequence current transformer by means of an existing microcomputer protecting device of a transformer substation, when flowing zero-sequence current is larger than a setting value Izd0, transmitting a fault signal after setting time T1, and determining a faulted line; and when the zero-sequence voltage of a bus voltage transformer increases to a certain value Uzd0, determining single-phase grounding, and performing tripping-out on the circuit breaker which is serially connected with the grounding resistor after a time period T2. The high-accuracy arc extinguishing coil grounding system single-phase grounding wire selection method has advantages of realizing simple reconstruction, greatly improving wire selection accuracy on the condition that safe and stable system operation is not affected, reducing economic loss caused by wire selection error and ensuring continuous electric power supplying to electric power users.

Description

technical field [0001] The invention relates to a high-accuracy line selection method for a single-phase grounding system of an arc suppression coil grounding system. Background technique [0002] In our country, most of the 6~35kV medium voltage distribution network system adopts the non-direct grounding method of the neutral point, which is called the small current grounding system. The probability of single-phase-to-ground faults in the distribution network accounts for about 80% of the total faults. In the small current grounding system, the single-phase grounding poses little threat to the power grid and can continue to run for 1 to 2 hours. The neutral point wiring methods of my country's distribution network system include: the neutral point is not grounded, the neutral point is grounded through a small resistance, and the neutral point is grounded through an arc suppression coil. With the development of power grid construction, the transmission lines of the distrib...

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to provide a high-accuracy single-phase grounding line selection method for the arc-suppression coil grounding system, which can effectively solve the problem of low line selection accuracy of the current arc-suppression coil grounding system

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