Power system neutral point compound operation method

Abstract

This invention adopts neutral isolation function mode as the electric net in function: when the circuit is mono-directionally grounded, through the collection of the voltage and current signals of the electric net, judge the failure of the mono-directionally grounding as the metal permanent failure to output the information hinting to process the grounded failure, as to the electric arc failure, uses automatic delivering device to deliver arc-distinguishing coil to eliminate the mono-directional grounded failure, when the grounded failure is wiped off, exit the arc-distinguishing coil and resume the neutral isolation mode of the working order of the electric net. This invention can fully exert the mono-directional grounding capacity of the arc-distinguishing coil, in order to reduce the valve slipping rate of lighting strike and decrease the power off accidents. This invention is suitable for 35kV electrical net neutral point operation in mountainous area.

Description

technical field [0001] This patent relates to a neutral point operation mode of a power grid in a power system, especially a compound neutral point operation method suitable for normal and faulty operation of a 35kV power grid in mountainous areas. Background technique [0002] At present, the neutral point operation modes of the power grid in the power system mainly include insulation, direct grounding, grounding through arc suppression coils, and grounding through small resistance. There are two main operation modes for the neutral point of the 35kV power grid. When the single-phase grounding capacitance current of the power grid is less than 10A, the neutral point insulation operation mode is adopted; when the single-phase grounding capacitance current is greater than 10A, the neutral point is grounded through the arc suppression coil. . The lightning strike line is the most important cause of power grid single-phase short-circuit grounding, line tripping and power outag...

AI Technical Summary

Problems solved by technology

However, the improvement of the compensation degree of the arc suppressing coil hides that when the power grid is single-phase grounded due to a lightning strike, the short-circuit arc current at the ground point after the inductive current compensation of the arc suppressing coil changes from the single-phase grounding capacitive current to the inductive current , because the compensation of the arc suppression coil is too large, that is, the inductance current is too large, the current value of the grounding point after compensation will often exceed 10A, so that the single-phase grounding arc current is not easy to extinguish, that is to say, the arc suppression coil does not achieve elimination. The purpose of a single-phase-to-ground short-circuit fault will eventually lead to the tripping of the line

All in all, for the 35kV power grid in mountainous areas, the current operation mode of the neutral point of the power system cannot simultaneously solve the problem of three-phase voltage balance during normal operation and the problem of single-phase grounding short-circuit current arc extinguishing by arc suppression coils to eliminate single-phase grounding faults

Therefore, the 35kV power grid in mountainous areas often has frequent lightning trips and frequent power outages, resulting in huge economic losses.

Images