20kv distribution network neutral point grounding mode switching control method and device

Abstract

The invention discloses a method and a device for controlling switching of 20kV distribution network neutral grounding modes. The method comprises the steps of selecting grounding modes according to the capacitive current value of the power grid, if the capacitive current is greater than a threshold value, selecting a resistance grounding mode, forcibly switching a resistor and latching other logical judgment, if the capacitive current is smaller than the threshold value, and selecting a flexible grounding mode in which judgment on the characteristics and types of faults is carried out by virtue of real-time monitoring on voltages and currents, and meanwhile, judgment on special circumstances possibly occurring in the power grid, such as high resistance grounding fault and intermittent grounding fault, is carried out. According to the judgments, if resistor switching is started, the resistor switching moment is controlled, and meanwhile, accurate resistor switching is detected and confirmed by use of a resistor switching circuit.

Description

technical field [0001] The invention belongs to the field of automatic control methods and devices, and more precisely relates to a switching control method and device for a neutral point grounding mode of a 20kV power distribution network. Background technique [0002] In recent years, the technical feasibility and economic superiority of 20kV voltage level network construction in some areas of our country have been demonstrated. In the actual operation of the 20kV distribution network, the neutral point adopts the arc-suppression coil grounding method. When there is a fault, accurate and fast fault line selection and location cannot be realized. If it operates with a fault for a long time, some original 10kV booster equipment cannot meet the insulation requirements. Requirements, it may cause the breakdown of the weak link of the insulation, develop into a short circuit between phases, and expand the accident. With the small resistance grounding method, once a grounding t...

AI Technical Summary

Problems solved by technology

[0004] In view of the high cost of the switching device for the neutral point grounding mode of the 20kV distribution network in the prior art, and the existence of a single zero-sequence voltage criterion, it is easy to cause misoperation of the control device; failure to select the switching time of the grounding mode switching resistor is likely to cause damage to the power grid. Overvoltage impact; failure to judge and deal with special conditions such as resistance switching circuit faults, high-resistance grounding, and multiple transient faults in a short period of time will affect the reliable operation of the device. The present invention provides a 20kV distribution network Neutral point grounding mode switching control method and device

Images