Method and device for small current ground fault line selection under double bus operation mode

Abstract

The invention relates to a line selection method and device for small current grounding faults in a power system double busbar operation mode. The method is to collect the feeder isolating switch node signal, zero-sequence current signal and bus PT voltage signal in real time; according to the feeder isolating switch node signal information, classify the nature of the feeder belonging to the bus section; according to the classification results of the feeder, respectively extract I, II The PT signal of the segmental busbar and the zero-sequence current signal of the feeder to which the busbar segment belongs are used for real-time monitoring of small current grounding fault line selection; the device includes: feeder isolation switch node signal acquisition module, zero-sequence current signal acquisition module, bus PT voltage signal Acquisition module, main CPU module. The present invention classifies the property of the bus section to which the feeder belongs in real time by accessing the node information of the feeder isolating switch, so as to achieve the effect of adapting to different operation modes and ensure the reliability of faulty line selection.

Description

technical field [0001] The invention belongs to the field of relay protection automation in electric power systems, and relates to a method and device for single-phase grounding fault line selection on the 6-66kV outgoing line side of a substation or a power plant in the form of double-bus main wiring. The intelligent level of plant operation, especially a method and device for line selection of small current grounding faults under double busbar operation mode. Background technique [0002] The neutral point of my country's 6~66kV distribution network mostly adopts the method of not directly grounding the neutral point. In this system, when a single-phase ground fault occurs, the grounding short-circuit current is very small, so it is called a small current grounding system. The advantage of the low-current grounding system is that it can continue to run for 1-2 hours when a single-phase grounding occurs. In most cases, the fault can automatically disappear and the insulatio...

AI Technical Summary

Problems solved by technology

In this way, for the traditional small current grounding line selection equipment, when a fault occurs, there may be a situation that the faulty line belongs to the non-faulty bus section, but the faulty bus section cannot normally select the faulty line

If the configuration of the small current grounding line selection equipment is frequently adjusted in real time according to the operation mode of the feeder, it will take time and effort, and it does not conform to the development direction of intelligent and integrated equipment in power system substations and power plants

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