Electric leakage protection method for coal mine based on current principle of compensation grounding reactance branch

Abstract

The invention discloses an electric leakage protection method for a coal mine based on a current principle of a compensation grounding reactance branch. In the method, in a normal state, the size of grounding impedance of a grounding branch is obtained according to a zero-sequence voltage during operation of a non-grounding system and a zero-sequence current of the grounding reactance branch; the grounding impedance of the grounding branch is sent to all nodes of the next class of the same voltage class in real time through a communication network; and when a grounding failure occurs, because the zero-sequence voltages of systems of the same voltage class are the same, the current of the grounding reactance branch is compensated by a corresponding algorithm, and a current distribution relation through the reactance or arc suppression coil grounding system is equivalent to the non-grounding system, so that grounding wire selection or electric leakage protection is realized. By the method, the defects of the conventional underground electric leakage protection method are overcome, and the sensitivity and selectivity of grounding protection and electric leakage protection can be effectively improved.

Description

technical field [0001] The invention relates to the technical field of electric power protection, in particular to a coal mine leakage protection method based on the principle of compensating grounding reactance branch current. Background technique [0002] Leakage protection is one of the three major protections in coal mines. Whether the underground single-phase grounding protection is reliable or not directly affects the safe and reliable operation of coal mines. At present, the problem of underground grounding protection in coal mines is quite prominent, and the phenomenon of false operation and refusal to operate is serious. Leapfrog tripping caused by phase-to-phase and grounding protection is common in underground protection systems. [0003] Since coal mines mainly use cable power supply lines, the capacitive current is very large when there is a ground fault, so the 6KV and 10KV systems of coal mines generally adopt the arc suppression coil grounding method. The lo...

AI Technical Summary

Problems solved by technology

After a grounding fault occurs in the underground cable, the grounding protection is required to operate according to the principle of the smallest power failure range. Due to the compensation effect of the arc suppression coil, it is difficult for the underground grounding protection to operate reliably and accurately.

Ground substations in coal mines with arc-suppression coils can take advantage of the adjustability of arc-suppression coils. It is not difficult to select the grounding line of the ground substation itself, but these technologies and algorithms cannot be applied to underground switches at all levels after multi-level distribution and

Images