Self-adaptive selective leakage protection system and method for mine low-voltage electric network

Abstract

The invention discloses a self-adaptive selective leakage protection system and method for a mine low-voltage electric network. The system comprises a microcontroller module, double Ethernet communication circuit modules, an A / D (Analog-to-Digital) conversion circuit module, a leakage testing circuit module, a key operation circuit module, a noise elimination and filter circuit module, an electric network voltage and zero sequence voltage transmission circuit module, a plurality of branch zero sequence current transmission circuit modules, a liquid crystal display circuit module and a leakage tripping output circuit module. The method comprises the following steps: firstly, signal acquisition; secondly, signal collection, storage, analysis and processing; thirdly, manual leakage test existence judgment; fourthly, manual leakage test failure judgment and judged result output; fifthly, insulation parameter measurement and storage; sixthly, electric network leakage judgment; and seventhly, electric network leakage judged result output and leakage protection. The self-adaptive selective leakage protection system is novel and reasonable in design, strong in self-adaptability for different network structures of a mine power supply system, high in leakage detecting speed, reliable and accurate in action and high in popularization and application values.

Description

technical field [0001] The invention relates to the technical field of mine power supply safety, in particular to an adaptive selective leakage protection system and method for mine low-voltage power grids. Background technique [0002] The underground space of the coal mine is small, the heat dissipation is unfavorable, the air is humid, and there are flammable and explosive gas and coal dust. In this special production environment, strict protection measures must be taken for leakage that may cause electric sparks. The leakage protection of general mine power grid must be quickly judged, accurately select the leakage branch, and reliably act on the trip. In the existing selective leakage protection device, the starting criterion (judgment of whether leakage fault occurs) of leakage selection (judgment selection of leakage branch) is detected by detecting zero-sequence voltage U 0 To achieve, that is, when the zero-sequence voltage is greater than the artificially set zero...

AI Technical Summary

Problems solved by technology

The leak detection relays all contain zero-sequence reactors. Manually adjusted zero-sequence reactors will appear in full compensation and over-compensation states due to changes in the operation mode of the power grid or cutting off part of the power supply line for some reason, so that the power direction of the device will be protected. Enter the dead zone and lose the selective leakage protection function

Moreover, the existing direct current detection type total leakage detection relay can only detect the ground insulation resistance of the power grid, but cannot detect the ground capacitance, can only detect the ground insulation resistance of the power grid, and cannot give a specific The insulation condition of the branch circuit cannot easily judge and select leaks

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