Low current grounding route selection system and determining method

Abstract

The invention discloses a low current grounding route selection system and a determining method. The low current grounding route selection system comprises high frequency traps, band pass filters, a high frequency signal source, and a high frequency signal relay protection device. The route selection systems are disposed on outlet wires electrically connected with three-phase power supply busbars. The outlet wires comprise three phase outlet wires, which are respectively A phase outlet wires, B phase outlet wires, and C phase outlet wires. One high frequency trap is disposed on every phase outlet wire between the corresponding three-phase power supply busbars, and the head part and the end part of every phase outlet wire are respectively provided with one high frequency trap. Every phase outlet wire between two high frequency traps is connected with the corresponding high frequency signal relay protection device by the corresponding band pass filter. Every phase outlet wire is connected with the corresponding high frequency signal source by the corresponding band pass filter. The above mentioned system and the determining method adopting the above mentioned system are advantageous in that which one of the outlet wires among the three phases of the three-phase power supply busbar is grounded is determined quickly.

Description

technical field [0001] The invention relates to the technical field of power grids, in particular to a small current grounding line selection system and a judging method. Background technique [0002] When a single-phase grounding occurs in a neutral point indirect grounding grid (also known as a small current grounding system), since the current at the fault point is very small, and the line voltage between the three phases remains symmetrical, it has no effect on the power supply of the load. Therefore, in general, it is allowed to continue to run for 1 to 2 hours without tripping immediately, which is also the main advantage of using neutral point indirect grounding operation. However, after a single phase is grounded, the voltage of the other two phases to ground will increase. times. In order to prevent the fault from further expanding into a two-point or multi-point grounding short circuit, a signal should be sent in time so that the operator can take measures to el...

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Problems solved by technology

[0005] The purpose of the present invention is to solve the problem in the prior art that it is impossible to accurately judge which outgoing line is grounded among the outgoing lines between the three-phase power bus bars, and hereby provide a small current grounding line selection system and a judgment method

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