Grounding line selection device based on low current

Abstract

The invention discloses a grounding line selection device based on low current. The device comprises a microcomputer and a plurality of zero-sequence transformers, the microcomputer is provided with a serial communication interface, the zero-sequence transformers are connected with the microcomputer via the serial communication interface, and the zero-sequence transformers are connected in parallel to the microcomputer; a voltage transformer is connected with an open delta on the microcomputer, and the voltage transformer, the microcomputer and the zero-sequence transformers form a circuit and are connected to a bus outgoing line; the microcomputer comprises a main control board, a power panel, a display module, an infrared remote controller, an external analog input terminal, an external opening-inserting control button and an alarm circuit; an external opening-inserting quantity input terminal, a relay output terminal, a CAN communication terminal and an insulated resistance monitoring input terminal are integrated on the main control board; the external analog input terminal is connected with the main control board via the power panel; the alarm circuit is connected with the main control board via a communication cable; the external opening-inserting control button is connected with the main control board via the display module; and the infrared remote controller is connected with the main control board via the display module.

Description

technical field [0001] The invention specifically relates to a grounding line selection device based on small current. Background technique [0002] Most of the 3KV-66KV distribution network in my country adopts the small current grounding method, that is, the neutral point non-effective grounding method, including the neutral point non-grounding system and the neutral point grounding system through the arc suppression coil; the advantages of the neutral point non-effective grounding system The reason is that in most cases, the arc can be automatically extinguished and the insulation can be restored when a single-phase ground occurs. However, when a permanent ground fault occurs, in order to prevent the expansion of the fault due to the increase of the non-faulted phase voltage, the fault line must be determined and cut off as soon as possible, which raises the problem of single-phase ground fault line selection; Most of them use a single relay protection device to detect an...

AI Technical Summary

Problems solved by technology

However, when a permanent ground fault occurs, in order to prevent the expansion of the fault due to the increase of the non-faulted phase voltage, the fault line must be determined as soon as possible and cut off. This raises the problem of line selection for single-phase ground faults; Most of them use a single relay protection device to detect and analyze the steady-state characteristics of the fault to select the line when a ground fault occurs; but when a ground fault actually occurs, the relay protection device will be affected by the system operation mode, line length and load. Influenced by many factors such as harmonics, resulting in wrong selection, missing selection, multiple selection

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