Opening and closing device

Abstract

The invention discloses an opening and closing device, comprising: a first voltage relay, which closes the contacts when the increased value of the zero-sequence voltage in the secondary circuit reaches a preset value; a first time relay, which is used to After the contact of the first voltage relay is closed, the contact is closed after a delay of t1; the first intermediate relay is used to close the trip contact of the primary loop operating handle after the contact of the first time relay is closed; the second time The relay is used to close the contact after a delay of t2 after the contact of the first voltage relay is closed; the second intermediate relay is used to trip the secondary circuit operation handle after the contact of the second time relay is closed. The contact is closed. The opening and closing device provided by the present invention can automatically open and close the first circuit, the second circuit and the third circuit, realize rapid and reliable removal of the ground fault line of the 6kv neutral point ungrounded system, reduce the scope of influence, and ensure personal safety .

Description

technical field [0001] The invention relates to grounding protection of power supply system lines, in particular to an opening and closing device. Background technique [0002] At present, the 6KV neutral point ungrounded power supply system is widely used in equipment such as box transformers and distribution stations. [0003] In the prior art, for the grounding protection of the 6KV neutral point ungrounded power supply system line, the line selection trip is usually realized by collecting unbalanced (zero-sequence) current. When the zero-sequence current reaches the preset value, the relay is controlled to trip, but the zero-sequence The current is not easy to collect, and it is often not enough to reach the action of the device and trip the circuit breaker. [0004] Based on this, the inventor of the present application found that, despite repeated transformations, replacement of the transformer transformer and upgrading of the main board of the protection device, the ...

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Problems solved by technology

[0003] In the prior art, for the grounding protection of the 6KV neutral point ungrounded power supply system line, the line selection trip is usually realized by collecting unbalanced (zero-sequence) current. When the zero-sequence current reaches the preset value, the relay is controlled to trip, but the zero-sequence The current is not easy to collect, and it is often not enough to reach the action of the device and trip the circuit breaker

[0004] Based on this, the inventor of the present application found that, despite repeated transformations, replacement of the transformer transformer and upgrading of the main board of the protection device, the problem of accurate tripping of the faulty line was not solved, so that the power supply of the electrical equipment was in a state where the voltage of one phase decreased and the voltage of two phases increased for a long time state, thereby damaging electrical equipment and voltage transformers and cables on power supply lines, and even personal electric shock accidents

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