A three-half connection mode current loop inspection and short circuit operation method

Abstract

The invention provides a short-connection operation method for current loop maintenance employing a three-second connection mode. The short-connection operation method comprises the steps of paving an insulating pad; detecting current values of terminals at a secondary side and a protective side of a terminal box separately and determining a fault current transformer, a normal current transformer and the terminal, corresponding to the fault current transformer, at the secondary side; finding out each connecting sheet corresponding to the fault current transformer from the terminal box and sequentially disconnecting each found connecting sheet; grounding one end of a ground wire, connecting the other end of the ground wire and a Cn phase of the fault current transformer, and carrying out short-connection on the terminal at the secondary side of the fault current transformer through a short-connection line according to the short-connection order of a Cn-phase, a Cc-phase, a Bn phase, a Bb phase, an An phase and an Aa phase; after the fault current transformer is maintained, reversely dismantling the short-connection line and dismantling the ground wire; and reconnecting each broken connecting sheet. Through implementation of the short-connection operation method, the inaccuracy of the operation method in the prior art can be overcome; and maloperation of a protection device is avoided.

Description

technical field [0001] The invention relates to the technical field of substation maintenance, in particular to a short-circuit operation method for maintenance of a current loop in a three-half connection mode. Background technique [0002] Such as figure 1 As shown, in a 500kV substation three-half circuit breaker wiring circuit, the main protection adopts the secondary side and current of two current transformers, that is, the tripping protection current of the protection device is the current phase of the secondary side of the two current transformers. When the maximum value of the sum is added, when one current transformer is out of service and the other current transformer continues to operate, the protection is still in the operating state. If the method is not correct, it may cause the protection device to malfunction during the operation. [0003] For example, in the absence of any safety measures, the on-site staff blindly used short-circuit wires to short-circui...

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Problems solved by technology

[0002] like figure 1 As shown, in a 500kV substation three-half circuit breaker wiring circuit, the main protection adopts the secondary side and current of two current transformers, that is, the tripping protection current of the protection device is the current phase of the secondary side of the two current transformers. When the maximum value of the sum is added, when one current transformer is out of service and the other current transformer continues to operate, the protection is still in the operating state. If the method is not correct, it may cause the protection device to malfunction during the operation.

[0003] For example, in the absence of any safety measures, the on-site staff blindly used short-circuit wires to short-circuit the CT-2-Aa phase and CT-2-An phase of the secondary side of the CT-2 current transformer. The resistance is equivalent to the coil resistance of the protection device, and the short connection will generate a shunt, which will cause an unbalanced current to occur, which will cause the protection device to trip

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