Injection-type rotor grounding protection secondary circuit breakage judging device, judging method and protection method
A rotor grounding and secondary circuit technology, which is applied in the direction of emergency protection circuit devices, instruments, electrical components, etc., can solve problems such as circuit damage and disconnection, protection device rotor grounding protection refusal to operate, etc., to prevent rotor grounding protection from refusal moving effect
Active Publication Date: 2021-10-01
NR ELECTRIC CO LTD +1
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Problems solved by technology
[0003] The purpose of the present invention is to overcome the deficiencies in the prior art, provide a secondary circuit breakage judging device, judgment method and protection method of the injected rotor grounding protection, and solve the problem that the injection rotor grounding protection does not consider circuit damage in the prior art. Possibility of disconnecting wires, resulting in the technical problem that the protection device may refuse to operate the rotor grounding protection
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[0023] Aiming at the situation that the rotor grounding protection refuses to operate due to the disconnection fault of the rotor secondary circuit, the invention provides an injection type rotor grounding protection secondary circuit disconnection judging device, judging method and protection method. The principle is as follows: theoretical analysis shows that the injection At the moment when the square wave power supply voltage is switched, the level change will cause the generator rotor winding to charge and discharge the ground capacitance, and then generate a charging and discharging transient current on the sampling resistor. When a high-power resistance of a certain injection circuit is disconnected, the equivalent capacitance in the circuit decreases, and the corresponding transient current of the sampling resistor charging and discharging will also decrease. Through simulation analysis, it is found that the transient state of the two cases at the instant of 20ms delay i...
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The invention discloses an injection-type rotor grounding protection secondary circuit breakage judging device, a judging method and a protection method, including a sampling resistor voltage acquisition module, a transient current calculation module, a circuit breakage current threshold calculation module, and a breakage discrimination module , respectively measure the voltage of the sampling resistor under the two working conditions of normal injection rotor grounding loop and disconnection of one of the injection loop high-power resistance, and calculate the transient current of the sampling resistor under the two working conditions; according to the sampling resistance in the two working conditions The transient current under the condition determines the circuit disconnection current threshold; when the real-time transient current of the sampling resistor is less than the circuit disconnection current threshold, it is determined that the secondary circuit of the injected rotor grounding protection is disconnected. The protection device acts after a short delay and outputs an alarm. The invention can identify the disconnection fault of the secondary circuit of the injected rotor, remind the user to check and repair, and prevent the rotor grounding protection from refusing to operate due to the disconnection fault of the secondary circuit of the rotor.
Description
technical field [0001] The invention belongs to the technical field of electric power system relay protection, and relates to an injection type rotor grounding protection secondary circuit disconnection judging device, judging method and protection method. Background technique [0002] Rotor ground faults are common in generator faults, so the reliability of rotor ground fault protection becomes very important. Injection-type rotor ground protection is one of the most widely used rotor ground protection methods in the field. A high-power resistor is connected in series in the secondary circuit of the injection-type rotor ground protection. Due to the high excitation voltage and large harmonic content of the rotor circuit, long-term After operation, the secondary circuit of the rotor may be damaged and disconnected, especially the damage of high-power resistors is more common. If the generator rotor has a ground fault after the secondary circuit is disconnected, the ground r...
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IPC IPC(8): H02H7/08G08B21/18
CPCG08B21/185H02H7/08
Inventor 钟守平王光陈俊张琦雪陈佳胜郭自刚
Owner NR ELECTRIC CO LTD