A Partial Loss of Excitation Fault Identification Method with Pulse Loss

Abstract

The invention discloses a partial loss of excitation fault identification method for pulse loss. By analyzing and comparing the difference between six pulse waves in one cycle of the excitation voltage, the partial loss of excitation fault for pulse loss is identified. When comparing, for each For the pulse data, remove the largest 10% data, which can reduce the impact of the excitation voltage peak on the calculation during rectification and commutation; remove the smallest 50% data, so that the sampling data of the normal pulse wave without missing pulses is basically larger The positive value of the positive value, the average value will not decrease or even close to 0 due to the negative part of the excitation voltage, while the pulse wave average value of the missing pulse is generally close to 0 or less than 0, which is quite different from the pulse wave without missing pulses. Use this difference to identify partial loss of field faults where pulses are missing.

Description

technical field [0001] The invention relates to a partial demagnetization fault identification method for pulse loss, which belongs to the technical field of electric power system relay protection. Background technique [0002] As the protection of total loss of excitation fault caused by loss of excitation or partial loss of excitation fault caused by reduced excitation, loss of excitation protection is already one of the protections that must be configured for synchronous motors with excitation systems such as generators and condensers. [0003] Pulse loss is one of the types of faults that lead to partial loss of excitation. After the pulse is lost, the average value of the excitation voltage will decrease to a certain extent due to the decrease in the output pulse number of the rectifier circuit of the excitation system. Since the average value of the excitation current is proportional to the average value of the excitation voltage, the average value of the excitation cu...

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Problems solved by technology

[0003] Pulse loss is one of the types of faults that lead to partial loss of excitation. After the pulse is lost, the average value of the excitation voltage will decrease to a certain extent due to the decrease in the number of output pulses from the rectifier circuit of the excitation system.

Since the average value of the field current is proportional to the average value of the field voltage, the average value of the field current will also decrease, resulting in a partial loss of field fault

[0004] At present, the criterion of the rotor side of the loss-of-excitation protection configured for generator protection or condenser protection is the criterion of excitation low voltage. The voltage criterion can only simply judge the magnitude of the excitation voltage, but cannot judge whether the excitation voltage has a fault of pulse loss

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