Method and device for diagnosing failure state of circuit breaker

Abstract

The invention provides a method and device for diagnosing the failure state of a circuit breaker. The method comprises the following steps of obtaining a current signal characteristic value f0 (t10, i10 and S0) of an opening and closing coil in a circuit breaker predelivery test; obtaining a current signal, in the power-on process, of the opening and closing coil of a circuit breaker to be tested; performing morphological filtering processing on the current signal to obtain the de-noised current signal of the opening and closing coil of the circuit breaker to be tested; calculating a corresponding characteristic value f1(t11, i11 and S1) of the de-noised current signal; judging whether the value meets the formula shown in the specification; if the value meets the formula shown in the specification, further judging whether the value meets a formula shown in the specification; if the value does not meet the formula shown in the specification, judging that an iron core of the circuit breaker is normal and a power supply of the opening and closing coil fails; if the value does not meet the formula shown in the specification, further judging whether the value meets the formula that (S1-S0)/S0 is larger than theta; if the value meets the formula that (S1-S0)/S0 is larger than theta, judging that starting lagging failures happen to the iron core of the circuit breaker. According to the technical scheme, the diagnosing efficiency can be improved, and the diagnosing precision can be obviously improved. The requirement that the circuit breaker is diagnosed online on site can be well met.

Description

technical field [0001] The invention relates to the technical field of circuit breaker monitoring, in particular to a method for diagnosing a fault state of a circuit breaker and a device for diagnosing a fault state of a circuit breaker. Background technique [0002] Circuit breakers are important devices in power systems. The reliability of circuit breaker performance is directly related to the operation reliability of the entire power grid, so the real-time evaluation of the working status of circuit breakers is of great significance. More and more different online monitoring methods have been proposed. Existing literature usually uses wavelet transform method to extract the waveform characteristics of the monitored object, or only records the characteristic points of the monitored object waveform without any processing. Correspondingly, in terms of state evaluation and fault diagnosis of high-voltage circuit breakers, the existing literature can only make judgments base...

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Problems solved by technology

[0003] Zhang Yongkui of Hebei University of Technology and others published a DSP-based hardware circuit in the second issue of Volume 49 of "High Voltage Apparatus (High Voltage Apparatus)". Through the combination of wavelet analysis and dynamic time warping, the signal is processed and the circuit breaker is identified. The method of fault type, however, this method introduces wavelet decomposition, which reduces the speed of signal processing and is not conducive to the real-time monitoring of circuit breakers

[0004] In the Chinese invention patent with the publication numb

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