Multi-source partial discharge positioning and discharge type identification method for switch cabinet

Abstract

The invention discloses a multi-source partial discharge positioning and discharge type identification method for a switch cabinet. The method comprises the following steps: 1) developing a switch cabinet partial discharge ultrasonic monitoring device which is mainly composed of an ultrasonic sensor, a wireless power frequency synchronization module, a signal conditioning circuit, a signal collection and FPGA preprocessing unit, and device software; 2) detecting an internal ultrasonic signal of the switch cabinet by using the switch cabinet partial discharge ultrasonic monitoring device; 3) calculating equivalent time and equivalent frequency distribution of the ultrasonic signal, and separating the discharge ultrasonic signal from the environmental noise by adopting a map filtering technology and combining with phase map distribution; and 4) on-line locking the multi-source partial discharge positioning of the switch cabinet and judging the discharge type based on the partial discharge ultrasonic signal phase map after the signal-noise separation. According to the scheme, the real-time separation of the discharge signal and the noise signal is realized, and the effects of multi-source partial discharge positioning and discharge type judgment of the switch cabinet are achieved.

Description

technical field [0001] The invention relates to a multi-source partial discharge location and discharge type identification method for a switch cabinet. Background technique [0002] Partial discharge is an early manifestation of insulation failure of various high-voltage power equipment. Although the discharge amplitude is small in the initial stage, it continues to develop and eventually leads to the deterioration of equipment insulation, resulting in discharge phenomenon. Therefore, online monitoring of partial discharge and timely formulation of maintenance plans are one of the important means to ensure the safety and stability of power equipment, and are of great significance to improving the reliability of power supply. [0003] At present, the commonly used partial discharge monitoring methods of switchgear include UHF method, transient ground wave method and ultrasonic method. Among them, the ultra-high frequency method is based on the electromagnetic wave excited b...

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Problems solved by technology

[0004] However, in practical applications, the ultrasonic method is susceptible to interference from environmental noise and on-site mechanical noise, which will affect the sensitivity and accuracy of partial discharge monitoring, and even lead to misjudgment and missed judgment of the operating status of the switchgear in severe cases.

The existing denoising methods mainly include filtering method and wavelet transform method, but both methods will cause distortion of the original ultrasonic signal

At the same time, due to the many types of insulation defects in the switchgear, the discharge signal amplitude, frequency distribution and other characteristics are inconsistent, it is difficult to determine the denoising parameters such as filter cut-off frequency, optimal wavelet function, number of decomposition layers, wavelet threshold and threshold function