Partial discharge direction finding method based on ultrahigh-frequency phased array principle in substation

Abstract

The invention discloses a partial discharge direction finding method based on an ultrahigh-frequency phased array principle in a substation. The method includes following steps: (1) acquiring and recording partial discharge signals in the substation by employing the ultrahigh-frequency phased array and a digital detection device with high sampling rate; (2) focusing the partial discharge signals to form narrowband signals at a reference frequency point by employing a broadband focusing algorithm; (3) performing direction-of-arrival estimation on the narrowband signals by employing a narrowband direction finding algorithm; and (4) obtaining the point with maximum azimuth density with combination of multiple direction-finding results, namely the azimuth of the partial discharge signals. According to the method, the size of the ultrahigh-frequency phased array is small so that tour inspection is facilitated, and the spatial resolution is high; and according to the method, for the partial discharge signals in the substation, the partial discharge signals are converted to the narrowband signals by employing the focusing algorithm, and the azimuth of the partial discharge signals is obtained by employing the direction finding algorithm so that the direction-finding precision is high, and the ability of suppressing noise interference is great.

Description

Technical field: [0001] The invention relates to the field of partial discharge detection, in particular to a partial discharge direction finding method based on the UHF phased array principle in a substation. Background technique: [0002] Partial discharge is not only the main cause of insulation failure of power equipment, but also an important symptom and detection method of insulation defects. At present, the partial discharge detection based on ultra-high frequency technology carried out at home and abroad usually installs the sensor on specific single equipment such as gas-insulated combined electrical equipment and transformers. The partial discharge detection and direction finding of substation equipment are mainly for specific equipment, and all power equipment in the substation may have partial discharge. If a partial discharge monitoring system is installed on secondary equipment such as bushings and circuit breakers, the cost is extremely high and the maintenanc...

AI Technical Summary

Problems solved by technology

At present, the partial discharge detection based on ultra-high frequency technology carried out at home and abroad usually installs the sensor on specific single equipment such as gas-insulated combined electrical equipment and transformers. The partial discharge detection and direction finding of substation equipment are mainly for specific equipment, and all power equipment in the substation may have partial discharge. If a partial discharge monitoring system is installed on secondary equipment such as bushings and circuit breakers, the cost is extremely high and the maintenance workload is also heavy. Therefore, relevant scholars at home and abroad A partial discharge detection and location system in open substation based on UHF sensor array is proposed

[0003] The existing substation partial discharge detection and positioning system based on UHF sensor array adopts the time difference principle. The inventors found that this method has the following disadvantages: the antenna array is too large, which is not conducive to inspection; when the signal-to-noise ratio is low, The accuracy of time delay calculation is reduced; the time difference equation is a nonlinear equation, and the calculation is complicated

This algorithm has high direction finding accuracy, low resolution threshold and estimation deviation, but it can only be used to process narrowband signals, not suitable for direction finding of broadband partial discharge signals

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