电力变压器局放信号检测的阈值法除噪技术

Valve-value Methods for Eliminating Noises in Transformer Partial Discharge Signal's Detection

以有效抑制电力变压器局放检测中的干扰信号为目的,从阈值的选取和算法上的改进两方面着手,介绍了3种基于小波变换的去噪方法,包括软硬阈值结合法、依据BirgeMassart策略确定阈值降噪法和模平方处理方法。以高压实验室实际超高频法检测变压器模型放电信号为对象,考察了各种方法去噪的优点和不足。结果表明各方法有各自的适应性,在实际应用中应根据实际情况加以选择使用。去噪结果表明此些方法有效、可行,从而为电力变压器局放信号检测的去噪环节提供了有效的参考依据。

In order to restrain effectively the interferential signals of transformer partial discharge, the paper proposes three methods for eliminating noises based on wavelet transform technique: (a) a method that combines both soft and hard valve values, (b) a method that determines the valve value according to the Birge-Massart strategy, and (c) a method that uses module square, from two aspects, namely, proper selection of valve value and algorithm improvement. The proposed methods have been applied to the actual laboratory discharge signal of transformer model, which is detected by the UHF. The results show that these methods are applicable and significantly effective although they have their own merits and drawbacks. These methods are useful for providing effective reference for eliminating noise of transformer partial discharge signal’s detection.