Local discharge development process diagnosis method based on pulse-train analysis

Abstract

The invention discloses a local discharge development process diagnosis method based on pulse-train analysis. The diagnosis method comprises extracting pulse-train characteristics and building a fingerprint library and a discharge type and development process determination course; the diagnosis method specifically comprises the steps of firstly, acquiring a local discharge signal under a typical defect condition and preprocessing the signal, secondly, carrying out pulse-train characteristic extraction and analyzing the characteristic quantity by use of three spectrograms including a delta u spectrogram, a delta t frequency distribution diagram and a delta u / delta t spectrogram, extracting 9 characteristic parameters from the three spectrograms and building a discharge fingerprint library, and finally, finding out the discharge type and the discharge development stage both having the highest similarity to data to be diagnosed from the fingerprint library by use of the minimum Euclidean distance as diagnosis conclusions. The local discharge development process diagnosis method based on the pulse-train analysis is characterized in that the discharge information is utilized sufficiently, the influence of space charges and surface charges generated by last discharge on subsequent discharge is taken into account, and the algorithm implementation process is simple and the recognition rate is high; as a result, the local discharge development process diagnosis method is applicable to the diagnosis of the local discharge type and the discharge development process in a power device and assessment on discharge hazard.

Description

【Technical field】 [0001] The invention relates to a partial discharge detection technology in the technical field of high voltage and insulation, in particular to a method for diagnosing the development process of partial discharge based on pulse sequence analysis. 【Background technique】 [0002] During the operation of power equipment, its insulation will gradually deteriorate under the joint action of electrical, thermal, mechanical and environmental factors, resulting in a decrease in the mechanical strength or insulation performance of the insulation system. In terms of electrical aging, it is generally considered to be caused by partial discharge. Domestic and foreign studies have shown that partial discharge can effectively reflect the internal insulation faults of large equipment such as transformers and bushings, especially for early fault detection, which is much more effective than dielectric loss measurement and oil chromatography analysis. Therefore, detecting t...

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Problems solved by technology

However, there are still two key problems when evaluating the development degree of discharge and equipment insulation status (remaining life) based on the measurement results: (1) The phase distribution characteristics of different discharge types are described based on the partial discharge PRPD spectrum, but there is no Considering the discharge time series, that is, the interaction between successive discharges, space charge effects, etc. are not considered; (2) Under the same defect, no effective characteristic parameters can be extracted to characterize the discharge development degree from the beginning of the discharge to the breakdown process

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