Research On Suppression Of Partial Discharge Interference Signal Of AC UHV Transformer

The on-site partial discharge test of the AC UHV transformer is the key assessment method for the transformer installation quality assessment and commissioning.During the test,the partial discharge waveform reading and analysis are required,as well as the identification of the internal insulation defects of the transformer.The UHV transformer is bulky and has a height of more than ten meters.There are many external interference signals in the test,which makes the partial discharge signal unrecognizable and affects the normal development of the test.In response to this problem,this paper combined the characteristics of the field test of partial discharge of UHV transformers,analyzed the interference signals that may occur in the test,and classified and processes these signals.Space electromagnetic interference signals could not be shielded by traditional methods such as single-point grounding method and grounding wire externally insulated sheath.Therefore,this paper focused on the characteristics and suppression methods of space electromagnetic interference.First,laboratory simulation tests were carried out on five typical spatial electromagnetic interferences,and their characteristics were analyzed.Second,the acquisition mode and propagation characteristics of space electromagnetic interference signals in the local partial discharge test were studied.By selecting the capacitive coupling acquisition method,the external interference signal at the scene was obtained,and the source of the electromagnetic interference signal in the field space was compared and judged.Third,study the principle and processing method of space electromagnetic interference signal suppression.Space electromagnetic interference signals were classified into periodic interference and random interference.For these two types of interference,the adaptive filtering technique was used to process periodic interference and the wavelet transform technique was used to process random interference signals.Fourth,through the characteristic analysis of the partial discharge signal and related literature research,the function could be used to simulate the partial discharge signal and to simulate the external space electromagnetic interference signal.The joint scheme of adaptive filtering technology and wavelet transform technology was used to separate the partial discharge signal and the noise signal,which verifies the feasibility of the scheme.Through this research,a treatment scheme for suppressing the partial discharge interference signal of UHV transformer was proposed to ensure the smooth progress of the partial discharge test and ensure the safe and reliable operation of the transformer.