基于扩展Debye模型仿真的回复电压特征量分析

Analysis of RVM Characteristics Based on the Extended Debye Model Simulation

回复电压测量方法(return voltage measurement,RVM)能有效检测变压器固体绝缘的含水量,然而对于含有局部峰值点的回复电压极化谱难以给出明确的诊断结论。文中在扩展Debye模型基础上,仿真分析了模型参数变化对极化谱和主时间常数CTC、回复电压峰值最大值Urmax的影响规律,并提出将扩展Debye模型不同时间常数支路数作为新的特征量,最后验证了该特征量的可行性。仿真和试验结果表明:RVM极化谱前、中、尾3部分分别对应着油纸绝缘变压器油中偶极子转向极化、油纸界面极化和绝缘纸内偶极子转向极化、纸内界面极化;油纸绝缘老化会使扩展Debye模型各支路极化电阻减小,极化电容增大,时间常数减小;当变压器油老化严重时,极化谱有可能出现局部峰值;扩展Debye模型各时间常数支路数可作为新的RVM特征量,各时间常数支路数的变化也可使极化谱产生局部峰值,现场试验也验证了新特征量的有效性。

Return voltage measurement （RVM）method can effectively detect the transformer solid insulation moisture content, but it is difficult to get the definite diagnostic results from polarization spectrum with multi- ple local peaks. This paper analyzed influence law of circuit parameters change on polarization spectrum and CTC, Um~ based on the extended Debye model simulation, and put forward branch number of the extended De- bye model as a new characteristic, finally verified the feasibility of this characteristic. Simulation and ex- perimental results show that： The front of RVM polarization spectrum depends on oil dipole steering polar- ization of transformer ; The middle of RVM polarization spectrum depends on oil-paper interfacial polariza- tion; The end of RVM polarization spectrum depends on dipole steering polarization and interfacial polariza- tion in insulation paper. Oil-paper insulation aging will increase polarization capacitance, decrease polariza- tion resistance and time constant of each extended Debye model branch. There may be a partial polarization spectral peak when the transformer oil aging serious. Branch number of extended Debye model could be used as a new RVM characteristic and changing of branch number may produce local peaks of polarization spectrum. Moreover the front of the polarization spectrum＇s local peaks reflected the condition of the trans- former insulation oil and field test also verified the validity of the new characteristic.