电容耦合电路对变压器的脉冲频率响应研究

Study on Pulse Frequency Response of Capacitor Coupled Circuit to Transformer

针对电力变压器绕组机械故障在线监测问题,提出了一种在线脉冲频率响应分析(IFRA)对变压器运行进行诊断的方法。建立了电容耦合电路和变压器绕组的等效电气模型,研究了电容耦合电路的频率响应对在线脉冲频率响应的影响。模拟了电容被合变化和套管介质去穿引起的电容耦合电路参数变化,并研究了它们对在线脉冲频率响应信号的影响。实验结果表明:在低频段内,在线IFRA信号与绕组信号的趋势相反;在中高频段内,在线IFRA信号与绕组信号的趋势存在恒定的差异,且两个信号的共振和反共振位置相同。

Aiming at the on-line monitoring of mechanical faults in power transformer windings,this paper proposes a method for online pulse frequency response analysis(IFRA)to diagnose transformer operation,establishes the equivalent electrical model of capacitive coupling circuit and transformer winding,and studies the capacitive coupling circuit.The effect of the frequency response on the online pulse frequency response.The changes of capacitive coupling circuit parameters caused by capacitive coupling changes and casing dielectric breakdown are simulated,and their effects on the online pulse frequency response signal are studied.The experimental results show that in the low frequency band,the trend of the online IFRA signal is opposite to that of the winding signal.In the mid-high frequency band,there is a constant difference between the trend of the online IFRA signal and the winding signal,and the resonance and anti-resonance positions of the two signals are the same.