基于振动的油浸式电力变压器短路累积效应试验研究

Experiment on Short Circuit Cumulative Effect of Oil-immersed Power Transformer Based on Vibration Signals

针对绕组累积损伤有可能导致变压器突发性故障,严重威胁电网安全稳定运行的问题,以某油浸式电力变压器为研究对象,对其进行多次短路试验。通过分析短路试验前后及短路试验过程中油箱壁振动信号的变化规律,发现多次短路冲击后,无论短路电抗变化超标与否,变压器振动信号的频谱、幅值,铁心振动信号的基频幅值与施加电压平方的线性关系、以及绕组振动信号的基频幅值与流过绕组的负载电流平方的线性关系都会发生明显变化。试验结果表明,多次短路冲击会使变压器内部产生机械累积损伤,振动信号能够比较灵敏反映这种短路累积效应的特征量。

In allusion to the problem of sudden fault of the transformer probably caused by winding cumulative damages which may seriously threaten safe and stable operation of the power grid, one oil-immersed power transformer is taken for studying short circuit experiments. By analyzing change law of vibration signals of the oil tank wall before and after experi- ments and in the process of short circuit experiments, it is observed that after several times of short circuit impact, no matter whether change of short circuit reactance exceeds standard or not, frequency spectrum and amplitude of vibration signals of the transformer, linear relationship between fundamental frequency amplitude of vibration signal of the iron core and square of applied voltage as well as linear relationship between fundamental frequency amplitude of winding vibration signals and square of load current flowing through winding will all change obviously. Experimental results indicate that repeated short circuit impact will produce mechanical cumulative damages inside the transformer and vibration signals can sensitively reflect characteristic quantity of this kind of short circuit cumulative effect.