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随着我国电网联系的增强,为降低设备成本,可以不使用电抗器限制工频过电压,在超、特高压输电线路中用快速接地开关(high speed grounding switches,HSGS)来快速熄灭电弧将是一种很好的办法。分析了单相接地瞬时性故障和永久性故障时流过HSGS的电流信号的不同特点。利用Prony法每隔1个工频周期快速拟合该电流信号,提取出工频量的幅值,分析所得到的一系列幅值信息发现,瞬时性故障时工频量的幅值必然从一个稳定值跳跃到另一新值并在新值保持稳定,而永久性故障则不然,据此可判别故障的性质。Prony法对于非平稳信号具有良好的拟合效果,能够实现频率的自适应分解,且克服了傅里叶算法不能处理非平稳信号的缺点,对于信号的变化反应敏感。Matlab/Simulink仿真结果表明了该方法的有效性和准确性。
With the strengthening of China’s power grid, in order to reduce equipment costs, you can not use the reactor to limit the power frequency over-voltage, ultra-high voltage transmission lines with fast ground switches (high GSGS) to quickly turn off the arc will be A good way. The different characteristics of current signals flowing through HSGS during single-phase grounding transient fault and permanent fault are analyzed. The Prony method is used to quickly fit the current signal every one frequency cycle to extract the amplitude of the worker’s frequency. A series of amplitude information is analyzed to find that the magnitude of the worker’s frequency inevitably increases from one The steady value jumps to another new value and remains stable at the new value, whereas the permanent one is not, whereby the nature of the fault can be judged. The Prony method has a good fitting effect on non-stationary signals, and can adaptively decompose frequencies. It overcomes the disadvantage that Fourier algorithms can not handle non-stationary signals and is sensitive to signal changes. Matlab / Simulink simulation results show the effectiveness and accuracy of the proposed method.