基于Hilbert变换的串联电容补偿线路距离保护

Distance Protection for Series Capacitor Compensated Lines Based on Hilbert Transform

利用Hilbert变换得到了实信号幅值函数的特点,分析了串联电容前后故障时故障电流幅值函数的不同:串联电容前故障时,幅值函数不能表征故障电流的包络线;串联电容后故障时,幅值函数可以表征故障电流的包络线。据此提出了基于Hilbert变换的串联补偿线路故障点位置的识别判据,结合传统的距离保护形成了适用于串联补偿线路的距离保护新方案,能有效解决超越问题。PSCAD仿真验证了该方案的有效性。

The characteristics of the amplitude function of real signals are obtained by means of Hilbert transform,and the distinction between the current amplitude function when a fault occurs before and after the series capacitors is analyzed.When the fault occurs in front of the capacitors,the amplitude function cannot characterize the envelope curve of the fault current.On the contrary,the amplitude function can characterize the envelope curve of the fault current when the fault occurs after the capacitors.Accordingly,a new fault point recognition criterion for series compensated lines is derived based on the Hilbert transform.It is integrated with the traditional distance protection to form a new series compensated line protection scheme which can effectively avoid the overreach problem and ensure sufficient sensitivity.The availability of this scheme is verified by PSCAD simulation.