直流输电系统S变换奇异能量谱故障定位

Fault location of HVDC transmission system based on S-transform singular energy spectrum

针对高压直流输系统故障定位中精度不足问题,提出一种基于S变换奇异能量谱的直流输电系统故障定位方法.该方法采用S变换对故障前后一定时间窗的故障行波电压、电流模量信号组进行主频提取,解决了时频域直流输电故障行波信号主频率精确提取问题.但由于故障行波模量间存在耦合和折反射,导致系统各模量主频混叠,辨识困难,为了到达各模量主频辨识,采用奇异能量频谱对故障行波S变换矩阵降维、特征选取、幅值优化、精确分辨,定位系统故障位置.采用PSCAD建立双极直流输电模型对基于S变换奇异能量谱的直流输电系统故障定位予以仿真,结果表明系统定位最小误差率0.001 8%、平均误差率0.097 76%,是一种行之有效的高压直流系统故障定位方法.

Aiming at the problem of insufficient accuracy in fault location of HVDC transmission system,a fault location method for HVDC transmission system based on S-transform singular energy spectrum is proposed.This method uses S-transformation to fault traveling wave voltage and current modulus signals for a certain time window before and after fault.The group performs the main frequency extraction,which solves the problem of accurate extraction of the main frequency of the traveling wave signal in the time-frequency domain direct current transmission.However,due to the coupling and deflection between the fault traveling wave modes,the main frequency aliasing of the system is difficult to identify.In order to reach the main frequency identification of each modulus,the singular energy spectrum is used to reduce the dimension of the fault traveling wave S-transform matrix,feature selection,amplitude optimization,precise resolution,and locate the fault location of the system.Using PSCAD to establish a bipolar direct current transmission model based on S transform,the fault location of the dc power transmission system with singular energy spectrum is simulated.The results show that the minimum error rate of system positioning is 0.001 8% and the average error rate is 0.097 76%.It is an effective fault location method for high voltage DC system.