基于移动三采样点法的短路故障电流过零点预测研究

Research on zero crossing prediction of short-circuit fault current based on moving three sampling points method

提出采用移动三采样点法进行短路故障电流参数辨识,根据短路电流数学模型,利用采样电流值不断求解电流模型特征参数,进而还原短路电流波形和预测短路电流过零点。在仿真软件中设置理想信号进行算法原理正确性验证,结果表明移动三采样点法计算得到的电流模型参数误差小、电流波形拟合度高,能快速并精确预测短路电流过零点。在离线仿真软件中构建电力网络模型,仿真得到各种工况下短路电流数据,结合实际短路故障录波数据进行算法有效性验证,结果表明移动三采样点法零点预测精度高,误差均小于1 ms,满足相控开断要求。最后将移动三采样点法与改进递推最小二乘法进行比较,结果表明移动三采样点法具有预测时间较短的优点。

The moving three sampling points method is proposed to identify the parameters of short-circuit fault current,the characteristic parameters of the current model are continuously solved by using the sampled current value according to the mathematical model of short-circuit current,so as to restore the short-circuit current waveform and predict the zero crossing point of the short-circuit current.In the simulation software,the ideal signal is set to verify the correctness of the algorithm principle.The results show that the error of current model parameters calculated by the moving three sampling points method is small,the current waveform fitting degree is high,and the short-circuit current zero-crossing point can be predicted quickly and accurately.The power network model is built in the off-line simulation software,the short-circuit current data under various working conditions are obtained by simulation,and the algorithm effectiveness is verified by combining with the actual short-circuit fault recording data.The results show that the zero-crossing prediction accuracy of the moving three sampling points method is high,and the prediction zero error is less than 1 ms,which meets the requirements of phase-controlled interruption.Finally,compared with the improved recursive least square method,the moving three sampling points method has the advantage of shorter prediction time.