基于直流电流有限时域预测算法的换相失败预防策略

针对故障暂态期间直流电流精确预测困难的问题,建立了含平波电抗器的直流线路暂态数学模型。计及暂态期间换相角变化的影响,提出一种直流电流变化量的预测方法,可准确预测暂态期间的直流电流变化。构建了基于换相期间直流电流变化量的换相失败预测判据,以实现首次换相失败的预测判别,并提出一种可有效预防首次换相失败的控制策略。基于PSCAD/EMTDC仿真平台搭建了CIGRE直流标准测试模型,不同故障情况下的仿真结果验证了所提方法及控制策略的有效性。

Preventive Strategy for Mitigation of Commutation Failure Based on Finite Time Domain Prediction Algorithm of DC Current

In order to solve the difficulties in the accurate prediction of DC current during fault transient period, a DC line transient mathematical model with flat wave reactor is presented. Considering the change of overlap angle during transient period, a prediction method of DC current variation is proposed for the accurate prediction of DC current variation. And a commutation failure prediction criterion based on DC current variation during commutation is constructed to realize the prediction of the first commutation failure. Meanwhile, a control strategy which can effectively prevent the first commutation failure is proposed. The DC system model of CIGRE high voltage direct current (HVDC) benchmark model is built based on PSCAD/EMTDC simulation platform. The simulation results of different fault situations reveal that the proposed method and control strategy are effective.