交流电网主动防御直流偏磁体系

为了有效预防直流偏磁危害，提出交流电网主动防御直流偏磁体系，包括交流电网现阶段直流偏磁风险评估、治理以及电网扩建阶段的风险评估、优化。提出了基于等效绕组直流电流的变压器偏磁情况评价方法。以湖北电网为例，通过调整交流电网运行方式后，湖北电网各变电站的绕组等效直流电流均降为10 A以下，杨家湾站绕组等效直流电流下降62.4%，安福寺站绕组等效直流电流下降53.2%。运用遗传算法的交叉、变异模块，对湖北电网的直流偏磁措施进行优化布点，优化布点后系统绕组等效直流电流下降50.95%。运用人工蜂群优化算法，对新建变电站站址进行优化计算，使得新建变电站直流偏磁风险最小，对直流偏磁最严重的朝阳变电站站址进行重新规划后，朝阳站绕组等效直流电流下降了71.3%。

DC Bias Active Defense System for AC Power Grid

In order to effectively prevent damage caused by DC bias, an active defense system for AC power grid is proposed. The system includes not only DC bias current risk evaluation and improvement for current network, but also evaluation and optimization for future grid expansion. A transformer DC bias evaluation method is proposed based on equivalent winding DC current. Taking Hubei power grid for example, winding DC currents of all transformers in Hubei power grid are reduced to below 10 A by adjusting operation method. Equivalent winding DC current of Yangjiawan Station drops by 62.4%, and that of Anfusi Station drops by 53.2%. Crossover and mutation of genetic algorithm module is used for optimizing stationing of DC bias suppression measures in Hubei power grid, after which the equivalent winding DC current of the whole system decreases by 50.95%. Artificial colony algorithm is used for optimization of substation site selection to minimize the DC bias risk of the new-built substation. Equivalent winding DC current of Chaoyang substation decreased by 71.3% after site optimization.