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由于缺乏对直流电流全局分布的考虑,传统隔直装置投切方法容易造成区域内其他变压器出现中性点直流电流被动超标.为了有效地指导偏磁治理工作,提出一种基于隔直装置全局优化投切的偏磁治理方法.首先根据直流电位衰减规律确定交流系统建模范围,其次结合交流系统等效电阻网络、变电站与接地极地理位置分布情况,采用场–路耦合分析思想建立全局隔直装置优化投切数学模型,最后以全局中性点直流电流最大值最小为目标进行寻优,得到最优投切方案.通过宜昌地区电网实际参数验证所提方法(基于穷举法寻优)隔直效果优于传统方法,同时为了保证在交流系统规模扩大后寻优的效率,采用多种智能方法对优化问题进行求解,验证了智能算法同样可以实现趋近于穷举法的隔直效果.“,”The conventional switching method of DC blocking devices can easily lead to the current through neutral point of other transformers in regional network over standard passive, due to the lack of consideration of the global distribution of DC current. To effectively guide the suppression of DC bias, an optimization approach for the switching of DC blocking devices was presented. Firstly, the model scope of AC system was determined by the attenuation law of DC voltage in the soil. Besides, the mathematical model for global optimal switching of DC blocking devices was established by field-circuit coupling method with the equivalent resistance network of AC system and the location distribution of substations and ground electrodes. Finally, the optimal scheme can be obtained by minimizing the maximum DC current through the neutral point of transformer. With the actual parameters of Yichang power grid, the superiority of the proposed method (optimizing by exhaustive method) is verified by comparing the result of conventional method. Furthermore, in order to ensure the efficiency of optimization when the scale of AC system is enlarged, various intelligent algorithms are used to solve the optimization problem which verify that the result of intelligent algorithm can also approximated to that of the exhaustive method.