中性点串接小电阻均摊电网GICs的计算方法

Calculation Method for Allocating Averagely GICs of Power Grid By Placing Small Resistor in Neutral-point

流经变压器中性点的地磁感应电流(geomagnetically induced current,GIC)的大小不同,在GIC较大的变压器中性点采用串接电容器的方法治理GIC,会造成GIC故障高风险节点转移,使影响的范围扩大。基于中性点串接小电阻减轻GIC对高风险节点变压器的影响,提出了全网变压器均摊电网GIC的解决思路,考虑双电压等级电网GIC的相互影响,研究了均摊电网GIC的建模方法,以及不同类型的变压器、大地电性构造和电网结构等因素影响的处理方法;以变压器的中性点GIC量值、串接电阻量值和治理投资成本最小等目标函数为约束条件,提出了基于非支配排序遗传算法(elitist nondominated sorting genetic algorithm,NSGA-II)的中性点串接小电阻均摊电网GIC的优化算法。仿真验证的结果表明,基于NSGA-II的优化算法能获得较好的Pareto最优解集,且加权带精英策略的优化串接小电阻均摊电网GIC计算方法有效。

Due to the difference of magnitude of （geomagnetically induced current,GIC） flowing through neutral transformer groundings, a scheme for mitigating the adverse effects by installing capacitor at transformers which are the most vulnerable effects to GIC can redirect the flow of GIC to the neighboring transformers and potentially exacerbate the effects. Base on the thinking of installing small resistor at neutral point of transformers for reducing the risk of GIC and allocating averagely GIC of all transformers in the grid, considering the characteristics of GIC interaction in a dual-voltage-level power, the paper proposed the modeling method of GIC and approaches of the type of transformers, the structure of earth electrical properties, the topology of the gird. The non-dominant sorting genetic algorithm （NSGA-II） was used for optimal placement small resistor in transformer neutral point to averagely allocate the GIC of power grid, while satisfying minimizes the maximal value of GIC in transformer neutral point, the total cost and value small resistor placement. Research results show that the NSGA-II has better distribution of the Pareto solution set, and were validity in terms of optimal placement of small resistor to averagely allocate the GIC by the method of weighted elitist.