基于改进NSGA2算法的考虑风机接入电能质量的多目标电网规划

Improved NSGA2 Algorithm Based Multi-objective Planning of Power Grid With Wind Farm Considering Power Quality

大规模风电并网必然会给电力系统带来一系列的电能质量问题,为保证电网投资经济性和电能质量最优,考虑风机出力以及负荷预测的不确定性,利用机会约束规划方法构建了以线路总长度最短,风电场并网公共连接点处的电压闪变水平最低为目标的风电场多目标电网规划模型。针对传统优化算法的目标权重人为选择以及常规NSGA2算法的局部收敛等问题,提出将正态分布交叉(normal distribution crossover,NDX)算子引入到NSGA2算法中,借助NDX算子加强算法的全局搜索能力,优化出最佳的电网规划方案。对IEEE6节点系统的仿真结果表明所提方法具有较高的决策效率,得到的含风电场电网的规划方案,在保证经济性的同时,也使风机并网点的电能质量达到更高的品质。

Large scale wind farms connected to grid would bring power system a series of power quality problems. In order to ensure power grid investment economy and power quality optimization, considering the uncertainty of power output of wind farm and load forecasting, chance-constrained planning method based the multi-objective planning model for power network containing wind farm was constructed with the goals of the shortest line and the least voltage flicker level of point of common coupling（PCC）. Aiming at the problems of man selection of the weight for each objective of traditional optimization algorithm and local convergence of conventional NSGA2 algorithm, the normal distribution crossover（NDX） was introduced into NSGA2 algorithm to enhance the global search ability, so as to obtain the best optimization scheme of power network planning. IEEE 6-bus system was used as an example, and the simulation results show that the proposed method has higher efficiency of decision-making. Besides, the optimal planning scheme improves power quality of PCC while ensuring the investment economy.