V2G模式下城市电网电压质量概率评估方法

Probabilistic Evaluation Method of Voltage Quality for Urban Power Network Considering Vehicle to Grid

传统基于确定性潮流和静态概率潮流的电压质量评估方法无法考虑到城市电网中不确定因素的时变性,因此将动态概率潮流应用于电动汽车与电网双向能量传输(vehicle to grid,V2G)模式下的城市电网电压质量评估。建立城市电网中基础负荷和电动汽车功率的动态概率模型,运用基于半不变量法的动态概率潮流算法求得城市电网节点电压概率分布,进而得到1 d中城市电网电压合格率,最终评估V2G模式下城市电网的电压质量。仿真结果表明:电动汽车以V2G模式接入会造成城市电网电压质量下降,但相比于无序充电方式,V2G模式下城市电网电压质量较高,评估结果对未来V2G控制策略的制定以及城市电网规划都具有重要的参考价值。

Conventional power quality evaluation methods based on deterministic power flow and static probability power flow fail to consider time-variability of uncertain factors in urban power network. Therefore, dynamic probability power flow is applied to evaluate voltage quality for urban power network considering vehicle to grid （V2G）. Dynamic probability models of basic load and electric vehicle＇s power are built. Probabilistic distributions of node voltage in urban power network are obtained using dynamic probability power flow based on cumulant method. And then daily voltage qualified rate of urban power network is acquired. Finally, voltage quality for urban network considering V2G is evaluated Simulation results show that electric vehicles under V2G mode can result in decline of voltage quality of urban power network. But voltage quality of urban network under V2G mode is still superior to that under uncoordinated charging mode. Evaluation results have important reference values for formulating V2G control strategy and planning urban power network in future.