基于光伏并网点电压优化的配电网多时间尺度趋优控制

Multi-time-scale Slack Optimal Control in Distribution Network Based on Voltage Optimization for Point of Common Coupling of PV

为应对高比例分布式光伏并网引起的电压越限和电压波动问题,充分发挥光伏逆变器的实时无功调节能力,提高光伏消纳率,提出基于光伏并网点电压优化的配电网多时间尺度趋优控制方法。长时间尺度下,建立以配电网运行成本期望值最小为目标,考虑状态变量机会约束的两阶段动态随机优化调度模型,制定传统无功电压设备和光伏并网点电压的经济趋优调度计划。短时间尺度下,以并网点电压调度值为追踪目标,提出基于并网点PV-PQ-QV节点类型转换的自适应趋优控制策略,实时调整光伏无功出力和有功削减量。为提高算法效率,提出二阶锥规划与基于拉丁超立方采样概率潮流交互迭代的随机最优潮流解耦法求解两阶段动态随机优化调度模型。算例结果表明,所提方法能够有效解决配电网实时运行过程的电压安全问题,并提高系统运行的经济性。

In order to solve the problems of voltage violation and voltage fluctuation caused by high proportion of distributed photovoltaic (DPV) in distribution network (DN), take full advantages of the reactive power adjusting capacity of photovoltaic (PV) inverter in real time and improve the accommodation rate of PV, a slack optimal control method in DN based on voltage optimization of point of common coupling (PCC) for PV via multi-time-scale coordination is proposed. On the long-time-scale, a two-stage dynamic stochastic optimal dispatch (DSOD) model considering chance constraint of state variables is built to minimize the operation cost, and an economic slack optimal dispatching plan of traditional reactive power and voltage equipment and PCC voltage of PV is developed. On the short-time-scale, in order to track the PCC voltage dispatching value, an adaptively slack optimal control strategy based on node type transformation of PCC is proposed to adjust the real-time reactive power output and active power curtailment of PV. In order to improve algorithm efficiency, a stochastic optimal power flow decoupling method by interactive iteration between second-order cone programing and probabilistic power flow based on Latin hypercube sampling is proposed to solve the two-stage DSOD model. The simulation results show that the proposed method can effectively solve the problems of voltage security and improve the operation economy of DN in real-time mode.