基于随机因子及优化下垂的多端直流配电网控制策略

Control Strategies for Multi-terminal DC Distribution Network Based on Random Factor and Optimized Droop

多端直流配电网通常采用下垂控制策略以实现潮流的优化调配,与无需站间通信的微电网下垂控制策略不同,直流配电网需利用站间通信获得各站实时潮流,基于优化比例系数进行配电潮流的优化调度控制。设计了基于配电变压器容量及负荷状态估计的优化比例系数,各站基于该系数进行优化下垂控制;设计了通信故障时基于概率分布抽样叠加的负荷潮流分布算法,得到基于时间尺度的各台区随机因子控制目标值。针对补偿随机因子控制产生的有功偏差,基于下垂特性曲线得到随机因子控制的补偿控制目标值,从而实现潮流的动态平衡控制。最后,在PSCAD中建立了基于所提控制策略的三端直流配电网模型,仿真结果表明该控制策略可实现有/无通信下直流配电网的优化调度及动态平衡。

Multi-terminal DC distribution network usually adopts the droop control strategy to optimize power flow.Unlike the microgrid droop control which needs no communication,DC distribution network needs communication between stations to collect real-time power flow of each station,and the power flow optimization can be realized based on the optimal scale factor.Based on the capacity of distribution transformer and load state estimation,the optimal scale factor is designed and adopted for optimal droop control in each station.Based on the probability distribution and sampling superposition for communication failure,a load flow distributed algorithm is then designed to obtain the time scale based random factor control target value.In order to compensate the active flow deviation generated by random factor control,the compensation instruction value is obtained according to the droop characteristic curve to realize the dynamic balance of the power flow.Finally,a simulation model of three-terminal DC distribution network is established based on the proposed control strategy in PSCAD.Simulation results show that the optimized scheduling and dynamic balance of multi-terminal DC distribution can be realized with or without communication.