面向高比例光伏消纳的低压交直流混合配电网时-空协调优化方法

Spatial-Temporal Coordinated Optimization Method of Low Voltage Hybrid AC/DC Distribution Network for Accommodation of High-Proportion PVs

随着双碳目标的提出,分布式光伏大规模接入配电网已成为未来发展的必然趋势。然而,大量分布式光伏并网加剧了低压配电网的电压越限、三相不平衡和功率倒送问题,给配电网的稳定运行带来了巨大挑战。针对高比例分布式光伏的消纳问题,充分挖掘低压交直流配电网和储能的功率调节潜力,提出了一种基于电压源型换流器(voltage source converter,VSC)和储能的时空协调优化方法。首先,分析了VSC和储能在空间和时间层面的功率转移特性;其次,以光伏切机量最小和网损最小为目标,以储能和VSC功率为优化变量,建立低压交直流混合配电网时-空协调优化模型,并将所提模型转化为二阶锥规划模型进行求解;最后,以典型低压交直流混合配电网为例,通过仿真证明了所提方法可以有效改善光伏并网导致的电压问题和功率倒送问题,提升低压配电网的光伏消纳能力。

With the proposed carbon-neutral target,the integration of large-scale distributed photovoltaics(PVs)to distribution network has become an inevitable trend.However,the integration of PVs aggravates the voltage violation,three-phase unbalance and reverse power of low voltage distribution network,which brings great challenges to the stable operation of the distribution network.In view of the accommodation problem of high-proportion PVs,this paper fully taps the power regulation potential of low voltage hybrid AC/DC distribution network and energy storage,and a spatial-temporal coordinated optimization method based on voltage source converter(VSC)and energy storage is proposed.Firstly,the power transfer characteristics of VSC and energy storage at the spatial and temporal levels are analyzed.Secondly,a spatial-temporal coordinated optimization model of low voltage hybrid AC/DC distribution network is established with the objective of minimizing the PV curtailment and power losses,and the power of energy storage and VSC are optimization variables.The proposed model is transformed into a second-order cone programming model to solve.Finally,taking the typical low voltage hybrid AC/DC distribution network as an example,the simulation results show that the proposed method can effectively improve the voltage and reverse power problems caused by PVs,and enhance the PV accommoda⁃tion capability of low voltage distribution network.