多端柔性直流配电网运行策略优化研究

Operation Strategy Optimization of Multi-terminal Flexible DC Distribution Network

直流配电网在提高系统运行效率、改善供电可靠性、提高电能质量和实现新能源安全有效接入等配电系统所面临的关键问题上具有显著优势,因此直流配电网的应用受到了广泛关注。直流配电网的运行策略研究对其实用性具有重要意义。而目前的研究主要从控制方面入手,较少考虑调度方案,造成运行策略较为片面。为此,提出了将控制策略与调度方案相结合的多端柔性直流配电网运行策略优化方案。首先给出了系统运行方式,分析了换流站控制方式选取原则,然后针对主从式控制策略,以换流站控制方式及控制指令(电压定值与有功定值)为优化变量建立了直流配电网多目标优化模型,最后以多端环状直流配电网为算例求解出调度方案。算例验证了所提模型的经济性以及将换流站控制方式纳入优化变量的合理性。该策略的实施能够减少电网公司购电成本和环境价值成本,降低系统网损。

DC distribution network has obvious advantages in improving the operating efficiency, enhancing the reliability of power supply, improving the power quality and realizing safe and efficient access of new energy resources. Thus, the application of DC distribution network receives wide attention. Study on the operation strategy of DC distribution network is of great significance to its practical application. The current research mainly starts from the aspect of control, and less consideration is given to the scheduling scheme, resulting in a one-sided operation strategy. An operation optimization strategy of multi-terminal flexible DC distribution network is proposed that combines control strategy and scheduling scheme. Firstly, the operation mode of system is given and the converter control mode selection principles are analyzed. Then, a multi-objective optimization model of DC power distribution network is established, taking the converter station control mode and control command as the optimization variables. Finally, a multi-terminal meshed DC power distribution network is taken as an example to obtain the scheduling scheme. The example demonstrates the economy of the proposed model and the rationality of taking converter control mode as one of the optimization variables. The implementation of the strategy can reduce the purchase cost and environmental cost of Grid Company, reduce the loss of the power grid.