考虑N-1安全约束的分布式电源出力控制可视化方法

配电网运行需满足N-1安全准则,而现有文献中的分布式电源(DG)优化运行模型均未计及N-1准则,所得出力策略未必满足系统安全要求。为解决这一基础性问题,提出了一种考虑N-1安全约束的DG出力控制可视化方法。首先,介绍了配电系统安全域理论,给出了安全域、安全边界和安全距离的概念、模型和意义。其次,利用坐标变换技术,定义了风光转换系数,以研究以风电和光伏发电为代表的DG组合的出力特性。然后,分析了考虑节点电压限制和N-1潮流约束的DG出力上限求解方法。此外,以每条馈线为研究单位,给出了DG出力控制可视化流程。最后,通过修改的IEEE RBTS-Bus4配电系统算例进行了验证,结果表明建立的DG出力控制方法具有合理性和可视化的特点,并能满足N-1安全。在保证资产效率最大化的同时,此法为含DG的配电网在线安全监视、评价提供了一定的理论和实践凭据。

Visualization Method of Output Power Control of Distributed Generators Considering N-1 Security Constraint

Distribution operation must satisfy N-1 security criterion. However, it has not been taken into account in modern optimization operation models of distributed generators (DGs), which may not satisfy security demands. In order to solve the fundamental problem, this paper proposes a new visualization method of controlling output power of DG considering N-1 security constraint. Firstly, the distribution system security region (DSSR) theory is introduced, and the concept, the model and the meaning for the security margin and the security distance is analyzed. Secondly, wind-photovoltaic conversion factor by using coordinate transformation technique is defined to analyze output power characteristics of distributed generation combination with wind power and photovoltaic generation. Next, the method to calculate output limit of DG is analyzed with the constraint of bus voltage and N-1 power flow. Then, the visualization flow chart of output power control is introduced for DG in a feeder line unit. Finally, the modified IEEE RBTS-Bus4 distribution system is presented to prove that the controlling method of output power of DG is correct and has the characteristic of visualization under the N-1 security principle. While ensuring asset efficiency maximized, this method improves theoretical and practical credentials for real-time security monitor and assessment of distribution networks including DG. This work is supported by National High Technology Research and Development Program of China (863 Program) (No. 2014AA051901).