基于证据理论的电网稳控系统可控容量不确定性分析

Reliability Analysis of Security and Stability Control Systems Based on Evidence Theory

电网安全稳定控制系统(security and stability control system,SSCS)构成电网稳定防御第二道防线,其可控容量反映SSCS维持频率稳定的能力。站点控制路径可用性和可控容量波动性,增加了对SSCS可控容量评估的难度。文章提出了一种SSCS可控容量不确定性分析方法。基于执行站(executive station,EX)可控容量波动特性,采用证据理论方法建立EX基本可信度分配模型。改进SSCS概率加权邻接矩阵,建立站点控制概率模型以修正EX基本可信度分配。考虑站点控制容量与控制路径相关性,建立SSCS可控容量联合可信度分配模型。计算可控容量的似然累积分布(likelihood cumulative probability distribution,LCPD)和信任累积分布(belief cumulative probability distribution,BCPD),量化电网功率缺额下SSCS保全能力。通过与传统概率方法比较,验证了所提可控容量不确定分析方法的有效性。

Security and stability control systems(SSCSs)are the second type of defense system for power grids.Their controllable power demonstrates their capability of maintaining frequency stability.However,control path station availability and controllable power fluctuations increase the difficulty of assessing the controllable power of SSCSs.In this study,a controllable capacity uncertainty analysis method for SSCS is proposed.Based on the fluctuation characteristics of the controllable capacity at the executive station(EX),a basic reliability allocation model of the EX is established using evidence theory.A station control probability model is established by improving the probability-weighted adjacency matrix,and the basic confidence assignment of EX is modified.By considering the correlation between the station control capacity and the control path,a joint credibility allocation model for the controllable capacity of SSCSs is derived.The likelihood cumulative probability distribution(LCPD)and belief cumulative probability distribution(BCPD)of controllable capacity are defined.Numerical results show that the proposed model quantifies the preservation ability of the SSCS against a power shortage.The effectiveness of the proposed method is verified by comparing it with a traditional probabilistic method.