交直流系统可观测性分析

AC-DC System Observability Analysis

基于潮流定解条件对交直流系统可观测性进行了分析。该方法将直流系统中的每个换流站视为独立的单元,在直流系统整体不可观测的情况下,仍能合理利用其中换流站的量测,以尽可能扩大交直流系统的可观测范围。文中对交直流系统中交流部分和直流部分的相互影响进行了详细讨论,并归纳出用于交直流系统可观测性判断的规则。指出交直流系统边界节点上的交流电压幅值和注入量测是交流部分和直流部分的耦合变量,应用直流相关系数的概念和交替迭代的思想,提出了有效的交直流系统可观测性判断方法。在算例分析中,指出了直流线路的可观测性对状态估计程序收敛的影响,并验证了文中所述算法的效果。

The observability of AC-DC system is analyzed based on the solvable condition of power flow.Each converter station in DC system is considered as a unit to overcome the difficulty in merging and extending observable islands,when DC system is not observable as a whole but some converter stations of it are still observable.It is pointed out that AC voltage magnitude and injection measurements in the boundary nodes of AC system and DC system are coupling variables,and the interaction between AC system and DC system is discussed in detail.Combining with the DC correlation coefficient and the presented disposing rules,a new algorithm for AC-DC system observability analysis is proposed.Numeric test shows that the proposed algorithm is valid and efficient,and the influence of DC line on the convergence of AC-DC system state estimation is also presented.