基于电压方程和功率方程判别式的非负性，已经提出了多个基于线路局部信息的电压稳定指标，并且多年来被广泛引用，但目前并没有对这些指标的理论推导和数值计算的正确性进行严格证明。该文在理论上证明这些指标中的7个只在一定特殊条件下才与PV曲线相一致，而在通常情况下这些指标并不能用以进行电压稳定性的评估。3个测试系统的仿真结果证实了本文理论证明的正确性。

Based on the nonnegative property of the discriminator of voltage equation and power flow equation, some line-based voltage stability indices have been proposed in famous journals and widely quoted for many years. But the correctness of these indices in theoretical derivations and calculations has not been strictly proved. This paper theoretically proves that seven of these indices are consistent with the PV curve only under very restrictive conditions and actually cannot be used in determining voltage instability in general cases. The simulation results using three test systems verified the theoretical proof.

国家自然科学基金项目(50577073)；国家重点基础研究发展计划项目(973项目)(2004CB217908)；重庆市科委自然科学基金计划资助项目(CSTC,2008BB6039)。