A fast calculation static voltage stability index based on wide area measurement system

With the fact that voltage stability indexes commonly used in power system have vague physical significance and poor linearity which cannot be applied on online monitoring of system voltage stability, this paper proposes a fast calculation voltage stability index of L_fci based on the feasible solution domain of branch voltage. It can be obtained by simple algebraic computation with the measuring information of PMU and can satisfy online application. This index is also derived from a more accurate model with the consideration of capacitance of branches. Moreover, we demonstrate that L_fci is still accurate with the consideration of voltage characteristic of loads. Finally, simulations of IEEE 14-bus system and New England 39-bus system are made to compare L_fci with other voltage stability indexes. The simulation result proves that L_fci is an ideal voltage stability index with good accuracy and linearity which can be applied on online monitoring of voltage stability.