A new assessment method to voltage vulnerability within the static energy frame

Voltage vulnerability has been important in power system security research. Considering the characteristic that the voltage are mainly influenced by the reactive power, the potential energy margin which can embody the impacts from the reactive load, the reactive output of generator, the reactive compensation, and so on, was proposed as the benchmark, and then, the degree index and the trend index of voltage vulnerability were derived, the impacts of grid topology and the reactive power inject ingredients on the voltage vulnerability were discussed. On this base, the assessment index of branch vulnerability was proposed to compute the distance of the current value of branch transmission to the initial value and ascertain the vulnerable area. In IEEE-30bus system, the feasibility and exactness of this method are identified by the simulation.