Extended load-flow arithmetic for voltage stability analysis

In this paper, a novel load-flow arithmetic for voltage stability analysis is studied where models of various dynamic elements in power systems are taken into account. It simultaneously solves the load flow equation and the state equation of dynamic elements and gets both the voltage amplitude, phase of all buses and the inner state variables of the dynamic elements. In this arithmetic different limits are considered and the assumption of PV bus, PQ bus and slack bus are eliminated, so the result is closer to the real operation condition. Using a flow arithmetic based on continuation-power-flow (CPF) method, the critical point of voltage stability of the system can be computed. The proposed method is demonstrated on a test system and the results are compared with the conventional power flow method