A fast simulation method for mid-term voltage stability

Based on the quasi-static-state (QSS) approximation, a fast simulation method for mid-term voltage stability is discussed in this paper. Since dynamics on mid-term voltage stability are slow by nature, QSS approximation is adopted to neglect transient dynamic details and find voltage evolution through obtaining a sequence of transient equilibrium points. A new control technique for the simulation step is proposed to speed up the simulation. The continuation power flow method is adapted with the ratios of on-load tap changers (OLTC) as the control parameters whenever numerical divergence is likely to happen. The very dishonest Newton method is applied to reducing the factorization time. Simulations on a real-life system fully confirm the effectiveness of the novel method.