Voltage stability is a major concern in the planning and operation of electric power systems. This book provides a clear, in-depth explanation of voltage stability, covering both transient and longer-term phenomena and presenting proven solutions to instability problems. The book describes equipment characteristics for transmission, generation, and distribution/load subsystems of a power system, together with methods for the modelling of equipment. Readers will find static and dynamic computer simulation examples for small equivalent power systems and for a very large power system, plus an account of voltage stability associated with HVDC links. They will also get helpful planning and operating guidelines, computer methods for power flow and dynamic simulation, and descriptions of actual voltage instability incidents.