Influences of dynamic voltage stability on power transmission capability of South China power grid from West China to East China

Using commercial power system security evaluation software VAST which is first led into China and according to the planned data for the year of 2005, the influence of dynamic voltage stability of South China power grid for middle- and long-term on its power transmission capability from West China to East China is researched, the research results show that under low load level and adequate reactive power the voltage of load buses can be effectively restored by adjusting on-load tap changer (OTLC). Under the high load level and inadequate reactive power the adjustment of OTLC may cause the action of over-excitation limiters, therefore, the shortage of reactive power of power grid will be aggravated and the serious shortage of reactive power may lead to voltage collapse in power grid, therefore, dynamic voltage stability is an important aspect influencing the power transmission capability of South China power grid from West China to East China.