Control strategy of voltage stability based on generator dynamic reactive power releasing

It is hard to determine critical point of voltage stability exactly for some online voltage stability algorithm and its decision-making time is required to be very small, which hinders its practical application on power system. A novel control strategy of voltage stability based on generator dynamic reactive power releasing is presented to deal with the problem. When voltage collapse happens, stator current and rotor current of generator is increased temporarily to improve its reactive power output, which can restore voltage adjustment capability of those generators whose reactive power has already reached their limit, prevent voltage collapse and achieve much more decision-making time for voltage stability control. Load voltage weak node is identified by coefficient of tangent plane equation of boundary of prefault voltage stability region. Load shedding strategy on load voltage weak node set is calculated by successive optimization algorithm which is implemented after process of generator dynamic reactive power releasing is over. Study shows that the presented control strategy of voltage stability can prevent voltage collapse and provide technical supporting for online application of voltage stability control algorithm, which has been validated by simulation test of IEEE 39 system.