An Integrated High Side Var/Voltage Control for Improvement of Transient Voltage Stability

Transient voltage stability is becoming one of the urgent issues of larger-scale receiving-end power systems. The root cause of voltage instability after a fault occurs is that the reactive power supply cannot meet the demand. The reactive power reserve of synchronous generators has relatively large capacity while much lower cost. To take full advantage of the dynamic reactive power reserve, this paper propose an integrated high side var/voltage control ((IHSVC)-C-2) for power plants in receiving-end power systems. The (IHSVC)-C-2 can regulate the voltage at a point beyond the generator terminals by providing terminal voltage reference value for the excitation system, meanwhile, it can make the whole plant offer the largest dynamic var support in a coordinated way. Firstly, The (IHSVC)-C-2 control equation is introduced in detail. Secondly, a test receiving-end system is established in PSCAD /EMTDC according to the typical parameters of China Southern Power Grid. Thirdly, the effect of (IHSVC)-C-2 is verified in simulation. In addition, the start time and end time of (IHSVC)-C-2 is discussed.