Research On Generator Reactive Power In Multi-Infeed HVDC Receiving-end Power System In CSG

China Southern Power Grid has built eight high-voltage direct current transmission lines, and this eight HVDC lines are placement in Guangdong province. If the HVDC system by the end of the multi-placement severe AC fault, so that by the end of the AC system reactive power demand increases, causing the system voltage instability or voltage collapse. During a serious failure to meet the exchange by the end of the system reactive power demand, on the one hand we must vigorously apply the new dynamic reactive power compensation device, but more important is the full use of the power of large capacity and low cost of synchronous generator dynamic reactive power capacity.The impact of different types of excitation system on the dynamic var output of the generator should be investigated to get a measure of available var reserve for the target generator. Firstly, taking the wet-season operation data of China Southern Power Grid in 2013 as the studied system scenario, the different types of excitation control system are summarized. Two major excitation systems have wide-spread applications, i.e., the static self-parallel excitation and the AC rotating excitation. Then the relationship between the deviation of generator terminal voltage and the responding var increment is examined based on electromechanical transient simulation performed in the software of BPA. The sensitivity between them is calculated and referred as a quantitative index indicating the transient voltage support capability of a generator. Finally, frequency-domain analysis by MATLAB have been applied to compare the changes of bode plot area brought by different excitation parameters for both the mentioned two excitation systems. The results are consistent with simulation results. Consequently, the influence of different types of generator excitation system on the characteristic of a generator’s dynamic reactive power is obtained, which provides a solid basis for the selection of the type and parameters of excitation systems to support transient voltage in China Southern Power Grid.Simulation shows that generators have a greater potential in providing dynamic reactive power. When HSVC is adopted, the transient voltage stability is improved.