The Research On Voltage Stability And Control Stratagem Of Hunan Receiving-end Grid

Voltage stability is the most important issue in electric power system. With the development of economy and the improvement of the living standard, the electric load increase fast in central and south of Hunan Province. As there is no power source planning over the next few years in the south power grid, The voltage stability remains to be a persistent problem to the safe and stable operation of the power grid in the future period of time. For ensuring safe and stable operation of Hunan power grid, the voltage stability assessment of Hunan receiving-end grid in advance has great meaning.In the paper, by using PSASP6.28program, the voltage stability of Hunan power network is studied according to four typical load levels and the analysis of the volatage stability of Hunan power grid includes two sides, one is small-disturbance static voltage stabilitity, the other is transient voltage stability in power system faults. the effect of introducing the Static Var Compensator (SVC) and Thyristor Controlled Series Capacitor (TCSC) to Hunan grid on static voltage stability margin and transient voltage stability level is analysied. By using a new small-disturbance voltage stability criterion to get the static voltage stability limit in the normal and N-1check. The essay evaluates the transient voltage stability level by the aspects of the receiving-end grid internal fault、the power flow section of the transmission line fault and the combination of the two faults, finds the instability mode which causes the voltage problems, which can provide a basis for preventing voltage callapse. The participation factor and the sensitivitity of the node is sorted for finding out the weak region of voltage stability according to the sensitivity method. As the Flexible AC Transmission System (FACTS) devices prove to be a new voltage control method, the essay evaluates the effects on the static voltage stability margin and transient voltage level after setting the SVC in weak node and TCSC in transimission line, and analysis the equivalent parameters of SVC and TCSC.Aiming at the increasingly outstanding voltage stability problem, comparing with the conventional way, the essay point out that it is a better measure to improve the voltage stability of Hunan power network by installing FACTS devices.