Influence Of Reactive Power Compensation On Power System Transient Voltage Stability

Voltage stability is an important aspect of power system stability, The factorsinfluencing voltage stability and the relationship between voltage stabili ty and anglestability have been important theoretical and engineering issues for a long time. Dueto the complexity of the actual grid, these issues also showing complex relationship.Systematic and in-depth studies, which are combined with the specific characteristicsof different grid are needed to draw conclusions in line with the actual grid.Taking Hunan power grid as the engineering background, this paper studies thevoltage stability of the power system, and focus on the influence of reactive powercompensation upon voltage stability. Hunan Power Grid located at the end of the gridin the Central Region, and it is a large receiver system of Central China Power Grid.Numerous of simulation analysis shows: when Hunan Power Grid running in the smallpower transmission mode during the wet period, prominent voltage stability problemswill be present. Therefore, this paper briefly summarizes the classification of powersystem stability and the research status of voltage stability. And this papersystematically expounded the mathematical model and its main analytical methods ofvoltage stability. First, we systematically studied the characteristics of Hunan PowerGrid running in the small power transmission mode during the wet period, andthrough the analysis of the characteristics of the Hunan Power Grid’s trenddistribution, under the conditions of three load levels in Southern Hunan and HunanPower Grid is running in the small power transmission mode during the wet period,and transient stability scan analysis when three-phase short circuit at differentlocations of the500kV main network. We comprehensively grasped the main problemof the Hunan Power Grid’s system stability, when it is running in the small powertransmission mode during the wet period.By respectively using static sensitivity and dynamic trajectory sensitivityanalysis, and systematically studied the voltage pilot bus distribution of Hunan PowerGrid’s main network, which is220kV and above. The results showed that the voltagepilot buses are not only the most sensitive nodes of voltage level for reactive powercompensation capacity changes, which is under normal operating mode, but also theweak nodes of transient Voltage stability. Based on this, we also systematicallystudied the effects of reactive power compensation and system boot mode on transient voltage stability. Research has shown that configured the most sensitive line withadequate shunt capacitors compensation can effectively improve the system’s normaloperating voltage level, but the system will be more prone to transient voltageinstability. Overall, the use of comparable SVC reactive power compensation capacitycan not only meet the requirements of the voltage levels under normal operatingconditions, but also can significantly improve the level of transient voltage stability.The systematic boot mode has a crucial influence on transient voltage stability. Ingeneral, no matter the shunt capacitor compensation or SVC dynamic reactive powercompensation, an appropriate increase of the boot proportion of the end grid cansignificantly improve the transient voltage stability. Based on this conclusion, thispaper presents the necessary regional boot capacity ratio to ensure the transientvoltage stability of Hunan Power Grid under the different reactive powercompensation. For the above conclusions, we give a reasonable explanation by using asimple equivalent system.This article comes from the studies of engineering research of the actual grid, It’sresults and conclusions have engineering reference value for network planning designand operation scheduling.