.2015 Southern Power Grid Voltage Stability Analysis Calculated

Due to the voltage instability or collapse, many power systems abroad lose load and even blackout occurs in large areas. For this, the voltage stability becomes focus of power fields as well as these subjects around the voltage stability such as the mechanism of voltage instability, the indexes of voltage stability and power grid, the strategy to avoid the voltage instability and so on, have drawn much attention of researchers. In 2015, five Southern Power Grids in China including Yunnan, Guizhou, Guangxi, Guangdong, have more and more closely links, and regional load quickly increases; Regional reactive power support and voltage stability are under a severe test. Therefore, it is necessary to develop new methods for voltage stability assessment and suggest measures to prevent voltage instability according to the practical operation of power systems. It is of great significance to prevent voltage instability of power systems and improve the reliability of transmission networks.Owing to hundreds of buses and different lines of voltage in southern grid,it is more comples to make analysis on voltage stability.In this paper,adopting Fast Analysis of Stability Using EEAC and Simulation Technologies,I make a comprehensive analysis for voltage stability with modal method,Identify the key load bus,lines and units as well as the relatively weak region of power grid. At the same time,modal analysis is adopted to calculate regional load margin in the each provincial power grid and evaluate the capacity for load bearing the power change.While to key load bus impacting the voltage stability,the reseach tries to improve it through different ways of compensation.Finally, assessment that the power grid's capacity to bear the large disturbance is made through the transient voltage stability analysis. Transient safe margin is used as a basis for the judging transient voltage stability. Transient voltage security ensures the two-element for transient voltage stability and transient voltage dip. The Yunnan Power Grid as base in 2015, latch-up in DC, line N-1 and the generator N-1 failure of transient voltage stability are analyzed.