Study On Transient Voltage Stability Of Receiving Power Network

With increasing scale of power system, voltage collapse accidents have happened many times. Voltage stability problem has become one of the issues that international power system industry and academia focus on. This dissertation conducts research work on the transient voltage stability, and discusses mechanisms, influencing factor and the improvement of transient voltage stability.First, this paper analyses the mechanisms of transient voltage stability, drawing the conclusion that transient voltage stability should be expounded from transmit electricity power ability limit of transmission lines, dynamic characteristics of load and insufficient reactive power supply in receiving-end grid. Build the example system, and discuss the impact of load level, load model and induction motor percentage on the transient voltage stability. Consider the improvement effects of adding STATCOM at load buses.Due to the nonlinear characteristics of reactive power compensation devices, the paper proposes an equivalent reactive power valuation method for the analysis of transient voltage stability. The method evaluates the effectiveness of dynamic var compensation and can be applied to dealing with the site selection and the capacity determination of dynamic var sources. This method has been tested in the study and planning system in the grid system.Assessment method of load shedding valuation for transient voltage stability based on D-ERC can determine the sensitivity of load shedding. And then building the security regions on total load space, which can be more comprehensive and richer analysis of transient voltage stability of the power system to alleviate transient voltage instability problems. This method has been applied in the planning grid in 2015.