Improving Static Voltage Stability By Minimum Eigenvalue Sensitivity

In recent years, with the accelerating process of industrialization and growingscale of power systems, voltage stability issues have become more prominent. Atpresent, the construction of China’s state grid is moving to the direction of ultra-highvoltage, long-distance transmission, large area network interconnection and electricitymarketization, which has given rise to more complex power grid structure, andstronger possibility of voltage instability accidents. Several major blackouts occurringover the past decades, had caused huge economic losses and brought greatinconvenience to people’s production and life. Therefore, a study of power systemvoltage stability, with the aim of seeking measures to improve voltage stability, is ofhigh significance.Voltage stability analysis methods are generally divided into dynamic and staticanalysis methods, the latter of which is widely used by virtue of its small computationand large capacity of information as well as other advantages.This article first summarizes the details of research in static voltage stability,expounds the continuous power flow method which can accurately calculate thecritical point of voltage, and also introduces the sensitivity indicator and characteristicvalues of static voltage stability.The eigenvalue structure analysis is then introduced. The derivation of relevantformulas indicates the minimum modulus eigenvalues of the Jacobian matrix can beused as a static voltage stability margin to analyze characteristics of voltage instability.In addition, eigenvalue structure analysis method can be used to determine the weaknodes, weak area, key transmission branch and key engine of the power system.Then, find out the specific system parameters which has a significant impact onstatic voltage stability margin based on the eigenvalue structure analysis method. Andlists the calculation equation of the minimum modulus eigenvalue sensitivity tosystem parameters, and writes a calculation program.Finally, based on the analysis of IEEE-30-node system, the unstable voltagenode and the specific system parameters which have a significant impact on static voltage stability are identified. According to the analysis, targeted measures were putforward to improve the stability of voltage.