The Analysis Of Voltage Stability And The Method Of Dynamic Reactive Power Compensation Based On Impedance Modulus Margin

Since the eighties of the twentieth century, dozens of voltage collapse accidentsof power system occurred in the worldwide.These accidents have caused a tremendousimpact on the economy and people’s lives, and brought very serious consequences, sothe voltage stability problems become a priority issue on studying power system.This paper describes the current main research contents and analysis methods ofvoltage stability. Firstly, studying from the mechanism, evaluation index and controlmeasures to analyze voltage stability. Secondly, sum up a variety of analyticalmethods of the voltage stability, do the main research on static analysis methods anddynamic analysis methods.Because the power system is a nonlinear dynamical system, This paper apply theintegrated dynamic equivalents analysis method based on Thevenin equivalentprinciple to prove the maximum power transfer condition of the nonlinear powersystem is the integrated dynamic equivalent impedance modulus equals to the staticequivalent load impedance modulus. And basing on the integrated dynamicequivalence principle, revealing the relationship between the impedance modulusmargin index and the voltage stability: the impedance modulus margin index canvisually assess the degree of voltage stability, according to the impedance modulusmargin sizes, it can sort the load buses’s strength of the voltage stability. The smallerthe impedance modulus margin, which means that the heavier the load, the farther thedistance with electrical power bus, the weaker the voltage stability, so it can identifyweak bus for voltage stability of the power system based on the impedance modulusmargin index.Reactive power balance determines the overall voltage level of the system, thepower system needs sufficient reactive support to maintain the voltage level.Reasonably compensating reactive power, you can save investment costs, reducenetwork losses and improve system stability. In reactive power compensation,determining the installation location, capacity of compensation, and optimumoperation for the reactive power compensation devices is very important researchcontents. In this paper, based on the impedance modulus margin index, a new methodfor the dynamic reactive power compensation optimize is proposed. By real-timetracking the impedance modulus margin index of load bus, dynamically search for thebest installation location for the reactive power compensation device. Then considering the actual installation capacity constraints, the installation effect and thecost, install the minimum compensation capacity device that meets the configurationtarget to the selected location, the final optimal configuration scheme of dynamicreactive power compensation device is determined. Finally, through the simulationand analysis of IEEE-30buses system to verify the correctness of the new method forthe dynamic reactive power compensation optimize configuration based on impedancemodulus margin index.