Application Of Voltage Instability Risk Of Power System

Power System Voltage Stability both in domestic and foreign has always been adifficult subject that experts and scholars studied, especially in recent years, thedevelopment of the power system is being toward the direction of high voltage, highpower, and long-distance transmission, the accidents of system collapse caused byvoltage instability occurred repeatedly at home and abroad. Power system voltageinstability risk assessment and management has been taken more and more attentionon the staff of power system. In order to solve this issue, the research of voltageinstability risk is proposed based on the Thevenin equivalent theory and risk theory inthis paper.The purpose and significance of the subject selection and definition of voltagestability and voltage instability mechanism were introduced firstly, and then the mainmethods for voltage instability analysis and risk theory had been detailed introduced.The core of this paper is the application of risk theory, the risk assessment for voltageinstability was made by calculating the probability and consequences of voltageinstability. The flow of system was calculated firstly to get the voltage and power ofstudied load node, the related sensitivity of the power was obtained by the partialderivative the node voltage, this sensitivity was used to calculate the needed Theveninequivalent parameters, then the probability of voltage instability was taken by voltageinstability criterion, and the consequences of voltage instability was acquired throughthe power network quantified calculation to define voltage instability indicators.Finally, the desired level of voltage instability risk was acquired.Then based on SCADA system of the whole network information of powersystem voltage instability level hierarchy and level of risk forecast problem is studied.Described in this article the calculation method of evaluation of the grid voltageinstability risk levels, and the corresponding risk rating and voltage instability riskanalysis of forecast system architecture diagram were proposed. Finally, the Thevenin equivalent parameters’ feasibility and effectiveness involtage instability risk assessment was verified through IEEE RTS-79systemexamples.