Study On Risk Assessment Of Power Gird Operation Modes Based On Monte Carlo Simulation

With the development trend of China’s electric power system to the ultra-highpressure, long-distance, high-capacity and regional networking, the application ofnew technologies and equipment and the gradual establishment of the electricitymarket mechanisms, modern power grid is a highly complex dynamic systems. Therisk of random component failure resulting in large area blackout is increasing, theblackout also cause a great loss of economic and social benefits, and at the same timeoccur more and more serious consequences; With the advance of the electricity market,the randomness of the operation of the market makes the power grid operation modechange frequently. Various random factors reflect the uncertainty of the power gridoperation. Scheduling operating person is difficult to quantify the true risk of the grid,and thus face increasing pressure. Therefore, the accurate, fast, comprehensive of griddispatching operation risk assessment has great significance to power systemoperation planning.The grid scheduling run the basic steps of the risk assessment include: the choiceof system status, the analysis of the system state, system risk index calculation andscheduling operation mode selection. Use the analytical method or Monte Carlosimulation to determine the operating state of the generator sets, transformers, linesand determine the state of the system; the analysis of the system state is mainly powerflow calculation. Through multiple simulation and the accumulation of stateenumeration， modifying the reliability index， get the final indicators. Finally,comparing the different operation modes of the risk indicators, choose the lowest riskof running.In this paper, we conducted intensive studies on the basic method of griddispatching operation risk assessment. First of all, established mathematical model ofgrid dispatching operation risk assessment, based on sequential Monte Carlomethod.Then,use generator and load active power as control variables, use the totalrisk index value as the objective function, by means of nonlinear programmingmethod for solving a system failure caused by the loss of load.Make use of local riskinformation to determine the weak link of the grid. Last, analyze on the IEEE-RTS79test system, Verification the effectiveness of the proposed methods. The main contentsinclude the following aspects: 1.This article describes the outage model of power system component and theprinciples and characteristics of three basic Monte Carlo probabilistic simulationmethods:sequential Monte Carlo simulation nonsequential Monte Carlo simulation,State transition sampling.On this basis, discusses the Basic principles, the basic stepsand key indicators of Monte Carlo method of power system reliability evaluationalgorithm..2.Established composite generation and transmission system of risk assessmentmodels and algorithms, acquisition system condition by Monte Carlo Status samplingmethod. Analytical the system status we have obtained, which relates to the AC powerflow calculation, to determine whether the components overload, depth search thedetermine whether the system melting, calculation the optimum load reduction. Then,Accumulate to form the reliability indices of system and load point.3. Establish the grid scheduler runs the risk assessment algorithm flow and Indexsystem. Complete the Monte Carlo method for grid scheduling run the risk assessmentprocedures for the preparation in VC++6.0platforms. Finally, do the scheduling runthe risk assessment in the IEEE-RTS79system using this program. Executequantitative evaluation about two different situations of the standard system. One isthe normal mode of operation of the system risk indicators; another case is theoperation of the system in case of failure risk indicators. Found weaknesses in thesystem through the analysis of data, proposed the improve program.