Pmu Measurements Of The Power System State Estimation

The study status quo of power system estimation in the world and the actual application status of power system estimation in China are introduced.According the actual situation of China, this paper discusses the problems of network modeling, and proposes some method of network modeling. The method according to IEC61970 to exchange external network model is studied too. The usual state estimation algorithm was analyzed and compared, the actual application status of state estimation algorithm in China is discussed.An improved optimal PMU placement algorithm is proposed for guaranteeing full network observability and having minimum number of PMU. The proposed algorithm effectively combines heuristic method with simulated annealing (SA) method to avoid losing the optimal solution. Initial placement result from heuristic method is improved by the proposed placement principles, the search scope of SA method is reduced by new placement model, and the calculation speed is improved. A topology method of network observability using incidence matrix is studied in this paperThis paper analyzes the error of PMU measurements and points out the essentiality of state estimation based PMU measurements. Linear measurement equation and linear static state estimation algorithm based right-angle coordinate are proposed when only PMU measurements are used. This paper improves the state prediction method using load forecasting and load flow. A new error covariance ahead equation is proposed, and then a new linear dynamic state estimation algorithm is proposed too. The using condition of linear state estimation is discussed in this paper.The method used to align the PMU measurement and SCADA measurement is proposed in this paper. The method using state conversion forecast to get forecast state and node inject current vector is proposed in this paper too. And then, linear static state estimation algorithm using PMU real-time measurement and forecast node inject current vector, and linear dynamic state estimation algorithm using PMU real-time measurement and forecast state are proposed. These two algorithms are combined with traditional state estimation to form a hybrid algorithm. The linear state estimation algorithm is used to reduce calculation time and traditional state estimation algorithm is used to ensure calculation precision. The algorithm is suitable to any PMU placement status.The effectiveness of the proposed algorithm is illustrated with numerical simulation using IEEE test system and Northeast power system.