Least squares class power system state estimation algorithm efficiency analysis

This paper focuses on integrated comparative analysis of three kinds of classical states estimation algorithms from theory based on least squares method, including weighted least squares method, fast decoupled method, and the equivalent current measurement transformation method. The simulation experiment of IEEE14, 30 and 118 node system by MATLAB is carried out, then the efficiency analysis of three kinds of algorithms is done from the results of estimate, the number of iterations, the objective function and running time. Some conclusions are obtained. First, the weighted least squares method has the best estimation quality, good convergence rate, but the large amount of calculation, so it is not suitable for large-scale power system. Second, fast decoupled method has similar estimation quality. The weighted least squares method computes fast when the node system is small; the fast decoupled method has fast calculation speed when the node system is big. The process of fast decoupled method is relatively complex and applicable to high voltage system analysis. Third, the calculation speed of the equivalent current measurement transformation method is the fastest, but the estimation quality is the worst, and it is only suitable for the measurement system in which the measurement of the active power and reactive power is paired. Analysis and comparison of the results are helpful for selecting appropriate state estimation algorithm.