A Reliable and Fast-decoupled Weighted Least Square State Estimation for Power Systems

This article presents a new, fast-decoupled WLS SE technique based on modified line flow and voltage magnitude measurements in rectangular coordinates. The measurement equations are rotated by appropriate line admittance angle for zeroing the off-diagonal blocks of the Jacobian matrix and decoupling the SE problem into two sub-problems without making any assumptions on voltage magnitudes, angles, and r/x ratios. The approach is simple and uses constant sub-Jacobian and gain matrices that need to be factorized only once and is solved similar to the FDSE technique. Test results of the PM on five test systems indicate that the PM is efficient, reliable, accurate, and suitable for on-line applications.