Distribution fast decoupled state estimation by measurement pairing

A three-phase fast decoupled state estimation method is presented for distribution systems. The weighted least square (WLS) approach is used. A current-based formulation is discussed first and then the decoupled version. The proposed method produces a constant symmetric gain matrix which can be decoupled into two identical sub-gain matrices. The method offers good performance in handling the distribution system and is many times faster than other formulations, especially for large systems. An observability test is discussed.