A Unified Distribution System State Estimator Using the Concept of Augmented Matrices

Distribution system state estimation (DSSE) is becoming an essential element of many distribution management systems (DMS), serving as the basis of numerous smart grid applications. In this paper, a new DSSE approach is proposed based on the modified augmented nodal analysis formulation, which is known to have advantageous numerical characteristics. Special consideration is given to the estimation of transformer and regulator tap positions, as they are seldom telemetered on the distribution level. The proposed approach can be easily derived from existing power flow and short-circuit calculation algorithms, thus unifying the major steady-state analysis tools for distribution systems. The proposed DSSE algorithm is tested on the IEEE 8500-Node Test Feeder, and is shown to have good accuracy and efficiency. The proposed DSSE approach is also compared to existing algorithms and shown to have better convergence while yielding a more accurate solution.