State Estimation of the Tanzanian Power System Network Using Non-Quadratic Criterion and MATLAB Environment

Abstract

Power system state estimation is an effective online tool for monitoring, control and for providing consistent database in energy management systems. This paper presents an algorithm for state estimation of the Tanzanian power system network using a non-quadratic state criterion. Equality and inequality constraints existing in a power system are included in formulating the estimation problem. Equality constraints are target values used in load flow analysis and are included in power system state estimation in order to restore observability to those parts of the power system network which are permanently or temporarily unobservable. Inequality constraints are limits such as minimum and maximum reactive power generation, transformer tap and phase-shift. The solution techniques used is primal-dual interior point logarithmic barrier functions to treat the inequality constraints. An algorithm is developed using the method and a program coded in MATLAB is applied in implementing the simulation. Computational issues arising in the implementation of the algorithm are presented. The simulation results demonstrate that the primal-dual logarithmic barrier interior point algorithm is a useful numerical tool to compute the state of an electrical power system network. The inequality constraints play essential role in enhancing the reliability of the estimation results. Also, it is expected that significant benefit could be gained from application of the constrained state estimation algorithm to the Tanzanian power system network.