Power system state estimation using IP barrier method

A new formulation of the power system state estimation problem and a new solution technique is presented. The formulation allows for inequality constraints such as generator VAr limits and transformer tap ratio limits. The solution technique uses a logarithmic barrier function to treat inequality constraints. Non-quadratic criteria for power system state estimation have to facilitate bad data detection and identification. The weighted least absolute value criteria have the desired bad data rejection property. This paper shows that the logarithmic barrier function can accommodate inequality constraints, and then applying the Newton method to solve the KKT equation leads to a problem structure which is identical to that of the non-linear least square problem. The number of iterations needed for convergence does not increase linearly with problem size, unlike the LP algorithm.