DefinePK

Abstract

State Estimation techniques are widely used to estimate the operating state of power systems in the most reliable manner so that the estimated state variables reflect the current system state faithfully and these studies enable the energy management centre to operate the system in a secure manner under normal as well as contingent conditions. Those algorithms which generate a fairly good estimate in spite of the presence of bad measurements are considered to be comparatively superior and WLAV based SE has been widely accepted as one such technique whose output is almost immune to the existence of bad measurements. In this paper, a new line flow based WLAV state estimation (WLAV-LFBSE) technique for power systems using line flows and bus voltage magnitudes as state variables has been suggested. A constant, line flow based Jacobean matrix has been arrived at through suitable manipulation of network equations and this technique generates an output which are in terms of quantities of  real concern namely  line flows and bus voltage magnitudes. As these quantities undergo wide variations due to load changes, it becomes essential to study the performance of the algorithm under varying loads. The proposed method has been tested on standard test systems taking into account these load variations and the results are analysed.