A new optimal reactive power scheduling method for loss minimization and voltage stability margin maximization using successive multi-objective fuzzyLP technique

Insufficient reactive power support in a power grid results in under voltag es at load centres and also limits the real power transfer capacities of th e transmission systems leading to voltage collapse. An optimal reactive pow er scheduling method is sought which minimizes real power transmission loss and maximizes Voltage Stability Margin (VSM) submect to the utmost satisfa ction of all the violated load bus voltage constraints. A Multi-objective F uzzy LP (MFLP) method of solution in the Successive LP (SLP) framework is p roposed to solve the problem, A set of least singular values of the load fl ow Jacobian is used as VSM indicator. This set is expressed in terms of the control vector and is maximized in the proposed formulation to maximize VS M, Results of the tests of the proposed method on modified IEEE 6 bus and 5 7 bus systems are presented. The changes in the load flow Jacobian singular values during scheduling are studied.