Optimal real and reactive power allocation for real power loss and marginal cost reduction

The transmission loss minimization is one aspect of power system operation that needs much attention. The real and reactive power generation scheduling that results in heavy flows tend to incur greater losses, threaten security, and ultimately making certain generation patterns undesirable. Generation levels mainly based on economic criteria may lead to higher losses and therefore diminished security is a serious concern for the systems. In this paper, network sensitivity between load voltages and source voltages is used as the basis to evaluate optimal real power generation allocation for loss and marginal cost reduction and a method for optimum allocation of reactive power in day-to-day operation of power system for loss reduction is presented The technique will try to utilize fully the reactive power sources in the system to improve the voltage profile and to minimize the real power losses besides meeting the optimal real power generation levels. The method involves successive solution of steady state power flows and optimization of reactive power control variables using linear programming techniques. The proposed method has been applied to few systems and the results obtained on a 24-bus Indian practical equivalent EHV system are presented for illustration.