Economic Concerns in Optimal Power Dispatch in the Presence of a Generalized Unified Power Flow Controller under Practical Constraints

In power system restructuring, pricing the electrical power plays a vital role in cost allocation between suppliers and consumers. In optimal power dispatch problem, not only the cost of active power generation but also the costs of reactive power generated by the generators, shunt capacitors, transmission losses and device investment costs should be considered. In this paper, a more realistic multi-fuel total cost objective is formulated by considering all the above mentioned costs. As the characteristics of reactive power cost curve are similar to that of active power cost curve, a non-convex reactive power cost function is formulated. The formulated cost function is optimized by satisfying equality, in-equality and practical constraints and also device limits using the proposed uniform distributed two-stage particle swarm optimization. In this paper, power injection model of generalized unified power flow controller (GUPFC) including converter switching losses is presented. The proposed objective functions are optimized in the presence of UPFC and GUPFC and finally suitable device is identified for the standard IEEE-30 bus test system. © 2015, The Institution of Engineers (India).