Optimal Reactive Power Procurement With Voltage Stability Consideration in Deregulated Power System

Power systems are mostly run under stressed operating conditions due to rapidly increasing demand but inadequate expansion in generation and transmission capacity. Thus voltage stability has become a major concern in present day power system operation which depends on the availability and distribution of reactive power. It becomes very important to ensure the presence of sufficient amount of reactive power source in the network for secure and reliable operation of electrical power system. This paper mainly deals with short-term reactive power procurement (RPP) problem assuming an already established real power market. Contributions of this paper are three fold. First, this paper presents three new RPP methods which are formulated as optimum power flow (OPF) problems. OPFs are solved using Artificial Bee Colony (ABC) algorithm as population based stochastic solution methods are more suitable for solving reactive power optimization problem. Second, a detailed analysis of voltage stability for proposed RPP problems are performed for both normal and contingency condition to find out how these new formulations affect voltage stability. Third, proposed methods are compared with the classical RPP formulations, e.g., Minimization of L-index and loss Minimization. Finally results are reported for both test system and a large practical system.