Security Based Economic Operation of Electric Power System

Abstract The increased loading of transmission lines, the insufficient local reactive power supply, and the transmission of power through long distances have been major reason behind voltage problems. Optimal powerflow, on the other hand, allocates real and reactive power generation among available generators and/or var sourses. Given that the general trend is towards higher loading of the system and closer to the security limits, this paper develops a mathematical model for economic operation which integrates the voltage security assessment. The paper provides the location, causes, and cures for voltage collapse as an integral part of economic operation problem, which is decomposed into security assessment and optimal powerflow subproblems. The security assessment subproblem provides a set of security constraints in the form of security margins or proximity to voltage collapse and voltage security. The optimal power flow subproblem provides real and reactive power outputs of generators and/or var sources, and transformer tap settings under the set of security constraints.