A novel two-stage optimization method for the reliability based security constraints unit commitment in presence of wind units

Abstract

In the restructured power system environment, independent system operator solves the Reliability-security constraint unit commitment (R–SCUC) problem that included reliability, economic issue and security. Therefore, in the modern bulk of power systems, the existing centralized methods cannot solve the complex issues such as large power system complexity. In this paper, a novel two-level optimization approach for a reliable, secure, and optimal generation scheduling is proposed. The power system is divided into several zones, in which each one solves its own R–SCUC problem. In the face of different uncertainties and time-dependent sources such as wind units there is new challenges in power systems reliability. In the proposed approach, load forecasting and wind units simulated based on the Gaussian probability distribution function and weibull probability distribution function (PDF), respectively. Energy bid modeling is formulated to fit the R–SCUC problem. In order to take into account reliability model, intelligent search techniques, i.e., TEENS, LOLP, are implemented in the whole power system. The proposed methods are performed in a 6-bus network, IEEE 118-bus and IEEE 4672-bus test systems. The presented approach has been programed by GAMS, and the results show the effectiveness of the proposed methodology to enhance security and reliability of the power system.