A hybrid LR-secant method-invasive weed optimisation for profit-based unit commitment

Abstract

This paper proposes a hybrid Lagrangian relaxation (LR)-secant method-invasive weed optimisation (IWO) for solving profit-based unit commitment (PBUC) problem. The PBUC problem is one of the important optimisation problems in deregulation. The objective of generation companies (GENCOs) in deregulated environment is to schedule the generating units for maximising the profit. Three stages are involved in the suggested method. The unit commitment problem is solved by Lagrangian relaxation (LR) for a given forecasted power demand, reserve and electricity price by incorporating various constraints, then optimal output powers for committed units are determined by secant method and finally IWO is applied to update the Lagrangian multipliers based on the duality gap between the primal cost and duality cost. It has been tested for various test cases such as 3 units, 10 units and 20 units system to prove the applicability of the proposed method. Simulation results have been compared with existing methods available in the literature. A comparison of the simulation results of the recommended method with the results of previous published methods shows that this method provides a qualitative solution.