Unit Commitment Considering Position of Interruptible Load in Energy and Reserve Simultaneous Market

In this paper security constrained unit commitment (SCUC) is employed for simultaneous clearing of energy and reserve markets. Spinning reserve of production units and interruptible loads (IL) are used as system operation reserve. Some restrictions on the use of interruptible loads, such as maximum load curtailed, maximum curtailment hour in a day, maximum length of each curtailment are also considered. Expected energy not supplied (EENS) is considered as a criterion for undesirable load shedding of system and a method is proposed for EENS calculation in presence of interruptible load in the stochastic model. In the proposed model, a twostage stochastic mixed integer programming (SMIP) is used for considering the uncertainties of the power system. The goal of this program is the unit commitments with their energy production and the scheduled spinning reserve for each production unit and IL for the next day. Monte Carlo simulation is implemented for scenario generation for various production units and transmission lines random outages, the uncertainties in load prediction and refusal of the IL from ISO instructions. Next, the backward scenario reduction method is used for computational burden reduction where the problem accuracy remains desirable. Impact of IL location has been studied on the system reliability, too. It is shown that the IL location will be effective on the power flow of transmission lines at critical moments, congestion and increasing of marginal price. The proposed model is applied to the IEEE reliability test system (IEEE-RTS) to demonstrate its effectiveness.