Bilevel model for security-constrained and reliability transmission and distribution substation energy management considering large-scale energy storage and demand side management

Abstract

This paper proposes a bi-level optimization problem to integrated transmission operation model with energy management of autonomous distribution substations. In this approach, independent distribution substation entities, in the lower levels, operate their own networks and send decisions to the upper level transmission market operator that clears the day-ahead market based on security-constrained unit commitment considering the worst-contingency state of transmission units and branches, and DC power flow models. The lower level is a mixed integer linear programming model of the distribution substations with the aim of increasing their benefit, considering optimal charge and discharge of large-scale energy storage systems by controlling the number of charging/discharging actions and demand side management model by controlling the number of load shifting actions. The upper level of the proposed model is security-constrained unit commitment considering a multi-objective function. In the upper level, the goal is to minimize production, no-load, startup, shutdown and active power curtailment costs, and also the unavailability of the generation units. An exact methodology based on reformulation-and-decomposition is proposed to solve this challenging bi-level program. The proposed model has been tested on the standard distribution substations and transmission network, which shows that the proposed model has an effective performance for both systems, and provides more realistic results. The simulation results showed that the proposed model with the approach of integrating distribution network substations in the transmission network increases the profitability of distribution networks and also reduces the costs of operating the transmission network. For example, it has been shown that with the proposed approach, the profitability of distribution networks can be increased by 30 percent, as well as operating costs in the transmission network has been reduced by up to 3 percent.