Flexible-reliable linear AC security constrained unit commitment considering uncertainties and renewable energy sources

Abstract

In this paper, AC security-constrained unit commitment (AC-SCUC) is presented in the transmission network considering flexibility and reliability limits in the presence of renewable resources, energy storage and demand response plan. This minimization scheme considers the sum of expected operating costs and network reliability minus the benefit of network flexibility as the objective function. This problem is related to AC power flow equations, the operation model of storage, demand response, renewable sources, and non-renewable generation units, technical limits of the network, including indices of operation, reliability, flexibility, security. and the stability of the network. In this plan, load, renewable power, energy price, and availability of network equipment are uncertainties. In this paper, in order to accurately evaluate reliability and flexibility indices, stochastic planning is adopted to model the aforementioned uncertainties. The design has non-linear and non-convex constraints; therefore, to reach a unique solution in low computing time, the linear approximation model is incorporated. AC-SCUC linear modeling along with simultaneous modeling of operation, economic, flexibility, reliability, security, and stability indices along with stochastic modeling of uncertainties to accurately evaluate flexibility and reliability indices are considered as the contributions of this scheme. The obtained numerical results indicate the ability of the proposed scheme in improving the economic and technical condition of the transmission network with regard to the optimal management of energy sources, storage devices, and demand response. So, the scheme can obtain high reliability conditions for the transmission network by considering the high penalty price. Also, by considering a high incentive price for flexibility, non-renewable resources, storage devices, and demand response have been able to achieve high flexibility for the network. Optimal energy management of resources, storage devices, and demand response has significantly enhanced the network's operation status.