Bi-level robust scheduling for multi-terminal DC distribution networks considering uncertainties of loads and renewable energies. (May 2022)

• Record Type: Journal Article
• Authors: Wang, Shouxiang; Liu, Qi; Ji, Xingquan; Zhao, Qianyu
• Is Part Of: International journal of electrical power & energy systems. Volume 137(2022)
• Publication Date: 2022-05
• Subjects: DC distribution network -- Robust scheduling -- Linear power flow model -- Droop control -- Operation reference power; Electrical engineering -- Periodicals; Electric power systems -- Periodicals; Électrotechnique -- Périodiques; Réseaux électriques (Énergie) -- Périodiques; Electric power systems; Electrical engineering; Periodicals; 621.3
• DOI: 10.1016/j.ijepes.2021.107899
• Languages: English
• ISSNs: 0142-0615

Abstract

Highlights: The bi-level scheduling method can improve the security and economy of DC distribution networks. The uncertain scenarios are directly established based on the linear power flow model. The constraints based on the confidence intervals of loads and renewable energies are established to improve the system security. Abstract: The randomness of loads and renewable energies affects the security of DC distribution networks. In this paper, a bi-level robust scheduling method is proposed to improve the security and economy of droop-controlled DC distribution networks. The upper-level scheduling aims to minimize the variance of node voltage deviation from rated value with the optimization of voltage source converter (VSC) operation reference power. The lower-level scheduling aims to minimize the power purchase cost with the optimization of energy storage systems (ESSs). Based on the linear power flow model of droop-controlled DC distribution networks, the upper-level scheduling model is converted to a least square programming model and the lower-level scheduling model is converted to a linear programming model, which can be solved with high computation efficiency. In the scheduling model of VSC operation reference power, the uncertain scenarios are directly established based on the linear power flow model of droop-controlled DC distribution networks to improve the calculation speed of robust algorithm. The adjustable confidence intervals of load variations are used to coordinate the robustness and conservatism. The VSC operation reference power and ESS charging/discharging power are coordinated through iterative optimization. The simulation results of two DC distribution networks show that the proposed scheduling method can effectively improve the security and economy of DC distribution networks.