Tri-level scheduling of integrated electric vehicle parking lots and solar distributed generations in local and wholesale electricity markets

Abstract

This study investigates a tri-level optimal market strategy for the integrated electric vehicle fleets and solar distributed generations (IEVSDG) to engage in the local electricity market (LEM) as a strategic price-maker. The distribution company (Disco) which operates the LEM, participates in the wholesale electricity market (WEM) to provide its consumers, is also a strategic price-maker. For this purpose, the IEVSDGs are integrated at the first level of the optimization problem, while the Disco operator and WEM operator form the second and third levels, respectively. In other words, Disco acts as an intermediary retailer that links the LEM (modelled by IEEE 69-bus distribution system) to WEM (modelled by an IEEE 24-bus transmission network). The study puts forward a novel solution strategy, where the second and third level problems are conjoined through the Karush–Kuhn–Tucker (KKT) conditions. Moreover, the equilibrium point between the first level and this conjoined problem is achieved through the alternating direction method of multipliers (ADMM). In a hybrid robust optimization (RO) and stochastic programming (SP) approach, the uncertain specifications, such as the arrival/departure times and daily travelled miles are modelled through the SP scenarios. On other hand, the RO was deployed to handle solar power forecasting uncertainties. Different case studies of dumb and smart charging were devised to evaluate the method. The outcomes show that the proposed three-level approach leads to 57.21% reduction in the LEM price, and 0.86% reduction in the WEM price. Furthermore, the smart charging strategy eliminated 105 MWh of load interruptions.

Keywords

• Alternating direction method of multipliers
• Electric vehicles
• Local electricity market
• Robust optimization
• Stochastic programming
• Wholesale electricity market