Energy management of cooperative microgrids with P2P energy sharing in distribution networks

Abstract

To handle the mismatch problem between local demand and local generation in microgrids (MGs), the paradigm of peer-to-peer (P2P) energy sharing among neighboring MGs has been considered as a promising solution for improving the utilization of local distributed energy resources and saving the energy bills for all MGs. Existing works on cooperative MGs usually consider the high-level energy sharing and trading strategies but little about the physical constraints (e.g. voltage tolerance and power flow constraints) in the underlying distribution network. Hence, their solutions may not be applicable to practical power systems. This paper proposes an optimization problem that aims at minimizing the overall energy cost and the P2P energy sharing losses in a distribution network consisting of multiple MGs and explicitly incorporates the practical constraints (e.g., power balance and battery's operational constraints). The proposed optimization problem is difficult to solve directly due to the non-convex constraints. Nevertheless, motivated by the very recent result in radial distribution networks, the proposed non-convex optimization problem can be relaxed to a second-order cone programming (SOCP) problem without incurring any loss of optimality. We apply the proposed problem to a radial distribution network testbed and obtain the corresponding optimal energy management strategy, which exploits the diversified energy consumption profiles to dynamically coordinate multiple MGs and reduces the total energy bill of all MGs. Moreover, an interesting observation from the simulation results is that the cooperation scheme in the P2P sharing network is significantly affected by the MGs' relative locations in the distribution network.