Hierarchical Structure Design and Primary Energy Dispatching Strategy of Grid Energy Router

Abstract

As a core device of energy Internet, the energy router is deployed to manage energy flow between the renewable energy and electric grid. In this paper, a hierarchical structure of grid energy router is proposed to greatly facilitate peer-to-peer energy sharing among energy routers. It can be placed at critical buses to make active distribution networks develop into multiple interconnected prosumer-based autonomous systems. To alleviate the mismatch between the medium-time dispatch and device-level control caused by the forecast error of distributed generation, a bi-level primary energy dispatching strategy is proposed to fully utilize the energy buffer of multiple grid energy routers. The power variation in short-time scale is well suppressed by sharing energy buffer in the upper-level control, and the energy buffer is further optimized to better absorb the variation. Combining measured information, the lower-level control is designed to track the optimized instruction of energy buffer in real-time scale, which is a distributed process. The power flow constraint is assumed to be handled by medium-time dispatch, and the current constraint of the device is only taken into consideration. Finally, simulation results demonstrate the effectiveness of proposed hierarchical structure and primary energy dispatching strategy of the grid energy router.