Demand Management of Active Distribution Network Using Coordination of Virtual Synchronous Generators

This article proposes a hierarchical control structure to address two major issues in power systems: 1) power imbalance during events when output power from distributed generations (DGs) is not fully consumed; 2) reduction of inertia constant and damping effect in overall power systems due to integration of DGs. To address these issues, a hierarchical control structure for a virtual synchronous generator (VSG) based active distribution network (ADN) is proposed to achieve three objectives; 1) to regulate the point of common coupling (PCC) of ADN according to demand; 2) to coordinate all VSGs to share active and reactive power proportionately; 3) to ensure that the error in reactive power sharing caused by the unequal line impedances will not disturb the demand at PCC. The uniqueness of this study lies in the fact that the VSG coordination of the PCC demand management for ADN has never been implemented. Furthermore, the proposed method does not require a large battery energy storage (BES) system to balance the output voltages of all DGs. This strategy will not only increase the revenue of distribution companies but will also provide power to the customers with enhanced quality and lower rate of change of frequency (RoCoF).