From Grid Feeding to Grid Supporting Converters: A Constant Power Active Distribution Network Perspective

Currently, more power electronics converter-based generators are replacing synchronous generators (SG) which is creating two problems for overall power systems: 1) Negative impact of excess amount of power from non-dispatchable generating units which is not consumed. 2) Inertia constant reduction. In order to address these problems, this paper proposes a strategy to regulate the point of common coupling (PCC) of active distribution network (ADN) with constant active and reactive power so that the whole ADN acts as a constant PQ node. A virtual synchronous generator (VSG) based network with active power coordination capability is presented to enhance inertia of overall ADN. All distributed generation (DGs) units are operated without maximum power point tracking (MPPT) mode in order to convert them from non-dispatchable to dispatchable units. A detailed analysis on the effect of grid feeding and grid supporting converters on the PCC of a constant power ADN is also presented. MATLAB/SIMULINK environment is used to test our strategy and verify the results.