Research On Impact Of Micro Grid On Voltage Stability Of Distribution Network

Distributed generation provides clean, efficient energy using renewable energy andnew energy. Micro grid provides methods for large-scale application of distributedgenerations using reasonable output control and energy management technologies.However, the Micro grid application, the penetration of its power to the grid change theone-way energy transfer of power system, which causes great impacts on the stability ofexisting power grid. Power system voltage stability is one of the first. On the basis of theresearch background of distributed generation and micro grid, the impact to voltagestability for the grid with micro grid accessing is studied in this dissertation.First of all, several common distributed generation technologies and the definition ofmicro grid are introduced, Following which, taking the typical micro grid structureproposed by CERTS as an example, the paper describes micro grid technology in detail.Secondly, around voltage stability analysis to distribution network with micro grid,establish micro grid models including distributed generator interfaces and the load.Meanwhile, the power flow calculation model and approach of distribution network withmicro grid is proposed for different kinds of distributed generator by the four node typessuch as PQ, PV, PI and P-Q（V）.And then, according to power flow based voltage stability analysis of distributionnetwork and the features of wind power and micro grid, an on-line voltage stability indexfor the distribution network with wind power micro grid is proposed, which is tested andverified in simulation.At last, based on the change of steady-state voltage stability margin of power system,It is studied that the impact to voltage stability for grid with micro grid accessing inpercept of the micro grid penetration capability, accessing position and types of distributedgeneration.