Research On Some Key Techniques Of Micro-Grid Operation

Micro-grid can take good advantage of distributed energy resources,however the researches on the characteristics of micro-grid operation and itsrelevant techniques are not mature enough. Energy allocation between DG,energy storage and loads directly impact the stability and economics ofmicro-grid. After the micro-grid inserted, the power flow and short circuitcurrent of the distribution network will change. In order to ensure the safetyand stability of the distribution network including micro-grid, it is necessaryto analyze micro-grid’ influence on the distribution network and to putforward countermeasures accordingly. This paper mainly does research onmodeling and simulation, energy management system and the analysis ofeffect on the automatic equipments. The main points studied in the paper areas follows:(1) Component models of the micro-grid are built, including solar cellmodel, CCHP model, battery energy storage unit model, the control strategiesof inverter model, both grid-tied and islanding. A whole micro-grid model isalso built, to research the characteristics of the micro-grid and provide electricfoundation of energy management system research.(2) The structure of the energy management of micro-grid as well as theoptimization model are analyzed. Based on that, this paper put forward animproved optimization model. This model gives priority to use the powerproduced by DG, and takes operating expense as the objection function. Andthe operating expense of each micro source is simplified reasonably. To solvethe complicated optimization function, it is necessary to study the modernoptimization algorithms. A method combined with exterior penalty functionand particle swarm optimization is put forward to solve the core function. (3) Based on the built simulation model of the micro-grid, the effect onthe automatic equipment is studied, mainly including effect on the autoreclose and spare power automatic switching. And the improvedmeasurements are proposed to decrease or even eliminate the effect.(4) The conclusion of those research results, as well as the furtherresearch directions are given.