Research On Load Control Strategy In Microgrid

In recent years, with the problems of environmental issues and oil crisis becoming increasingly prominent, national governments, technology providers and academic societies put more emphasis on the study of renewable energy. Because the demand response technology has the ability to adjust peak value when necessary, to reduce the impact on the system effectively caused by intermittent power fluctuation and has important significance to the microgrid's safe and economic operation at the same time, it becomes one of the hotspots.Firstly, we summarized the research status of the microgrid centralized load control strategies. On this basis, we described and analyzed price mechanism, load classification and the participate process and method of demand response in detail. For the price mechanism, we mainly analyzed the ladder price and the time-of-use price(TOU), and the applicable scope of these two price mechanism was also analyzed. Secondly, according to the different of residents' load type, the residents load could be divided into controllable load and uncontrollable load. And for the controllable load, we mainly analyzed the energy consumption characteristics of electric vehicles(EV) and heating ventilating and air conditioning(HVAC). This paper also designed the participation process and method of demand response in power supply and demand side.Secondly, we modeled the EV and HVAC load. In order to develop load control strategy, for the controllable load of EV, we proposed the disorder charging mathematical model based on Monte Carlo method, and the order charging mathematical model base on the time of use strategy. While for the load model of HVAC, a typical temperature control equipment thermodynamic model was used, and the dynamic response behavior base on time of use price was analyzed.Finally, based on the load modeling, we proposed the microgrid load control strategy, this strategy contained three minimum targets, these were microgrid power supply cost, environmental cost, and the subsidy cost for the controllable load, and the whole target was optimized using primal-dual interior point method. The simulation is carried out in a typical small microgrid system, analyzing the social benefits of the residential customers adopting ladder price and TOU price. For the users adopting ladder price, in order to illustrate the reduction of the electricity bills, we simply used their response efforts to analyze. While for the users adopting TOU price, we proposed two cases to illustrate, that is, consider the control of controllable load and do not consider the control of the controllable load in the optimized scheduling. In the two cases, we discussed the effects on the microgrid's load curve, the new energy output and the efficiency of the supply side and user side. The results proved that by considering the controllable load, it could reduce the load peaks and valleys difference, reduce microgrid power supply costs and environmental costs, and it can also increase the users' profitability without affecting their comfort.