The Study On Mechanism Of Controllable Loads To Providing Reserve And Capacity Evaluation

The reserve capacity of power system is provided by generators and the regional tie-line power. Along with the changing of generating composition and the increasing ratio of the large capacity thermal power units, the reserve cost provided by generating side becomes more and more expensive. As the large capacity intermittent energy connecting to the grid, the reserve capacity and quality need to be improved. So the traditional reserve provided by generating side should be changed, and the new reserve provider will be exploited. Strengthening the research and utilization of load side will promote the rapid development of intelligent grid and ensure the safe and stable operation of the power system.As typical thermostatic controllable loads, air conditioners have certain storage properties. By means of controlling their target temperatures and not changing their effectiveness, air conditioners can provide reserve for power system. In order to depict appropriately the working characteristics of air conditioners, accurately model need to be constructed. Considering a variety of factors which affected the loads’ working condition, a precise physical model of air conditioner load based on the cubic equation of state was constructed. Single-zone aggregation model based on Monte Carlo simulation method was proposed. The influence of key parameter’s distribution characteristic to aggregated power demand was analysed.In order to depict appropriately the diversity of the parameters distribution characteristics and get precise aggregated power demand, aggregation method based on the availability of weather information was proposed. Thiessen Polygon Method was applied to divide geographical scope into a few subregions. The only meteorological station in every subregion provides weather information to the subregion. So, the parameters will be more precise and the aggregated result will be more accurately. According to the information of international meteorological stations in Shandong Province, Shandong grid was divided into a few subregions and the air conditioners were aggregated by multi-zones aggregation method. The results comparison of single-zone aggregation and multi-zones aggregation verified the accuracy of multi-zone aggregation method.Based on the multi-zones aggregation model, a large number of simulation experiments about the aggregated loads reserve dynamic process were carried out. Nonlinear regression model about the loads reserve response time and reserve capacity was constructed. Simulation example verified the accuracy and availability of the proposed method and constructed model.