Research On Frequency Response Strategy And Parameter Optimization Configuration Of Air Conditioning Load

With a large amount of intermittent renewable energy being incorporated into the power system,frequency fluctuations caused by the imbalance between supply and demand side occur frequently.It is difficult to maintain the grid frequency in the normal range by relying solely on the reserve capacity of the power generation side,and it is necessary to coordinate the load side for frequency emergency control.Air conditioning(AC)loads have thermal energy storage characteristic,and can participate in frequency response in a short time without causing significant negative impact on user utility.At the same time,the applications of grid-friendly technology on the user side fully realize the response potential of AC loads.In the process of AC load response,it is the key to properly coordinate the response effect and user utility to set the triggering condition of responsive action.The household AC loads are taken as an example in this paper,focusing on the key parameter configuration of triggering AC loads response.Response strategy and parameter configuration method of AC loads is researched.The main contributions are described as follows:(1)Considering the influence of urban microclimate on outdoor temperature,a AC loads aggregated model is built.Meanwhile,a method is proposed to evaluate the regulation potential of aggregated AC loads.A third-order physical model of an individual AC is established,by analyzing the thermal dynamic process and periodic operation characteristics of AC load.Taking into account the influence of urban microclimate on AC loads,the Monte Carlo sampling method is used to build the AC cluster aggregation model,based on the correction of outdoor temperature.The model can achieve high simulation accuracy,suitable for aggregation of large-scale AC loads.In addition,under the effect of urban microclimate,the state transition time of aggregated AC loads will decrease when set temperature of AC loads changes.Finally,according to the virtual energy storage characteristics of AC loads,the regulation potential of aggregated AC loads is derived.(2)A decentralized control strategy for AC loads considering user’s thermal comfort is proposed to solve the problem that AC loads frequency response which have negative impact on users’ utility.Under the framework of the home energy management system,a distributed control method based on grid-friendly technology is designed.The intelligent controller monitors frequency of power system in realtime,and controls the self-response of AC loads.For the demand of real-time operation,the humidity-temperature index is used to quantify the user’s thermal comfort,and the power demand of aggregated AC loads is adjusted according to the real-time comfort and system frequency deviation.The control strategy can effectively suppress the trend of frequency drop and reduce the negative impact of AC loads response on users’ utility.In addition,the response trigger parameters are researched,and found that the larger the response threshold or monitoring period is,the worse the response effect.(3)A self-adaptive method of monitoring period and a parameter optimization configuration scheme is proposed to solve the problem that response triggering parameters configuration for coordinating AC loads response effect and users’ utility.The self-adaptive method is designed to dynamically adjust monitoring period according to the real-time frequency change rate,and improve the flexibility of parameters adjustment during the frequency modulation process.A multi-objective optimization model is presented which the objective functions are maximum frequency deviation,time for frequency exceeds the normal range,response probability and monitoring cost.The single-area power system model with AC loads group and wind turbine is established in the MATLAB simulation platform.The NSGA-II algorithm is used to solve the optimization problem,and the optimal scheme of parameter configuration is determined according to the fuzzy set theory.Simulation results show the superiority of the self-adaptive adjustment method,and finds out that best tradeoff can be made between response effect and users’ utility when the response threshold is 0.2 Hz and monitoring period is between 5 and 6s.According to the research of AC loads frequency response,a decentralized control strategy considering the user’s thermal comfort and an optimal configuration scheme of response triggering parameters are proposed in this paper,which reduce the negative influence of load control on users and suppress grid frequency drop depth,achieving an optimal balance between response effect and users’ utility.The research on AC loads is practical for the configuration of AC loads response trigger parameters.It also provides a useful reference for the research of other temperature control loads control methods.