Study On Electric Water Heater Model Construction And Demand Side Frequency Regulation Control Strategy

Frequency is one of the key indexes of the power system,which directly affects the normal operation of the power generation equipment and the load.In order to reduce environmental pollution and the dependence on nonrenewable energy,the capacity of new energy power generation is increasing day by day.Because of its random,unpredictable and other characteristics,the power system frequency quality is presenting the overall downward trend.Comparing with the traditional power generation side frequency regulation method,the demand side frequency regulation which is mainly composed by the household load with the energy storage characteristics has fast response,environmentally friendly and other features.Aiming at the load of electric water heater(EWH),this paper studies the demand side frequency regulation ability from modeling the aggregation of EWH and proposing its demand side frequency regulation control strategy.Firstly,the principle of energy interaction of EWH has been analyzed and a single EWH model has been constructed,the single model accuracy has been verified.The distribution of the key aggregate parameters of the population of EWH load has been determined,the domestic water model has been constructed.The aggregate model of EWH load has been constructed based on Monte Carlo method,the aggregate error caused by the aggregate method has been calculated.The influence of the key parameters on the demand side frequency regulation abiliy of EWH has been analyzed by simulation.Secondly,the control mode of EWH load has been analyzed,the demand side adaptive frequency regulation strategy has been proposed.The frequency regulation process of the aggregation of EWH load which response to the power system high and low frequency event has been theoretical analyzed based on state queueing method,the reasons of the recovery peak and trough phenomenons caused by the change of temperature setpoint have been analyzed.Simulation by the examples,the influence of the frequency regulation standby capacity of the aggregation of EWH caused by the temperature setpoint change size and the frequency event occurrence period have been given,the response ability of EWH load to high and low frequency events have been compared,the change trend of the response ability of EWH load to high and low frequency events have been determined.The response ability of the aggregation of EWH load to the signal of continuous change temperature setpoint has been analyzed.Then,the traditional frequency regulation characteristics have been analyzed.The coordination mode of EWH load which in response to power system first,second frequency regulation have been proposed based on the demand side adaptive frequency regulation strategy.The state change of EWH load which response to power system first,second frequency regulation have been determined based on finite state machine.The cooridination mode of EWH load in response to the major frequency accident in the time of first frequency regulation has been given.Finally,the equivalent power system first and second frequency regulation model have been constructed.The effectiveness of the response of the aggregation of EWH load response to the power system first,second frequency regulation have been verified by simulation.The influence of the different parameters setting on the power system frequency regulation has been given.The fan-to-grid frequency regulation model has been constructed.The limit wind power penetration of the power system with the controlled EWH load has been evaluated.