The equivalent load is proposed as the total reference value of power generators with stable and controllable output in microgrids based on the difference between total load and combined wind-solar power. By reserving in the demand-side to energy management system(EMS)

water-storage heater(WSH)group responses control signal to suppress power fluctuations of equivalent load in microgrids. Firstly

the equivalent load model and evaluation indicator based on reservation change frequency of combined wind-solar power are established

the feasibility analysis of WSH group in demand-side participating in energy management in a microgrid is conducted

temperature model of WSH group is set up by considering conduction energy

transposition energy and heating energy. Secondly

considering the time and amount of demand-side reservation water or conventional water

user active control and WSH temperature upper limit values

dynamic controllable WSH group is set up and it's reverse temperature value is calculated. According to sorted reverse temperature value

two process of cutting in standby WSH and cut out heating WSH are unified

thus a control strategy to suppress power fluctuations of equivalent load in microgrids is proposed based on demand-side reservation and WSH group response. Finally

by applying case data in an actual microgrid

the effectiveness of the control strategy is verified. This work is supported by International Science & Technology Cooperation Program of China(No. 2013DFG61520).