Evaluation of the Maximum Wind Power Penetration of a Power System Including Controllable Electric Water Heaters

In order to study the effect of load participating in the demand side frequency modulation (DSFM) of electric water heater on increasing the maximum wind power penetration of wind power integration system, an adaptive frequency modulation control strategy with variable user participation and a coordinated control strategy frequency modulation are proposed. Based on finite state machine (FSM), the state change of the load of electric water heaters (EWH) is given. And a power grid-connected wind generator model that includes the wind turbine model, wind speed model and the primary and secondary frequency modulation model of electric power system is constructed. The model is used to evaluate the maximum wind power penetration of power system under different frequency constraints through wind generator output simulation, power system frequency simulation and frequency quality analysis. The results show that the power system with electric water heaters participating in DSFM has strong wind power absorption ability. Under the condition of multi-group frequency constraints, the system's maximum wind power penetration is obviously improved. And its frequency stability is much greater than that of the power system relying on traditional frequency modulation.