Real-time pricing based frequency control and smoothing of PV and WTG output power variations in islanded micro-grid

Recently, penetration of renewable energy sources is remarkable. However, it causes system frequency deviation that means decrease of system reliability. In order to solve this problem, this paper proposes frequency control method using demand response (DR) and suppression of power output for renewable energy sources. It is assume that the consumption power of end-user is controlled automatically by smart appliances that decides the switch on/off using electric price. The electric price is given by real-time pricing method which is one of the DR methods. In addition, the suppression of power output for Photovoltaic Generator (PV) and Wind Generator (WG) is introduced. The suppression of power output for PV has been performed by controlling operating point, and that for WG is performed by controlling the pitch-angle of the blade. Furthermore, battery which has fast response characteristic is used, because the DR has slow response characteristic due to communication delay and mechanical delay. The effectiveness of the proposed method is verified by computer simulations.