System frequency control using emergency demand response in power systems with large-scale Renewable Energy Sources

Recently, the introduction of Renewable Energy Sources (RESs) has been remarkable. However, the RESs are the cause of output power fluctuation which depends upon the weather condition. It also causes system frequency to deviate that means reliability of system is decreased. In particular, RES's output power which varies steeply and significantly is a cause of concern. Due to these output power fluctuations, the supply-demand balance gets worse, in the worst case, massive blackout can occur. In this paper, we propose emergency demand response (EDR) method to prevent the steep output power fluctuation of the RESs. The EDR adjusts the supply-demand balance by changing the consumed power of controllable load depending on system frequency drop. When the system frequency drops steeply, the system frequency is restored rapidly within acceptable range using the EDR.