Submitted: March 2015

Abstract

With the growing trend of modern countries such as Germany and Denmark using renewable energies, frequency stability has become more of a concern. The fluctuating green energies such as wind power raise the risk of frequency oscillation.

The power grids are growing rapidly and with the technology development more and more electrical devices are connecting to the system. Cooperative Dynamic Demand Response, in the future smart grid could be a key to make the system more efficient at the cost of increased risk of aggregate demand spikes.

In this Master Thesis we investigate the risks and benefits of applying Dynamic Demand Control (DDC) to domestic refrigerators to stabilize the grid frequency.

We explore the absence of critical facts in DDC such as food safety, and represent the results of applying these controls to DDC model. We also detect two serious phenomena that might happen while using DDC: synchronization, and Fluctuation Carrying Phenomenon (FCP).

We introduce our new approach Check And Wait (CAW), and indicate that although it improves the grid stability remarkably, it decreases the risk of FCP and synchronization significantly.