A delay based optimization scheme for peak load reduction in the smart grid

A measurement campaign based on commodity wireless sensors shows that the majority of thermostatic loads in a user premise are described by periodic pulse waves. The superposition of these loads results to high peak power demand and costs in the network. We propose a novel first stage of optimization in the smart grid which reduces external on/off command flow for demand response between the controller and the smart appliances. A phase management scheme is developed that defines optimal time shifts (delays) on the periodic loads in order to provide peak power reduction over a limited time horizon. A gradient descent optimization technique, based on Taylor series, is applied to determine the phases of the pulses in discrete time steps. A centralized control scheme is explored, applied from the controller of the smart grid to smart devices that fall within its administrative domain. It is found that respectable peak power reduction can be achieved by the centralized scheme with a drawback the redundant data transfer in the network. The main advantage by implementing the proposed algorithm is that direct on/off control of the smart grid upon the smart devices of the users can be avoided. As a consequence, user discomfort is reduced and higher penetration of smart grid services is expected.