THE DEGREES OF
FREEDOM IN THE SMART GRID
The user comfort defines the degrees of freedom
for optimization and control in the smart grid which is based on command flow in the network that change the state of operation (on/off) of specific “smart” flexible appliances. The flexible appliances can be related to non-emergency power tasks that can be transferred to off peak hours, i.e. the washing machine or EV charging problem. They incorporate an initiation point in time a, a deadline of execution d and a power level of the task d. They can also be thermostatic loads that can be switched off and on without affecting users’ comfort due to thermal inertia.
This type of device usually incorporates a ratio
Tmin/Tmax, where Tmin is the minimum time the device must operate to produce a comfort value l which is acceptable by the user and Tmax is the maximum time the smart grid can switch off the device so as the comfort value reaches its lower comfort limit lmin [6].