Werberg

If you use a sonoff mini as a load shedding detector you can probably create a scene in the sonoff/ewelink app that can operate another sonoff device that will control that circuit. 
When building the scene in the app you're basically telling it that if there is load shedding AND it's happening between these hours then only can the circuit get power
Both devices and your wifi must be on backup power so they're always on and ready
I have used the mini to disconnect certain heavy loads when there is load shedding but haven't yet used the time conditions that I know are in the app. 
There are people on the forum that would know exactly how you could do this so hopefully they'll provide you some info.. 
Here is an example of a device that gets signal from the sonoff mini used as loadshedding sensor