When it is necessary to reduce demand on the power system, the power system sends a load control signal to {HEAD ~ a controller} at the consumer indicating that supply of power to {TAIL ~ the first load} is to be interrupted 
When it is necessary to reduce demand on the power system , the power system sends a load control signal to { HEAD ~ a controller } at the consumer indicating that supply of power to { TAIL ~ the first load } is to be interrupted
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH