System and method for limiting energy consumption

Abstract From the Canadian patent

A demand limiting system is provided for a large electrical energy customer with at least one modulating load. A master control unit continually compares the actual power usage to the desired rate of power usage. When the desired power consumption rate is exceeded by a first amount, the master provides a hold signal to an associated slave control unit, which prevents further loading of the modulating load. When the desired rate of power consumption is exceeded by a second amount, the master provides a reduce signal to the slave unit, which begins to reduce the load. While the hold signal is calling for a reduced load only a, fraction of the time is utilized to reduce the load and the, …