Method and apparatus for adaptive demand limiting electric consumption through load shedding

An apparatus for shedding electrical loads of an electrical system to maintain power consumption below a predetermined target level, the apparatus comprising:

• sensor means for sensing said power consumption of said electrical system and generating load information representative of said power consumption;
• memory means for storing information;
• and
• processor means for executing a predetermined program;
• said processor means, said memory means, and said sensor means being operatively interconnected;
• said processor means effecting storage of said load information in said memory means;
• said processor means including a predictor means for forecasting a predicted load to be shed for a predetermined future period to keep said load level below said target level, said processor means issuing shed control signals to selected electrical loads within said electrical system to shed appropriate electrical loads of said selected electrical loads in accordance with said predicted load to be shed, said processor means effecting storage of shed information indicative of the amount of electrical load being shed, said predictor means employing a statistical algorithm involving a forecast of energy requirements for said predetermined future time period calculated from said load information and said shed information, said statistical algorithm further generating a maximum forecast of energy requirements for said predetermined future time period in accordance with an error factor and said forecast of energy requirements, said predicted load to be shed being calculated in accordance with said maximum forecast of energy requirements, wherein said error factor is calculated from differences between said forecast of energy requirements for said future period made during at least one of a plurality of previous time periods and a sum of shed information and load information during said at least one of said plurality of previous time periods.

A method of controlling aggregate electrical load of an electrical system to a load level below a predetermined level, said electrical system including a sensor for providing load information representative of the electrical load being used, a processor configured to issue shed control signals to selected devices within said electrical system to shed appropriate devices of said selected devices to keep said low level below said predetermined target level, said processor generating shed information indicative of the amount of electrical load being shed, and memory means for storing said load and shed information, the method comprising the steps of:

• forecasting an energy requirement for a predetermined future in accordance with said load information and said shed information:
• calculating a maximum forecast of energy requirements for said predetermined future time period in accordance with said forecast of energy requirements and an error factor, said error factor being related to a difference between said forecast of energy requirements during at least one of a plurality of previous periods and load information during at least one of said plurality of previous periods;
• calculating a predicted load to be shed for said future time period in accordance with said maximum forecast of energy requirements;
• and
• issuing shed control signals to said selected devices within said electrical system to shed appropriate devices of said selected devices to keep said load level below said predetermined target level, wherein said error factor is calculated from differences between said forecast of energy requirements for said predetermined future time period made during a previous time period and a sum of said load information and said shed information during said previous time period.