Method of power demand control with time dependent target

• US 4,136,393 A
• Filed: 07/18/1977
• Issued: 01/23/1979
• Est. Priority Date: 07/18/1977
• Status: Expired due to Term

• Current Assignee: Westinghouse Electric Company LLC (Brookfield Asset Management Incorporated)
• Original Assignee: Westinghouse Electric Company LLC (Brookfield Asset Management Incorporated)
• Inventors: Fox, Richard Q.
• Primary Examiner(s): Wise, Edward J.
• Application Number:
  US05/816,560
• Time in Patent Office: 554 Days
• Field of Search: 364/492, 364/493, 307/35, 307/39, 307/41, 307/52, 307/62, 324/103
• US Class Current: 700/291
• CPC Class Codes: G01R 21/00 Arrangements for measuring electric power or power factor G01R7/12 takes precedence
• CPC Class Codes: H02J 2310/54 according to a pre-established time schedule
• CPC Class Codes: H02J 2310/60 Limiting power consumption in the network or in one section of the network, e.g. load shedding or peak shaving
• CPC Class Codes: H02J 3/144 Demand-response operation of the power transmission or distribution network
• CPC Class Codes: Y02B 70/3225 Demand response systems, e.g. load shedding, peak shaving
• CPC Class Codes: Y04S 20/222 Demand response systems, e.g. load shedding, peak shaving

Abstract

The invention relates to power demand control of a number of loads in a plant facility in order to keep the power within a demand limit at the end of a demand period. During the billing period the invention provides for a demand limit floating up and/or down over the demand periods, and means is provided to dampen control action whenever the demand limit would tend to oscillate up and down over the successive demand periods.

Claims

1. A method of limiting the power demand of a plant facility having controllable and non-controllable loads by switching said controllable loads during successive demand periods and selectively in accordance with a pre-established priority list, comprising the steps of:

assigning at the beginning of a given demand period a predetermined demand limit to be met at the end of said given demand period;

recording the actual demand at the end of said given demand period;

assigning for a subsequent demand period a demand limit other than said predetermined demand limit, said other demand limit being equal to said recorded actual demand when said actual demand differs from said predetermined demand limit by a predetermined amount;

predicting a demand at the end of any demand period and deriving a demand error by reference to the assigned demand limit with said predicted demand; and

switching said controllable loads during the demand period to minimize said error.

2. The method of claim 1, with the further steps of:

providing a first signal representative of said predetermined demand limit assigned for said given demand period;

storing a second signal representative of the actual demand recorded at the end of said given demand period; and

comparing said first and second signals for establishing said other demand limit when said first signal differs from said second signal by at least said minimum amount.