Method and arrangement for limiting electric power required by electric loads

• US 8,288,889 B2
• Filed: 11/05/2009
• Issued: 10/16/2012
• Est. Priority Date: 12/19/2008
• Status: Active Grant

• Current Assignee: ABB Schweiz AG (ABB Limited)
• Original Assignee: Abb Oy (ABB Limited)
• Inventors: Holmberg, Mikael
• Primary Examiner(s): Cavallari, Daniel
• Application Number:
  US12/613,187
• Publication Number:
  US 20100156178A1
• Time in Patent Office: 1,076 Days
• Field of Search: 307/9.1, 307/10.1, 307/35, 700/22, 700/295
• US Class Current: 307/35
• CPC Class Codes: B63B 27/10 of cranes
• CPC Class Codes: H02J 1/14 Balancing the load in a network
• CPC Class Codes: H02J 2310/12 The local stationary network supplying a household or a building
• 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 3/14 by switching loads on to, or off from, network, e.g. progressively balanced loading
• CPC Class Codes: H02J 4/00 Circuit arrangements for mains or distribution networks not specified as ac or dc
• CPC Class Codes: Y02B 70/3225 Demand response systems, e.g. load shedding, peak shaving
• CPC Class Codes: Y02P 80/14 District level solutions, i.e. local energy networks
• CPC Class Codes: Y04S 20/222 Demand response systems, e.g. load shedding, peak shaving

Abstract

A method and arrangement for limiting an electric power required by at least two electric loads, each of which has a predetermined priority level, the arrangement comprising means (31, 32, 33) for monitoring a total electric power required by the at least two electric loads (21, 22, 23), and means (31, 32, 33) for reducing, in a priority-level-wise manner, individual electric powers required by the electric loads (21, 22, 23) having the predetermined priority levels by starting from electric load or loads having the lowest priority level and proceeding, one priority level at a time, towards the highest priority level until the monitored total electric power does not exceed a predetermined threshold value.

Claims

1. A method for limiting an electric power required by at least two electric loads, each of which has a predetermined priority level, the method comprising:

reducing the total electric power required by the at least two electric loads according to the predetermined priority levels of the electric loads if the total electric power exceeds a predetermined threshold value by reducing, in a priority-level-wise manner, individual electric powers required by the electric loads having the predetermined priority levels by starting from electric load or loads having the lowest priority level and proceeding, one priority level at a time, towards the highest priority level until the monitored total electric power does not exceed the predetermined threshold value, wherein the reducing of the total electric power comprises;

communicating individual electric powers required by the electric loads from each of the at least two electric loads to each other;

monitoring in each of the at least two electric loads the total electric power required by the at least two electric loads;

communicating the predetermined priority levels and predetermined minimum power levels of the electric loads from each of the at least two electric loads to each other; and

determining in the electric loads if the individual electric power required by the electric load in question should be reduced on the basis of the predetermined threshold value and the information communicated from the other electric loads.

2. The method of claim 1, wherein each of the at least two electric loads has a predetermined minimum power level wherein the reducing of an individual electric power required by an electric load or loads of a given priority level comprises:

reducing the individual electric power required by the electric load to the predetermined minimum power level.

3. The method of claim 1, wherein each of the at least two electric loads has a predetermined minimum power level wherein the reducing of an individual electric power required by an electric load or loads of a given priority level comprises:

reducing gradually the individual electric power required by the electric load until the predetermined minimum power level is reached or until the monitored total electric power does not exceed the predetermined threshold value.

4. A non-transitory computer readable medium comprising computer program code embodied thereon, wherein execution of the program code in a computer causes the computer to carry out the steps of the method according to claim 1.

5. An arrangement for limiting an electric power required by at least two electric loads, each of which has a predetermined priority level, the arrangement being configured to:

reduce the total electric power required by the at least two electric loads according to the predetermined priority levels if the total electric power exceeds a predetermined threshold value, by reducing, in a priority-level-wise manner, individual electric powers required by the electric loads having the predetermined priority levels by starting from electric load or loads having the lowest priority level and proceeding, one priority level at a time, towards the highest priority level until the monitored total electric power does not exceed the predetermined threshold value, wherein the arrangement comprises, in connection with each of the at least two electric loads;

means configured to communicate the individual electric powers required by the electric loads, the predetermined priority levels and predetermined minimum power levels of the electric loads to each other;

means configured to monitor the total electric power required by said at least two electric loads; and

means configured to determine if the individual electric power required by the electric load in question should be reduced on the basis of the predetermined threshold value and the information communicated from the other electric loads.

6. The arrangement of claim 5, wherein each of the at least two electric loads has a predetermined minimum power level wherein the arrangement is configured to, when reducing an individual electric power required by an electric load or loads of a given priority level, reduce the individual electric power required by the electric load to the predetermined minimum power level.

7. The arrangement of claim 5, wherein each of the at least two electric loads has a predetermined minimum power level wherein the arrangement is configured to, when reducing an individual electric power required by an electric load or loads of a given priority level, reduce gradually the individual electric power required by the electric load until the predetermined minimum power level is reached or until the monitored total electric power does not exceed the predetermined threshold value.

8. The arrangement of claim 5, wherein at least one of the at least two electric loads comprises at least one electric drive.

9. An electric drive, the electric drive being configured to:

monitor a total electric power required by at least two electric loads, wherein one of the at least two electric loads is the electric drive;

reduce an electric power required by the electric drive on the basis of a predetermined threshold value, the monitored total electric power required by the at least two electric loads, and predetermined priority levels of the at least two electric loads; and

communicate an individual electric power required by the electric drive, the predetermined priority level of the electric drive, and a predetermined minimum power level of the electric drive to other loads of the at least two electric loads.