Optimized decoupling and load shedding

• US 10,476,268 B2
• Filed: 02/09/2018
• Issued: 11/12/2019
• Est. Priority Date: 02/09/2018
• Status: Active Grant

• Current Assignee: Schweitzer Engineering Laboratories, Incorporated
• Original Assignee: Schweitzer Engineering Laboratories, Incorporated
• Inventors: Gubba Ravikumar, Krishnanjan, Manson, Scott M., Armstrong, Benjamin E.
• Primary Examiner(s): Brown, Michael J
• Application Number:
  US15/893,405
• Publication Number:
  US 20190252883A1
• Time in Patent Office: 641 Days
• Field of Search: 700286, 700287, 700295, 700297
• CPC Class Codes: G05B 13/041 in which a variable is automatically adjusted to optimise the performance
• CPC Class Codes: H02J 2203/20 Simulating, e g planning, reliability check, modelling or computer assisted design [CAD]
• CPC Class Codes: H02J 2310/12 The local stationary network supplying a household or a building
• CPC Class Codes: H02J 3/14 by switching loads on to, or off from, network, e.g. progressively balanced loading
• CPC Class Codes: H02J 3/381 Dispersed generators
• CPC Class Codes: Y02B 70/3225 Demand response systems, e.g. load shedding, peak shaving
• CPC Class Codes: Y02E 60/00 Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
• CPC Class Codes: Y04S 20/222 Demand response systems, e.g. load shedding, peak shaving
• CPC Class Codes: Y04S 40/20 Information technology specific aspects, e.g. CAD, simulation, modelling, system security

Abstract

The present disclosure describes load shedding management systems and methods. A load shedding management system may simulate multiple load shedding actions. Based on the simulations the load shedding management system may select a load shedding action. The load shedding management system may send a signal to trip a set of breakers to implement the load shedding action.

Claims

1. An intelligent electronic device (IED) for managing load shedding on a microgrid during an overload condition, comprising:

a communications interface to receive overload condition signals and send signals to manage load shedding;

a contingency breaker in communication with the communications interface, wherein the contingency breaker trips based on user preferences; and

a processor to;

calculate, if the contingency breaker has tripped, a first power deficiency on the microgrid during the overload condition if the microgrid imports power from the utility and does not use incremental reserve margins of generators in the microgrid,

calculate, if the contingency breaker has tripped, a second power deficiency on the microgrid during the overload condition if the microgrid uses the incremental reserve margins of the generators in the microgrid and does not import power from the utility,

determine a first set of loads to shed based on the first power deficiency, and a second set of loads to shed based on the second power deficiency if the contingency breaker has tripped, and

selectively implement a load shedding action based on one of the first and the second sets of loads to shed.

2. The IED of claim 1, wherein the processor compares the first set and the second set of loads to determine which set has the fewest loads, wherein the load shedding action comprises shedding the set with the fewest loads.

3. The IED of claim 1, wherein to implement the load shedding action when the second set of loads is to be shed, the processor:

signals, via the communications interface, a utility breaker to open;

prepares a message indicating that the second set of loads should not use power; and

signals, via the communications interface, the generators in the microgrid to provide the incremental reserve margins.

4. The IED of claim 1, wherein to implement the first load shedding action the processor:

prepares a message indicating that the first set of loads should not use power, and that the microgrid should maintain a utility connection; and

signals, via the communications interface, the generators in the microgrid to maintain a current power output.

5. The IED of claim 1, wherein user preferences comprise a priority order for loads in the microgrid, and wherein a load shedding action corresponding to a set with lower priority loads is implemented.

6. The IED of claim 1, wherein if the user preferences indicate that a utility connection should be maintained the first set of loads is shed and the generators in the microgrid maintain a current power output.

7. The IED of claim 1, wherein the processor calculates the first power deficiency and the second power deficiency in parallel.

8. A method for managing load shedding on a microgrid during an overload condition, the method comprising:

determining, via a processor, a first load shedding action corresponding to the microgrid maintaining a utility connection by;

calculating a first power deficiency on the microgrid during the overload condition if the microgrid imports power from the utility and does not use incremental reserve margins of generators in the microgrid, and

selecting a first set of loads to shed based on the calculated first power deficiency;

determining, via the processor, a second load shedding action corresponding to the microgrid disconnecting the utility connection by;

simulating opening a utility breaker,

calculating a second power deficiency on the microgrid during the overload condition if the microgrid uses the incremental reserve margins of the generators in the microgrid and does not import power from the utility, and

selecting a second set of loads to shed based on the calculated second power deficiency; and

selectively implementing one of the first or the second load shedding action based on one of the first set and the second set of loads to shed by modifying power generation and consumption of the microgrid.

9. The method of claim 8, further comprising comparing the first set and the second set to determine which set has the fewest loads, wherein a load shedding action corresponding to the set with the fewest loads is implemented.

10. The method of claim 8, wherein implementing the second load shedding action comprises:

signaling the utility breaker to open;

preventing loads in the second set of loads from using power; and

receiving power from the incremental reserve margins of the generators in the microgrid.

11. The method of claim 8, wherein implementing the first load shedding action comprises:

preventing loads in the first set of loads from using power;

preventing the generators in the microgrid from using the incremental reserve margins; and

receiving additional power from the utility.

12. The method of claim 8, wherein implementing one of the first load shedding action or the second load shedding action is further based on customer preferences.

13. The method of claim 12, wherein customer preferences comprise a priority order for loads in the microgrid, and wherein a load shedding action corresponding to a set with lower priority loads is implemented.

14. The method of claim 12, wherein if the customer preferences indicates that the utility connection should be maintained the first load shedding action is implemented.

15. The method of claim 8, wherein determining the first load shedding action and the second load shedding action is done in parallel.

16. A system for managing load shedding on a microgrid during an overload condition, comprising:

a utility breaker configured to selectively remove the microgrid from a utility line;

a contingency breaker to receive an overload condition signal indicating that the microgrid does not have sufficient power for all of the loads on the microgrid, wherein the contingency breaker trips based on user preferences and the overload condition signal; and

an intelligent electronic device (IED) in communication with the contingency breaker and the utility breaker, the IED to;

calculate a first power deficiency on the microgrid during the overload condition if the microgrid imports power from the utility and does not use incremental reserve margins of generators in the microgrid,

calculate, if the contingency breaker has tripped, a second power deficiency on the microgrid during the overload condition if the microgrid uses the incremental reserve margins of the generators in the microgrid and does not import power from the utility,

determine a first set of loads to shed based on the first power deficiency, and a second set of loads to shed based on the second power deficiency if the contingency breaker has tripped, and

selectively implement a load shedding action based on one of the first and the second sets of loads to shed to modify power generation and consumption of the microgrid.

17. The system of claim 16, wherein the IED is further to compare the first set and the second set of loads to determine which set has the fewest loads, wherein the load shedding action comprises shedding the set with the fewest loads.

18. The system of claim 16, wherein to implement the load shedding action when the second set of loads is to be shed, the IED:

signals the utility breaker to open;

interrupts power to the second set of loads; and

signals the generators in the microgrid to provide the incremental reserve margins.

19. The system of claim 16, wherein to implement the first load shedding action, the utility breaker remains closed, and the IED:

interrupts power to the first set of loads; and

signals the generators in the microgrid to maintain a current power output.

20. The system of claim 16, wherein the IED calculates the first power deficiency and the second power deficiency in parallel.