SYSTEMS AND METHOD FOR OBTAINING A LOAD MODEL AND RELATED PARAMETERS BASED ON LOAD DYNAMICS

• US 20110251732A1
• Filed: 04/10/2010
• Published: 10/13/2011
• Est. Priority Date: 04/10/2010
• Status: Active Grant

• Current Assignee: Schweitzer Engineering Laboratories, Incorporated
• Original Assignee: Schweitzer Engineering Laboratories, Incorporated
• Inventors: Donolo, Marcos A., Schweitzer, Edmund O. III, Whitehead, David E.
• Granted Patent: US 8,706,309 B2
• Time in Patent Office: Days
• US Class Current: 700/297
• CPC Class Codes: H02J 13/00004 characterised by the power network being locally controlled
• CPC Class Codes: H02J 13/00006 characterised by information or instructions transport means between the monitoring, controlling or managing units and monitored, controlled or operated power network element or electrical equipment
• CPC Class Codes: H02J 13/00034 the elements or equipment being or involving an electric power substation
• 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 3/003 Load forecast, e.g. methods or systems for forecasting future load demand
• CPC Class Codes: H02J 3/12 for adjusting voltage in ac networks by changing a characteristic of the network load
• CPC Class Codes: H02J 3/14 by switching loads on to, or off from, network, e.g. progressively balanced loading
• 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 10/18 using switches, relays or circuit breakers, e.g. intelligent electronic devices [IED]
• 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

Disclosed are systems and methods for calculating load models and associated tunable parameters that may be used to describe the behavior of loads connected to an electric power distribution system. The load models may be utilized to predict variations in demand caused by changes in the supply voltage, and may be utilized in determining an optimized control strategy based on load dynamics. Any action which causes a disruption to the electric power distribution system may provide information regarding the composition or dynamics of connected loads. Such actions may be referred to as modeling events. Modeling events may occur with some frequency in electric power distribution systems, and accordingly, a number of data sets may be acquired under a variety of conditions and at a variety of times. Load models may include static load models, dynamic load models, or a combination of static and dynamic load models.

Claims

1. An electric power distribution system to distribute power to at least one load, comprising:

a first load;

a first intelligent electronic device (IED) configured to interface with the electric power distribution system, comprising;

a first network communications interface;

a first processor; and

a first computer-readable storage medium, comprising;

software instructions executable on the first processor that enable the first IED to perform operations, including;

identifying a first modeling event;

receiving a first plurality of measurements representing electrical conditions in at least a portion of the electric power distribution system prior to each modeling event and subsequent to each modeling event; and

,

calculating a first load model based on the first plurality of measurements, the first load model representing a predicted response of the first load to a variation in at least one electrical characteristic of power distributed by the electric power distribution system.

2. The electric power distribution system of claim 1, further comprising:

a bus connected to the first load;

a second IED configured to interface with the electric power distribution system, comprising;

a network communications interface to communicate with the first IED;

a sensor component configured to make measurements on the bus;

a second processor; and

a second computer-readable storage medium, comprising;

software instructions executable on the second processor that enable the second IED to perform operations, including;

identifying a second event based on measurements made by the sensor component;

recording a second plurality of measurements representing electrical conditions in at least a portion of the electric power distribution system prior to each modeling event and subsequent to each modeling event;

generating a load dynamics report comprising the second plurality of measurements; and

transmitting the load dynamics report to the first IED.

3. The electric power distribution system of claim 2, wherein the software instructions executable on the first processor further enable the first IED to perform operations, including:

receiving the load dynamics report;

identifying the second event as a second modeling event;

calculating a second load model based on the second plurality of measurements, the second load model representing a predicted response of the second load to a variation in at least one electrical characteristic of power distributed by the electric power distribution system; and

determining an optimized control strategy based on the first calculated load model and the second calculated load model.

4. The electric power distribution system of claim 2, wherein each of the first IED and the second IED further comprise an external time input configured to receive an external time signal from an external time source;

and

wherein the software instructions executable on each of the first processor and the second processor further enable the first IED and the second IED to perform operations, including;

recording a time based on the external time source and associated with each of the first plurality of measurements and the second plurality of measurements.

5. The electric power distribution system of claim 1, wherein the first load model further represents sensitivity of the first load to variations in voltage of power distributed by the electric power distribution system.

6. The electric power distribution system of claim 1, further comprising:

a bus connected to the first load;

a capacitor bank in electrical communication with the bus; and

wherein the first modeling event comprises electrically connecting the capacitor bank to the bus.

7. The electric power distribution system of claim 1, further comprising:

a bus connected to the first load;

a transformer in electrical communication with the bus; and

wherein the first modeling event comprises an adjustment of an output voltage of the transformer.

8. The electric power distribution system of claim 1, further comprising:

a first bus;

a second bus;

a primary transformer in electrical communication with the first bus and the second bus;

a secondary transformer; and

wherein the first modeling event comprises electrically connecting the secondary transformer to the first bus and the second bus.

9. The electric power distribution system of claim 1, further comprising:

a first bus;

a second bus;

a primary transmission line in electrical communication with the first bus and the second bus;

a secondary transmission line; and

wherein the first modeling event comprises electrically connecting the secondary transmission line to the first bus and the second bus.

10. The electric power distribution system of claim 1, further comprising:

a second load;

a breaker for selectively connecting the second load to the electric power distribution system; and

wherein the first modeling event comprises actuating the breaker to electrically connect the second load to the electric power distribution system.

11. The electric power distribution system of claim 1, further comprising:

identifying that the first load comprises a constant impedance load;

wherein the specified condition comprises the electric power distribution system exceeding a ratio of power consumption to power generation; and

wherein the first optimized control strategy comprises reducing voltage provided to the first load.

12. The electric power distribution system of claim 1, further comprising:

identifying that the first load comprises a constant power load;

wherein the specified condition comprises the electric power distribution system exceeding a ratio of power consumption to power generation; and

determining a first optimized control strategy based on the first calculated load model;

wherein the first optimized control strategy comprises electrically disconnecting the first load from the electric power distribution system.

13. The electric power distribution system of claim 1, wherein the software instructions executable on the first processor further enable the first IED to perform operations, including:

adjusting the first load model based upon at least one of a season, a day of the week, and a time of the day in which the first modeling event occurs.

14. An IED configured to interface with an electric power distribution system to distribute power to a plurality of loads, the IED comprising:

a processor; and

a computer-readable storage medium comprising;

software instructions executable on the processor that enable the IED to perform operations, including;

identifying a first modeling event;

recording a first plurality of measurements representing electrical conditions in at least a portion of the electric power distribution system prior to each modeling event and subsequent to each modeling event; and

,

calculating a load model based on the first plurality of measurements, the load model representing a predicted response of the first load to a variation in at least one electrical characteristic of power distributed by the electric power distribution system.

15. The IED of claim 14, further comprising a sensor component configured to monitor at least one of voltage, frequency, current, reactive power, and real power of at least a portion of the electric power distribution system;

and

wherein identifying a first modeling comprises detecting a change in at least one of voltage, frequency, current, reactive power, and real power using the sensor component.

16. The IED of claim 14, further comprising:

a sensor component configured to monitor at least one of voltage, frequency, current, reactive power, and real power of at least a portion of the electric power distribution system; and

wherein the software instructions executable on the processor further enable the IED to perform operations including;

monitoring at least one of voltage, frequency, current, reactive power, and real power prior to and subsequent to a second modeling event; and

re-calculating the load model based on the first modeling event and the second modeling event.

17. The IED of claim 14, wherein the software instructions executable on the processor further enable the IED to perform operations, including:

adjusting the load model based upon at least one of a season, a day of the week, and a time of the day in which the first modeling event occurs.

18. The IED of claim 14, further comprising:

an IED external time input configured to receive an external time signal from an external time source; and

wherein the software instructions executable on the processor further enable the IED to perform operations, including;

recording a time based on the external time source and associated with each of the plurality of measurements.

19. The IED of claim 14, wherein the load model comprises a static load model.

20. The IED of claim 14, wherein the load model comprises a dynamic load model.

21. The IED of claim 14, wherein the IED comprises a voltage regulator controller.

22. The IED of claim 14, wherein the IED comprises a capacitor bank controller.

23. The IED of claim 14, wherein the IED comprises a switch controller.

24. The IED of claim 14, further comprising:

an IED network communications interface to communicate with other networked devices; and

wherein the software instructions executable on the processor further enable the IED to perform operations including;

transmitting a load dynamics report via the network.

25. A method of controlling an electric power distribution system, the method comprising:

identifying a plurality of modeling events;

collecting a plurality of measurements associated with each of the plurality of modeling events, each of the plurality of measurements representing electrical conditions in at least a portion of the electric power distribution system prior to each modeling event and subsequent to each modeling event; and

,

calculating a load model based on the plurality of measurements and representing a predicted response of the first load to a variation in at least one electrical characteristic of power distributed by the electric power distribution system.

26. The method of claim 25, further comprising:

identifying that the first plurality of loads comprises a specified ratio of constant impedance loads.

27. An intelligent electronic device (IED) in electrical communication with an electric power delivery system comprising electric power delivery equipment, the IED comprising:

a sensor component for receiving a signal from electric power delivery equipment;

a processor for receiving and processing data from the sensor component representative of the signal from the electric power delivery equipment; and

,

a monitored equipment interface for receiving commands from the processor and communicating the commands to the electric power delivery equipment;

a computer-readable storage medium in communication with the processor, the computer-readable storage medium including;

a modeling event module of instructions for the processor to identify a modeling event; and

a parameter estimation module of instructions for the processor to calculate differences between data from the sensor component before the modeling event and to calculate a first load model depending on the calculated differences, the load model representing a predicted response of a portion of the electric power delivery system to a variation in an electrical characteristic of power delivered by the electric power delivery system.