Devices and methods for decentralized power factor control

• US 8,838,285 B2
• Filed: 07/26/2011
• Issued: 09/16/2014
• Est. Priority Date: 07/26/2011
• Status: Active Grant

• Current Assignee: GE Digital Holdings LLC (General Electric Co. (Italy))
• Original Assignee: General Electric Company
• Inventors: Milosevic, Borka, Toit, Willem Hendrik Du, Vukojevic, Aleksandar
• Primary Examiner(s): PATEL, RAMESH B
• Application Number:
  US13/191,400
• Publication Number:
  US 20130030597A1
• Time in Patent Office: 1,148 Days
• Field of Search: 700/186, 700/291, 700295-298, 700/286, 703/18
• US Class Current: 700/298
• CPC Class Codes: H02J 13/00002 characterised by monitoring
• 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 3/00 Circuit arrangements for ac mains or ac distribution networks
• CPC Class Codes: H02J 3/16 by adjustment of reactive power
• CPC Class Codes: H02J 3/1821 using shunt compensators H02J3/1807, H02J3/1878 take precedence
• CPC Class Codes: H02J 3/1878 using tap changing or phase shifting transformers
• CPC Class Codes: Y02E 40/30 Reactive power compensation
• CPC Class Codes: Y02E 40/70 Smart grids as climate change mitigation technology in the energy generation sector
• CPC Class Codes: Y02E 60/00 Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
• CPC Class Codes: Y04S 10/00 Systems supporting electrical power generation, transmission or distribution
• CPC Class Codes: Y04S 10/16 Electric power substations
• CPC Class Codes: Y04S 10/22 Flexible AC transmission systems [FACTS] or power factor or reactive power compensating or correcting units
• CPC Class Codes: Y04S 10/30 State monitoring, e.g. fault, temperature monitoring, insulator monitoring, corona discharge
• CPC Class Codes: Y04S 40/20 Information technology specific aspects, e.g. CAD, simulation, modelling, system security

Abstract

Devices and methods for the decentralized, coordinated control of the power factor on an electrical distribution system are provided. For example, a controller may include a network interface and data processing circuitry. The network interface may receive first measurements associated with a segment of an electrical distribution system and transmit a control signal configured to control equipment of the segment of the electrical distribution system. The data processing circuitry may run simulations of the segment of the electrical distribution system in various equipment configurations, selecting from among the various equipment configurations an equipment configuration that is expected to cause the power factor to approach a desired value. The data processing circuitry then may generate the control signal, which may cause the equipment of the segment of the electrical distribution system to conform to the equipment configuration and thereby control the power factor.

Claims

1. A first controller configured to provide decentralized coordinated control over a first segment of an electrical distribution system supplied by a first substation while a second controller is providing decentralized coordinated control over a second segment of the electrical distribution system supplied by a second substation, the first controller comprising:

a network interface configured to receive first measurements associated with the first segment of the electrical distribution system supplied by the first substation and transmit a control signal configured to control equipment of the first segment of the electrical distribution system, wherein the first controller is configured not to control equipment of the second segment of the electrical distribution system supplied by the second substation that is controlled by the second controller; and

data processing circuitry configured to run first digital simulations of the first segment of the electrical distribution system simulating various equipment configurations based at least in part on the first measurements, to select from among the various equipment configurations an equipment configuration that is expected to cause a power factor on the first segment of the electrical distribution system to approach a desired value, and generate the control signal, wherein the control signal is configured to cause the equipment of the first segment of the electrical distribution system to conform to the equipment configuration but not to control equipment of the second segment.

2. The controller of claim 1, wherein the control signal is configured to control the equipment of the first segment of the electrical distribution system, wherein the equipment comprises at least one capacitor, and wherein the data processing circuitry is configured to run digital simulations of the first segment of the electrical distribution system simulating various equipment configurations, wherein the various equipment configurations comprise various capacitor switching solutions, and wherein the data processing circuitry is configured to select from among the various capacitor switching solutions a capacitor switching solution that is expected to cause the power factor on the first segment of the electrical distribution system to approach the desired value.

3. The controller of claim 2, wherein the capacitor switching solution indicates that a single one of a plurality of capacitors of the first segment of the electrical distribution system is to be switched on or off.

4. The controller of claim 2, wherein the capacitor switching solution indicates that a combination of a plurality of capacitors of the first segment of the electrical distribution system are to be switched on or off.

5. The controller of claim 4, wherein the data processing circuitry is configured to determine a switching order of the combination of the plurality of capacitors.

6. The controller of claim 1, wherein the network interface is configured to obtain the first measurements from a plurality of remote terminal units, wherein the first measurements comprise:

a voltage magnitude at a low side bus of the first substation of the first segment of the electrical distribution system;

a voltage magnitude at capacitors of the first segment of the electrical distribution system;

a voltage magnitude at low sides of voltage regulators of the first segment of the electrical distribution system;

tap positions of the voltage regulators;

real and reactive power flows at capacitors and at all junction points between the capacitors and the voltage regulators and the first substation;

real and reactive power flows at a high side bus of the substation or real and reactive power flows from each feeder of the first segment of the electrical distribution system, or both;

real and reactive demand from each commercial or industrial, or commercial and industrial, load between the substation and any of the capacitors; and

end of line voltages of the first segment of the electrical distribution system or a voltage drop between a last measurement point and an end of a feeder.

7. The controller of claim 1, wherein the data processing circuitry is configured to determine a plurality of operational parameters of the first segment of the electrical distribution that are expected to vary depending on the various equipment configurations, wherein the plurality of operational parameters comprises the power factor on the first segment of the electrical distribution system and:

a voltage deviation over the first segment of the electrical distribution system;

or

a reduction in power losses over the first segment of the electrical distribution system;

or both.

8. The controller of claim 7, wherein the data processing circuitry is configured to select the equipment configuration, wherein the selected equipment configuration is non-dominated in relation to others of the various equipment configurations.

9. The controller of claim 7, wherein the data processing circuitry is configured to select the equipment configuration from among the various equipment configurations by:

selecting one or more first equipment configurations that are expected to cause the power factor to most closely approach the desired value from among the various equipment configurations; and

selecting an equipment configuration that is expected to cause active power losses to be reduced the most from among the one or more first equipment configurations.

10. The controller of claim 1, wherein the data processing circuitry is configured to run second digital simulations of the first segment of the electrical distribution system based at least in part on the selected equipment configuration before generating the control signal to determine whether the selected equipment configuration is expected to cause a voltage violation on the first segment of the electrical distribution system and, when the selected equipment configuration is expected to cause the voltage violation, to determine a tap position for a voltage regulator of the first segment of the electrical distribution system that is expected to prevent the voltage violation from occurring.

11. The controller of claim 1, wherein the network interface is configured to receive second measurements associated with the first segment of the electrical distribution system a period of time after transmitting the control signal, wherein the second measurements reflect an actual effect of the equipment configuration on the first segment of the electrical distribution system, and wherein the data processing circuitry is configured to determine whether the second measurements indicate a voltage violation and, when the second measurements indicate the voltage violation, to vary the equipment configuration to prevent the voltage violation.

12. The controller of claim 11, wherein the data processing circuitry is configured, when the second measurements indicate the voltage violation, to identify a voltage regulator of the first segment of the electrical distribution system that is situated closest to the first substation of the electrical distribution system, to calculate a lower or higher tap position associated with the voltage regulator that is expected to prevent the voltage violation and, when the tap position is not higher than a maximum tap position or lower than a minimum tap position, to cause the voltage regulator to assume the tap position and, when the tap position is higher than the maximum tap position or lower than the minimum tap position, to cause a switchable capacitor of the first segment of the electrical distribution system that is located furthest from the first substation of the electrical distribution system or that is the largest capacitor of the first segment of the electrical distribution system to be switched on or off.

13. The controller of claim 1, wherein the data processing circuitry is configured, after transmitting the control signal, to cause one or more voltage regulators of the first segment of the electrical distribution system to cause a high side voltage of the one or more voltage regulators to be approximately equal to a low side voltage of the first substation that supplies voltage to the first segment of the electrical distribution system.

14. A method for controlling first and second segments of an electrical distribution system while the first segment is providing power to a recovered portion of the second segment, using respective first and second application platforms, the first application platform controlling only equipment of the first segment and the second application platform controlling only equipment of the second segment, the method comprising:

running a power factor control function on the second segment using the second application platform, wherein the power factor control function is configured to cause a power factor on the second segment to approach a certain value;

while the second application platform is running the power factor control function on the second segment, running a violation check function on the first segment using the first application platform, wherein the violation check function is configured to prevent or mitigate a voltage violation on the first segment; and

after running the power factor control function on the second segment using the second application platform, running the power factor control function on the first segment using the first application platform, wherein the power factor control function is configured to cause a power factor on the first segment to approach the certain value.

15. The method of claim 14, comprising communicating a minimum voltage of the second segment from the second application platform to the first application platform while the first application platform is running the violation check function on the first segment or while the first application platform is running the power factor control function on the first segment, or both.

16. The method of claim 14, comprising communicating from the second application platform to the first application platform an indication that the second supervisory has finished running the power factor control function when the second supervisory has finished running the power factor control function and communicating from the first application platform to the second application platform an indication that the first supervisory has finished running the power factor control function when the first supervisory has finished running the power factor control function.

17. The method of claim 14, comprising, while the first application platform is running the power factor control function on the first segment, running a violation check function on the second segment using the second application platform, wherein the violation check function is configured to prevent or mitigate a voltage violation on the second segment.

18. An article of manufacture comprising:

one or more tangible, non-transitory machine-readable storage media having instructions encoded thereon for execution by a processor of a first electronic device, the instructions configured to perform power factor control over a first feeder supplied by a first substation of an electrical distribution system without controlling a second feeder supplied by a second substation of the electrical distribution system that is being controlled by a second electronic device, the instructions comprising;

instructions to receive measurements associated with the first feeder of the electrical distribution system;

instructions to simulate a distribution power flow on the first feeder according to various capacitor switching solutions of at least one capacitor of the first feeder using the measurements;

instructions to determine an expected voltage deviation, reduction in power loss, and power factor associated with the various capacitor switching solutions based at least in part on the simulated distribution power flow on the first feeder;

instructions to select a non-dominated capacitor switching solution from among the various capacitor switching solutions in which the power factor most closely approaches a certain value;

instructions to control capacitors of the first feeder according to the non-dominated capacitor switching solution but not to control any equipment of the second feeder.

19. The article of manufacture of claim 18, wherein the instructions to simulate a distribution power flow on the first feeder comprise instructions to simulate an effect of distributed generation on the first feeder.

20. The article of manufacture of claim 18, comprising instructions to transmit at least one of the measurements to the second electronic device associated with the second feeder of the electrical distribution system.