Devices and methods for decentralized coordinated volt/VAR control

• US 8,761,954 B2
• Filed: 07/26/2011
• Issued: 06/24/2014
• 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:
  US13/191,422
• Publication Number:
  US 20130030599A1
• Time in Patent Office: 1,064 Days
• Field of Search: 700/286, 700/291, 700295-298, 703/18
• US Class Current: 700/298
• CPC Class Codes: H02J 2310/58 The condition being electrical
• 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: Y04S 20/222 Demand response systems, e.g. load shedding, peak shaving

Abstract

Devices and methods for decentralized coordinated Volt/VAR control are provided. Such a device may allow, for example, an operational parameter such as voltage, power losses, a combination of these, and/or power factor to be optimized on a segment of an electrical distribution system under certain conditions. For example, a controller may include a network interface to receive measurements and data processing circuitry to optimize a voltage deviation, active power losses, or a combination thereof, based at least in part on the total load on the segment of the electrical distribution system.

Claims

1. A controller comprising:

a network interface configured to 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; and

data processing circuitry configured;

to determine a total load on the segment of the electrical distribution system;

to run a first simulation of the 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, depending at least in part on the total load;

a first equipment configuration that is expected to cause a voltage deviation of the segment of the electrical distribution system to most closely approach a first desired value without causing voltage violations or power factor to fall beneath a power factor threshold;

a second equipment configuration that is expected to cause the voltage deviation of the segment of the electrical distribution system to more closely approach the first desired value than otherwise and active power losses of the segment of the electrical distribution system to more closely approach a second desired value than otherwise without causing voltage violations or power factor to fall beneath the power factor threshold;

or

a third equipment configuration that is expected to cause the active power losses of the segment of the electrical distribution system to most closely approach the second desired value without causing voltage violations or power factor to fall beneath the power factor threshold; and

to generate the control signal, wherein the control signal is configured to cause the equipment of the segment of the electrical distribution system to conform to the equipment configuration.

2. The controller of claim 1, wherein the data processing circuitry is configured to select the first equipment configuration when the total load is within a first range, the second equipment configuration when the total load is within a second range, and the third equipment configuration when the total load is within a third range, wherein the first range is higher than the second range and the third range and wherein the second range is higher than the third range.

3. The controller of claim 1, wherein the data processing circuitry is configured to determine a power factor on the segment of the electrical system and select a fourth equipment configuration that is expected to cause the power factor to most closely approach a desired power factor value when the power factor is less than a power factor threshold.

4. The controller of claim 1, wherein the control signal is configured to control the equipment of the segment of the electrical distribution system, wherein the equipment comprises at least one capacitor, and wherein the data processing circuitry is configured to run the simulation of the segment of the electrical distribution system simulating various equipment configurations, wherein the various equipment configurations comprise various capacitor switching configurations.

5. The controller of claim 4, wherein the capacitor switching configuration indicates that a single one of a plurality of capacitors of the segment of the electrical distribution system is to be switched on or off.

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

7. The controller of claim 6, wherein the data processing circuitry is configured to determine a switching order of the combination of the plurality of capacitors.

8. 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 a substation of the segment of the electrical distribution system;

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

a voltage magnitude at low sides of voltage regulators of the 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 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 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 segment of the electrical distribution system or a voltage drop between a last measurement point and an end of a feeder.

9. The controller of claim 1, wherein the data processing circuitry is configured to run a second simulation of the 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 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 segment of the electrical distribution system that is expected to prevent the voltage violation from occurring.

10. The controller of claim 1, wherein the network interface is configured to receive second measurements associated with the 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 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.

11. The controller of claim 10, wherein the data processing circuitry is configured, when the second measurements indicate the voltage violation, to identify a voltage regulator of the segment of the electrical distribution system that is situated closest to a 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 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 segment of the electrical distribution system that is located furthest from the substation of the electrical distribution system or that is the largest capacitor of the segment of the electrical distribution system to be switched on or off.

12. 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 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 a substation that supplies voltage to the segment of the electrical distribution system.

13. A method comprising:

determining, using a first substation application platform associated with a first segment of an electrical distribution system or a second substation application platform associated with a second segment of the electrical distribution system, an estimated cost of generating power at a current or future time period on the first segment of an electrical distribution system or the second segment of the electrical distribution system, or both; and

determining to run, using the first substation application platform or the second substation application platform;

a voltage control function to cause a voltage deviation of the first segment or the second segment, or both, to most closely approach a first desired value without causing voltage violations or power factor to fall beneath a power factor threshold;

a Volt/VAR control function to cause the voltage deviation of the first segment or the second segment, or both, to more closely approach the first desired value than otherwise and active power losses of the first segment or the second segment, or both, to more closely approach a second desired value than otherwise without causing voltage violations or power factor to fall beneath the power factor threshold;

a power loss reduction function to cause the active power losses of the first segment or the second segment, or both, to most closely approach the second desired value without causing voltage violations or power factor to fall beneath the power factor threshold;

or

a power factor control function to cause the power factor to most closely approach a desired power factor value;

or

a combination thereof;

based at least in part on the estimated cost of generating power during the current or future time period.

14. The method of claim 13, wherein the power loss reduction function is determined to be run when the estimated cost of generating power is less than a first threshold and a second threshold, the Volt/VAR control function is determined to be run when the estimated cost of generating power is equal to or greater than the first threshold and less than the second threshold, and the voltage control function is determined to be run when the estimated cost of generating power is equal to or greater than the second threshold.

15. The method of claim 13, comprising controlling the first segment and the second segment while the first segment is providing power to a recovered portion of the second segment by:

running the voltage control function, the Volt/VAR control function, the power loss reduction function, or the power factor control function, or the combination thereof, on the second segment using the second substation application platform;

while the second application platform is running the voltage control function, the Volt/VAR control function, the power loss reduction function, or the power factor control function, or the combination thereof, on the second segment, running a violation check function on the first segment using the first substation application platform, wherein the violation check function is configured to prevent or mitigate a voltage violation on the first segment; and

after running the voltage control function, the Volt/VAR control function, the power loss reduction function, or the power factor control function, or the combination thereof, on the second segment using the second substation application platform, running the voltage control function, the Volt/VAR control function, the power loss reduction function, or the power factor control function, or the combination thereof, on the first segment using the first substation application platform.

16. The method of claim 15, comprising communicating a minimum voltage of the second segment from the second substation application platform to the first substation application platform while the first substation application platform is running the violation check function on the first segment or while the first substation application platform is running the voltage control function, the Volt/VAR control function, the power loss reduction function, or the power factor control function, or the combination thereof, on the first segment, or both.

17. The method of claim 15, comprising communicating from the second substation application platform to the first application platform an indication that the second substation application platform has finished running the voltage control function, the Volt/VAR control function, the power loss reduction function, or the power factor control function, or the combination thereof, when the second substation application platform for has finished running the voltage control function, the Volt/VAR control function, the power loss reduction function, or the power factor control function, or the combination thereof, and communicating from the first substation application platform for to the second substation application platform an indication that the first substation application platform has finished running the voltage control function, the Volt/VAR control function, the power loss reduction function, or the power factor control function, or the combination thereof, when the first substation application platform has finished running the voltage control function, the Volt/VAR control function, the power loss reduction function, or the power factor control function, or the combination thereof.

18. The method of claim 15, comprising, while the first substation application platform is running the voltage control function, the Volt/VAR control function, the power loss reduction function, or the power factor control function, or the combination thereof, on the first segment, running a violation check function on the second segment using the second substation application platform, wherein the violation check function is configured to prevent or mitigate a voltage violation on the second segment.

19. An article of manufacture comprising:

one or more tangible, machine-readable storage media having instructions encoded thereon for execution by a processor of an electronic device, the instructions comprising;

instructions to receive measurements associated with a feeder of an electrical distribution system;

instructions to determine an expected load on the feeder at a present or future time period;

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

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

instructions to select a non-dominated capacitor switching configuration from among the various capacitor switching configurations;

a first capacitor switching configuration that is expected to cause a voltage deviation of the segment of the electrical distribution system to most closely approach a first desired value without causing voltage violations or power factor to fall beneath a power factor threshold;

a second capacitor switching configuration that is expected to cause the voltage deviation of the segment of the electrical distribution system to more closely approach the first desired value than otherwise and active power losses of the segment of the electrical distribution system to more closely approach a second desired value than otherwise without causing voltage violations or power factor to fall beneath the power factor threshold;

or

a third capacitor switching configuration that is expected to cause the active power losses of the segment of the electrical distribution system to most closely approach the second desired value without causing voltage violations or power factor to fall beneath the power factor threshold;

wherein the first, second, or third capacitor switching configuration is selected based at least in part on the expected load on the feeder at the present or future time period; and

instructions to control capacitors of the feeder according to the non-dominated capacitor switching configuration during the present or future time period.

20. The article of manufacture of claim 19, comprising instructions to transmit at least one of the measurements to another electronic device associated with another feeder of the electrical distribution system.