Systems and methods for edge of network voltage control of a power grid

• US 9,014,867 B2
• Filed: 06/04/2012
• Issued: 04/21/2015
• Est. Priority Date: 09/16/2011
• Status: Active Grant

• Current Assignee: Sentient Energy Technology LLC
• Original Assignee: Varentec Incorporated (KOCH Industries Incorporated)
• Inventors: Divan, Deepakraj, Dillon, Andrew
• Primary Examiner(s): SHECHTMAN, SEAN P
• Application Number:
  US13/488,330
• Publication Number:
  US 20130096724A1
• Time in Patent Office: 1,051 Days
• Field of Search: None
• US Class Current: 700/297
• CPC Class Codes: G05B 13/02 electric
• CPC Class Codes: G05B 15/02 electric
• CPC Class Codes: H02J 3/16 by adjustment of reactive power
• CPC Class Codes: H02J 3/1828 with stepwise control, the possibility of switching in or out the entire compensating arrangement not being considered as stepwise control
• CPC Class Codes: Y02E 40/30 Reactive power compensation
• CPC Class Codes: Y04S 10/22 Flexible AC transmission systems [FACTS] or power factor or reactive power compensating or correcting units

Abstract

Systems and methods for an edge of network voltage control of a power grid are described. In some embodiments, a system comprises a distribution power network, a plurality of loads, and a plurality of shunt-connected, switch-controlled VAR sources. The loads may be at or near an edge of the distribution power network. Each of the loads may receive power from the distribution power network. The plurality of shunt-connected, switch-controlled VAR sources may be located at the edge or near the edge of the distribution power network where they may each detect a proximate voltage. Further, each of the VAR sources may comprise a processor and a VAR compensation component. The processor may be configured to enable the VAR source to determine whether to enable the VAR compensation component based on the proximate voltage and to adjust network volt-ampere reactive by controlling a switch to enable the VAR compensation component.

Claims

1. A system comprising:

a distribution power network;

a plurality of loads at an edge of the distribution power network, each of the plurality of loads configured to receive power from the distribution power network; and

a plurality of shunt-connected, switch-controlled Volt-Ampere Reactive (“

VAR”

) sources at the edge of the distribution power network, each of the plurality of shunt-connected, switch-controlled VAR sources configured to detect a proximate voltage at the edge of the distribution power network, each of the plurality of shunt-connected, switch-controlled VAR sources comprising a processor and a VAR compensation component, the processor configured to;

enable the corresponding shunt-connected, switch-controlled VAR source to non-continuously monitor the proximate voltage by waiting for a delay and then evaluating the proximate voltage to determine, after the delay, whether to enable the corresponding VAR compensation component based on the proximate voltage; and

adjust network VAR by controlling a switch to enable the corresponding VAR compensation component based on the determination;

wherein the delay extends for a predetermined length of time;

wherein the delay of each of the plurality of shunt-connected, switch-controlled VAR sources is not equal.

2. The system of claim 1, wherein different delays of different members of the plurality of shunt-connected, switch-controlled VAR sources prevents infighting between at least two of the different members.

4. The system of claim 1, wherein the switch comprises a semiconductor switch in series with a Negative Temperature Coefficient (“

NTC”

) or resistor, and wherein the semiconductor switch in series with the NTC or resistor is in parallel with a relay.

5. The system of claim 4, wherein the semiconductor switch is controlled by a first signal from the processor and the relay is controlled by a second signal from the processor, wherein the semiconductor switch controls enabling the VAR compensation component and relieves the relay of switching stress.

6. The system of claim 5, wherein the relay conducts when the semiconductor switch is active thereby reducing semiconductor device conduction losses.

7. The system of claim 6, wherein the semiconductor switch is configured to deactivate when the relay conducts.

8. The system of claim 1, wherein at least two of the plurality of shunt-connected, switch-controlled VAR sources are on a low voltage side of a transformer of the power distribution network.

9. The system of claim 1, wherein the VAR compensation component comprises a capacitor or an inductor.

10. The system of claim 1, wherein each of the processors of the plurality of shunt-connected, switch-controlled VAR sources is configured to enable the corresponding shunt-connected, switch-controlled VAR source to determine whether to enable the corresponding VAR compensation component based on the proximate voltage comprises each of the processors of the plurality of shunt-connected, switch-controlled VAR sources configured to determine whether to enable the VAR compensation component based on a comparison of the proximate voltage to a voltage set point.

11. The system of claim 10, wherein at least two of the plurality of shunt-connected, switch-controlled VAR sources comprise communication modules configured to receive the respective voltage set point.

12. The system of claim 10, wherein each of the plurality of shunt-connected, switch-controlled VAR sources increases leading VAR if the voltage set point is higher than the detected proximate voltage and decreases leading VAR if the voltage set point is lower than the detected proximate voltage.

13. The system of claim 10, wherein the communication module is configured to update the voltage set point and wherein a rate of update of the voltage set point is significantly slower than adjusting the network VAR by controlling the switch to enable the VAR compensation component based on the determination.

14. The system of claim 10, wherein the at least two of the plurality of shunt-connected, switch-controlled VAR sources receive different voltage set points.

15. The system of claim 1, wherein the processor is further configured to detect an overvoltage condition and disable the switch based on the detected overvoltage condition.

16. The system of claim 1, wherein the system self-determines which VAR compensation components of the plurality of VAR sources are enabled and which VAR compensation components of the plurality of VAR sources are not enabled.

3. A system comprising:

a distribution power network;

a plurality of loads at an edge of the distribution power network, each of the plurality of loads configured to receive power from the distribution power network; and

a plurality of shunt-connected, switch-controlled Volt-Ampere Reactive (“

VAR”

) sources at the edge of the distribution power network, each of the plurality of shunt-connected, switch-controlled VAR sources configured to detect a proximate voltage at the edge of the distribution power network, each of the plurality of shunt-connected, switch-controlled VAR sources comprising a processor and a VAR compensation component, the processor configured to;

enable the corresponding shunt-connected, switch-controlled VAR source to non-continuously monitor the proximate voltage by waiting for a delay and then evaluating the proximate voltage to determine, after the delay, whether to enable the corresponding VAR compensation component based on the proximate voltage; and

adjust network VAR by controlling a switch to enable the corresponding VAR compensation component based on the determination;

wherein the delay extends for a predetermined length of time;

wherein the delay of at least two of the plurality of shunt-connected, switch-controlled VAR sources is equal but the delay of a third of the plurality of shunt-connected, switch-controlled VAR sources is not equal.

17. A method comprising:

detecting, by a first shunt-connected, switch-controlled Volt-Ampere Reactive (“

VAR”

) source at an edge of a distribution power network proximate to a first load, a first proximate voltage, the first load configured to receive power from the distribution power network, the first shunt-connected, switch-controlled VAR source comprising a first processor and a first VAR compensation component;

non-continuously monitoring the first proximate voltage by waiting for a first delay and then evaluating the first proximate voltage to determine, after the first delay, by the first processor of the first shunt-connected, switch-controlled VAR source, whether to enable the first VAR compensation component based on the first proximate voltage, wherein the first delay extends for a first predetermined length of time;

adjusting, by the first VAR compensation component of the first shunt-connected,switch-controlled VAR source, a network VAR based on the first determination;

detecting, by a second shunt-connected, switch-controlled VAR source at the edge of the distribution power network proximate to a second load, a second proximate voltage, the second shunt-connected, switch-controlled VAR source comprising a second VAR compensation component and a second processor;

non-continuously monitoring the second proximate voltage by waiting for a second delay and then evaluating the second proximate voltage to determine, after the second delay, by the second processor of the second shunt-connected, switch-controlled VAR source, whether to enable the second VAR compensation component based on the second proximate voltage, wherein the second delay extends for a second predetermined length of time;

adjusting, by the second VAR compensation component of the second shunt-connected, switch-controlled VAR source, the network VAR based on the second determination;

wherein the first delay is not equal to the second delay.

18. The method of claim 17, wherein the first delay and the second delay of the first and second shunt-connected, switch-controlled VAR sources, respectively prevents infighting between the first and second shunt-connected, switch-controlled VAR sources.

19. The method of claim 17, wherein adjusting, by the first VAR compensation component of the first shunt-connected, switch-controlled VAR source, the network VAR based on the first determination comprises controlling a semiconductor switch with a first signal from the processor of the first shunt-connected, switch-controlled VAR source to enable the first VAR compensation component and to relieve a relay in parallel with the semiconductor switch of switching stress.

20. The method of claim 19, further comprising, conducting current, by the relay, when the semiconductor switch is active thereby reducing semiconductor switch conduction losses.

21. The method of claim 20, further comprising deactivating the semiconductor switch while the relay conducts current.

22. The method of claim 17, wherein the first VAR compensation component comprises a capacitor or an inductor.

23. The method of claim 17, wherein the determining, by the first processor of the first shunt-connected, switch-controlled VAR source, whether to enable the first VAR compensation component based on the first proximate voltage comprises determining, by the first processor, whether to enable the first VAR compensation component based on a comparison of a first voltage set point to the first proximate voltage.

24. The method of claim 23, further comprising receiving the first voltage set point by a communication module of the first shunt-connected, switch controlled VAR source.

25. The method of claim 23, wherein adjusting, by the first VAR compensation component of the first shunt-connected, switch-controlled VAR source, the network VAR based on the determination comprises increasing leading VAR if the first voltage set point is higher than the detected first proximate voltage or decreasing leading VAR if the first voltage set point is lower than the detected first proximate voltage.

26. The method of claim 23, further comprising updating the first voltage set point at a rate that is significantly slower than adjusting, by the first VAR compensation component of the first shunt-connected, switch-controlled VAR source, a network VAR based on the first determination.

27. The method of claim 23, determining, by a second processor of the second shunt-connected, switch-controlled VAR source, to enable a second VAR compensation component of the second shunt-connected, switch-controlled VAR source based on a comparison of a second voltage set point to a second proximate voltage to the second shunt-connected, switch-controlled VAR source, wherein the first voltage set point is not equal to the second voltage set point.

28. A method comprising:

coupling a first switch-controlled Volt-Ampere Reactive (“

VAR”

) source in shunt on a distribution power network, the first switch-controlled VAR source being proximate to a first load at an edge of the distribution power network, the first load being configured to receive power from the distribution power network, the first switch-controlled VAR source configured to detect a first proximate voltage at the edge of the distribution power network, the first switch-controlled VAR source comprising a first VAR compensation component and a first processor, the first processor configured to;

non-continuously monitor the first proximate voltage by waiting for a first delay and then enabling the first switch-controlled VAR source to determine after the first delay whether to enable the first VAR compensation component based on the first proximate voltage; and

adjust network VAR by controlling a first switch to enable the first VAR compensation component based on the first determination, wherein the first delay extends for a first predetermined length of time;

coupling a second switch-controlled VAR source in shunt on the distribution power network, the second switch-controlled VAR source being proximate to a second load at the edge of the distribution power network, the second load being configured to receive power from the distribution power network, the second switch-controlled VAR source configured to detect a second proximate voltage at the edge of the distribution power network, the second switch- controlled VAR source comprising a second VAR compensation component and a second processor, the second processor configured to;

non-continuously monitor the second proximate voltage by waiting for a second delay and then enabling the second switch-controlled VAR source to determine after the second delay whether to enable the second VAR compensation component based on the second proximate voltage; and

adjust network VAR by controlling a second switch to enable the second VAR compensation component based on the second determination, wherein the second delay extends for a second predetermined length of time;

wherein the first delay is not equal to the second delay.

29. The method of claim 28, wherein the first delay and the second delay of the first and second shunt-connected, switch-controlled VAR sources, respectively prevents infighting between the first and second shunt-connected, switch-controlled VAR sources.

30. The method of claim 28, wherein the first processor configured to adjust the network VAR by controlling the first switch to enable the first VAR compensation component based on the first determination comprises the first processor configured to control a semiconductor switch with a first signal to enable the first VAR compensation component and to relieve a relay in parallel with the semiconductor switch of switching stress.

31. The method of claim 30, wherein the relay is configured to conduct when the semiconductor switch is active thereby enabling reduction of conduction losses by the semiconductor device.