OPTIMIZING VOLTAGE AND VAR ON THE ELECTRIC GRID USING DISTRIBUTED VAR SOURCES

• US 20150311718A1
• Filed: 04/24/2015
• Published: 10/29/2015
• Est. Priority Date: 04/24/2014
• Status: Active Grant

• Current Assignee: Sentient Energy Technology LLC (KOCH Industries Incorporated)
• Original Assignee: Varentec Incorporated (KOCH Industries Incorporated)
• Inventors: DIVAN, DEEPAKRAJ, MOGHE, ROHIT
• Granted Patent: US 10,680,438 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H02J 3/18 Arrangements for adjusting, eliminating or compensating reactive power in networks for adjustment of voltage H02J3/16
• CPC Class Codes: Y02E 40/30 Reactive power compensation

Abstract

A plurality of edge of network grid volt ampere reactive (VAR) sources are provided in a power system in order to effectuate control at a customer level, which in turn effectuates control at a feeder level, which in turn effectuates control of an entire power system or wide area electric grid network. By optimally selecting voltage setpoints and applying such voltage setpoints to the plurality of edge of network grid VAR sources, the power system can be configured to self-balance, power factor compensation can be determined without the need for measuring load power factor. Moreover, traditionally volatile voltages at the feeder can be flattened, and VAR control can be realized.

Claims

1. A computer-implemented method for voltage and volt ampere reactive (VAR) control of a power system, comprising:

determining a transformer voltage setpoint; and

determining voltage setpoints for a set of distributed VAR devices implemented in the power system to be equal to that of the transformer voltage setpoint to effectuate self-balancing of the power system.

2. The computer-implemented method of claim 1, further comprising dispatching the voltage setpoints to the set of distributed VAR devices, the set of distributed VAR devices being distributed along a feeder, wherein the dispatching of the voltage setpoints is performed via at least one of wired and wireless communication mechanisms from a central command location.

3. The computer-implemented method of claim 1, further comprising dispatching the transformer voltage setpoint to a transformer operatively connected to the set of distributed VAR devices, wherein the dispatching of the transformer voltage setpoint is performed via at least one of wired and wireless communication mechanisms from a central command location.

4. The computer-implemented method of claim 1, further comprising determining whether any voltages associated with each of the set of distributed VAR devices exceed a voltage limit.

5. The computer-implemented method of claim 1, wherein the voltage setpoints for the set of distributed VAR devices are set substantially similar to each other.

6. The computer-implemented method of claim 1, wherein each of the set of distributed VAR devices are operatively connected to a secondary side of the transformer, the transformer comprising a service transformer of the power system, each of the set of distributed VAR devices having a distributed control algorithm and implementing zero-droop voltage control.

7. The computer-implemented method of claim 6, wherein the power system comprises a self-balancing power system such that the actual reactive power flow is reduced to zero subsequent to injecting reactive power into or pulling reactive power from a primary side of the power system.

8. The computer-implemented method of claim 1, wherein at least one of a substation load tap changer transformer and a line voltage regulator are operated in accordance with a secondary voltage setpoint distinct from the transformer voltage setpoint to enable a change in VARs drawn at a feeder level.

9. The computer-implemented method of claim 8, further comprising one of increasing or decreasing the transformer voltage setpoint and the secondary voltage setpoint in unison to increase or decrease, respectively, power draw by one or more loads, power change sensitivity being dependent upon a type of the one or more loads.

10. The computer-implemented method of claim 8, further comprising one of increasing or decreasing the transformer voltage setpoint and the secondary voltage setpoint independently with respect to each other to at least one of provide centralized control for at least one of power and VARs drawn by a feeder of the power system, stabilize secondary voltage levels, reduce voltage drop across the service transformer, and increase voltage and VAR control predictability.

11. The computer-implemented method of claim 1, wherein the self-balancing occurs pursuant to at least a subset of the set of distributed VAR devices operating such that a primary side voltage equalizes with a secondary side voltage due to flow of VARs into the primary side, the flow of VARs automatically ceasing upon equalization of the primary side and the secondary side voltages resulting in zero net VARs.

12. The computer-implemented method of claim 11, further comprising leaving capacitor banks present on the primary side uncompensated for.

13. The computer-implemented method of claim 1, wherein the self-balancing occurs independent of VAR measurements.

14. The computer-implemented method of claim 1, wherein the self-balancing occurs independent of feeder topology information.

15. The computer-implemented method of claim 1, wherein each of the set of distributed VAR devices comprises one of an edge of network grid optimization device, a dedicated VAR source, a static synchronous compensator (STATCOM), an inverter, a VAR-enhanced smart meter, or an electric vehicle charger.

16. A system, comprising:

a service transformer;

a load coupled to the service transformer, and

at least one distributed VAR device coupled to the load, the at least one distributed VAR device being operative in response to a voltage setpoint, wherein the voltage setpoint is associated with a controllable transformer on a high-voltage or primary side.

17. The system of claim 16, wherein the controllable transformer comprises one of a substation load tap changer transformer or a line voltage regulator.

18. The system of claim 16, wherein the voltage setpoint of the at least one distributed VAR device is determined based upon a measured actual reactive power flow and a reference reactive power flow.

19. The system of claim 16, wherein the at least one distributed VAR device is operatively connected to a secondary side of the service transformer, has a distributed control algorithm, and implements zero-droop voltage control.

20. The system of claim 16 comprising a self-balancing power system such that actual reactive power flow is reduced to zero subsequent to injecting reactive power into or pulling reactive power from a primary side of the system.