Bidirectional capacitor bank control

Patent metadata

Field	Value
Publication number	US-11114858-B2
Application number	US-201916571983-A
Country	US
Kind code	B2
Filing date	Sep 16, 2019
Priority date	Sep 16, 2019
Publication date	Sep 7, 2021
Grant date	Sep 7, 2021

Abstract

The present disclosure relates to controlling a capacitor bank using current measurements from different current sensors depending on the power flow direction. For example, the system may perform capacitor bank control operations using current measurements from a first current sensor coupled to the power line between an initial source and the capacitor bank when power is flowing in a first power flow direction on the power line. The system may determine that power flow on the power line has changed from flowing in the first power flow direction to flowing in a second power flow direction from an updated source, different from the initial source. The system may, upon detecting the change in the power flow direction perform control operations of the capacitor bank using current measurements from a second current sensor between an updated source and the capacitor bank.

First claim

What is claimed is:

1. A capacitor bank control system, comprising:
memory; and
a processor operatively coupled to the memory, wherein the processor is configured to execute instructions stored on the memory to cause the processor to:
perform capacitor bank control operations using current measurements from a first current sensor coupled to the power line between an initial source and the capacitor bank when power is flowing in a first power flow direction on the power line;
determine that power flow on the power line has changed from flowing in the first power flow direction to flowing in a second power flow direction from an updated source, different from the initial source; and
upon detecting the change in the power flow direction, perform control operations of the capacitor bank using current measurements from a second current sensor between the updated source and the capacitor bank, wherein at least one of the first sensor and the second sensor is a wireless current sensor, and wherein the power flow direction is determined using the phase difference between the current measurements of at least one of the first current sensor and the second current sensor and voltage measurements of a voltage sensor of the capacitor bank control system.

2. The capacitor bank control system of claim 1 , comprising a first wireless current sensor as the first sensor and a second wireless current sensor as the second current sensor, wherein the first wireless current sensor and the second wireless current sensor are configured to communicate current measurements wirelessly to the capacitor bank control system.

3. The capacitor bank control system of claim 2 , wherein the first wireless current sensor and the second wireless current sensor are configured to operate using electrical energy captured by the power line.

4. The capacitor bank control system of claim 1 , wherein the first current sensor is a wired current sensor electrically connected to the capacitor bank control system via at least one conductor and wherein the second current sensor is the wireless current sensor configured to communicate current measurements wirelessly.

5. The capacitor bank control system of claim 1 , comprising a potential transformer as the voltage sensor.

6. The capacitor bank control system of claim 1 , wherein the processor is configured to execute instructions stored on the memory to cause the processor to:
calculate a load difference between a first load detected using current measurements from the first current sensor and a second load detected using current measurements from the second current sensor;
verify a capacitor bank status based on the load difference; and
provide a signal indicating the capacitor bank status.

7. The capacitor bank control system of claim 1 , wherein the first sensor is one of a set of three current sensors on each phase of a three-phase power line between the initial source and the capacitor bank, and wherein the second current sensor is one of a set of three current sensors on each phase of a three-phase power line between the updated source and the capacitor bank, wherein the first current sensor and the second current sensor are on the same phase of the three-phase power line with the capacitor bank electrically connected therebetween.

8. The capacitor bank control system of claim 7 , wherein the processor is configured to send a signal to an individual switch that controls connection and disconnection of the capacitor bank with the same phase of the first current sensor and the second current sensor.

9. The capacitor bank control system of claim 7 , wherein the processor is configured to send signals to a ganged switching device that controls three-phase connection and disconnection of several capacitors connected together in the capacitor bank based on the current measurements.

10. The capacitor bank control system of claim 1 , wherein the first power flow direction comprises power flowing from the initial source to the capacitor bank and one or more first loads, and wherein the second power flow direction comprises power flowing in the opposite direction from the updated source to the capacitor bank and one or more second loads.

11. A method, comprising:
connecting a first current sensor on a power line between an initial power source and a connection of a capacitor bank;
connecting a second current sensor on the power line between an updated power source and the connection of the capacitor bank; and
configuring a capacitor bank controller (CBC) to control the capacitor bank using the first current sensor when power flows from the initial source towards the capacitor bank and to control the capacitor bank using the second current sensor when power flows from the updated power source to the capacitor bank, wherein the CBC is configured to:
calculate a load difference between a first load detected using current measurements from the first current sensor and a second load detected using current measurements from the second current sensor;
verify a capacitor bank status based on the load difference; and
provide a signal indicating the capacitor bank status.

12. The method of claim 11 , comprising connecting the second current sensor on the power line while the CBC is online.

13. The method of claim 11 , wherein the first current sensor and the second current sensor are wireless current sensors that communicate current measurements wirelessly to the CBC.

14. The method of claim 11 , wherein the first current sensor is a wired combination sensor that provides voltage measurements and current measurements from the first side of the power line.

15. The method of claim 11 , comprising setting the control of the capacitor bank to perform at least one of power factor control and VAR control.

16. A non-transitory, computer-readable medium comprising instructions configured to be executed by one or more processors of a capacitor bank controller (CBC) comprising a first current sensor on a power line, wherein the instructions are configured to cause operations comprising:
receiving an input indicating that a second current sensor has been added to the power line;
updating the CBC to perform control operations using current measurements from either the first current sensor or the second current sensor depending on a power flow direction upon receiving the input;
detecting, via the CBC, a change in the power flow direction on the power line; and
changing, via the CBC, control operations from using current measurements of the first current sensor to using current measurements of the second sensor upon detecting the change in the power flow direction.

17. The non-transitory, computer-readable medium of claim 16 , wherein the instructions are configured to cause operations comprising:
receiving, from the first sensor positioned on a first side of the capacitor bank, current measurements from power flowing towards a first aggregate load comprising the capacitor bank and one or more first loads; and
receiving, from the second sensor positioned on the second side of the capacitor bank, current measurements from power flowing towards a second aggregate load comprising the capacitor bank and one or more second loads.

18. The non-transitory, computer-readable medium of claim 16 , wherein the instructions are configured to cause operations comprising selecting either the first current sensor or the second current sensor to communicate with at a given time.

19. The non-transitory, computer-readable medium of claim 16 , wherein the instruct

Assignees

• Schweitzer Engineering Lab Inc

Inventors

• Hao Kei
• Feltis Mark W
• Malla Naresh

Classifications

• H02J13/12

  Monitoring network conditions, e.g. electrical magnitudes or operational status · CPC title

• H02J13/1331

  using wireless data transmission · CPC title

• Y02E60/00

  Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation · CPC title

• Y04S10/30

  State monitoring, e.g. fault, temperature monitoring, insulator monitoring, corona discharge · CPC title

• G01R19/14

  Indicating direction of current; Indicating polarity of voltage · CPC title