# US 11,114,858 B2 · Bidirectional capacitor bank control

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- Number: US 11,114,858 B2
- Document ID: US11114858B2
- Status: Granted
- Kind: B2
- Application number: 16/571,983
- Filed: 2019-09-16
- Published: 2021-03-18
- Granted: 2021-09-07
- Earliest claimed: 2019-09-16
- Assignees: Schweitzer Engineering Laboratories, Inc.
- Applicants: Schweitzer Engineering Laboratories, Inc.
- Inventors: Kei Hao; Mark W. Feltis; Naresh Malla
- Web page: https://patentgrep.com/patent/US11114858B2

## CPC

- H02J 3/18: Arrangements for adjusting, eliminating or compensating reactive power in networks
- H02J 3/1828: with stepwise control, e.g. switched capacitor banks
- G01R 15/146: {Measuring arrangements for current not covered by other subgroups of G01R15/14, e.g. using current dividers, shunts, or measuring a voltage drop (if no voltage isolation is involved G01R1/203 or G01R19/0092)}
- G01R 15/18: using inductive devices, e.g. transformers
- G01R 19/14: Indicating direction of current; Indicating polarity of voltage
- H02J 13/12: Monitoring network conditions, e.g. electrical magnitudes or operational status
- H02J 13/1331: {using wireless data transmission}
- Y02E 40/30: Reactive power compensation
- Y02E 40/70: Smart grids as climate change mitigation technology in the energy generation sector
- Y02E 60/00: Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y04S 10/22: Flexible AC transmission systems [FACTS] or power factor or reactive power compensating or correcting units
- Y04S 10/30: State monitoring, e.g. fault, temperature monitoring, insulator monitoring, corona discharge
- Y04S 40/126: using wireless data transmission
- H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12)
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y04S: SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS

## 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.

## Claims

### Claim 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.

### Claim 2 (depends on 1)

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.

### Claim 3 (depends on 2)

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.

### Claim 4 (depends on 1)

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.

### Claim 5 (depends on 1)

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

### Claim 6 (depends on 1)

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.

### Claim 7 (depends on 1)

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.

### Claim 8 (depends on 7)

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.

### Claim 9 (depends on 7)

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.

### Claim 10 (depends on 1)

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.

### Claim 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.

### Claim 12 (depends on 11)

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

### Claim 13 (depends on 11)

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.

### Claim 14 (depends on 11)

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.

### Claim 15 (depends on 11)

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.

### Claim 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.

### Claim 17 (depends on 16)

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.

### Claim 18 (depends on 16)

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.

### Claim 19 (depends on 16)

The non-transitory, computer-readable medium of claim 16, wherein the instructions are configured to cause operations comprising sending a signal to a switching device to electrically connect or disconnect the capacitor bank to perform at least one of power factor control and VAR control based on the current measurements upstream of the capacitor bank.

### Claim 20 (depends on 16)

The non-transitory, computer-readable medium of claim 16, wherein the input is a user input.