CA2086650A1 - Multi-bushing single-phase electric distribution transformer for feeder phase current balancing - Google Patents
Multi-bushing single-phase electric distribution transformer for feeder phase current balancingInfo
- Publication number
- CA2086650A1 CA2086650A1 CA 2086650 CA2086650A CA2086650A1 CA 2086650 A1 CA2086650 A1 CA 2086650A1 CA 2086650 CA2086650 CA 2086650 CA 2086650 A CA2086650 A CA 2086650A CA 2086650 A1 CA2086650 A1 CA 2086650A1
- Authority
- CA
- Canada
- Prior art keywords
- phase
- balancing
- transformer
- feeder
- load
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/26—Arrangements for eliminating or reducing asymmetry in polyphase networks
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
- Y02E40/50—Arrangements for eliminating or reducing asymmetry in polyphase networks
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Supply And Distribution Of Alternating Current (AREA)
Abstract
MULTI-BUSHING SINGLE-PHASE ELECTRIC DISTRIBUTION TRANSFORMER
FOR FEEDER PHASE CURRENT BALANCING
Abstract In three-phase electric power distribution systems, kilowatt-hour conductor losses can be reduced by keeping the current flows in all three-phases as equal to each other as possible.
A secondary benefit of phase balancing is an improved voltage regulation.
At present, phase balancing can be achieved by taking the phase-current measurements, detecting a feeder with a significant current unbalance,identifying a single-phase transformer connected to the highest loaded phase, and then manually reconnecting it to the lowest loaded phase. The operation involves time consuming activities in engineering, and the deployment of personnel, equipment and resources for its execution, plus loss of revenue and/or inconveniences caused by an outage of several minutes duration.
In this invention, a single-phase transformer is provided with:
three high-voltage bushings, and an internal high voltage side three-position load-break switch. All the necessary connections are already in place, and through the operation of the switch the transformer load is transferred from the highest loaded phase to the lowest loaded phase; thereby tending to an equilibrium of circuit phase currents and therefore reducing the system losses.
The invention makes the phase-balancing process fast, easy, convenient, safe, and economical.
FOR FEEDER PHASE CURRENT BALANCING
Abstract In three-phase electric power distribution systems, kilowatt-hour conductor losses can be reduced by keeping the current flows in all three-phases as equal to each other as possible.
A secondary benefit of phase balancing is an improved voltage regulation.
At present, phase balancing can be achieved by taking the phase-current measurements, detecting a feeder with a significant current unbalance,identifying a single-phase transformer connected to the highest loaded phase, and then manually reconnecting it to the lowest loaded phase. The operation involves time consuming activities in engineering, and the deployment of personnel, equipment and resources for its execution, plus loss of revenue and/or inconveniences caused by an outage of several minutes duration.
In this invention, a single-phase transformer is provided with:
three high-voltage bushings, and an internal high voltage side three-position load-break switch. All the necessary connections are already in place, and through the operation of the switch the transformer load is transferred from the highest loaded phase to the lowest loaded phase; thereby tending to an equilibrium of circuit phase currents and therefore reducing the system losses.
The invention makes the phase-balancing process fast, easy, convenient, safe, and economical.
Description
: . :
208665 0 ~ ~
MULTI-BUSHING SINGLE-PHASE ELECTRIC DISTRIBUTION TRANSFORMER
FOR FEEDER PHASE CURRENT BALANCING
Specification - Disclosure Page 1 of 3 In a three-phase system minimum losses are obtained when all three-phases carry equal current.
For example, a one kilometre long, three-phase line with 336.4 MCM
stranded aluminum conductors carrying phzase currents of 400 Amps, 500 Amps and 600 Amps has conductor I R losses, at 50 Degrees Centigrade, of 144.05 kW. By balancing the current in the three-phases, to 500 Amps each, the losses are reduced to 140.3 kW.
This invention relates to a single-phase electric distribution transformer that with two or three high-voltage bushings and through an internal high-voltage switch can be re-connected to other phase(s), making the sy-~tem load more symmetrical and thereby reducing the conductor losses on the feeder.
One, two or more units of this type,and of the same or different kVA sizes, as necessary, can be installed on a feeder to reach a reasonable balance of the phase currents.
The high-voltage switch can be manually or electrically operated.
The electrical operation of the switch can be effected from a local signal (manual or automatic) or from a remotely transmitted signal(e.g. radio, power line carrier,audio-tone, etc) manually, or automatically originated.
The i nv enti on appli es t o utility, and industrial/commercial/residential two orthree-phase electric power distribution systems, with single phase transformers and operating voltages from 1 Volt to 250000 Volts AC, RMS, phase-to-ph~se, and a power capacity from 0.1 kVA to 100000 ~VA.
This invention can be implemented on any type of single-phase transformer; e.g. dry-type liyuid or gas-filled, completely self-protected or non-protected, over-head or under-ground, pole-mounted, pad-mounted or submersible, with two or more windings,independent or auto-connected windings,with or without taps, with or without on-load tap-changers,etc.
The normal application of this invention in a three-phase system i9 expected to have three-bushings, but devices with only two-bushings and a two-position switch could be also utilized in two-phase or three-phase systems.
The internally mounted high voltage load-break switch can have oil, vacuum or ~ulphur hexafluoride as the insulating and/or the interrupt1ng medium.
The potential for loss reduction through phase balancing in just North-America is enormous. Millions of kilowatt-hours can be saved annually.
Phase balancing is currently effected by measuring the phase currents in a circuit to detect a significant unbalance, then finding a transformer that is connected to the highest loaded phase, and reconnecting it to the phase with the lowest load.The process is repeated several times until a reasonable phase current equilibrium is reached.
- 2086~so MULTI-BUSHING SINGLE-PHASE ELECTRIC DISTRIBUTION TRANSFORMER
FOR FEEDER PHASE CURRENT BALANCING
Specification - Disclosure Page 2 of 3 This involves a considerable expenditure of engineering time, man-power, equipment and tools. Due to its cost, phase balancing actions are generally infrequent; one or two per feeder each year, at the most.
I have found that by having on each distribution circuit one, two or more phase-balancing transformers, the system operator can balance the feeder by the simple expedient of measuring the circuit phase currents, and if a significant unbalance is detected then operating the phase-balancing transformer(s) high voltage switch to the appropriate position.
Time, money and hassle are saved.
Depending on the level of automation, the phase-balancing transformer can be operated locally, or remotely from a load control or load-dispatch centre.
Additionally, automatic operation is possible. A phase unbalance detector relay (which can be easily implemented with long existing technology) can trigger the high voltage switch to reconnect the phase-balancing transformer from the highly loaded phase(s) to the low loaded phase.(s). In this level of automation, the operator is oblivious to the changes that are occurring in the system. After the initial investment there are no operational costs.
Automatic operation can be effected locally or remotely as well. -The current transformerq and control equipment instead of being mounted on or near the phase balancing transformer are mounted remotely.
Subject to the nature of the load, freguent phase changes can be executed, several times during the day if necessary.
The objective is always to save money by reducing losses through phase balancing.
Recapping,this invention makes the phase balancing process easy, quick, convenient, qafe, and economical.
Figure No. 1 shows the connections for a three-bushing, single-phase, phase-to-neutral connected phase-balancing transformer with a manually operated switch.
Figure No.2 shows the connections for a three-bushing, single-phase, phase-to-phase connected phase-balancing transformer with a manually operated switch.
Figure No. 3 shows the connections for a three-bushing, single-phase, phase-to-neutral connected phase-balancing transformer with a manually or electrically operated switch. Three current transformers are also shown feeding the control box for local automatic control. An external connection is also indicated for remote operation of the switch.
Figure No. 4 shows the connections for a three-bushing, single-phase, phase-to-phase connected phase-balancing transformer with a manually or electrically operated switch. Three current transformers are also shown feeding the control box for local automatic control. An external connection is also indicated for remote operation of the switch.
MULTI-BUSHING SINGLE-PHASE ELECTRIC DISTRIBUTION TRANSFORMER -FOR FEEDER PHASE CURRENT BALANCING .
Specification - Disclosure Page 3 of 3 These would be the typical connections. Other are possible. For example,a two-bushing single-phase tran~former in which the load can be transferred from just one phase to another; rather than to ~.
two others.
~ --~ . ---. . . .....
208665 0 ~ ~
MULTI-BUSHING SINGLE-PHASE ELECTRIC DISTRIBUTION TRANSFORMER
FOR FEEDER PHASE CURRENT BALANCING
Specification - Disclosure Page 1 of 3 In a three-phase system minimum losses are obtained when all three-phases carry equal current.
For example, a one kilometre long, three-phase line with 336.4 MCM
stranded aluminum conductors carrying phzase currents of 400 Amps, 500 Amps and 600 Amps has conductor I R losses, at 50 Degrees Centigrade, of 144.05 kW. By balancing the current in the three-phases, to 500 Amps each, the losses are reduced to 140.3 kW.
This invention relates to a single-phase electric distribution transformer that with two or three high-voltage bushings and through an internal high-voltage switch can be re-connected to other phase(s), making the sy-~tem load more symmetrical and thereby reducing the conductor losses on the feeder.
One, two or more units of this type,and of the same or different kVA sizes, as necessary, can be installed on a feeder to reach a reasonable balance of the phase currents.
The high-voltage switch can be manually or electrically operated.
The electrical operation of the switch can be effected from a local signal (manual or automatic) or from a remotely transmitted signal(e.g. radio, power line carrier,audio-tone, etc) manually, or automatically originated.
The i nv enti on appli es t o utility, and industrial/commercial/residential two orthree-phase electric power distribution systems, with single phase transformers and operating voltages from 1 Volt to 250000 Volts AC, RMS, phase-to-ph~se, and a power capacity from 0.1 kVA to 100000 ~VA.
This invention can be implemented on any type of single-phase transformer; e.g. dry-type liyuid or gas-filled, completely self-protected or non-protected, over-head or under-ground, pole-mounted, pad-mounted or submersible, with two or more windings,independent or auto-connected windings,with or without taps, with or without on-load tap-changers,etc.
The normal application of this invention in a three-phase system i9 expected to have three-bushings, but devices with only two-bushings and a two-position switch could be also utilized in two-phase or three-phase systems.
The internally mounted high voltage load-break switch can have oil, vacuum or ~ulphur hexafluoride as the insulating and/or the interrupt1ng medium.
The potential for loss reduction through phase balancing in just North-America is enormous. Millions of kilowatt-hours can be saved annually.
Phase balancing is currently effected by measuring the phase currents in a circuit to detect a significant unbalance, then finding a transformer that is connected to the highest loaded phase, and reconnecting it to the phase with the lowest load.The process is repeated several times until a reasonable phase current equilibrium is reached.
- 2086~so MULTI-BUSHING SINGLE-PHASE ELECTRIC DISTRIBUTION TRANSFORMER
FOR FEEDER PHASE CURRENT BALANCING
Specification - Disclosure Page 2 of 3 This involves a considerable expenditure of engineering time, man-power, equipment and tools. Due to its cost, phase balancing actions are generally infrequent; one or two per feeder each year, at the most.
I have found that by having on each distribution circuit one, two or more phase-balancing transformers, the system operator can balance the feeder by the simple expedient of measuring the circuit phase currents, and if a significant unbalance is detected then operating the phase-balancing transformer(s) high voltage switch to the appropriate position.
Time, money and hassle are saved.
Depending on the level of automation, the phase-balancing transformer can be operated locally, or remotely from a load control or load-dispatch centre.
Additionally, automatic operation is possible. A phase unbalance detector relay (which can be easily implemented with long existing technology) can trigger the high voltage switch to reconnect the phase-balancing transformer from the highly loaded phase(s) to the low loaded phase.(s). In this level of automation, the operator is oblivious to the changes that are occurring in the system. After the initial investment there are no operational costs.
Automatic operation can be effected locally or remotely as well. -The current transformerq and control equipment instead of being mounted on or near the phase balancing transformer are mounted remotely.
Subject to the nature of the load, freguent phase changes can be executed, several times during the day if necessary.
The objective is always to save money by reducing losses through phase balancing.
Recapping,this invention makes the phase balancing process easy, quick, convenient, qafe, and economical.
Figure No. 1 shows the connections for a three-bushing, single-phase, phase-to-neutral connected phase-balancing transformer with a manually operated switch.
Figure No.2 shows the connections for a three-bushing, single-phase, phase-to-phase connected phase-balancing transformer with a manually operated switch.
Figure No. 3 shows the connections for a three-bushing, single-phase, phase-to-neutral connected phase-balancing transformer with a manually or electrically operated switch. Three current transformers are also shown feeding the control box for local automatic control. An external connection is also indicated for remote operation of the switch.
Figure No. 4 shows the connections for a three-bushing, single-phase, phase-to-phase connected phase-balancing transformer with a manually or electrically operated switch. Three current transformers are also shown feeding the control box for local automatic control. An external connection is also indicated for remote operation of the switch.
MULTI-BUSHING SINGLE-PHASE ELECTRIC DISTRIBUTION TRANSFORMER -FOR FEEDER PHASE CURRENT BALANCING .
Specification - Disclosure Page 3 of 3 These would be the typical connections. Other are possible. For example,a two-bushing single-phase tran~former in which the load can be transferred from just one phase to another; rather than to ~.
two others.
~ --~ . ---. . . .....
Claims
MULTI-BUSHING SINGLE-PHASE ELECTRIC DISTRIBUTION TRANSFORMER
FOR FEEDER PHASE CURRENT BALANCING
Specification - Claims Page 1 of 1 The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:
An electrical single-phase distribution transformer of any type e.g. dry-type liquid or gas-filled; Completely Self-Protected or non-protected; copper or aluminum windings; steel or amorphous core; over-head or underground; pole-mounted or pad-mounted or submersible, with two or more windings,independent or auto-connected windings,with or without taps, with or without on-load tap-changers,with tapered or full insulation,etc.
and with primary,secondary (and tertiary) voltage windings with operating voltages from 1 Volt AC RMS to 250000 Volts AC RMS, and with power capacities from 0.1 kVA to 100000 kVA, and with two or more bushings on the high voltage side, and with an oil, vacuum or sulphur hexafluoride insulated internally mounted load-break switch, manually or electrically operated - with two or more positions - to permit the transferring of load from one of the primary phases to another.
FOR FEEDER PHASE CURRENT BALANCING
Specification - Claims Page 1 of 1 The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:
An electrical single-phase distribution transformer of any type e.g. dry-type liquid or gas-filled; Completely Self-Protected or non-protected; copper or aluminum windings; steel or amorphous core; over-head or underground; pole-mounted or pad-mounted or submersible, with two or more windings,independent or auto-connected windings,with or without taps, with or without on-load tap-changers,with tapered or full insulation,etc.
and with primary,secondary (and tertiary) voltage windings with operating voltages from 1 Volt AC RMS to 250000 Volts AC RMS, and with power capacities from 0.1 kVA to 100000 kVA, and with two or more bushings on the high voltage side, and with an oil, vacuum or sulphur hexafluoride insulated internally mounted load-break switch, manually or electrically operated - with two or more positions - to permit the transferring of load from one of the primary phases to another.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2086650 CA2086650A1 (en) | 1993-01-04 | 1993-01-04 | Multi-bushing single-phase electric distribution transformer for feeder phase current balancing |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2086650 CA2086650A1 (en) | 1993-01-04 | 1993-01-04 | Multi-bushing single-phase electric distribution transformer for feeder phase current balancing |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2086650A1 true CA2086650A1 (en) | 1994-07-05 |
Family
ID=4150935
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2086650 Abandoned CA2086650A1 (en) | 1993-01-04 | 1993-01-04 | Multi-bushing single-phase electric distribution transformer for feeder phase current balancing |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2086650A1 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5952617A (en) * | 1996-04-19 | 1999-09-14 | Jersey Central Power & Light Company | Power transformer and coupling means |
| US9865410B2 (en) | 2013-09-25 | 2018-01-09 | Abb Schweiz Ag | Methods, systems, and computer readable media for topology control and switching loads or sources between phases of a multi-phase power distribution system |
| US10033176B2 (en) | 2010-11-10 | 2018-07-24 | Abb Research Ltd. | Fault interrupting devices and control methods therefor |
-
1993
- 1993-01-04 CA CA 2086650 patent/CA2086650A1/en not_active Abandoned
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5952617A (en) * | 1996-04-19 | 1999-09-14 | Jersey Central Power & Light Company | Power transformer and coupling means |
| US10033176B2 (en) | 2010-11-10 | 2018-07-24 | Abb Research Ltd. | Fault interrupting devices and control methods therefor |
| US9865410B2 (en) | 2013-09-25 | 2018-01-09 | Abb Schweiz Ag | Methods, systems, and computer readable media for topology control and switching loads or sources between phases of a multi-phase power distribution system |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Dead |