GB2473014A - Single and multi-phase current sensor and current transformer - Google Patents
Single and multi-phase current sensor and current transformer Download PDFInfo
- Publication number
- GB2473014A GB2473014A GB0914913A GB0914913A GB2473014A GB 2473014 A GB2473014 A GB 2473014A GB 0914913 A GB0914913 A GB 0914913A GB 0914913 A GB0914913 A GB 0914913A GB 2473014 A GB2473014 A GB 2473014A
- Authority
- GB
- United Kingdom
- Prior art keywords
- current
- resistive shunt
- current transformer
- resistive
- sensor
- 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.)
- Granted
Links
- 239000004020 conductor Substances 0.000 abstract description 21
- 238000012545 processing Methods 0.000 abstract description 16
- 239000012212 insulator Substances 0.000 abstract description 8
- 238000005259 measurement Methods 0.000 abstract description 8
- 230000007935 neutral effect Effects 0.000 abstract description 6
- 238000010438 heat treatment Methods 0.000 abstract description 4
- 238000001514 detection method Methods 0.000 description 2
- 238000004364 calculation method Methods 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 231100000518 lethal Toxicity 0.000 description 1
- 230000001665 lethal effect Effects 0.000 description 1
- 230000013011 mating Effects 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 238000011144 upstream manufacturing Methods 0.000 description 1
- 238000004804 winding Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R15/00—Details of measuring arrangements of the types provided for in groups G01R17/00 - G01R29/00, G01R33/00 - G01R33/26 or G01R35/00
- G01R15/14—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks
- G01R15/18—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using inductive devices, e.g. transformers
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R15/00—Details of measuring arrangements of the types provided for in groups G01R17/00 - G01R29/00, G01R33/00 - G01R33/26 or G01R35/00
- G01R15/14—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks
- G01R15/18—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using inductive devices, e.g. transformers
- G01R15/183—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using inductive devices, e.g. transformers using transformers with a magnetic core
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/10—Measuring sum, difference or ratio
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H71/00—Details of the protective switches or relays covered by groups H01H73/00 - H01H83/00
- H01H71/02—Housings; Casings; Bases; Mountings
- H01H71/0207—Mounting or assembling the different parts of the circuit breaker
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H83/00—Protective switches, e.g. circuit-breaking switches, or protective relays operated by abnormal electrical conditions otherwise than solely by excess current
- H01H83/14—Protective switches, e.g. circuit-breaking switches, or protective relays operated by abnormal electrical conditions otherwise than solely by excess current operated by imbalance of two or more currents or voltages, e.g. for differential protection
- H01H83/144—Protective switches, e.g. circuit-breaking switches, or protective relays operated by abnormal electrical conditions otherwise than solely by excess current operated by imbalance of two or more currents or voltages, e.g. for differential protection with differential transformer
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/26—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to difference between voltages or between currents; responsive to phase angle between voltages or between currents
- H02H3/32—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to difference between voltages or between currents; responsive to phase angle between voltages or between currents involving comparison of the voltage or current values at corresponding points in different conductors of a single system, e.g. of currents in go and return conductors
- H02H3/33—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to difference between voltages or between currents; responsive to phase angle between voltages or between currents involving comparison of the voltage or current values at corresponding points in different conductors of a single system, e.g. of currents in go and return conductors using summation current transformers
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R21/00—Arrangements for measuring electric power or power factor
- G01R21/06—Arrangements for measuring electric power or power factor by measuring current and voltage
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Measuring Instrument Details And Bridges, And Automatic Balancing Devices (AREA)
Abstract
A current balance-type current sensor or circuit breaker suitable for measurement of AC or DC current in an electrical network, comprising a current transformer 9 and resistive shunt 1 connected in series with a line in conductor (at fixing location 14) wherein the resistive shunt is located within the central aperture of the current transformer. The shunt may be coaxial with the line out neutral conductor 6. The sensor may further comprise a resistive shunt temperature sensor 4 in locating grove 12 in the insulator 2 at the axial mid-point of each resistive shunt; and an ambient temperature sensor 5 in the current transformer case 7. The device may comprise processing electronics to determine residual / earth leakage, differential current, component temperatures, voltage and/or power. This arrangement utilises the available space to maximise the rated current capability of the combined sensor and minimise power loss due to heating.
Description
Title: Single & Multi Phase Current Sensor Combined with a Current Transformer
Background to the invention
Residual I earth leakage I differential current protection is required in the majority of states throughout the world in order to protect persons from potentially lethal leakage currents & equipment from damage. The most commonly used method for earth leakage detection is by comparing the line AC current supplied to the load circuit to the return AC current from the load circuit and determining if there is an imbalance.
The most widely used embodiment of this detection method is by using a null balanced AC current transformer whereby the line in and out conductors are passed through the transformer. If there is an imbalance between the line in and out AC currents an AC current is induced into a secondary winding the magnitude of this induced AC current is proportional to the imbalance AC current.
This embodiment has a number of draw backs namely current transformer size both outside diameter & inside diameter which limits it's application & current rating by limiting the cross section of the line in & out conductors that pass through thus limiting the capacity of each conductor to carry current.
This invention enables a combined resistive shunt based current sensor with a current transformer enabling AC & DC current & thus given a known resistance the power measurement in a single phase or a plurality of phases that operates within the available space taken by a null balance AC current transformer used for the measurement of residual I earth leakage I differential current. This invention also utilises the available space to maximise the rated current capacity & minimise the power loss due to heating.
Description
This invention relates to a current sensor capable of measuring both phase and differential currents. The invention is the combination of two different types of current sensor in a construction that is in the same space as required by a current transformer The invention enables a resistive shunt based current sensor capable of measuring AC & DC current in a single phase or a plurality of phases to be combined to an existing current transformer thus maximising the rated current capability of the combined sensor in a given space.
The invention is a current sensor used to measure AC and DC current in an electrical network comprising a current transformer and resistive shunts connected in series with a plurality of line in conductors said resistive shunts located within the central aperture of the current transformer said resistive shunts & temperature sensors are located in an insulator housing which has a locating feature that aligns with a mating feature in the current transformer case A resistive shunt is connected in series with the line in phases and is located within the aperture of the current transformer. The remaining line out conductor passing through the aperture of the current transformer & thus when the resistive shunt sensor connected in series with the line in conductor & the line out conductor are located & pass through the aperture of the current transformer the measurement of the differential current flowing in a load circuit is possible.
Current flowing in each line in phase may be calculated by measuring the voltage drop across each resistive shunt at the shunt sense connections. The calculation means maybe an electronic circuit or computer algorithm.
The resultant AC & DC current measurement in each line in phase can be processed by the suitable processing electronics can calculate residual I earth leakage or differential current and determine the power in each phase & the overall power in a plurality of phases.
Further processing of the measurements from the resistive shunt sensor having a plurality of resistive shunts & monitoring of the null balance current using the current transformer enables both differential AC & DC current measurement in the same space by using suitable processing electronic enables the presence of a DC residual current. Each resistive shunt has a scalable cross section to enable maximum usage of the available cross sectional area in a given current transformer aperture thus maximising the rated current capability.
The use of resistive shunt sensors enables a high degree of AC & DC current measurement accuracy over a wide ambient temperature range. This invention also includes a local ambient temperature sensor located in the current transformer case which coupled to suitable processing electronics can determine the local ambient temperature and an algorithm operable to compensate the calculated current in both the toroidal and shunt current sensors and a resistive shunt temperature sensor located at the axial mid point of the resistive shunt sensor to enable active temperature compensation of the measured current in each line phase and when coupled to suitable processing electronics can measure the temperature change across the axial mid point of the resistive shunt and determine a temperature shift either side of the axial centre of the resistive shunt indicating an over temperature failure of a component or device upstream or downstream of the resistive shunt The use of both resistive shunt sensors and a current transformer when coupled to suitable processing electronics can measure & detect current signatures.
A combined resistive shunt current sensor and current transformer where the current transformer can be a toroidal type, split core type of either symmetrical or a non symmetrical shape.
Embodiment I Example
Figure 1 shows a series of sketches of a single phase embodiment using a single resistive shunt in the line in phase combined with a toroidial current transformer Figure 2 shows a series of sketches of a multi phase embodiment with a single resistive shunt for each line in phase combined with a toroidial current transformer Figure3 shows a series of sketches of a single or multiphase embodiment with a resistive shunt wire in each line in phase combined with a toroidial current transformer
Description of diagrams
Figure 1 shows an embodiment having a resistive shunt 1 having a circular cross section thus enabeling the maximum usage of available space within the aperture of a whole or split toroidial transformer case thus allowing the maximisation of rated current & the lowest power loss due to heating is assembled axially to the insulator 2 & this sub assembly in located axially within the central aperture of the current transformer case 7 & located by the locating feature 10 sufficient that both resistive shunt sense points 11 are equally placed either side of the residual current sensor case 2 housing the current transformer 9. Alternativle the resistive shunt having a rectangular cross section thus enabling the maximum usage of available space within the aperture of a split core or race track current transformer.
The resistive shunt sense wires 3 are connected to the resistive shunt sense points 11. The resistive shunt temperature sensor 4 is located in the insulator 2 in the locating groove 12 in placed axially so that the resistive shunt temperature sensor in located at the axial centre of the resistive shunt 1. The ambient temperature sensor 5 is located in the current transformer case 2 at the location 13. The line out neutral conductor 6 having a suitably matched circular cross section to that of the resistive shunt 1 is assembled axially through the centre aperture of the insulator 2. The line in conductors are fixed either side of the resistive shunt 1 at the fixing locations 14. The current transformer contact pins 8 & the resistive shunt sense wires 3 & the resistive shunt temperature sensor 4 & the ambient temperature sensor 5 are all connected to a suitable electrical circuit & processing electronics. The line in current passing through the resistive shunt 1 & the line out current passing through the neutral conductor 6 can be monitored by the processing electronics using the current transformer 9 & the output pins 8 to determine if there is an imbalance of the nulling current induced in the current transformer. The current in the line in conductor fixed to the resistive shunt 1 can be measured by taking a voltage drop across the resistive shunt 1 at the sense points 11 using the resistive shunt sense wires 3. The resistive shunt 1 having a temperature stable & known resistance allows the processing electronics to calculate the temperature & current & voltage & power in the line in phase using a suitable algorithm.
Figure 2 shows a further embodiment having a plurality of resistive shunts 20 each having a circular cross section & design suitable to maximise the available space to provide the maximum current rating & the lowest power loss due to heating are assembled radially to the insulator 21 & this sub assembly in located axially within the central aperture of the current transformer case 25 & located by the locating feature 31 sufficient that all resistive shunt sense points 30 are equally placed either side of the current transformer case 25 housing the current transformer 28. The plurality of resistive shunt sense wires 23 are connected to the plurality of resistive shunt sense points 30. The plurality of resistive shunt temperature sensors 24 are located in the insulator 21 in the plurality of locating grooves 33 & placed axially so that the resistive shunt temperature sensors 24 are located at the axial centre of the each of the plurality of resistive shunts 20. The ambient temperature sensor 27 is located in the current transformer case 25 at the location 29. The line out neutral conductor 22 having a suitably matched cross section to that of the resistive shunts is assembled axially through the centre hole of the insulator 21. The line in conductors are fixed either side of the plurality of resistive shunts 20 at the fixing locations 32. The current transformer contact pins 26 & the plurality of resistive shunt sense wires 23 & the plurality of resistive shunt temperature sensors 24 & the ambient temperature sensor 27 are all connected to a suitable electrical circuit & processing electronics. The line in current passing through the plurality of resistive shunts 20 & the line out current passing through the neutral conductor 22 can be monitored by the processing electronics using the current transformer 28 & the output pins 26 to determine if there is an imbalance of the nulling current induced in the current transformer. The current in each of the line in conductors fixed to the plurality of resistive shunts 20 can be measured by taking a voltage drop across each resistive shunt 20 at the sense points 30 using the resistive shunt sense wires 23.
Each resistive shunt 20 having a temperature stable & known resistance allows the processing electronics to calculate the temperature & current & voltage & power each of the line in phases using a suitable algorithm.
Figure 3 shows a further embodiment of a combined current transformer 57 & resistive shunt wire 50 based current sensor arrangement. This arrangement is less effective at enabling higher current rating & less power loss due to a less efficient usage of available space at the centre aperture of the current transformer case 56.
This embodiment having a circuit on a printed circuit board 51 which has an opening through which the current transformer 57 and the current transformer case 56 & the output pins 55 are placed & are connected electrically to the circuit board 51. The ambient temperature sensor 58 is placed in the current transformer case 56 & connected to the circuit board 51 at location 61. The resistive shunt wire temperature sensor 59 is fixed at the mid point along the length of the resistive shunt wire 50 by a suitable means. The resistive shunt wire 50 & the line out conductor 54 are then assembled through the central aperture in the current transformer case 56. The resistive shunt wire temperature sensor 59 is then connected electrically to the circuit board 51 at location 60. The resistive shunt wire 50 is connected electrically at either end to the circuit board 51 at location 65. The line in conductors 52 are each connected electrically to the circuit board 51 at location 65. The circuit board 51 ouput contacts 62 connected to the current transformer output pins 55 and the output contacts 64 connected to the ambient temperature sensor 58 and the output contacts 66 connected to the resistive shunt wire temperature sensor 59 and the output contacts 63 connected to the resistive shunt wire 50 contacts 65 are all connected to a suitable electric circuit & processing electronics. The line in current passing through either a single or a plurality of resistive shunt wires 50 & the line out current passing through the line out neutral conductor 54 can be monitored by the processing electronics using the current transformer 57 & the output pins 55 to determine if there is an imbalance of the nulling current induced in the current transformer 57. The current in each of the line in conductors fixed to either a single or a plurality of resistive shunt wires 50 can be measured by taking a voltage drop across each resistive shunt wire 50 at the sense points 65. Each resistive shunt wire 50 having a temperature stable & known resistance allows the processing electronics to calculate the temperature & current & therefore power for each of the line in phases using a
suitable algorithm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB0914913A GB2473014B (en) | 2009-08-27 | 2009-08-27 | Single and Multi Phase Current Sensor Combined with a Current Transformer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB0914913A GB2473014B (en) | 2009-08-27 | 2009-08-27 | Single and Multi Phase Current Sensor Combined with a Current Transformer |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB0914913D0 GB0914913D0 (en) | 2009-09-30 |
| GB2473014A true GB2473014A (en) | 2011-03-02 |
| GB2473014B GB2473014B (en) | 2014-07-16 |
Family
ID=41171960
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB0914913A Expired - Fee Related GB2473014B (en) | 2009-08-27 | 2009-08-27 | Single and Multi Phase Current Sensor Combined with a Current Transformer |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2473014B (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2014010411A1 (en) * | 2012-07-11 | 2014-01-16 | Yazaki Corporation | Shunt resistance type current sensor |
| CN103646766A (en) * | 2013-11-14 | 2014-03-19 | 苏州长量电器有限公司 | Ultra-thin large current transformer |
| CN104764983A (en) * | 2015-03-18 | 2015-07-08 | 胡妍 | Insulator detection device |
| GB2524312A (en) * | 2014-03-20 | 2015-09-23 | C & S Technology Ltd | Combined current sensor |
| WO2017021248A1 (en) * | 2015-07-31 | 2017-02-09 | Siemens Aktiengesellschaft | Current transformer having multi-turn conductive rod |
| CN109030902A (en) * | 2018-08-17 | 2018-12-18 | 国网山东省电力公司烟台供电公司 | A kind of current transformer |
| CN110244257A (en) * | 2019-07-26 | 2019-09-17 | 华立科技股份有限公司 | The earth detector and method of electric energy meter |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3725741A (en) * | 1971-06-30 | 1973-04-03 | Westinghouse Electric Corp | Differential transformer mounting arrangement particulary for ground fault interrupter apparatus |
| US4688134A (en) * | 1985-01-10 | 1987-08-18 | Slater Electric Inc. | Ground fault circuit interrupter and electronic detection circuit |
| US5907461A (en) * | 1997-10-01 | 1999-05-25 | Eaton Corporation | Molded case circuit breaker with ground fault protection and signaling switches |
| GB2412511A (en) * | 2001-06-08 | 2005-09-28 | Eaton Electric Ltd | Measuring residual current and power consumption |
-
2009
- 2009-08-27 GB GB0914913A patent/GB2473014B/en not_active Expired - Fee Related
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3725741A (en) * | 1971-06-30 | 1973-04-03 | Westinghouse Electric Corp | Differential transformer mounting arrangement particulary for ground fault interrupter apparatus |
| US4688134A (en) * | 1985-01-10 | 1987-08-18 | Slater Electric Inc. | Ground fault circuit interrupter and electronic detection circuit |
| US5907461A (en) * | 1997-10-01 | 1999-05-25 | Eaton Corporation | Molded case circuit breaker with ground fault protection and signaling switches |
| GB2412511A (en) * | 2001-06-08 | 2005-09-28 | Eaton Electric Ltd | Measuring residual current and power consumption |
Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2014010411A1 (en) * | 2012-07-11 | 2014-01-16 | Yazaki Corporation | Shunt resistance type current sensor |
| US9395396B2 (en) | 2012-07-11 | 2016-07-19 | Yazaki Corporation | Shunt resistance type current sensor |
| CN103646766A (en) * | 2013-11-14 | 2014-03-19 | 苏州长量电器有限公司 | Ultra-thin large current transformer |
| GB2524312A (en) * | 2014-03-20 | 2015-09-23 | C & S Technology Ltd | Combined current sensor |
| EP2924447A1 (en) | 2014-03-20 | 2015-09-30 | C&S Technology Ltd. | Combined current sensor |
| CN104764983A (en) * | 2015-03-18 | 2015-07-08 | 胡妍 | Insulator detection device |
| WO2017021248A1 (en) * | 2015-07-31 | 2017-02-09 | Siemens Aktiengesellschaft | Current transformer having multi-turn conductive rod |
| CN106710857A (en) * | 2015-07-31 | 2017-05-24 | 西门子公司 | Current transformer with multi-turn conducting rod |
| CN106710857B (en) * | 2015-07-31 | 2018-12-11 | 西门子公司 | Current transformer with multiturn conducting rod |
| CN109030902A (en) * | 2018-08-17 | 2018-12-18 | 国网山东省电力公司烟台供电公司 | A kind of current transformer |
| CN109030902B (en) * | 2018-08-17 | 2021-01-15 | 国网山东省电力公司烟台供电公司 | Current transformer |
| CN110244257A (en) * | 2019-07-26 | 2019-09-17 | 华立科技股份有限公司 | The earth detector and method of electric energy meter |
Also Published As
| Publication number | Publication date |
|---|---|
| GB0914913D0 (en) | 2009-09-30 |
| GB2473014B (en) | 2014-07-16 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 20180827 |