WO2020007239A1 - 电流互感器 - Google Patents

电流互感器 Download PDF

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Publication number
WO2020007239A1
WO2020007239A1 PCT/CN2019/093544 CN2019093544W WO2020007239A1 WO 2020007239 A1 WO2020007239 A1 WO 2020007239A1 CN 2019093544 W CN2019093544 W CN 2019093544W WO 2020007239 A1 WO2020007239 A1 WO 2020007239A1
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WO
WIPO (PCT)
Prior art keywords
component
core components
interface
transformer
core
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.)
Ceased
Application number
PCT/CN2019/093544
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English (en)
French (fr)
Inventor
罗守南
李芳�
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Fortive Shanghai Industrial Instrumentation Technologies R&D Co Ltd
Original Assignee
Fortive Shanghai Industrial Instrumentation Technologies R&D Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
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Application filed by Fortive Shanghai Industrial Instrumentation Technologies R&D Co Ltd filed Critical Fortive Shanghai Industrial Instrumentation Technologies R&D Co Ltd
Priority to KR1020217000391A priority Critical patent/KR20210025591A/ko
Priority to JP2021500149A priority patent/JP2021530683A/ja
Priority to EP19831125.0A priority patent/EP3819923B1/en
Priority to US17/257,482 priority patent/US20210265110A1/en
Publication of WO2020007239A1 publication Critical patent/WO2020007239A1/zh
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F38/00—Adaptations of transformers or inductances for specific applications or functions
    • H01F38/20—Instruments transformers
    • H01F38/22—Instruments transformers for single phase AC
    • H01F38/28—Current transformers
    • H01F38/30—Constructions
    • 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
    • G01R15/185—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 with compensation or feedback windings or interacting coils, e.g. 0-flux sensors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/02—Casings
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/24—Magnetic cores
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/24—Magnetic cores
    • H01F27/26—Fastening parts of the core together; Fastening or mounting the core on casing or support
    • H01F27/263—Fastening parts of the core together
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/28—Coils; Windings; Conductive connections
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/34—Special means for preventing or reducing unwanted electric or magnetic effects, e.g. no-load losses, reactive currents, harmonics, oscillations, leakage fields
    • H01F27/36—Electric or magnetic shields or screens
    • H01F27/363—Electric or magnetic shields or screens made of electrically conductive material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/42—Circuits specially adapted for the purpose of modifying, or compensating for, electric characteristics of transformers, reactors, or choke coils
    • H01F27/422—Circuits specially adapted for the purpose of modifying, or compensating for, electric characteristics of transformers, reactors, or choke coils for instrument transformers
    • H01F27/427—Circuits specially adapted for the purpose of modifying, or compensating for, electric characteristics of transformers, reactors, or choke coils for instrument transformers for current transformers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F38/00—Adaptations of transformers or inductances for specific applications or functions
    • H01F38/20—Instruments transformers
    • H01F38/22—Instruments transformers for single phase AC
    • H01F38/28—Current transformers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F38/00—Adaptations of transformers or inductances for specific applications or functions
    • H01F38/20—Instruments transformers
    • H01F38/22—Instruments transformers for single phase AC
    • H01F38/34—Combined voltage and current 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
    • G01R15/186—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using inductive devices, e.g. transformers using current transformers with a core consisting of two or more parts, e.g. clamp-on type
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F38/00—Adaptations of transformers or inductances for specific applications or functions
    • H01F38/20—Instruments transformers
    • H01F38/22—Instruments transformers for single phase AC
    • H01F38/28—Current transformers
    • H01F38/30—Constructions
    • H01F2038/305—Constructions with toroidal magnetic core
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F38/00—Adaptations of transformers or inductances for specific applications or functions
    • H01F38/20—Instruments transformers
    • H01F38/22—Instruments transformers for single phase AC
    • H01F38/28—Current transformers
    • H01F38/32—Circuit arrangements
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F38/00—Adaptations of transformers or inductances for specific applications or functions
    • H01F38/20—Instruments transformers
    • H01F38/40—Instruments transformers for DC

Definitions

  • the present application relates to electronic measurement technology, and more particularly, to a detachable current transformer.
  • the purpose of this application is to provide a detachable multi-core current transformer to measure the current in the cable under test without power off.
  • This application discloses a current transformer, which includes a first transformer component and a second transformer component, both ends of the first transformer component have a first component end and a second component end, and the
  • the first transformer component includes a first group of stacked core components, the first group of core components defining a first interface at an end of the first component, and defining a first interface at an end of the second component.
  • Two interfaces; two ends of the second transformer component have a third component end and a fourth component end, and the second transformer component includes a second group of stacked core components, and the second group
  • a plurality of iron core components define a third interface at an end of the third component, and a fourth interface at an end of the fourth component.
  • At least one of the first interface and the second interface is detachably connected to at least one of the third interface and the fourth interface, so as to detachably connect the first transformer component and the second interface.
  • Transformer components; and the first transformer component and the second transformer component are configured such that when they are connected to each other, the first group of core components and the second group of core components are combined to form a plurality of A closed annular iron core, and coils are respectively wound on at least two closed annular iron cores of the plurality of closed annular iron cores; a closed area is defined between the first transformer component and the second transformer component To cause the cable under test to pass through the closed area, thereby generating an induced current related to the current in the cable under test in at least one of the coils.
  • At least one coil is wound outside the plurality of closed toroidal cores, which is configured to generate a sense related to a current in the cable under test when the cable under test passes through the closed area. Generate current.
  • the first plurality of core components includes two core components
  • the second plurality of core components includes two core components.
  • the two core components of the first plurality of core components and the two core components of the second plurality of core components are combined to form two closed annular irons.
  • a core, and a coil is wound on each of the closed ring cores, and two coils are wound on the outside of the two closed ring cores.
  • the first plurality of core components includes three core components
  • the second plurality of core components includes three core components.
  • the three core members of the first plurality of core members and the three core members of the second plurality of core members are combined to form three closed ring irons.
  • a coil is wound on each of the closed annular iron cores, and a coil is wound on the outside of the three closed annular iron cores.
  • the first plurality of core components includes four core components
  • the second plurality of core components includes four core components.
  • the four core members of the first plurality of core members and the four core members of the second plurality of core members are combined to form four closed ring irons. Core, and a coil is wound on each closed toroidal core.
  • the first transformer assembly further includes a first shell, the first shell is used to define the first plurality of iron core components therein; the second transformer assembly further includes A second shell configured to define the second plurality of iron core components therein; the first shell and the second shell are configured to serve as the first transformer assembly and the When the second transformer assembly is connected to each other, the first shell and the second shell are combined to form a closed ring shell, and the plurality of closed ring cores are accommodated therein.
  • the at least one coil wound externally is wound on the closed annular casing.
  • At least one of the first interface and the second interface and at least one of the third interface and the fourth interface have interdigitated structures to enable the interfaces to be interleaved when the interfaces are connected to each other. Ways to connect with each other.
  • each of the first, second, third, and fourth interfaces has a guide to guide the connection of the interface.
  • the guide of each interface includes a plurality of guide elements, each guide element surrounding one of the first plurality of core components or the second plurality of core components One end of the iron core member, and each guide element has a pair of convex portions and concave portions.
  • each guide element When the interface is connected to another interface, one of the pair of convex portions and concave portions and one of the guide elements of the other interface is connected. The convex part and the concave part cooperate.
  • the current transformer further includes one or more fasteners for fixing the first transformer component and the second transformer component together when the interfaces are connected to each other.
  • the first interface is detachably connected to the third interface
  • the second interface is detachably connected to the fourth interface
  • the first transformer component and the second transformer component have a semicircular shape.
  • coils are wound on at least two core members in the first plurality of core members and at least two core members in the second plurality of core members, When the first transformer component and the second transformer component are connected to each other, coils respectively wound on at least two closed toroids of the plurality of closed toroids are formed by the first group of multiples.
  • the coils on at least two of the core components and the coils on the corresponding at least two core components of the second plurality of core components are connected to each other.
  • At least one coil is wound outside the first plurality of core components, and at least one coil is wound outside the second plurality of core components.
  • first transformer component When interconnected with the second transformer assembly, at least one coil wound outside the plurality of closed annular cores is formed by the at least one coil wound outside the first plurality of core components and The corresponding at least one coil wound around the second plurality of core components is formed by connecting each other.
  • the coil wound on each of the first plurality of core components extends substantially the entire length from the end of the first component to the end of the second component. .
  • the coil wound on each of the second plurality of core components extends substantially the entire length from the end of the third component to the end of the fourth component. .
  • At least one of the first plurality of core members and the second plurality of core members is made of an iron-nickel alloy material.
  • a metal shielding layer is provided outside the core component and the coil of the first transformer component and the second transformer component to shield an external electric field.
  • the first transformer assembly further includes a first housing for defining the first plurality of core components therein, and the first housing is housed in In the metal shielding layer
  • the second transformer assembly further includes a second housing for defining the second plurality of core components therein, and the second housing is accommodated. In the metal shielding layer.
  • FIG. 1 is a schematic diagram showing the overall structure of a detachable multi-core current transformer according to an embodiment of the present application
  • FIG. 2 is a schematic structural diagram of a transformer component in the current transformer shown in FIG. 1;
  • FIG. 2 is a schematic structural diagram of a transformer component in the current transformer shown in FIG. 1;
  • FIG. 3 is an exploded view of a transformer component in the current transformer shown in FIG. 1;
  • FIG. 4 shows a schematic diagram of an interface of a transformer component in the current transformer shown in FIG. 1;
  • FIG. 5 shows a schematic structural diagram of the three closed annular iron cores in the current transformer shown in FIG. 1 after the installation is completed;
  • FIG. 6 shows a schematic diagram of a circuit for sensing a primary current in a cable under test according to another embodiment of the present application.
  • FIG. 1 shows a schematic diagram of the overall structure of the detachable multi-core current transformer
  • FIG. 2 and FIG. 3 show a transformer component (for example, the first mutual inductor) in the detachable multi-core current transformer
  • Figure 4 shows a schematic diagram of the interface of a transformer component (for example, the first transformer component) in the detachable multi-core current transformer
  • Figure 5 shows the detachable multi-core current transformer. Schematic diagram of the three closed loop iron cores in the core current transformer after connection.
  • the current transformer with three iron cores shown in the drawings of the present application is merely exemplary, and a detachable multi-core current transformer with two iron cores or four iron cores or another number of iron cores It can also be used to measure the AC and DC components of the current in the cable under test at the same time.
  • the current transformer 100 includes a first transformer component 1011 and a second transformer component 1012.
  • the shape of the first transformer component 1011 is generally a semi-circular shape, and the two ends thereof are respectively the ends of the first component and the second component. Component end.
  • the shape of the second transformer component 1012 is generally semi-circular, and the two ends of the second transformer component 1012 are the ends of the third component and the ends of the fourth component, respectively.
  • the two transformer assemblies 1011 and 1012 are connected in a generally circular ring shape after being connected.
  • the first transformer component 1011 may also have a semi-circular shape with an extension of no more than 180 degrees, such as an arc of about 120 degrees or other arcs.
  • the second transformer component 1012 may It is a semi-circular shape with an arc extending more than 180 degrees, for example, an arc extending to about 240 degrees or other arcs.
  • the two transformer assemblies 1011 and 1012 can also have other suitable shapes, as long as they can define a closed area between them to allow the cable under test to pass after connection.
  • the first transformer assembly 1011 includes a first casing 1041
  • the second transformer assembly 1012 includes a second casing 1042
  • coils are respectively wound on the first and second casings.
  • the first component end, the second component end, the third component end, and the fourth component end are respectively provided with a first interface 1021, a second interface 1031, a third interface 1022, and a fourth interface 1032.
  • the first interface 1021 can be detachably connected to the third interface 1022
  • the second interface 1031 can be detachably connected to the fourth interface 1032, thereby conveniently installing and removing two transformer components, so that the current transformer 100 can be removed. Switch between open and closed states.
  • the coil may be wound only on the first housing, or only the coil may be wound on the second housing.
  • only the connection between the first interface 1021 and the third interface 1022 can be disconnected, and the connection between the second interface 1031 and the fourth interface 1032 is always maintained, so that when the current transformer 100 is in a disassembled state
  • the two transformer components can be partially separated.
  • the gap between the disconnection of the first interface 1021 and the third interface 1022 is larger than the diameter of the cable under test, the cable under test may be allowed to pass through the gap.
  • only the connection between the second interface 1031 and the fourth interface 1032 may be disconnected.
  • the first transformer assembly 1011 includes a first group of three core members 1051, 1061, and 1071, and the three core members are enclosed in a first housing 1041.
  • the three core parts are generally semi-circular in shape, and have substantially the same size, and are stacked on top of each other so that the two ends of each core part are aligned with each other, and adjacent iron
  • the core components are electrically isolated from each other.
  • the core member is made of a magnetic material such as iron, nickel, or an iron-nickel alloy, and the magnetic material is preferably an iron-nickel alloy type material such as permalloy.
  • a metal shielding layer (not shown in the figure) outside the first casing 1041, which houses the first casing 1041, a first group of three core components, and each core component and the first casing The upper coil is used to protect the core from external electric fields.
  • a metal shielding layer is included in the first housing 1041.
  • Each core member 1051, 1061, or 1071 is wound with a coil (not shown in the figure), and optionally, the coil wound on each core member is generally from the end of the first component to the end of the second component Extending between the entire length.
  • the two ends of each iron core component respectively have an interdigitated structure at the first interface 1021 and the second interface 1031 for staggered connection with the interdigital structure of the third interface 1022 and the fourth interface 1032.
  • the interdigitated structures can have high mating accuracy, for example, the single-sided gap between the prongs can be as small as 0.05mm.
  • the first interface 1021 and the second interface 1031 may have a guide member for guiding the connection between the interfaces.
  • the guide at the first interface 1021 includes three guide elements, and each guide element surrounds one end of one of the core components in the first group of three core components for guiding the first The connection between the interface 1021 and the third interface 1022.
  • the guide element 1081 includes a convex portion 1111 and a concave portion 1121, which are respectively located at one end of the core component 1051.
  • the convex portion 1111 cooperates with a recess of the guide element of the third interface 1022.
  • the recess 1121 cooperates with a convex portion of the guide element of the third interface 1022.
  • the other two guiding elements at the first interface 1021 and the three guiding elements at the second interface 1031 all have the same structure as the guiding element 1081, and details are not described herein again. According to requirements, other numbers of guiding elements may be included at one interface, for example, the first interface 1021 and the second interface 1031 may each include only one guiding element.
  • the guide member may also have other suitable structures, for example, it may have a shaft-groove fitting structure.
  • the guide at the interface may be mounted on the first housing, the shield, or other components of the first transformer assembly.
  • the second transformer assembly 1012 includes a second group of three core components (not shown in Figs. 2 to 3) and other components enclosed in a second housing 1042.
  • the shape of the second transformer assembly 1012 and its various components , Structure, etc. are the same as or matched with the first transformer component 1011, which will not be repeated here.
  • Each of the second set of three core components corresponds to one of the first set of three core components.
  • the interdigitated structures at the interfaces can be staggered and joined to each other, thereby forming three stacked closed ring cores 105, 106 and 107 (see Figure 5).
  • the shape of the closed toroidal core may be a generally circular ring shape, or other suitable shapes having a closed loop.
  • the first shell 1041 and the second shell 1042 are connected to form a closed ring shell, and three closed ring cores are accommodated therein.
  • the three guiding elements at the first interface 1021 are respectively matched with the three guiding elements at the second interface 1022, and the three guiding elements at the second interface 1031 are respectively matched with the three guiding elements at the fourth interface 1032.
  • the convex part in each guide element is inserted into the concave part in the corresponding guide element, so as to guide the interfaces to be aligned during connection and prevent displacement.
  • One end of the coil on each core component is respectively connected to one end of the coil on the corresponding core component on the other transformer component, so that a complete coil is wound on each of the stacked closed loop cores, This facilitates the sensing of the current.
  • one end of the coil wound on the first casing 1041 and one end of the coil wound on the second casing 1042 are also connected to each other at the interface to form a complete coil wound on the complete casing.
  • only one of the two corresponding core components constituting the closed toroidal core is wound with a coil, that is, only half of the closed toroidal core is wound with Coil, no coil is wound on the other half.
  • a current transformer conforming to this design can also measure the DC and AC components of the current.
  • first casing and the second casing may be omitted, and the coils wound on the first casing and the second casing may be directly wound on the outside of the three stacked core components of the first group and the second group, respectively.
  • the current transformer may further include one or more fasteners for fixing the first and second transformer assemblies together when the interfaces are connected to each other.
  • the fastener may be a bolt and a nut or any other suitable element for fastening connection, which is not limited in this application.
  • the user may first disconnect the connection between the first interface and the third interface and / or the second interface and the fourth interface, so that the current transformer 100 is in a disassembled state.
  • the first transformer component 1011 and the second transformer component 1012 are at least partially separated, so that the cable under test can be placed between the two transformer components through the gap between the disconnected interfaces.
  • the operator can then reconnect the disconnected interface, reinstall the two transformer assemblies as a closed current transformer 100, and pass the cable under test through the enclosed area defined between the two transformer assemblies and maintain the Enclosed area.
  • an induced current related to the measured current is generated in the coil wound on the closed toroidal core.
  • a convenient and accurate measurement of the current in the cable under test can be achieved.
  • a multi-core current transformer that can be disassembled into two separate transformer components is provided, and the tested cable can enter and pass through the current transformer without powering down the device under test.
  • the enclosed area in the instrument makes it easy to measure the DC and AC components of the current in the cable under test.
  • This measurement device is particularly suitable for measurement of equipment that is not easy to power off and start, for example, it is particularly suitable for new energy sources such as solar power generation testing, medical instrument testing, electric vehicle testing, power analysis, and power quality testing.
  • FIG. 6 shows a circuit 200 for measuring current using the detachable multi-core current transformer described in FIGS. 1-5.
  • the circuit 200 includes a detachable multi-core current transformer 220 in a connected state, which includes three closed ring-shaped cores 221, 222, and 223 that are sequentially stacked.
  • the specific structure of the current transformer 220 has been described in detail above with reference to FIGS. 1-5.
  • FIG. 6 only shows the three closed toroidal cores of the current transformer in the connected state, and is wound around each The coil on the iron core, and other parts of the current transformer are hidden.
  • a coil W1 is wound on the iron core 221, a coil W2 is wound on the iron core 222, a coil W3 is wound on the iron core 223, and a coil W4 is wound on a case (not shown) that closes the three iron cores.
  • the coil has the same name
  • the ends are marked with black dots in the figure.
  • the cable under test 210 passes through the inner area inside the three closed ring cores, and the primary current I P flows through the cable under test 210. It should be understood that the circuit shown in FIG. 6 may also be implemented using a current transformer with two iron cores or with four iron cores or another number of iron cores.
  • the circuit 200 further includes an oscillator 230, which is coupled to the same-named end of the coil W1 and the non-same-named end of the coil W2 for driving the iron core 221 and the iron core 222.
  • the non-same name terminal of the coil W1 and the same name terminal of the coil W2 are respectively coupled to the first input terminal and the second input terminal of the peak detector 240, and the first input terminal and the second input terminal of the peak detector 240 are respectively connected through resistors. R1 and resistor R2 are connected to ground.
  • the output of the peak detector 240 is coupled to the first input of the power amplifier 250.
  • the first input of the power amplifier 250 is also coupled to the same-named terminal of the coil W3, the second input of the power amplifier 250 and the coil W3.
  • the non-same names are grounded separately.
  • the output terminal of the power amplifier 250 is coupled to the same-named terminal of the coil W4.
  • the circuit 200 flows through the cable under test primary current I P 210 to generate a magnetic flux in the core, the magnetic fluxes are offset in the secondary winding W4 current I S. Any remaining magnetic flux will be sensed by the three closed toroidal cores 221, 222, and 223 wound with a coil.
  • the iron core 221 and the iron core 222 are used to sense a direct current (DC) part of the residual magnetic flux, and the iron core 223 is used to sense an alternating current (AC) part of the residual magnetic flux.
  • the oscillator 230 drives the two iron cores (221, 222) for direct current part in the induced current into the saturation state in opposite directions. If the remaining DC magnetic flux is 0, the peak value of the generated current in both directions is equal; if the remaining DC magnetic flux is not 0, the difference between the peaks is proportional to the remaining DC magnetic flux.
  • the peak detector 240 is a double-peak detector for measuring a DC component in the primary current I P by comparing the peak values of the currents in two directions.
  • the iron core 223 is used to sense the AC component of the primary current I P and generate an induced current in the coil W3.
  • the output of the peak detector 240 after adding the AC component induced by the iron core 223 forms a control loop to generate secondary
  • the stage current I S is such that the magnetic flux is zero.
  • the power amplifier 250 is supplied to the secondary coil current I S W4.
  • the secondary current I S is a mirror current proportional to the primary current I P , and the measurement of the measured current I P can be achieved by measuring the secondary current I S.
  • the non-same name end of the coil W4 is connected to the load resistor 260 to convert the current signal in W4 to a voltage. Both ends of the load resistor 260 are also coupled to two input terminals of the precision amplifier 270.
  • the precision amplifier 270 is a very stable differential amplifier, which produces a highly accurate output voltage, which is proportional to the secondary current I S , so it can be used to characterize the primary current I P in the cable under test.
  • the number of turns of the coils W1, W2, W3, and W4 shown in FIG. 6 is only schematic. In practice, the present invention can be implemented by selecting an appropriate number of turns according to actual needs.
  • FIG. 6 shows a circuit for sensing current based on peak detection. It should be understood that the detachable multi-core current transformer disclosed in this application can also be used in other suitable current measurement circuits, such as a circuit based on self-excited oscillation detection, a circuit based on second harmonic detection, and the like.
  • the current transformers in FIGS. 1-5 can also be implemented with other numbers of iron cores.
  • the detachable multi-core current transformer may have two cores, and its structure is substantially the same as that of the detachable three-core current transformer described in reference to FIGS. 1-5, except that the first group
  • Each of the core components and the second plurality of core components each have two core components. In this way, when the first transformer component and the second transformer component are connected to each other, two closed annular cores can be formed, and each closed annular core is wound with a coil, which is equivalent to the coils W1 and W1 in FIG. 6. W2.
  • the detachable multi-core current transformer may also have four cores, and the structure is substantially the same as that of the detachable three-core current transformer described in reference to FIGS. 1-5, except that the first group Each of the core members and the second plurality of core members each have four core members.
  • the first transformer component and the second transformer component are connected to each other, four closed ring cores can be formed, and each closed ring core is wound with a coil, which is equivalent to the coil W1 in FIG. 6. W2, W3, and W4.
  • W2 W3, and W4 When the cable under test passes through the enclosed area defined between the two transformer components, the current in the cable under test can be measured by measuring the induced current in the coil equivalent to W4.

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Abstract

本申请公开了一种电流互感器，其包括第一互感器组件和第二互感器组件。第一互感器组件包括：第一组堆叠的多个铁芯部件，在第一互感器组件的末端处限定第一接口和第二接口。第二互感器组件包括：第二组堆叠的多个铁芯部件，在第二互感器组件的末端处限定第三接口和第四接口。第一接口和第二接口中的至少一个与第三接口和第四接口中的至少一个可拆卸地连接。第一互感器组件和第二互感器组件互相连接时，第一组多个铁芯部件与第二组多个铁芯部件组合形成多个闭合环形铁芯，并且在至少两个闭合环形铁芯上分别绕有线圈。在第一互感器组件和第二互感器组件之间限定的封闭区域使得在至少一个线圈中产生感生电流。

Description

电流互感器 技术领域
本申请涉及电子测量技术，更具体地，涉及一种可拆卸的电流互感器。
背景技术
随着各种电力系统在工业生产和日常生活中的广泛运用，需要能够准确、方便测量电流的装置以监控电力系统的安全有效运行。传统的环形电流互感器只能用于测量交流电流，无法测量直流电流，并且当测量频率较低的交流电流时也会产生较大误差。因此，在同时存在直流和交流电流的场合，需要一种可以同时准确测量电流的交流分量和直流分量的仪器。
目前，出现了具有多个环形铁芯的电流互感器，这种电流互感器能够同时测量通过其环形铁芯的导线中电流的交流分量和直流分量，并具有较高的测量精度。然而，在用这种多铁芯电流互感器进行测量时，为使被测导线能够通过互感器中的封闭区域，需要先将导线的至少一个端部从电路中断开，这会造成系统的暂时性断电。在许多情况下，这种暂时性的断电会带来很大的经济损失甚至安全隐患。
因此，需要一种能够在不需断电的情况下精确测量被测电缆中电流的仪器。
发明内容
本申请的目的在于提供一种可拆卸的多铁芯电流互感器，以在不需断电的情况下测量被测电缆中的电流。
本申请公开了一种电流互感器，其包括：第一互感器组件和第二互感器组件，所述第一互感器组件的两端带有第一组件末端和第二组件末端，并且所述第一互感器组件包括第一组堆叠的多个铁芯部件，所述第一组多个铁芯部件在所述第一组件末端处限定第一接口，在所述第二组件末端处限定第二接口；所述第二互感器组件的两端带有第三组件末端和第四组件末端，并且所述第二互感器组件包括第二组堆叠的多个铁芯部件，所述第二组多个铁芯部件在所述第三组件末端处限定第三接口，在所述第四 组件末端处限定第四接口。其中所述第一接口和第二接口中的至少一个与所述第三接口和第四接口中的至少一个可拆卸地连接，以可拆卸地连接所述第一互感器组件与所述第二互感器组件；并且所述第一互感器组件和所述第二互感器组件被配置为当其相互连接时，所述第一组铁芯部件与所述第二组铁芯部件组合形成多个闭合环形铁芯，并且在所述多个闭合环形铁芯中的至少两个闭合环形铁芯上分别绕有线圈；所述第一互感器组件与所述第二互感器组件之间限定封闭区域，以使被测电缆通过所述封闭区域，从而在所述线圈中的至少一个线圈中产生与所述被测电缆中的电流相关的感生电流。
在一些实施例中，在所述多个闭合环形铁芯的外部绕有至少一个线圈，其被配置为在被测电缆通过所述封闭区域时产生与所述被测电缆中的电流相关的感生电流。
在一些实施例中，所述第一组多个铁芯部件包括两个铁芯部件，所述第二组多个铁芯部件包括两个铁芯部件，当所述第一互感器组件与所述第二互感器组件相互连接时，所述第一组多个铁芯部件的两个铁芯部件与所述第二组多个铁芯部件的两个铁芯部件组合形成两个闭合环形铁芯，并且在每个闭合环形铁芯上都分别绕有一个线圈，而在所述两个闭合环形铁芯的外部还绕有两个线圈。
在一些实施例中，所述第一组多个铁芯部件包括三个铁芯部件，所述第二组多个铁芯部件包括三个铁芯部件，当所述第一互感器组件与所述第二互感器组件相互连接时，所述第一组多个铁芯部件的三个铁芯部件与所述第二组多个铁芯部件的三个铁芯部件组合形成三个闭合环形铁芯，并且在每个闭合环形铁芯上都分别绕有一个线圈，在所述三个闭合环形铁芯的外部绕有一个线圈。
在一些实施例中，所述第一组多个铁芯部件包括四个铁芯部件，所述第二组多个铁芯部件包括四个铁芯部件，当所述第一互感器组件与所述第二互感器组件相互连接时，所述第一组多个铁芯部件的四个铁芯部件与所述第二组多个铁芯部件的四个铁芯部件组合形成四个闭合环形铁芯，并且在每个闭合环形铁芯上都分别绕有一个线圈。
在一些实施例中，所述第一互感器组件还包括第一外壳，所述第一外壳用于将所述第一组多个铁芯部件限定在其中；所述第二互感器组件还包括第二外壳，所述第二外壳用于将所述第二组多个铁芯部件限定在其中；所述第一外壳和所述第二外壳被配置为当所述第一互感器组件与所述第二互感器组件互相连接时，所述第一外壳与所述第二外壳组合形成闭合环形壳体，将所述多个闭合环形铁芯容纳在其中，所述多个闭合环形铁芯的外部缠绕的所述至少一个线圈被缠绕在所述闭合环形壳体上。
在一些实施例中，所述第一接口和第二接口中的至少一个和所述第三接口和第四接口中的至少一个都具有叉指状结构，以在接口相互连接时能够以交错接合方式相互连接。
在一些实施例中，所述第一接口、第二接口、第三接口和第四接口中的每个都具有导向件以引导所述接口的连接。
在一些实施例中，每个接口的所述导向件都包括多个导向元件，每个导向元件都围绕所述第一组多个铁芯部件或第二组多个个铁芯部件中的一个铁芯部件的一端，并且每个导向元件都具有一对凸部和凹部，当所述接口与另一个接口连接时，所述一对凸部和凹部与所述另一个接口的导向元件的一对凸部和凹部相配合。
在一些实施例中，所述电流互感器还包括一个或多个紧固件，用于当所述接口相互连接时将所述第一互感器组件和第二互感器组件固定在一起。
在一些实施例中，所述第一接口与所述第三接口可拆卸地连接，所述第二接口与所述第四接口可拆卸地连接。
在一些实施例中，所述第一互感器组件和第二互感器组件具有半圆环形的形状。
在一些实施例中，所述第一组多个铁芯部件中的至少两个铁芯部件上和所述第二组多个铁芯部件中的至少两个铁芯部件上都绕有线圈，当所述第一互感器组件与所述第二互感器组件相互连接时，所述多个闭合环形铁芯中的至少两个闭合环形铁芯上分别缠绕的线圈是由所述第一组多个铁芯部件中至少两个铁芯部件上的线圈与所述第二组多个铁芯部件中对应的至少两个铁芯部件上的线圈相互连接形成的。
在一些实施例中，所述第一组多个铁芯部件的外部绕有至少一个线圈，所述第二组多个铁芯部件的外部绕有至少一个线圈，当所述第一互感器组件与所述第二互感器组件相互连接时，缠绕在所述多个闭合环形铁芯的外部的至少一个线圈是由缠绕在所述第一组多个铁芯部件外部的所述至少一个线圈与缠绕在所述第二组多个铁芯部件外部的对应的所述至少一个线圈相互连接形成的。
在一些实施例中，所述第一组多个铁芯部件中的每个铁芯部件上缠绕的线圈大体在从所述第一组件末端到所述第二组件末端之间的整个长度上延伸。
在一些实施例中，所述第二组多个铁芯部件中的每个铁芯部件上缠绕的线圈大体在从所述第三组件末端到所述第四组件末端之间的整个长度上延伸。
在一些实施例中，所述第一组多个铁芯部件和所述第二组多个铁芯部件中的至少一个铁芯部件由铁镍合金材料制成。
在一些实施例中，所述第一互感器组件和所述第二互感器组件的铁芯部件和线圈外具有金属屏蔽层，用于屏蔽外部电场。
在一些实施例中，所述第一互感器组件还包括第一外壳，所述第一外壳用于将所述第一组多个铁芯部件限定在其中，并且所述第一外壳被容纳在所述金属屏蔽层中； 所述第二互感器组件还包括第二外壳，所述第二外壳用于将所述第二组多个铁芯部件限定在其中，并且所述第二外壳被容纳在所述金属屏蔽层中。
以上为本申请的概述，可能有简化、概括和省略细节的情况，因此本领域的技术人员应该认识到，该部分仅是示例说明性的，而不旨在以任何方式限定本申请范围。本概述部分既非旨在确定所要求保护主题的关键特征或必要特征，也非旨在用作为确定所要求保护主题的范围的辅助手段。
附图说明
通过下面说明书和所附的权利要求书并与附图结合，将会更加充分地清楚理解本申请内容的上述和其他特征。可以理解，这些附图仅描绘了本申请内容的若干实施方式，因此不应认为是对本申请内容范围的限定。通过采用附图，本申请内容将会得到更加明确和详细的说明。
图1示出了根据本申请一个实施例的可拆卸多铁芯电流互感器的整体结构示意图；
图2示出了图1所示的电流互感器中的一个互感器组件的结构示意图；
图3示出了图1所示的电流互感器中的一个互感器组件的部件分解示意图；
图4示出了图1所示的电流互感器中的一个互感器组件的接口示意图；
图5示出了图1所示的电流互感器中的三个闭合环形铁芯在安装完成后的结构示意图；
图6示出了根据本申请的另一个实施例的用于感测被测电缆中的初级电流的电路的示意图。
具体实施方式
在下面的详细描述中，参考了构成其一部分的附图。在附图中，类似的符号通常表示类似的组成部分，除非上下文另有说明。详细描述、附图和权利要求书中描述的说明性实施方式并非旨在限定。在不偏离本申请的主题的精神或范围的情况下，可以采用其他实施方式，并且可以做出其他变化。可以理解，可以对本申请中一般性描述的、在附图中图解说明的本申请内容的各个方面进行多种不同构成的配置、替换、组合，设计，而所有这些都明确地构成本申请内容的一部分。
图1至图5示出了根据本申请一个实施例的可拆卸多铁芯电流互感器100。其中， 图1示出了该可拆卸多铁芯电流互感器的总体结构示意图；图2和图3示出了该可拆卸多铁芯电流互感器中的一个互感器组件(例如，第一互感器组件)的结构示意图；图4示出了该可拆卸多铁芯电流互感器中的一个互感器组件(例如，第一互感器组件)的接口示意图；图5示出了该可拆卸多铁芯电流互感器中的三个闭合环形铁芯在连接后的结构示意图。应当理解，本申请附图中示出的具有三个铁芯的电流互感器仅仅是示例性的，具有两个铁芯或者四个铁芯或者其他数目铁芯的可拆卸多铁芯电流互感器也可以用来同时测量被测电缆中电流的交流和直流分量。
如图1所示，电流互感器100包括第一互感器组件1011和第二互感器组件1012，第一互感器组件1011的形状大体为半环形，其两端分别为第一组件末端和第二组件末端。第二互感器组件1012的形状大体为半环形，其两端分别为第三组件末端和第四组件末端。这两个互感器组件1011和1012连接后大体呈圆环形。在一些实施例中，第一互感器组件1011也可以是延伸弧度不超过180度的半环形，例如为约120度的弧形或者其他弧度的弧形，相应地，第二互感器组件1012可以是延伸弧度超过180度的半环形，例如延伸为约240度的弧形或者其他弧度的弧形。两个互感器组件1011和1012还可以具有其他合适的形状，只要在连接后，它们之间能限定可以使被测电缆通过的封闭区域即可。
第一互感器组件1011包括第一外壳1041，第二互感器组件1012包括第二外壳1042，第一和第二外壳上分别缠绕有线圈。第一组件末端、第二组件末端、第三组件末端和第四组件末端分别带有第一接口1021、第二接口1031、第三接口1022和第四接口1032。第一接口1021可以与第三接口1022可拆卸地连接，第二接口1031可以与第四接口1032可拆卸地连接，从而方便地安装和拆卸两个互感器组件，使电流互感器100可以在拆开和闭合状态之间切换。在一些实施例中，可以仅在第一外壳上缠绕线圈，或者仅在第二外壳上缠绕线圈。
在一些实施例中，只有第一接口1021与第三接口1022之间的连接可以被断开，第二接口1031与第四接口1032之间始终保持连接，使得电流互感器100处于拆开状态时，两个互感器组件之间可以部分地分离。在实际测量时，只要第一接口1021与第三接口1022断开后的间隙大于被测电缆的直径，从而允许被测电缆通过该间隙即可。在一些替换的实施例中，只有第二接口1031和第四接口1032之间的连接可以被断开。
如图2-图3所示，第一互感器组件1011包括第一组三个铁芯部件1051、1061和1071，这三个铁芯部件被封闭在第一外壳1041中。在本实施例中，三个铁芯部件都是 大体半环形的形状，且具有大体相同的尺寸，并上下堆叠在一起，使每个铁芯部件的两端都彼此互相对齐，同时相邻铁芯部件之间彼此电隔离。铁芯部件由如铁、镍或铁镍合金等的磁性材料制成，该磁性材料优选为铁镍合金类材料，如坡莫合金。可选地，在第一外壳1041外还具有金属屏蔽层(未在图中示出)，其容纳了第一外壳1041、第一组三个铁芯部件以及每个铁芯部件和第一外壳上的线圈，用于保护铁芯不受外部电场的影响。在一些替代性的实施例中，金属屏蔽层包括在第一外壳1041中。
每个铁芯部件1051、1061或1071上都缠绕有线圈(未在图中示出)，并且可选地，每个铁芯部件上缠绕的线圈大体在从第一组件末端到第二组件末端之间的整个长度上延伸。每个铁芯部件的两端分别在第一接口1021和第二接口1031处具有叉指状结构用于与第三接口1022和第四接口1032的叉指状结构交错连接。叉指状结构间可以具有很高的配合精度，例如，叉边间的单边间隙可以小到0.05mm。
第一接口1021和第二接口1031处可以具有导向件，用于引导接口之间的连接。例如，如图4所示，第一接口1021处的导向件包括三个导向元件，每个导向元件都围绕第一组三个铁芯部件中的一个铁芯部件的一端，用于引导第一接口1021与第三接口1022的连接。以第一接口1021处围绕铁芯部件1051(未在图4中示出)一端的一个导向元件1081为例，导向元件1081包括一个凸部1111和一个凹部1121，分别位于铁芯部件1051一端的叉指状结构1091的两侧，当第一接口1021与例如第三接口1022(未在图4中示出)连接时，凸部1111与第三接口1022的导向元件的一个凹部相配合，凹部1121与第三接口1022的导向元件的一个凸部相配合。第一接口1021处的其他两个导向元件以及第二接口1031处的三个导向元件都具有与导向元件1081相同的结构，在此不再赘述。根据需要，在一个接口处可以包括其他数量的导向元件，例如第一接口1021和第二接口1031处可以都只包括一个导向元件。同时，导向件也可以具有其他合适的结构，例如可以具有轴-槽配合结构。接口处的导向件可以安装在第一互感器组件的第一外壳、屏蔽层或其它部件上。
第二互感器组件1012包括封闭在第二外壳1042中的第二组三个铁芯部件(未在图2-图3中示出)等部件，第二互感器组件1012及其各部件的形状、结构等都与第一互感器组件1011相同或与第一互感器组件1011相匹配，在此不再赘述。第二组三个铁芯部件中的每个铁芯部件都与第一组三个铁芯部件中的一个铁芯部件相对应。
当第一互感器组件1011的两个接口与第二互感器组件1012的两个接口分别相互连接时，接口处的叉指结构可以相互交错接合，从而形成三个堆叠的闭合环形铁芯105、 106和107(参见图5)。闭合环形铁芯的形状可以是大体圆环形的，也可以是其它合适的具有闭环的形状。第一外壳1041与第二外壳1042连接，形成一个闭合环形壳体，并将三个闭合环形铁芯容纳在其中。第一接口1021处的三个导向元件分别与第二接口1022处的三个导向元件相配合，第二接口1031处的三个导向元件分别与第四接口1032处的三个导向元件相配合，使得每个导向元件中的凸部都插入相应导向元件中的凹部中，从而引导各接口在连接时对齐，并防止移位。每个铁芯部件上的线圈的一端都分别与另一互感器组件上相应的铁芯部件上的线圈的一端连接，从而使每个堆叠的闭合环形铁芯上都缠绕有一个完整的线圈，这有利于电流的感测。类似地，在安装后，第一外壳1041上缠绕的线圈的一端与第二外壳1042上缠绕的线圈的一端也在接口处相互连接，从而形成缠绕在完整外壳上的完整线圈。
在一些实施例中，对于至少一个闭合环形铁芯，组成闭合环形铁芯的两个相应的铁芯部件中只有一个铁芯部件上绕有线圈，即某些闭合环形铁芯上只有半边绕有线圈，另半边没有线圈缠绕。符合此种设计的电流互感器也可以实现对电流的直流分量和交流分量的测量。
在一些实施例中，可以省去第一外壳和第二外壳，缠绕在第一外壳和第二外壳上的线圈可以直接分别缠绕在第一组和第二组三个堆叠的铁芯部件的外部。
在一些实施例中，电流互感器中还可包括一个或多个紧固件，用于在各接口互相连接时，将第一和第二互感器组件固定在一起。所述紧固件可以是螺栓和螺母或其他任意用于紧固连接的合适元件，本申请对此不做限制。
当需要测量被测电缆中的电流时，使用者可以先断开第一接口与第三接口之间和/或第二接口与第四接口之间的连接，使电流互感器100处于拆开状态，第一互感器组件1011和第二互感器组件1012至少部分地分离，从而可以将被测电缆通过被断开的接口间的缺口而置于两个互感器组件之间。操作者然后可以重新连接被断开的接口，使两个互感器组件重新安装为闭合的电流互感器100，并且使被测电缆穿过两个互感器组件之间限定的封闭区域并且保持在该封闭区域中。当被测电缆中有电流流过时，闭合环形铁芯上缠绕的线圈中会产生与该被测电流相关的感应电流。特别是，通过测量闭合环形壳体上的线圈中的感应电流，可以实现对被测电缆中电流方便而精确的测量。
在本实施例中，提供了一种可拆开为两个分离的互感器组件的多铁芯电流互感器，不需让被测设备断电就可以使被测电缆进入并穿过电流互感器中的封闭区域，从而方 便地对被测电缆中电流的直流和交流分量进行测量。这种测量设备特别适合用于不便于断电、启动的设备的测量，例如特别适合用于新能源如太阳能发电检测、医疗仪器检测、电动汽车试验、功率分析、电能质量检测等。
图6示出了一种使用图1-图5中所述的可拆卸多铁芯电流互感器来测量电流的电路200。电路200中包括处于连接状态的可拆卸多铁芯电流互感器220，其包括依次堆叠的三个闭合环形铁芯221、222和223。电流互感器220的具体结构已在上文中参考图1-图5详细描述，为清楚起见，图6中仅示出了连接状态的电流互感器中的三个闭合环形铁芯，以及缠绕在各铁芯上的线圈，而隐去了电流互感器中的其它部件。铁芯221上绕有线圈W1，铁芯222上绕有线圈W2，铁芯223上绕有线圈W3，封闭上述三个铁芯的壳体(未示出)上绕有线圈W4，线圈的同名端在图中用黑色圆点标记出。被测电缆210从三个闭合环形铁芯内部的内部区域中穿过，初级电流I P从被测电缆210中流过。应当理解，也可以使用具有两个铁芯或具有四个铁芯或者其他数目的铁芯的电流互感器来实施图6中所示的电路。
电路200中还包括振荡器230，所述振荡器230被耦接到线圈W1的同名端和线圈W2的非同名端，用于驱动铁芯221和铁芯222。线圈W1的非同名端和线圈W2的同名端分别被耦接到峰值检测器240的第一输入端和第二输入端，峰值检测器240的第一输入端和第二输入端还分别通过电阻R1和电阻R2接地。峰值检测器240的输出端被耦接到功率放大器250的第一输入端，功率放大器250的第一输入端还被耦接到线圈W3的同名端，功率放大器250的第二输入端和线圈W3的非同名端都分别接地。功率放大器250的输出端被耦接到线圈W4的同名端。
在电路200中，流过被测电缆210的初级电流I P在铁芯中产生磁通量，该磁通量被线圈W4中的次级电流I S所抵消。任何剩余的磁通量都会被绕有线圈的三个闭合环形铁芯221、222和223所感应。
铁芯221和铁芯222用于感应剩余磁通量的直流(DC)部分，铁芯223则用于感应剩余磁通量的交流(AC)部分。振荡器230以相反的方向驱动两个用于感应电流中直流部分的铁芯(221、222)进入饱和状态。如果剩余的直流磁通量为0，所产生的电流在两个方向的峰值相等；如果剩余的直流磁通量不为0，峰值之间的差值与剩余的直流磁通量成正比。峰值检测器240是双峰值检测器，用于通过比较两个方向电流的峰值，而测量初级电流I P中的直流分量。铁芯223用于感应初级电流I P中的交流分量，并在线圈W3中生成感应电流，峰值检测器240的输出在加上由铁芯223感应的 交流分量后，形成了控制回路以生成次级电流I S以使磁通量为零。功率放大器250将该次级电流I S提供到线圈W4。该次级电流I S是与初级电流I P成比例的镜像电流，通过对该次级电流I S的测量可以实现对被测电流I P的测量。
在一些实施例中，线圈W4的非同名端被连接到负载电阻260以将W4中的电流信号转换为电压。负载电阻260的两端还被耦接到精密放大器270的两个输入端。精密放大器270是非常稳定的差分放大器，其产生准确性很高的输出电压，该输出电压与次级电流I S成正比，因此可用来表征被测电缆中的初级电流I P。
图6中示出的线圈W1、W2、W3和W4缠绕的匝数只是示意性的，在实践中，可以根据实际需要选择适当的匝数来实施本发明。
图6示出了基于峰值检测的用于感测电流的电路。应当理解，本申请所公开的可拆卸多铁芯电流互感器还可以用于其他合适的电流测量电路中，比如基于自激振荡检测的电路、基于二次谐波检测的电路等。
在实践中，图1-图5中的电流互感器也可以被实施为具有其它数量的铁芯。在一些实施例中，可拆卸多铁芯电流互感器可以具有两个铁芯，其结构与参考图1-图5中所述的可拆卸三铁芯电流互感器大体相同，除了第一组多个铁芯部件和第二组多个铁芯部件中都分别具有两个铁芯部件。这样，当第一互感器组件与第二互感器组件相互连接时，可以形成两个封闭的环形铁芯，每个封闭环形铁芯上分别绕有一个线圈，相当于图6中的线圈W1和W2。两个封闭环形铁芯的外部还绕有两个线圈，分别相当于图6中的线圈W3和W4。当被测电缆穿过两个互感器组件之间限定的封闭区域中时，可以通过测量相当于W4的线圈中的感应电流以测量被测电缆中的电流。
在一些实施例中，可拆卸多铁芯电流互感器还可以具有四个铁芯，结构与参考图1-图5中所述的可拆卸三铁芯电流互感器大体相同，除了第一组多个铁芯部件和第二组多个铁芯部件中都分别具有四个铁芯部件。这样，当第一互感器组件与第二互感器组件相互连接时，可以形成四个封闭的环形铁芯，每个封闭环形铁芯上分别绕有一个线圈，相当于图6中的线圈W1、W2、W3和W4。当被测电缆穿过两个互感器组件之间限定的封闭区域中时，可以通过测量相当于W4的线圈中的感应电流以测量被测电缆中的电流。
应当注意，尽管在上文详细描述中提及了电流互感器和使用电流互感器的电流测量电路的若干模块或子模块，但是这种划分仅仅是示例性的而非强制性的。实际上，根据本申请的实施例，上文描述的两个或更多模块的特征和功能可以在一个模块中具 体化。反之，上文描述的一个模块的特征和功能可以进一步划分为由多个模块来具体化。
那些本技术领域的一般技术人员可以通过研究说明书、公开的内容及附图和所附的权利要求书，理解和实施对披露的实施方式的其他改变。在权利要求中，措词“包括”不排除其他的元素和步骤，并且措辞“一”、“一个”不排除复数。在本申请的实际应用中，一个元件可能执行权利要求中所引用的多个技术特征的功能。权利要求中的任何附图标记不应理解为对范围的限制。

Claims (19)

  1. 一种电流互感器，其特征在于，所述电流互感器包括：
    第一互感器组件，所述第一互感器组件的两端带有第一组件末端和第二组件末端，并且所述第一互感器组件包括第一组堆叠的多个铁芯部件，所述第一组多个铁芯部件在所述第一组件末端处限定第一接口，在所述第二组件末端处限定第二接口；和
    第二互感器组件，所述第二互感器组件的两端带有第三组件末端和第四组件末端，并且所述第二互感器组件包括第二组堆叠的多个铁芯部件，所述第二组多个铁芯部件在所述第三组件末端处限定第三接口，在所述第四组件末端处限定第四接口；
    其中所述第一接口和第二接口中的至少一个与所述第三接口和第四接口中的至少一个可拆卸地连接，以可拆卸地连接所述第一互感器组件与所述第二互感器组件；并且
    所述第一互感器组件与所述第二互感器组件被配置为当其相互连接时，所述第一组多个铁芯部件与所述第二组多个铁芯部件组合形成多个闭合环形铁芯，并且在所述多个闭合环形铁芯中的至少两个闭合环形铁芯上分别绕有线圈；所述第一互感器组件与所述第二互感器组件之间限定封闭区域，以使被测电缆通过所述封闭区域，从而在所述线圈中的至少一个线圈中产生与所述被测电缆中的电流相关的感生电流。
  2. 根据权利要求1所述的电流互感器，其特征在于，在所述多个闭合环形铁芯的外部绕有至少一个线圈，其被配置为在被测电缆通过所述封闭区域时产生与所述被测电缆中的电流相关的感生电流。
  3. 根据权利要求2所述的电流互感器，其特征在于，所述第一组多个铁芯部件包括两个铁芯部件，所述第二组多个铁芯部件包括两个铁芯部件，当所述第一互感器组件与所述第二互感器组件相互连接时，所述第一组多个铁芯部件的两个铁芯部件与所述第二组多个铁芯部件的两个铁芯部件组合形成两个闭合环形铁芯，并且在每个闭合环形铁芯上都分别绕有一个线圈，而在所述两个闭合环形铁芯的外部还绕有两个线圈。
  4. 根据权利要求2所述的电流互感器，其特征在于，所述第一组多个铁芯部件包括三个铁芯部件，所述第二组多个铁芯部件包括三个铁芯部件，当所述第一互感器组件 与所述第二互感器组件相互连接时，所述第一组多个铁芯部件的三个铁芯部件与所述第二组多个铁芯部件的三个铁芯部件组合形成三个闭合环形铁芯，并且在每个闭合环形铁芯上都分别绕有一个线圈，而在所述三个闭合环形铁芯的外部还绕有一个线圈。
  5. 根据权利要求1所述的电流互感器，其特征在于，所述第一组多个铁芯部件包括四个铁芯部件，所述第二组多个铁芯部件包括四个铁芯部件，当所述第一互感器组件与所述第二互感器组件相互连接时，所述第一组多个铁芯部件的四个铁芯部件与所述第二组多个铁芯部件的四个铁芯部件组合形成四个闭合环形铁芯，并且在每个闭合环形铁芯上都分别绕有一个线圈。
  6. 根据权利要求2-4中任意一项所述的电流互感器，其特征在于，
    所述第一互感器组件还包括第一外壳，所述第一外壳用于将所述第一组多个铁芯部件限定在其中；
    所述第二互感器组件还包括第二外壳，所述第二外壳用于将所述第二组多个铁芯部件限定在其中；
    所述第一外壳和所述第二外壳被配置为当所述第一互感器组件与所述第二互感器组件互相连接时，所述第一外壳与所述第二外壳组合形成闭合环形壳体，从而将所述多个闭合环形铁芯容纳在其中，所述多个闭合环形铁芯的外部缠绕的所述至少一个线圈被缠绕在所述闭合环形壳体上。
  7. 根据权利要求1-5中任意一项所述的电流互感器，其特征在于，所述第一接口和第二接口中的至少一个和所述第三接口和第四接口中的至少一个都具有叉指状结构，以在接口相互连接时能够以交错接合方式相互连接。
  8. 根据权利要求1-5中任意一项所述的电流互感器，其特征在于，所述第一接口、第二接口、第三接口和第四接口中的每个都具有导向件以引导所述接口的连接。
  9. 根据权利要求8所述的电流互感器，其特征在于，每个接口的所述导向件都包括多个导向元件，每个导向元件都围绕所述第一组多个铁芯部件或第二组多个铁芯部件中的一个铁芯部件的一端，并且每个导向元件都具有一对凸部和凹部，当所述接口与另一个接口连接时，所述一对凸部和凹部与所述另一个接口的导向元件的一对凸部和 凹部相配合。
  10. 根据权利要求1-5中任意一项所述的电流互感器，其特征在于，所述电流互感器还包括一个或多个紧固件，用于当接口相互连接时将所述第一互感器组件和所述第二互感器组件固定在一起。
  11. 根据权利要求1-5中任意一项所述的电流互感器，其特征在于，所述第一接口与所述第三接口可拆卸地连接，所述第二接口与所述第四接口可拆卸地连接。
  12. 根据权利要求1-5中任意一项所述的电流互感器，其特征在于，所述第一互感器组件和所述第二互感器组件具有半圆环形的形状。
  13. 根据权利要求1-5中任意一项所述的电流互感器，其特征在于，所述第一组多个铁芯部件中的至少两个铁芯部件上和所述第二组多个铁芯部件中的至少两个铁芯部件上都绕有线圈，当所述第一互感器组件与所述第二互感器组件相互连接时，所述多个闭合环形铁芯中的至少两个闭合环形铁芯上分别缠绕的线圈是由所述第一组多个铁芯部件中至少两个铁芯部件上的线圈与所述第二组多个铁芯部件中对应的至少两个铁芯部件上的线圈相互连接形成的。
  14. 根据权利要求2-4中任意一项所述的电流互感器，其特征在于，所述第一组多个铁芯部件的外部绕有至少一个线圈，所述第二组多个铁芯部件的外部绕有至少一个线圈，当所述第一互感器组件与所述第二互感器组件相互连接时，缠绕在所述多个闭合环形铁芯的外部的至少一个线圈是由缠绕在所述第一组多个铁芯部件外部的所述至少一个线圈与缠绕在所述第二组多个铁芯部件外部的对应的所述至少一个线圈相互连接形成的。
  15. 根据权利要求1-5中任意一项所述的电流互感器，其特征在于，所述第一组多个铁芯部件中的每个铁芯部件上缠绕的线圈在从所述第一组件末端到所述第二组件末端之间的整个长度上延伸。
  16. 根据权利要求1-5中任意一项所述的电流互感器，其特征在于，所述第二组多个铁 芯部件中的每个铁芯部件上缠绕的线圈在从所述第三组件末端到所述第四组件末端之间的整个长度上延伸。
  17. 根据权利要求1-5中任意一项所述的电流互感器，其特征在于，所述第一组多个铁芯部件和所述第二组多个铁芯部件中的至少一个铁芯部件由铁镍合金材料制成。
  18. 根据权利要求1-5中任意一项所述的电流互感器，其特征在于，所述第一互感器组件和所述第二互感器组件的铁芯部件和线圈外具有金属屏蔽层，用于屏蔽外部电场。
  19. 根据权利要求18所述的电流互感器，其特征在于，
    所述第一互感器组件还包括第一外壳，所述第一外壳用于将所述第一组多个铁芯部件限定在其中，并且所述第一外壳被容纳在所述金属屏蔽层中；和
    所述第二互感器组件还包括第二外壳，所述第二外壳用于将所述第二组多个铁芯部件限定在其中，并且所述第二外壳被容纳在所述金属屏蔽层中。
PCT/CN2019/093544 2018-07-02 2019-06-28 电流互感器 Ceased WO2020007239A1 (zh)

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