EP0350255A1 - Circuit de transformateur - Google Patents

Circuit de transformateur Download PDF

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Publication number
EP0350255A1
EP0350255A1 EP89306770A EP89306770A EP0350255A1 EP 0350255 A1 EP0350255 A1 EP 0350255A1 EP 89306770 A EP89306770 A EP 89306770A EP 89306770 A EP89306770 A EP 89306770A EP 0350255 A1 EP0350255 A1 EP 0350255A1
Authority
EP
European Patent Office
Prior art keywords
current transformer
legs
core
air gap
transformer according
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.)
Withdrawn
Application number
EP89306770A
Other languages
German (de)
English (en)
Inventor
Geoffrey Thomas Glass0N
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.)
TE Connectivity Australia Pty Ltd
Original Assignee
Dulmison Pty 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
Publication date
Application filed by Dulmison Pty Ltd filed Critical Dulmison Pty Ltd
Publication of EP0350255A1 publication Critical patent/EP0350255A1/fr
Withdrawn legal-status Critical Current

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Classifications

    • 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

Definitions

  • This invention relates to an improved type of current transformer particularly suitable for installation on a long length of conductor without the need to open and reclose the iron core of the current transformer around the conductor.
  • a current transformer for use with long continuous conductors comprising a core having at least two legs extending therefrom to form an air gap through which the continuous conductor may pass, the surface area of said legs adjacent said air gap being substantially greater than the cross-sectional area of said core.
  • said legs are substantially plate-like in form in the region of the air gap.
  • This prior art current transformer fully encloses a continuous conductor 1 with a iron core 2 having a secondary winding 3.
  • Figure 2 depicts a current transformer which has a gap 4 in the iron core to facilitate installation on a conductor. However as discussed below the performance of this type of current transformer is markedly inferior to that depicted in Figure 1.
  • the performance of a current transformer depends on the reluctance of the magnetic circuit. It is desirable for this to be as low as possible.
  • the reluctance of the iron core in Figure 1 can be expressed by the following simplified formula.
  • R is the magnetic reluctance K is a constant l is the mean length of the flux path around the iron core a is the area of the iron core ⁇ is the relative permeability of the iron (with respect to air)
  • the reluctance can similarly be expressed by - where l s is the mean length of the flux path in the iron core, where l a is the length of the air gap.
  • This value is approximately 100 times the reluctance of the closed iron core with 99% of the reluctance being across the air gap.
  • the current transformer comprises an iron core 2 and a pair of plate-like leg portions 5 extending therefrom to form an air gap 4.
  • Each leg of the iron core is spread into substantially flat plates each having a surface area "A" many times greater than the cross-sectional area of the iron core "a” with the air gap l a gap between the plates sufficient to permit entry of the conductor 1.
  • the reluctance of the magnetic circuit can be expressed by - where a is the cross-sectional area of the iron core.
  • A is the surface area of the flat section of the iron on each side of the air gap.
  • a current transformer consisting of a flat iron core formed into a U-shape as depicted in Figure 4.
  • the common requirement is that the surface area of the flat section of iron 5 on each side of the air gap 4 is many times that of the cross-sectional area of the iron core 2.
  • FIG. 5 A further embodiment of this invention is shown in Figure 5.
  • the secondary winding 3 which consists of one or more turns of conductor with the ends of the conductor connected together to form a continuous path for electric current, is so arranged that it forms the primary circuit of a second current transformer 6.
  • This embodiment combines the advantages of the open current transformer as previously discussed with the convenience of winding a large number of turns on a conventional design of current transformer.
  • FIG. 6 A further embodiment of the invention is shown in Figure 6.
  • the extended parts of the iron core may be curved rather than flat.
  • the surface area of the iron core 5 on each side of the air gap 4 is still many times larger than the cross sectional area of the iron core 2.
  • the air gap 4 is substantially constant and of sufficient width to allow passage of the conductor 1.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Transformers For Measuring Instruments (AREA)
EP89306770A 1988-07-07 1989-07-04 Circuit de transformateur Withdrawn EP0350255A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
AU918388 1988-07-07
AU9183/88 1988-07-07

Publications (1)

Publication Number Publication Date
EP0350255A1 true EP0350255A1 (fr) 1990-01-10

Family

ID=3699918

Family Applications (1)

Application Number Title Priority Date Filing Date
EP89306770A Withdrawn EP0350255A1 (fr) 1988-07-07 1989-07-04 Circuit de transformateur

Country Status (1)

Country Link
EP (1) EP0350255A1 (fr)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105334428A (zh) * 2015-11-30 2016-02-17 国家电网公司 配电网线路故障检测系统及方法
CN105334429A (zh) * 2015-11-30 2016-02-17 国家电网公司 配电网线路故障检测方法
CN105374507A (zh) * 2015-11-30 2016-03-02 国家电网公司 弧形铁芯线圈电流互感器及其制作方法
CN105469569A (zh) * 2015-11-30 2016-04-06 国家电网公司 基于配电网线路的电流信息远程无线通信传输装置及方法
CN105510694A (zh) * 2015-11-30 2016-04-20 国家电网公司 配电网线路电流采集装置及方法
WO2016166050A1 (fr) * 2015-04-14 2016-10-20 Omicron Electronics Gmbh Transformateur, dispositif d'essai et procédé d'essai d'un objet en essai d'une installation électrotechnique

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR671744A (fr) * 1929-03-20 1929-12-18 Cfcmug Transformateur de courant
DE1220519B (de) * 1964-02-20 1966-07-07 Hans Ritz Dr Ing Stromwandler zum UEbergreifen stromfuehrender, festverlegter Leiter, insbesondere Kabel oder Schienen
DE2460254A1 (de) * 1974-12-19 1976-06-24 Siemens Ag Messwandler

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR671744A (fr) * 1929-03-20 1929-12-18 Cfcmug Transformateur de courant
DE1220519B (de) * 1964-02-20 1966-07-07 Hans Ritz Dr Ing Stromwandler zum UEbergreifen stromfuehrender, festverlegter Leiter, insbesondere Kabel oder Schienen
DE2460254A1 (de) * 1974-12-19 1976-06-24 Siemens Ag Messwandler

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2016166050A1 (fr) * 2015-04-14 2016-10-20 Omicron Electronics Gmbh Transformateur, dispositif d'essai et procédé d'essai d'un objet en essai d'une installation électrotechnique
CN105334428A (zh) * 2015-11-30 2016-02-17 国家电网公司 配电网线路故障检测系统及方法
CN105334429A (zh) * 2015-11-30 2016-02-17 国家电网公司 配电网线路故障检测方法
CN105374507A (zh) * 2015-11-30 2016-03-02 国家电网公司 弧形铁芯线圈电流互感器及其制作方法
CN105469569A (zh) * 2015-11-30 2016-04-06 国家电网公司 基于配电网线路的电流信息远程无线通信传输装置及方法
CN105510694A (zh) * 2015-11-30 2016-04-20 国家电网公司 配电网线路电流采集装置及方法
CN105374507B (zh) * 2015-11-30 2017-07-14 国家电网公司 弧形铁芯线圈电流互感器及其制作方法
CN105334429B (zh) * 2015-11-30 2018-02-23 国家电网公司 配电网线路故障检测方法
CN105334428B (zh) * 2015-11-30 2018-08-03 国家电网公司 配电网线路故障检测系统及方法
CN105510694B (zh) * 2015-11-30 2018-08-03 国家电网公司 配电网线路电流采集装置及方法
CN105469569B (zh) * 2015-11-30 2018-12-21 国家电网公司 基于配电网线路的电流信息远程无线通信传输装置及方法

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