EP0453637A1 - Stromwandler - Google Patents

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Publication number
EP0453637A1
EP0453637A1 EP90122325A EP90122325A EP0453637A1 EP 0453637 A1 EP0453637 A1 EP 0453637A1 EP 90122325 A EP90122325 A EP 90122325A EP 90122325 A EP90122325 A EP 90122325A EP 0453637 A1 EP0453637 A1 EP 0453637A1
Authority
EP
European Patent Office
Prior art keywords
burden
reactance
current transformer
capacitor
transformer
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Withdrawn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
EP90122325A
Other languages
English (en)
French (fr)
Inventor
Takahiro C/O Itami Seisakusho Mitsubishi Aoyama
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.)
Mitsubishi Electric Corp
Original Assignee
Mitsubishi Electric Corp
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 Mitsubishi Electric Corp filed Critical Mitsubishi Electric Corp
Publication of EP0453637A1 publication Critical patent/EP0453637A1/de
Withdrawn legal-status Critical Current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
    • 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

Definitions

  • This invention relates to current transformers, and more particularly to current transformers to which a burden is connected and which are installed in a power station or a substation for the measurement and protection purposes.
  • Fig. 1 is an equivalent circuit diagram showing the organization of a conventional current transformer which is shown, for example, in K.Kamita, "Substation”, The Newest Advanced Experiment Lectures, Vol. 13, 3rd ed., April 30, 1977, Denki Shoin. In Fig.
  • r1 represents the resistance portion of the primary side leakage impedance; x1, the reactance portion of the primary side leakage impedance; r2, the resistance portion (converted to the primary side equivalent) of the secondary side leakage impedance; x2, the reactance portion (converted to the primary side equivalent) of the secondary side leakage impedance; r3, the resitance portion (converted to the primary side equivalent) of the externally connected burden; x3, the reactance portion (converted to the primary side equivalent) of the externally connected burden; y0, the exciting admittance; i1, the primary current; i2, the secondary current; and i3, the exciting current.
  • the current transformer continuously supplies an apparent power equal to: i2 ⁇ i2 ⁇ (r2 + r3 + j x2 + j x3) , wherein i2 is proportional to the primary current i1.
  • the conventional transformer having an externally connected burden has the following disadvantages.
  • the primary current i1 and hence the secondary current i2 proportional thereto is large, or when the secondary side leakgae impedance, r2 + j x2 , or the externally connected burden, r3 + j x3 , is large, the dimension of the core of the transformer should be large enough to avoid the saturation thereof.
  • the current transformer comprises: a primary winding which forms part of the main circuit carrying the current to be measured; and secondary winding magnetically coupled to the primary winding; a burden coupled across the secondary winding; and a variable capacitor.
  • r1 represents the resistance portion of the primary side leakage impedance
  • x1 the reactance portion of the primary side leakage impedance
  • r2 the resistance portion (converted to the primary side equivalent) of the secondary side leakage impedance
  • x2 the reactance portion (converted to the primary side equivalent) of the secondary side leakage impedance
  • r3 the resistance portion (converted to the primary side equivalent) of the externally connected burden
  • x3 the reactance portion (converted to the primary side equivalent) of the externally connected burden
  • y0 the exciting admittance; i1, the primary current; i2, the secondary current; and i3, the exciting current.
  • a variable capacitor having an adjustable capacitance C0 is connected in series with the externally connected burden, r3 + j x3, and hence with the secondary side leakage impedance, r2 + j x2.
  • the capacitance C0 of the capacitor is adjusted in such a manner that it is resonated serially with the reactance portion x2 (converted to the primary side equivalent) of the seconary side leakage impedance and the reactance portion x3 (converted to the primary side equivalent) of the externally connected burden.
  • the capacitive reactance and the combined inductive reactance cancel each other, so that the overall reactance of the secondary side circuit substantially vanishes. Consequently, the core of the transformer can be reduced in size, and a small-sized and inexpensive current transformer is realized.

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Transformers For Measuring Instruments (AREA)
EP90122325A 1990-04-20 1990-11-22 Stromwandler Withdrawn EP0453637A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP102990/90 1990-04-20
JP2102990A JPH043404A (ja) 1990-04-20 1990-04-20 変流器

Publications (1)

Publication Number Publication Date
EP0453637A1 true EP0453637A1 (de) 1991-10-30

Family

ID=14342142

Family Applications (1)

Application Number Title Priority Date Filing Date
EP90122325A Withdrawn EP0453637A1 (de) 1990-04-20 1990-11-22 Stromwandler

Country Status (2)

Country Link
EP (1) EP0453637A1 (de)
JP (1) JPH043404A (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111487486A (zh) * 2020-03-06 2020-08-04 深圳供电局有限公司 配电变压器在线监测方法、装置、计算机设备及存储介质

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE422920C (de) * 1924-11-02 1925-12-15 Siemens & Halske Akt Ges Verfahren und Einrichtung zur Pruefung von Stromwandlern, beispielsweise nach der Methode Schering und Alberti
DE752154C (de) * 1938-04-05 1953-04-27 Aeg Stabkernstromwandler
CH350710A (de) * 1956-11-09 1960-12-15 Bbc Brown Boveri & Cie Stromwandleranlage für Höchstspannungsanlagen

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE422920C (de) * 1924-11-02 1925-12-15 Siemens & Halske Akt Ges Verfahren und Einrichtung zur Pruefung von Stromwandlern, beispielsweise nach der Methode Schering und Alberti
DE752154C (de) * 1938-04-05 1953-04-27 Aeg Stabkernstromwandler
CH350710A (de) * 1956-11-09 1960-12-15 Bbc Brown Boveri & Cie Stromwandleranlage für Höchstspannungsanlagen

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111487486A (zh) * 2020-03-06 2020-08-04 深圳供电局有限公司 配电变压器在线监测方法、装置、计算机设备及存储介质
CN111487486B (zh) * 2020-03-06 2021-07-16 深圳供电局有限公司 配电变压器在线监测方法、装置、计算机设备及存储介质

Also Published As

Publication number Publication date
JPH043404A (ja) 1992-01-08

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Legal Events

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PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

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17P Request for examination filed

Effective date: 19901220

AK Designated contracting states

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Effective date: 19931020

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18D Application deemed to be withdrawn

Effective date: 19940302