US2834920A - Circuit for simulating transformer winding hot spot temperature - Google Patents

Circuit for simulating transformer winding hot spot temperature Download PDF

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Publication number
US2834920A
US2834920A US364702A US36470253A US2834920A US 2834920 A US2834920 A US 2834920A US 364702 A US364702 A US 364702A US 36470253 A US36470253 A US 36470253A US 2834920 A US2834920 A US 2834920A
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US
United States
Prior art keywords
resistance
transformer
windings
current
hot spot
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.)
Expired - Lifetime
Application number
US364702A
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English (en)
Inventor
Thomas C Lennox
Howard A Fohrhaltz
James F Mckenney
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.)
General Electric Co
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General Electric Co
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 General Electric Co filed Critical General Electric Co
Priority to US364702A priority Critical patent/US2834920A/en
Priority to JP1340054A priority patent/JPS306248B1/ja
Application granted granted Critical
Publication of US2834920A publication Critical patent/US2834920A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H6/00—Emergency protective circuit arrangements responsive to undesired changes from normal non-electric working conditions using simulators of the apparatus being protected, e.g. using thermal images

Definitions

  • our invention comprises a first resistance element having a high temperature coefficient of resistance submerged within said dielectric liquid, a current transformer inductively coupled to said neutral ground lead, a second resistance element having a low temperature coefiicient of resistance connected in series with said current transformer and said first resistance element, another transformer having two electrical windings, one winding of said another transformer connected across said second resistance element and the other winding of said another transformer having a relay coil and said first resistance element connected in series therewith.
  • Fig. 1 is a view of a transformer having a conventional temperature detector connected thereto.
  • Fig. 2 is an electrical circuit diagram of our invention.
  • Fig. 3 is a temperature-time curve of an insulated copper conductor which is heated internally as by the passage of current therethrough.
  • Fig. 4 is a temperature-time curve of a conventional temperature detector which is heated externally, as in a bath.
  • a transformer apparatus com prising a magnetic core 10 and electrical windings 11 submerged within a dielectric liquid 12 within a tank 13.
  • a terminal bushing 14 is mounted on the cover of the tank and a secondary line lead 15 extends from windings 11 to bushing 14.
  • a current transformer 16 is inductively coupled to lead 15.
  • Current transformer 16 sends a current proportional to load current through a heater element 17 submerged within dielectric liquid 12.
  • the temperature rise of heater element 17 above the temperature of the dielectric liquid 12 is detected by suitable means, as by a resistance temperature detector 18 having an indicating dial.
  • Fig. 3 is a curve of temperature rise versus time for a copper conductor such as heating coil 17 or the transformer winding 11.
  • Fig. 4 is a curve of temperature rise versus time for a body such as temperature detector 18.
  • a resistor element 19 having a low temperature coeflicient of resistance is connected in series with a heater resistor element 20 having a high temperature coefiicient of resistance.
  • the element 19 may be a material such as constantan and element 2! may be a material such as copper.
  • a transformer of appropriate ratio as a 1:1 ratio transformer, has one of its windings 21 connected across element 19.
  • the other winding 22 of the transformer has connected in series therewith a relay coil 23 and element 20.
  • a current transformer 24 Connected across series connected elements 19 and 20 is a current transformer 24 which is inductively coupled to a neutral ground lead 25 of three-phase grounding transformer 26 having a conventional three-phase magnetic core (not shown).
  • the heater resistance element 20 having a high temperature coefificient of resistance would be submerged in the dielectric liquid of transformer 26.
  • the relay 23 may be adapted to operate a circuit breaker as illustrated in Fig. 2, or to serve some other desired function.
  • the resistors 19 and 20 heat up.
  • the resistance of element 20 increases rapidly while the resistance of element 19 remains substantially constant. This leaves an effective voltage substantially equal to the difference between the voltages across elements 19 and 20 to energize the relay 23 and cause its contacts to open, or to perform some other desired function.
  • Energization of relay 23 can be arranged to occur when the resistance of element 20 reaches a value in accordance with a predetermined temperature.
  • an electrical circuit for simulating hot spot temperature in said windings comprising two series connected resistance elements, another transformer having two electrical windings, one of said another transformer windings connected across one of said resistance elements and the other of said another transformer windings connected in series with the other of said resistance elements, and means for sending a current proportional to a fault current in said neutral ground lead through said series connected resistance elements, one of said resistance elements having a high temperature coefiicient of resistance and the other of said resistance elements having a low temperature co efficient of resistance, said high temperature coefficient Letters of resistance resietance element submerged in said dielectric fluid, the polarity of said other of said another transformer windings and the polarity of the voltage drop in the resistance element which is serially connected with said other winding being opposed.
  • a three-phase grounding transformer apparatus comprising a magnetic core and electrical windings sur- 3.
  • a three-phase grounding transformer apparatus having a magnetic core and electrical windings surrounding said core, said windings and core submerged in a dielectric liquid, and a neutral ground lead extending from a neutral point in said windings to ground, an electrical circuit for simulating hot spot temperature in said windings, comprising two series connected resistance elements, one of said resistance elements having a high temperature coeflicient of resistance, and the other of said resistance elements having a low temperature coefficient of resistance, a current transformer inductively coupled to said neutral ground lead for causing a current proportional to a fault current in said three-phase grounding transformer windings to flow through said series connected resistance elements, said current transformer connected in series with said series connected resistance elements, said high temperature coeflicient of resistance resistance element submerged in said dielectric liquid, a 1:1 ratio transformer having two electrical windings, one of the windings of said 1:1 ratio transformer connected across said low tem perature coefficient
  • a grounding transformer apparatus having a magnetic core, electrical windings surrounding said core and a ground lead extending from a neutral point in said windings to ground, electrical means for simulating hot spot temperatures comprising a first resistance means having a low temperature coefficient of resistance, a second resistance means having a high temperature coefficient of resistance, means for passing a current proportional to the current in said ground lead through said first and second resistance means, and electrical means detectings connected in series with the other of said resistance elements so that the voltages appearing across said other resistance element and said other winding when a current is flowing through said series connected resistance elements will oppose each other, one of said resistance elements having a high temperature coefficient of resistance, and the other of said resistance elements having a low temperature coefficient of resistance, said high temperature coefficient of resistance resistance element submerged in said dielectric liquid, a relay coil connected to be responsive to the voltage difference of said series con: nected other resistance element and other winding, and a current transformer inductively coupled to said neutral ground lead and connected across said series connected resistance elements whereby a current proportion
  • electrical circuit means for simulating hot spot temperatures comprising a first resistance means having a low temperature coefficient of resistance connected in series with the second resistance means having a high tem perature coefficient of resistance, means for passing a current proportional to the current in said ground lead through said first and second resistance means, and electrical means detecting the difference in voltage drop appearing across said first and second resistances.
  • electrical circuit means for simulating hot spot temperatures comprising a first resistance means having a low temperature coefficient of resistance, a second resistance means having a high temperature coefficient of resistance, means for passing a current proportional to current in said ground lead through said first and second resistance means, and electrical means in series with one of said resistances providing a voltage proportional to but having polarity opposite to the voltage across the other said resistance.

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  • Protection Of Transformers (AREA)
  • Thermally Actuated Switches (AREA)
US364702A 1953-06-29 1953-06-29 Circuit for simulating transformer winding hot spot temperature Expired - Lifetime US2834920A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
US364702A US2834920A (en) 1953-06-29 1953-06-29 Circuit for simulating transformer winding hot spot temperature
JP1340054A JPS306248B1 (enrdf_load_stackoverflow) 1953-06-29 1954-06-28

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US364702A US2834920A (en) 1953-06-29 1953-06-29 Circuit for simulating transformer winding hot spot temperature

Publications (1)

Publication Number Publication Date
US2834920A true US2834920A (en) 1958-05-13

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US (1) US2834920A (enrdf_load_stackoverflow)
JP (1) JPS306248B1 (enrdf_load_stackoverflow)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3002128A (en) * 1957-08-29 1961-09-26 Gen Electric Overload protective means for electrical apparatus
US3155877A (en) * 1960-11-01 1964-11-03 Westinghouse Electric Corp Safety circuits for electric motors
US3260116A (en) * 1963-05-15 1966-07-12 Gen Electric Remote reading temperature indicating system
US3365618A (en) * 1965-10-21 1968-01-23 Texas Instruments Inc Thermally responsive protection circuit
US4623265A (en) * 1984-09-26 1986-11-18 Westinghouse Electric Corp. Transformer hot-spot temperature monitor
US4654806A (en) * 1984-03-30 1987-03-31 Westinghouse Electric Corp. Method and apparatus for monitoring transformers
US4754405A (en) * 1986-02-14 1988-06-28 Qualitrol Corporation Tri-phase electronic temperature controller
US4775245A (en) * 1986-12-12 1988-10-04 Qualitrol Corporation Multi-phase electronic temperature controller

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2403372A (en) * 1943-05-19 1946-07-02 Gen Electric Thermal protection of electric apparatus
US2491798A (en) * 1944-01-05 1949-12-20 Gen Electric Protected electrical apparatus

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2403372A (en) * 1943-05-19 1946-07-02 Gen Electric Thermal protection of electric apparatus
US2491798A (en) * 1944-01-05 1949-12-20 Gen Electric Protected electrical apparatus

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3002128A (en) * 1957-08-29 1961-09-26 Gen Electric Overload protective means for electrical apparatus
US3155877A (en) * 1960-11-01 1964-11-03 Westinghouse Electric Corp Safety circuits for electric motors
US3260116A (en) * 1963-05-15 1966-07-12 Gen Electric Remote reading temperature indicating system
US3365618A (en) * 1965-10-21 1968-01-23 Texas Instruments Inc Thermally responsive protection circuit
US4654806A (en) * 1984-03-30 1987-03-31 Westinghouse Electric Corp. Method and apparatus for monitoring transformers
US4623265A (en) * 1984-09-26 1986-11-18 Westinghouse Electric Corp. Transformer hot-spot temperature monitor
US4754405A (en) * 1986-02-14 1988-06-28 Qualitrol Corporation Tri-phase electronic temperature controller
US4775245A (en) * 1986-12-12 1988-10-04 Qualitrol Corporation Multi-phase electronic temperature controller

Also Published As

Publication number Publication date
JPS306248B1 (enrdf_load_stackoverflow) 1955-09-03

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