EP0111470B1 - Thermal protective device for transformers and inductances - Google Patents
Thermal protective device for transformers and inductances Download PDFInfo
- Publication number
- EP0111470B1 EP0111470B1 EP83890212A EP83890212A EP0111470B1 EP 0111470 B1 EP0111470 B1 EP 0111470B1 EP 83890212 A EP83890212 A EP 83890212A EP 83890212 A EP83890212 A EP 83890212A EP 0111470 B1 EP0111470 B1 EP 0111470B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- transformer
- winding
- vessel
- coolant
- oil
- 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
Links
- 230000001681 protective effect Effects 0.000 title description 2
- 238000004804 winding Methods 0.000 claims description 38
- 239000002826 coolant Substances 0.000 claims description 11
- 238000001816 cooling Methods 0.000 claims description 10
- 238000012544 monitoring process Methods 0.000 claims description 6
- 238000011144 upstream manufacturing Methods 0.000 claims 2
- 238000010438 heat treatment Methods 0.000 description 9
- 230000006978 adaptation Effects 0.000 description 1
- 230000006378 damage Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 230000007257 malfunction Effects 0.000 description 1
- 125000006850 spacer group Chemical group 0.000 description 1
Images
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
- H01F27/40—Structural association with built-in electric component, e.g. fuse
- H01F27/402—Association of measuring or protective means
-
- 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
- H01F27/40—Structural association with built-in electric component, e.g. fuse
- H01F27/402—Association of measuring or protective means
- H01F2027/404—Protective devices specially adapted for fluid filled transformers
-
- 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
- H01F27/40—Structural association with built-in electric component, e.g. fuse
- H01F27/402—Association of measuring or protective means
- H01F2027/406—Temperature sensor or protection
Definitions
- the invention relates to a device for the thermal monitoring of transformers and choke coils with forced circulation cooling, in particular oil circulation cooling, and forced flow of the cooling medium through the transformer or choke coil winding, which comprises a heating medium-filled vessel and a heating coil, this heating winding having a Current transformer is fed with a current proportional to the current of the transformer or inductor winding.
- transformers with forced oil cooling have the disadvantage that winding cooling is severely impaired if the oil pumps fail and thus the forced oil flow in the windings.
- measures such as power reduction or shutdown must be taken in accordance with the emergency operating regulations to prevent the thermal or electrical destruction of the transformer, the latter as a result of gas development. If transformer stations are unmanned, protective devices must take on this task.
- thermoal image To monitor the thermal condition of large transformers, the so-called “thermal image” is currently still preferably used.
- a temperature sensor in the hottest oil is superimposed by means of a heating coil on the calculated hot spot temperature jump Wickiung- ⁇ i.
- the temperature sensor can be a resistance wire (remote display) or a liquid-filled chamber (direct display with control contacts).
- the heating winding is fed with a current proportional to the winding current (thermocopy converter) and its thermal behavior should be adapted to that of the winding to be monitored. The latter requirement is usually only approximated, since it is practically impossible to take into account the large number of parameters with a simple heating winding.
- the hot-spot temperature jump is set to a calculated or measured operating state by means of the variable heating winding current (parallel resistance). This type of setting does not change the thermal resistance of the heating coil. From this it follows that the thermocopy can only correctly display the final value of the temperature jump without special adaptation to the thermal resistance of the winding to be monitored, but not the actual temperature profile when the load changes in the range of two to three winding time constants.
- thermocopy shows well for the normal operation of such cooled transformers. If all oil pumps fail, the thermal parameters of the windings change drastically. On the one hand, the heat transfer resistance rises to a multiple of the value that can be achieved with forced oil flow and, on the other hand, a large temperature spread along the winding to be cooled occurs due to the relatively large hydraulic resistances of the cooler and winding in order to maintain even a small natural oil flow. This ultimately serious increase in the hot spot temperature is not indicated by the normal thermocopy, since it is set to the thermal resistance of the winding in normal operation.
- the object of the invention is therefore to provide a device which avoids the disadvantages mentioned above and which has adequate thermal monitoring for transformers and choke coils with forced circulation cooling and with forced flow of the cooling medium through the winding of the transformer or the choke coil.
- the inventive device of the type mentioned is characterized in that the vessel is fed by a part of the cooling medium led from the choke coil or transformer boiler via a circulating pump and a cooler, the branch for this cooling medium before or after Circulation pump and is provided in front of the cooler.
- the vessel is arranged inside the transformer tank.
- the oil temperature in the transformer tank is decisive for the temperature level of the thermocopy device.
- the vessel is arranged outside the transformer tank.
- this vessel can be accommodated in a control cabinet, namely if the thermocopy device is only used for the transformer winding.
- a special embodiment of the invention is to be seen in the fact that a hydraulic equivalent resistor is provided for the transformer winding in the line which leads the cooling medium to the vessel. If the forced oil flow fails, the hydraulic resistance of the transformer winding for thermosiphon cooling becomes effective.
- Another feature of the invention is that a hydraulic replacement resistor for the cooler is provided in the line that leads the cooling medium to the vessel. If the forced oil flow fails, the hydraulic resistance of the oil cooler becomes effective for the thermosiphon effect.
- a check valve or a hydraulic shut-off device is provided as an equivalent resistor.
- This configuration is a simple design for the equivalent resistor. Economically, this solution is the most optimal.
- FIG. 1 shows a schematic diagram
- FIG. 2 shows a detail thereof
- FIG. 3 shows a section A-A of FIG. 2.
- the transformer winding 2 is arranged in the transformer tank 1. Outside the transformer boiler 1, the oil circulation pumps 3 and the oil cooler 4 necessary for the forced oil circulation cooling are provided. As is generally known, the forced cooling of the winding 2 is based on the fact that the oil coming from the transformer tank 1 is pumped back into the transformer tank 1 and directly into the windings 2 by the circulation pumps 3 via the oil coolers 4.
- the device for thermal monitoring consists of a vessel 5 - in this case arranged outside the transformer tank 1 -, a thermal sensor 6 and a heating winding 7 surrounding the thermal sensor 6.
- the winding 7 is connected to the current of the transformer winding 2 via a current transformer (not shown) proportional current fed.
- oil is supplied to the vessel 5 from the transformer tank 1 via one or more lines 8. This oil is branched off from the main lines 9 after the oil circulation pump 3 and before the oil coolers 4. After this .
- the oil flows back into the transformer boiler 1.
- a hydraulic equivalent resistor 10 for the transformer winding 2 is arranged in the line 8
- another hydraulic equivalent resistor 11 for the oil cooler 4 is arranged in front of this equivalent resistor 10.
- the equivalent resistors 10, 11 can consist of individual plates 12 which have bores 13.
- the required hydraulic resistance is achieved by a precisely defined arrangement of these plates 12, which are held together by a spacer bolt.
- this device takes into account the fact that in an emergency operation with one or no oil circulation pumps 3, the significantly increased temperature jump winding - oil is registered immediately.
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Transformer Cooling (AREA)
- Housings And Mounting Of Transformers (AREA)
- Protection Of Transformers (AREA)
- Testing Of Short-Circuits, Discontinuities, Leakage, Or Incorrect Line Connections (AREA)
- Tests Of Electronic Circuits (AREA)
Description
Die Erfindung betrifft eine Einrichtung zur thermischen Überwachung von Transformatoren und Drosselspulen mit erzwungener Umlaufkühlung, insbesondere Ölumlaufkühlung, und erzwungener Strömung des Kühlmediums durch die Transformatoren- bzw. Drosselspulenwicklung, die mit Kühlmedium gefülltes und einen Thermofühler umgebende Heizwicklung aufweisendes Gefäß umfaßt, wobei diese Heizwicklung über einen Stromwandler mit einem dem Strom der Transformatoren- bzw. Drosselspulenwicklung proportionalen Strom gespeist ist.The invention relates to a device for the thermal monitoring of transformers and choke coils with forced circulation cooling, in particular oil circulation cooling, and forced flow of the cooling medium through the transformer or choke coil winding, which comprises a heating medium-filled vessel and a heating coil, this heating winding having a Current transformer is fed with a current proportional to the current of the transformer or inductor winding.
Transformatoren mit erzwungener Ölkühlung weisen neben den bekannten Vorzügen den Nachteil auf, daß bei Ausfall der Ölpumpen und damit der forcierten Ölströmung in den Wicklungen die Wicklungskühlung stark beeinträchtigt wird. In einem solchen Störungsfall sind entsprechend den Notbetriebvorschriften Maßnahmen wie Leistungsreduktion oder Abschaltung zu treffen, die die thermische oder elektrische Zerstörung des Transformators, letztere infolge von Gasentwicklung, verhindern. Sind Trafostationen unbemannt, müssen Schutzgeräte diese Aufgabe übernehmen.In addition to the known advantages, transformers with forced oil cooling have the disadvantage that winding cooling is severely impaired if the oil pumps fail and thus the forced oil flow in the windings. In such a malfunction, measures such as power reduction or shutdown must be taken in accordance with the emergency operating regulations to prevent the thermal or electrical destruction of the transformer, the latter as a result of gas development. If transformer stations are unmanned, protective devices must take on this task.
Zur Überwachung des thermischen Zustandes von Großtransformatoren wird derzeit noch vorzugsweise das sogenannte « Thermische Abbild verwendet. Einem Temperaturfühler im heißesten Öl wird mittel einer Heizwicklung der rechnerische hot-spot-Temperatursprung Wickiung-Öi überlagert. Je nach Gerätetyp kann der Temperaturfühler ein Widerstandsdraht (Fernanzeige) oder eine flüssigkeitsgefüllte Kammer (direkte Anzeige mit Steuerkontakten) sein. Die Heizwicklung wird mit einem dem Wicklungsstrom proportionalen Strom (Thermokopiewandler) gespeist und soll in ihrem thermischen Verhalten demjenigen der zu überwachenden Wicklung angepaßt sein. Letztere Forderung wird meist nur angenähert erfüllt, da es praktisch nicht möglich ist, die Vielzahl der Parameter mit einer einfachen Heizwicklung zu berücksichtigen. Schließlich wird der hot-spot-Temperatursprung auf einen gerechneten oder gemessenen Betriebszustand hin mittels der veränderbaren Heizwicklungsstromes (Parallelwiderstand) eingestellt. Diese Art der Einstellung ändert den thermischen Widerstand der Heizwicklung nicht. Daraus leitet sich ab, daß die Thermokopie ohne spezielle Anpassung auf den thermischen Widerstand der zu überwachenden Wicklung nur den Endwert des Temperatursprunges richtig anzeigen kann, nicht jedoch den tatsächlichen Temperaturverlauf bei Laständerung im Bereich von zwei bis drei Wicklungs-Zeitkonstanten.To monitor the thermal condition of large transformers, the so-called "thermal image" is currently still preferably used. A temperature sensor in the hottest oil is superimposed by means of a heating coil on the calculated hot spot temperature jump Wickiung-Öi. Depending on the device type, the temperature sensor can be a resistance wire (remote display) or a liquid-filled chamber (direct display with control contacts). The heating winding is fed with a current proportional to the winding current (thermocopy converter) and its thermal behavior should be adapted to that of the winding to be monitored. The latter requirement is usually only approximated, since it is practically impossible to take into account the large number of parameters with a simple heating winding. Finally, the hot-spot temperature jump is set to a calculated or measured operating state by means of the variable heating winding current (parallel resistance). This type of setting does not change the thermal resistance of the heating coil. From this it follows that the thermocopy can only correctly display the final value of the temperature jump without special adaptation to the thermal resistance of the winding to be monitored, but not the actual temperature profile when the load changes in the range of two to three winding time constants.
Wie voran erwähnt, zeigt die Thermokopie für den Normalbetrieb von derart gekühlten Transformatoren gut an. Bei Ausfall aller Ölförderpumpen verändern sich die thermischen Parameter der Wicklungen drastisch. Einerseits steigt der Wärmeübergangswiderstand auf ein mehrfaches der mit forcierter Ölströmung erzielbaren Wertes an und zum anderen stellt sich zur Aufrechterhaltung einer auch nur geringen natürlichen Ölströmung über die relativ großen hydraulischen Widerstände von Kühler und Wicklung eine große Temperaturspreizung entlang der zu kühlenden Wicklung ein. Diese letztlich gravierende Erhöhung der hot-spot-Temperatur wird von der normalen Thermokopie nicht angezeigt, da sie auf den thermischen Widerstand der Wicklung im Normalbetrieb eingestellt ist.As mentioned above, the thermocopy shows well for the normal operation of such cooled transformers. If all oil pumps fail, the thermal parameters of the windings change drastically. On the one hand, the heat transfer resistance rises to a multiple of the value that can be achieved with forced oil flow and, on the other hand, a large temperature spread along the winding to be cooled occurs due to the relatively large hydraulic resistances of the cooler and winding in order to maintain even a small natural oil flow. This ultimately serious increase in the hot spot temperature is not indicated by the normal thermocopy, since it is set to the thermal resistance of the winding in normal operation.
Aufgabe der Erfindung ist es daher eine Einrichtung zu schaffen, die die oben angeführten Nachteile vermeidet und die eine ausreichende thermische Überwachung für Transformatoren und Drosselspulen mit erzwungener Umlaufkühlung und mit erzwungener Strömung des Kühlmediums durch die Wicklung des Transformators bzw. der Drosselspule.The object of the invention is therefore to provide a device which avoids the disadvantages mentioned above and which has adequate thermal monitoring for transformers and choke coils with forced circulation cooling and with forced flow of the cooling medium through the winding of the transformer or the choke coil.
Die erfindungsgemäße Einrichtung der eingangs erwähnten Art, ist dadurch gekennzeichnet, daß das Gefäß von einem Teil des aus dem Drosselspulen- bzw. Transformatorenkessel über eine Umwälz-Pumpe und einem Kühler geführtes Kühlmedium gespeist ist, wobei die Abzweigung für dieses Kühlmedium vor bzw. nach der Umwälz-Pumpe und vor dem Kühler vorgesehen ist.The inventive device of the type mentioned is characterized in that the vessel is fed by a part of the cooling medium led from the choke coil or transformer boiler via a circulating pump and a cooler, the branch for this cooling medium before or after Circulation pump and is provided in front of the cooler.
Mit dieser Erfindung ist es erstmals möglich die tatsächlichen thermischen, hydraulischen Verhältnisse der Transformatorenwicklung mit einer Einrichtung nachzuvollziehen. Dadurch ist auch eine optimale thermische Überwachung des Transformators bei einem Notbetrieb z. B. Ausfall der Umwälz-Pumpen gegeben.With this invention it is possible for the first time to understand the actual thermal, hydraulic conditions of the transformer winding with one device. This also ensures optimal thermal monitoring of the transformer during emergency operation, e.g. B. Failure of the circulation pumps.
Gemäß einer besonderen Ausgestaltung der Erfindung ist das Gefäß innerhalb' des Transformatorenkessels angeordnet. Dadurch ist die Öltemperatur im Transformatorenkessel maßgebend für das Temperaturniveau der Thermokopieeinrichtung.According to a special embodiment of the invention, the vessel is arranged inside the transformer tank. As a result, the oil temperature in the transformer tank is decisive for the temperature level of the thermocopy device.
Nach einem weiteren Merkmal der Erfindung ist das Gefäß außerhalb des Transformatorenkessels angeordnet. In diesem Fall kann dieses Gefäß in einem Schaltschrank untergebracht werden, nämlich wenn die Thermokopieeinrichtung nur für die Transformatorenwicklung Verwendung findet.According to a further feature of the invention, the vessel is arranged outside the transformer tank. In this case, this vessel can be accommodated in a control cabinet, namely if the thermocopy device is only used for the transformer winding.
Eine besondere Ausgestaltung der Erfindung ist darin zu sehen, daß in der Leitung die das Kühlmedium zum Gefäß führt, ein hydraulischer Ersatzwiderstand für die Transformatorenwicklung vorgesehen ist. Bei einem Ausfall der forcierten Ölströmung wird dadurch der hydraulische Widerstand der Transformatorenwicklung für die Thermosyphonkühlung wirksam.A special embodiment of the invention is to be seen in the fact that a hydraulic equivalent resistor is provided for the transformer winding in the line which leads the cooling medium to the vessel. If the forced oil flow fails, the hydraulic resistance of the transformer winding for thermosiphon cooling becomes effective.
Ein weiteres Merkmal der Erfindung ist, daß in der Leitung, die das Kühlmedium zum Gefäß führt, ein hydraulischer Ersatzwiderstand für den Kühler vorgesehen ist. Bei einem Ausfall der forcierten Ölströmung wird dadurch der hydraulische Widerstand der Öl-Kühler für die Thermosyphonwirkung wirksam.Another feature of the invention is that a hydraulic replacement resistor for the cooler is provided in the line that leads the cooling medium to the vessel. If the forced oil flow fails, the hydraulic resistance of the oil cooler becomes effective for the thermosiphon effect.
Nach einem Merkmal der Erfindung ist als Ersatzwiderstand ein Rückschlagventil od. ein hydraulisches Absperrorgan vorgesehen. Diese Ausgestaltung ist eine einfache Ausführung für den Ersatzwiderstand. Diese Lösung ist wirtschaftlich sicherlich die optimalste.According to a feature of the invention, a check valve or a hydraulic shut-off device is provided as an equivalent resistor. This configuration is a simple design for the equivalent resistor. Economically, this solution is the most optimal.
An Hand eines in der Zeichnung dargestellten Ausführungsbeispieles wird die Erfindung näher erläutert. Fig. 1 zeigt eine Prinzipskizze, Fig. 2 ein Detail daraus Fig. 3 einen Schnitt A-A der Fig. 2.The invention is explained in more detail with reference to an embodiment shown in the drawing. 1 shows a schematic diagram, FIG. 2 shows a detail thereof, FIG. 3 shows a section A-A of FIG. 2.
Gemäß der Fig. 1 ist im Transformatorenkessel 1 die Transformatorenwicklung 2 angeordnet. Außerhalb des Transformatorenkessels 1 sind die für die erzwungene Ölumlaufkühlung notwendigen Ölumwälz-Pumpen 3 und die ÖI-Kühler 4 vorgesehen. Wie ja allgemein bekannt beruht die forcierte Kühlung der Wicklung 2 darauf, daß das aus dem Transformatorenkessel 1 kommende Öl durch die Umwälz-Pumpen 3 über die Öl-Kühler 4 wieder in den Transformatorenkessel 1 und direkt in die Wicklungen 2 gepumpt wird.1, the transformer winding 2 is arranged in the transformer tank 1. Outside the transformer boiler 1, the oil circulation pumps 3 and the
Die Einrichtung zur thermischen Überwachung besteht aus einem Gefäß 5 - in diesem Fall außerhalb des Transformatorenkessels 1 angeordnet -, einem Thermofühler 6 und einer den Thermofühler-6 umgebenden Heizwicklung 7. Die Wicklung 7 wird über einen nicht dargestellten Stromwandler mit einem dem Strom der Transformatorenwicklung 2 proportionalen Strom gespeist. Ferner wird dem Gefäß 5 über eine bzw. mehrere Leitungen 8 Öl aus dem Transformatorenkessel 1 zugeführt. Dieses Öl wird aus den Hauptleitungen 9 nach der Ölumwälz-Pumpe 3 und vor den ÖI-Kühlern 4 abgezweigt. Nach dem . Umfließen der Wicklung 7 fließt das Öl wieder in den Transformatoren kessel 1. Vor dem Gefäß 5 ist in die Leitung 8 ein hydraulischer Ersatzwiderstand 10 für die Transformatorenwicklung 2 und vor diesen Ersatzwiderstand 10 ein weiterer hydraulischer Ersatzwiderstand 11 für die ÖI-Kühler 4 angeordnet.The device for thermal monitoring consists of a vessel 5 - in this case arranged outside the transformer tank 1 -, a
Die Ersatzwiderstände 10, 11 können aus einzelnen Platten 12 bestehen, die Bohrungen 13 aufweisen. Durch genaue definierte Anordnung dieser Platten 12, die über einen Distanzierungsbolzen zusammengehalten werden, wird der benötigte hydraulische Widerstand erreicht.The
Zu bemerken wäre noch, daß anstelle des hydraulischen Ersatzwiderstandes 10 für die Transformatorenwicklung 2, die Wicklung 7 entsprechend ausgebildet werden könnte. Ebenso könnten mehrere Einrichtungen für diese thermische Überwachung mehrerer Wicklungen parallel geschaltet werden.It should also be noted that instead of the hydraulic
Abschließend sei noch bemerkt, daß diese Einrichtung vor allem den Umstand berücksichtigt, daß bei einem Notbetrieb mit einer oder keiner Ölumwälz-Pumpen 3 der erheblich erhöhte Temperatursprung Wicklung - Öl sofort registriert wird.Finally, it should be noted that this device takes into account the fact that in an emergency operation with one or no oil circulation pumps 3, the significantly increased temperature jump winding - oil is registered immediately.
Claims (6)
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AT0414282A AT378623B (en) | 1982-11-15 | 1982-11-15 | DEVICE FOR THE THERMAL MONITORING OF LIQUID-COOLED TRANSFORMERS AND THROTTLE COILS |
| AT4142/82 | 1982-11-15 |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| EP0111470A2 EP0111470A2 (en) | 1984-06-20 |
| EP0111470A3 EP0111470A3 (en) | 1985-01-09 |
| EP0111470B1 true EP0111470B1 (en) | 1987-03-04 |
Family
ID=3560223
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP83890212A Expired EP0111470B1 (en) | 1982-11-15 | 1983-11-15 | Thermal protective device for transformers and inductances |
Country Status (5)
| Country | Link |
|---|---|
| US (1) | US4549817A (en) |
| EP (1) | EP0111470B1 (en) |
| JP (1) | JPS59112607A (en) |
| AT (1) | AT378623B (en) |
| DE (1) | DE3370093D1 (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4754405A (en) * | 1986-02-14 | 1988-06-28 | Qualitrol Corporation | Tri-phase electronic temperature controller |
| DE68904669T2 (en) * | 1988-03-29 | 1993-07-08 | Toshiba Kawasaki Kk | METHOD FOR MONITORING UNUSUAL INDICATORS IN A GAS-FILLED DEVICE AND A GAS-FILLED DEVICE WITH A MONITOR. |
| US6494617B1 (en) * | 1999-04-30 | 2002-12-17 | General Electric Company | Status detection apparatus and method for fluid-filled electrical equipment |
| JP2005302794A (en) * | 2004-04-07 | 2005-10-27 | Hitachi Industrial Equipment Systems Co Ltd | Transformer monitoring system |
| DE102011107375B4 (en) * | 2011-07-14 | 2013-02-21 | Maschinenfabrik Reinhausen Gmbh | Device for simulating and displaying the winding temperature of an electrical power transformer and suitable limiting circuit |
| DE102014220145A1 (en) * | 2014-10-06 | 2016-04-07 | Robert Bosch Gmbh | Cooling monitoring device for a transformer cooling a welding transformer |
| DE102016207393A1 (en) | 2016-04-29 | 2017-11-02 | Siemens Aktiengesellschaft | Replacement transformer with modular design |
Family Cites Families (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US31685A (en) * | 1861-03-12 | Table | ||
| US1597771A (en) * | 1921-05-11 | 1926-08-31 | Westinghouse Electric & Mfg Co | Transformer-cooling system |
| DE935852C (en) * | 1939-04-12 | 1955-12-01 | Siemens Ag | Method and device for monitoring the state of the dielectric, in particular the solid dielectric in oil transformers or the like. |
| FR931647A (en) * | 1945-07-16 | 1948-02-27 | Alsthom Cgee | New provision for marking the temperature of windings of electrical devices in oil or other liquid insulation |
| US3144770A (en) * | 1961-01-30 | 1964-08-18 | Gen Electric | Means for determining an internal condition in electrical apparatus |
| DE1175358B (en) * | 1963-03-04 | 1964-08-06 | Bbc Brown Boveri & Cie | Thermal overload protection device for electrical system parts |
| GB1161985A (en) * | 1966-07-26 | 1969-08-20 | English Electric Co Ltd | Device for Determining the Temperature of Electrical Apparatus |
| US3491597A (en) * | 1966-09-20 | 1970-01-27 | Anaconda Wire & Cable Co | Temperature monitored cable system and method |
| GB1153762A (en) * | 1967-05-04 | 1969-05-29 | Parsons & Co Ltd C A | Improvements in and relating to Temperature Measuring Devices |
| DE3006854C2 (en) * | 1980-02-23 | 1983-09-15 | Rainer Ing.(grad.) 4650 Gelsenkirchen Sanden | Cooling system with monitoring arrangement for the transformer cooling of a power plant machine transformer |
| US4394635A (en) * | 1981-04-16 | 1983-07-19 | General Electric Company | Method for determining dissolved gas concentrations in dielectric coolants |
-
1982
- 1982-11-15 AT AT0414282A patent/AT378623B/en not_active IP Right Cessation
-
1983
- 1983-11-14 US US06/551,601 patent/US4549817A/en not_active Expired - Fee Related
- 1983-11-15 JP JP58213435A patent/JPS59112607A/en active Pending
- 1983-11-15 DE DE8383890212T patent/DE3370093D1/en not_active Expired
- 1983-11-15 EP EP83890212A patent/EP0111470B1/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| EP0111470A2 (en) | 1984-06-20 |
| AT378623B (en) | 1985-09-10 |
| US4549817A (en) | 1985-10-29 |
| ATA414282A (en) | 1985-01-15 |
| DE3370093D1 (en) | 1987-04-09 |
| EP0111470A3 (en) | 1985-01-09 |
| JPS59112607A (en) | 1984-06-29 |
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