EN
Nuntia
Ascensio temperaturae transformatorum siccorum et oleo-immersorum, necnon ambitus ascensionis temperaturae
Sunt multae causae quae vitam operativam influunt transformatores sicci generis et transformatores in oleo mergitos Inter eas, temperatura est causa maxime momenti quae ad aetatem insulationis ducit et per consequens ad vitam operativam transformatorum. Propter distributionem caloris inaequalem intra transformatores, magnae differentiae temperaturarum in variis partibus occurrunt. Ideo ascensus temperaturae permittendus pro singulis partibus sub onere nominale specificatur ut operatio secura garantur.
---
I. Principia fundamentalia et calculi ascensus temperaturae
Classis insulationis et maxima temperatura permittenda
Transformatores oleo inmersi communiter usitant insulationem classis A, cuius maxima temperatura permittenda est 105℃.
- Calculus ascensus temperaturae permittendi (exempli gratia, pro spira)
Ascensus temperaturae permittendus = Maxima temperatura permittenda - Temperatura ambientis (cuius punctum referentiae est 40℃)
That is: 105℃ − 40℃ = 65℃ (Allowable temperature rise of the coil)
− The relationship between oil temperature and winding temperature
The temperature of transformer oil is usually about 10℃ lower than that of the windings. Therefore:
− The allowable temperature rise of the oil is: 65℃ − 10℃ = 55℃
− To prevent oil from aging, the temperature rise of the upper oil surface must not exceed 45℃
The actual operating temperature range
If the upper oil temperature is between 80℃ and 90℃, then the winding temperature will be approximately 95℃ to 105℃. Staying in this range for a long time will accelerate insulation aging.
---
II. Hazards of High-Temperature Operation for Dry-Type and Oil-Immersed Transformers
Insulation material deterioration
Expositio diuturna ad temperaturas altas faciet ut tabula isolans in fragilitatem convertatur et frangere facile possit, proprietates isolantes amittat, et periculum defectus augeat.
- Aetates olei isolantis
Aetas gravissima isolationis circumvolutionis accelerabit deterioratio olei isolantis, et vitam totalem transformatoris ulterius minuet.
- Conclusio
Consulendum est ne transformator ad temperaturas altas operetur, praesertim si operationes ad temperaturas altas diuturnae sunt.
---
III. Classificatio Graduum Isolationis Transformatorum
Classis isolationis indicat facultatem resistentiae ad calorem materiae isolantis, et classes diversae ad diversas temperaturas maximas permittendas respondent.
Transformatores oleo-immersi (septem gradus)
A, E, B, F, H, N, C
- Transformatores sicci (tres gradus diversi)
B, F, H
Take Class A as an example. Its meaning is: The sum of the transformer's operating temperature and the ambient temperature should not exceed 105℃; for other classes, the principle is the same.
---
IV. Temperature Rise Limit Diagram (Explanation)
- The temperature rise limit for oil-immersed transformers is shown in the diagram.
| Transformer Insulation Grades | A | E | B | F | H | N | C |
| Maximum allowable temperature (℃) | 105 | 120 | 130 | 155 | 180 | 200 | 220 |
| Winding temperature rise limit (K) | 60 | 75 | 80 | 100 | 155 | / | 150 |
- The temperature rise limit for dry-type transformers is shown in the diagram.
| Transformer Insulation Grades | B | F | H |
| Maximum allowable temperature (℃) | 130 | 155 | 180 |
| Winding temperature rise limit (K) | 80 | 100 | 125 |
Note: The magnitude of the temperature rise limit directly reflects the heat resistance performance of the insulating material, and is an important basis for selection and operation monitoring.
---
V. Core Security Principles
Dum tempus incrementi temperaturae non excedit limitem permisum, transformator tutus operari potest intra vitam specificatam servitii, quocumque modo temperatura ambientis mutetur.
