How to measure the temperature of transformer windings-INNO

The temperature monitoring of transformer windings is the key to ensuring their safe operation. The following are common temperature measurement methods and precautions, classified by reliability and application scenarios:

1. Doğrudan ölçüm yöntemi (most accurate)

Fiber optik sıcaklık ölçüm sistemi (recommended)
Prensip: Fiber optik sensörler (such as fluorescent fibers or FBG fibers) are embedded during winding manufacturing to directly measure the temperature of the wire.
Avantajları: Insulation, anti elektromanyetik girişim, accuracy up to ± 1 °C, suitable for high-voltage or ultra high voltage transformers (such as 500kV and above).
Dava: ABB and Siemens’ high-end transformers commonly use this type of system.
Kablosuz sensörler (emerging technology)
Prensip: Micro wireless temperature sensors (such as those based on SAW or RFID technology) are embedded between winding layers and transmit data through wireless signals.
Sınırlamalar: Metal koruma ve elektromanyetik girişim sorunlarının ele alınması gerekiyor, şu anda çoğunlukla transformatörleri test etmek için kullanılıyor.

2. Dolaylı hesaplama yöntemi (ana uygulama)

Termal simülasyon hesaplaması (IEC 60076-7 standart)
Yöntem: Üst yağ sıcaklığını ölçerek (TOST) ve yük akımı, sarma sıcak nokta katsayısının uygulanmasıyla birlikte, devir testi veya arıza teşhisi için kullanılabilir.

3. Geleneksel izleme yöntemleri (yardımcı referans)

Yağ sıcaklığı göstergesi+sargı sıcaklığı göstergesi (WTI)
Prensip: Yağ sıcaklık sensörü akım trafosu ile birleştirilmiştir (BT) Sargının sıcaklık artışını simüle etmek için sinyal, yaklaşık ± hatayla 5 °C.
Dikkat: Kalibrasyon her seferinde yapılmalıdır. 3 CT oranı hatalarından kaynaklanan yanlış kararları önlemek için yıllar.
Kızılötesi termal görüntüleme cihazı (harici algılama)
Kullanım: Yalnızca açıkta kalan sargı uçları veya yağ deposu yüzeyleri için geçerlidir, considering the effects of oil flow and heat dissipation, with poor accuracy (± 10 °C).

4. Precautions

Security threshold:
Conventional insulation (A sınıfı): winding hotspot ≤ 105 °C (IEC standard).
When overloaded: It is allowed to rise to 130 ℃ for a short period of time (refer to the manufacturer’s curve).
Data comparison: When the difference between direct method (fiber optik) and indirect method (thermal simulation) aşar 10 °C, it is necessary to investigate sensor or calculation model errors.
Summary and selection suggestions
New/important transformers: Priority should be given to embedding fiber optic systems.
Transformer in operation: WTI+thermal simulation calculation is used, and resistance method is used to verify during annual power outages.
Temporary monitoring: infrared+wireless sensor combination, suitable for troubleshooting.
For specific equipment models or installation details, please contact FJINNO

The installation difficulty of fiber optic temperature measurement system is moderate, mainly depending on the application scenario (such as transformer winding, şalt sistemi, jeneratör) and installation method (pre embedded vs later installation). Here are the key points:
1. Kurulum
The transformer winding needs to be embedded with optical fibers during the manufacturing stage, and the internal space of the winding is narrow, requiring high-voltage insulation treatment.
The later installation of switch cabinets/busbars requires only surface fixation without dismantling the equipment, but must avoid areas with strong electromagnetic interference.
2. Precautions
Operasyon: The fiber optic cable is fragile, and the bending radius must be greater than the value, otherwise it is prone to breakage.
Position limitation: The installation inside the transformer winding needs to be designed in collaboration with the manufacturer and cannot be modified later.
3. Suggestions for simplifying installation
New project: Priority should be given to pre embedded fluorescent fiber optic sensors, which will be integrated by the transformer manufacturer. Users only need to connect the demodulator.
Renovation project: Adopting external fiber optic probes (such as busbars and contacts), fixed with zip ties or thermal conductive adhesive, single point installation can be completed within 30 dakika.
4. Do you need professionals?
Evet: Trained technicians are required to operate, especially in high-pressure environments or precision equipment.
Exception: Low voltage scenarios such as switchgear can be completed by a guided electrician team.
Özet: If the transformer has been put into operation, it is recommended to choose an external fiber optic system (such as busbar monitoring), which is easy to install; If it is a new project, although the pre embedded design is complex in the initial stage, it has higher long-term reliability.