Working Principle of Transformer Winding Temperature Indicator

You asking so many questions!

Well put...GA

We can use any sensor that can measure temperature. Actually I meant that, I think we can not use the sensor directly to the winding because of high voltage problem. So we are using some indirect method for measuring winding temperature.

I asked about that......

It takes the temperature of the winding using some form of sensor, and converts it to a signal that can be displayed on some sort of indicating device.

All thermometers do that.

My question is how we can measure the temperature of the winding directly since there is high voltage problem exist. Insertion of a sensor to the winding and the associated system including the outside indicator will reduce the insulation between winding and outside body considerably. So I think we can't use the sensor directly.

That is my point of question. How the measurement of winding temperature is done ?

Is there any indirect measuring method ? What is the method ?

I hope now Tornado, Kvsridhar & PWslack could understand my point...

I think that only the transformer manufacture could have this information. The windings themselves will of course be hotter than the surrounding oil, by an amount proportional to the load on the transformer (with some adjustments for ambient temperature, etc.)

Finally I got something..

http://www.fasint.it/pdf_formazione/Monitoring_HV_Power_T_using_Fibreoptics.pdf

http://electronicdesign.com/article/analog-and-mixed-signal/monitor-transformer-winding-s-temperature-without-

Glad you got something, though the pages don't load in my PC. Anyway, i thought i mentioned opto-isolation in the PM we exchanged?

Right.. As you told one way is to isolate high voltage area optically.

The winding temp. is always going to be higher than the oil temp.Also the winding temp. is going to be proportional to the load, so by using these two values you can get winding temp.