How does a transformer oil temperature indicator work?

A transformer oil temperature indicator works by utilizing a temperature sensor, typically a thermocouple or resistance temperature detector (RTD), immersed in the transformer oil. As the oil temperature changes, the sensor generates a corresponding electrical signal. This signal is then transmitted to a display unit, which converts it into a readable temperature value. This allows for real-time monitoring of the oil temperature, ensuring the transformer operates within safe thermal limits to prevent overheating and potential damage.