WTI and OTI in Transformers

 

What is WTI and OTI in transfomers

Transformers play an important role in the electricity transmission and distribution process after the generation process. They are installed on substations to step down or step up the voltage values.

While “Oil” is fed into the transformer for cooling purposes. Both oil and the winding are enclosed in the tank which does not allow any physical interacting for the people on duty. Thus, monitoring of transformer winding and oil is only possible from outside. While OTI means Oil Temperature Indicator and WTI means Winding Temperature Indicator, the devices that show us the values of oil and winding temperature are called OTI and WTI respectively.

Since oil and the winding temperature are directly proportional to load, regular monitoring of oil and winding temperature is mandatory. In addition, since winding is dipped in the oil, as soon as the transformer winding temperature increases, the oil temperature also increases.

Reading of WTI and OTI

1.      WTI

 

source:  electricknowhow.com

·      The meter has 2 needles (black and red). The ‘black’ tells us the present condition of the winding temperature. The ‘red’ tells us the amount of winding temperature that has rose i.e., WTI tells us the present temperature and the maximum temperature of winding.

·      We can see 150-degree values of WTI, meaning at 150-160 degrees of winding will burn up and this is the maximum temperature value.

·      Tripping-In industries, the tripping values of WTI is usually set to given ‘alarm’ on 85-degrees and ‘tripping’ at 95-degrees.

2.     OTI

 

source: electricknowhow.com

·      Similarly, OTI has also 2 needles, showing the present and the maximum temperatures.

·      We can see 150-degree values of WTI, meaning at 150-160 degrees of winding will burn up and this is the maximum temperature value.

·      Tripping-In industries, the tripping values of WTI is usually set to given ‘alarm’ on 80-degrees and ‘tripping’ at 90-degrees.