OTI WTI Buchholz relay Insulation resistance testing
OTI & WTI Meter Calibration and Tripping Testing
These are generally precision instruments. A temperature indicator of power transformer is specially designed for protection of transformer in addition to its temperature indication and cooling control features. That means, this device performs three functions
1) These instruments indicate instantaneous temperature of oil and windings of transformer.
2) These also record maximum temperature rise of oil and windings.
3) These instruments operate high temperature alarm at a predetermined value of allowable temperature limit.
Buchholz Relay testing with tripping
In the field of electric power distribution and transmission, a Buchholz relay is a safety device mounted on oil-filled power transformers and reactors, equipped with an external overhead oil reservoir called a conservator. The Buchholz relay is used as a protective device sensitive to the effects of dielectric failure inside the equipment which cause production of gas.
This switch energized the trip circuit of the circuit breakers associated with the transformer immediately isolate the faulty transformer from the rest of the electrical power system by inter tripping the circuit breakers associated with both LV and HV sides of the transformer. This is how Buchholz relay functions.