What tests are done on transformer oil?
The “screen test” is a collection of physical, electrical and chemical tests for the transformer oil. These tests include dielectric breakdown, power factor, interfacial tension, acidity, and color. A larger quantity of oil is needed for these tests.
What is the BDV value of transformer?
As per IEC, the minimum breakdown voltage of transformer oil should be not less than 30 KV. The BDV of transformer oil does not depend on the voltage rating of the transformer. Minimum transformer BDV value for either 11 KV, 22 KV, 132 KV is the same. The minimum transformer oil BDV is 30 KV.
What is the BDV test?
BDV test means the Breakdown Voltage Test. This test is performed for verifying the dielectric strength of the oil of the transformer. Dielectric Strength is the maximum capacity to resist the voltage of insulating oil.
What is TTR testing?
Transformer Turns Ratio (TTR) testing is one of the most common ways of assessing the condition of a transformer’s windings and core. Throughout the life of a transformer, TTR results are compared against the nameplate ratings to reveal insulation deterioration, shorted turns, core heating or other abnormalities.
How do I increase BDV oil?
Dry and clean oil gives BDV results, better than the oil with moisture content and other conducting impurities.
What is Megger test of transformer?
The insulation resistance test (meggering) is of value for future comparison and also for determining if the transformer is to be subjected to the applied voltage test. The winding insulation resistance test is a DC high voltage test used to determine the dryness of winding insulation system.
What is DVDF test in transformer?
Double Voltage Double Frequency Test Set DVDF Test Set is Induced Over Voltage Test Set is used for testing the strength of insulation between turns and between other points of the transformers.
What is UST mode?
UST mode is used to measure insulation between two ungrounded terminals of the apparatus, isolate an individual section of insulation and test it without measuring other connected insulation.
What is PRV and PRD?
A Pressure Relief device (PRD of Transformer) is also called Pressure Relief Valve(PRV). A (PRV) is a type of valve used to release stored gas in various equipment in order to maintain an optimal pressure level. PRV opens gradually as pressure builds up in order to release the necessary amount of pressure.
What is the minimum megger value?
Insulation resistance should be approximately one megohm for each 1,000 volts of operating voltage, with a minimum value of one megohm.
How is IR value calculated?
R=1+V, Here R=resistance in mega ohm(MΩ) , V= equipment rated voltage in KV. So if we like to check a machine rated voltage is 11 KV, the minimum tolerated insulation resistance will be R=1+11=12MΩ, and for a motor with 220 voltage rating the IR value will be R=1+. 220=1.2MΩ.