Table of Contents
What are some of the causes of gasses being formed in transformer oil?
There are two reasons why key gases are formed – thermal and electrical disturbances. During thermal disturbances, gases are produced from the decomposition of oil and solid insulation.
What is gassing in a transformer?
Stray gassing of hydrogen refers to the generation of hydrogen under moderate temperatures in the transformer. The cause has been attributed to the refining process and the possible presence of certain incompatible materials in the transformer or additives in the oil.
Why transformer oil testing is required?
Transformer oil, a type of insulating and cooling oil used in transformers and other electrical equipment, needs to be tested periodically to ensure that it is still fit for purpose. This is because it tends to deteriorate over time.
Why is nitrogen used in transformers?
To put out the fire in a transformer, were it to occur, we can reduce the oxygen level by displacing it with nitrogen gas. The nitrogen pressure in the transformer also helps to reduce the top oil pressure and temperature which is critical for preventing an explosion.
How many types of faults are Categorised in DGA?
Within the triangle there are six (6) potential fault zones covering partial discharges, electrical faults (arcing high and low energy), and thermal faults (over various temperature ranges), plus a DT zone (mixture of thermal and electrical faults).
Is BDV of transformer oil used in 11kV substation?
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 DGA test for transformer oil?
Dissolved Gas Analysis (DGA) tests are performed on the transformer’s cooling and insulating oil. It is of necessity a laboratory test and not a field test. Field testing of transformer oil is usually confined to dielectric strength (spark gap) testing.
What is dissolved gas analysis for transformer insulating oil?
These gases can be detected in transformer insulating oil using sensitive and reliable Dissolved Gas Analysis (DGA) techniques for determining the type of pending or occurring fault. DGA is considered the best method for determining a transformer’s overall condition and is now a universal practice. Advantages of DGA include:
What is dissolved gas analysis (DGA)?
by Electrical4U Dissolved gas analysis (DGA) is the study of dissolved gases in transformer oil. It is also referred to as a DGA test. Whenever a transformer undergoes abnormal thermal and electrical stresses, certain gases are produced due to the decomposition of the transformer oil.
Why perform a transformer condition assessment and failure analysis?
For these reasons, transformer condition assessment and failure analysis is a high priority. Over time, electrical and thermal stresses on a transformer’s insulating materials (arcing, corona discharge, sparking, and overheating) can result in incipient transformer faults.