Table of Contents
What tests are performed for testing of 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 are the other methods of testing transformers?
Four Methods for Testing Transformers
- Turns Ratio Testing.
- Insulation Resistance Testing.
- Power Factor Testing.
- Resistance Testing.
Why do we test transformer oil?
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.
What is crackle test of transformer oil?
The crackle test is a standard laboratory test to detect the presence of water in lubricating oil. A drop of oil is placed on a hotplate that has been heated to approximately 400° F. The sample then bubbles, spits, crackles or pops when moisture is present.
How many types of transformer tests are there?
Transformer manufacturers perform two main types of transformer testing – type test of transformer and routine test of transformer. Some transformer tests are also carried out at the consumer site before commissioning and also periodically in regular and emergency basis throughout its service life.
What is the Colour of transformer oil?
Generally, oil that is yellow, orange, or even somewhat red in color is fresher and will work as intended. As oil ages, it transforms to a brown or black color and its efficacy diminishes.
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 BDV in transformer?
The dielectric strength of transformer oil is also known as the breakdown voltage (BDV) of transformer oil. Breakdown voltage is measured by observing at what voltage, sparking strands between two electrodes immersed in the oil, separated by a specific gap.
What are the methods to test transformer oil?
Visual Examination.
Why it is so important to test the transformer oil?
Transformer oil testing is important to: Determine essential electrical properties of transformer oil Identify if a certain oil is suitable for future use Detect whether regeneration or filtration is needed Reduce oil costs and enhance component life Prevent untimely failures and maximize safety
What standards to use for transformer oil testing?
International transformer oil testing standards VDE370-5/96 OVE EN60156 IEC 60156/97, ASTM1816-04-1 ASTM1816-04-2 ASTM877-02 ASTM877-02B AS1767.2.1 BS EN60156 NEN 10 156
What is the PPM test in transformer oil?
PPM stands for Parts Per Million. It is used to measure the weight of moisture divided by the value of oil. The moisture content in oil lowers the insulating system dielectric strength that permits flashover to harm a transformer. For example, for mineral oil, a generally accepted maximum moisture content is 35 ppm.