Did you know that over 70% of transformer failures start with contaminated oil? And the first warning sign? A low BDV value.

Breakdown Voltage (BDV) Testing is a laboratory method used to determine the dielectric strength of mineral insulating oil used in transformers and oil-filled electrical equipment. The test measures the voltage at which the oil electrically breaks down under standard conditions.

At Oorja Technical Services, we provide BDV testing of transformer oil through our NABL-accredited transformer oil testing laboratory. Conducted as per IS 6792:2023 / IEC 60156:2018, and guided by maintenance practices in IS 1866:2017 / IEC 60422:2013, our laboratory BDV testing helps industries assess insulation performance, detect contamination, and prevent transformer failures.

It is one of the most important preventive maintenance tests in electrical asset management — and we do it right.

WHY BDV TESTING MATTERS

Transformer oil plays two critical roles — it insulates the internal components and cools the transformer during operation. But over time, this oil degrades.

What reduces BDV?

• Moisture ingress
• Carbon particles from arcing
• Sludge formation
• Oxidation byproducts
• Dust and dirt

A low BDV value increases the risk of internal arcing, flashover, and complete insulation failure.

Benefits of Regular BDV Testing:

• Early detection of contamination
• Improved transformer reliability
• Reduced risk of electrical breakdown
• Compliance with industry safety standards
• Extended equipment service life
• Cost-effective preventive maintenance

Laboratory testing provides accurate, repeatable, and standard-compliant results — something field tests cannot guarantee.

BDV TEST METHOD: IS 6792:2023 / IEC 60156:2018

Our transformer oil testing laboratory follows strict procedures to ensure accuracy:

We use an automatic bdv tester for precise, repeatable results — eliminating human error.

BDV ACCEPTANCE CRITERIA

As per transformer oil bdv test standards, here's what the values mean:

Note: Acceptance values may vary based on equipment voltage class and internal maintenance policy. Always refer to equipment manufacturer guidelines.

For new oil as per IS 335, the minimum BDV should be 50 kV. For in-service transformers, values above 40 kV are generally acceptable.

WHAT YOU CAN DO WITH BDV TESTING

✔ Decide whether oil needs filtration or replacement
✔ Approve new oil before transformer commissioning
✔ Monitor oil condition periodically (quarterly/half-yearly)
✔ Compare oil quality trends over time
✔ Support preventive maintenance planning
✔ Ensure compliance with IS 1866:2017 guidelines
✔ Document oil health for audit purposes

 WHAT YOU SHOULD NOT DO

✘ Do not rely only on BDV for transformer health assessment
✘ Do not ignore moisture testing — it goes hand-in-hand with BDV
✘ Do not test visibly contaminated samples without pre-treatment
✘ Do not skip electrode cleaning between tests
✘ Do not compare results without considering the voltage class
✘ Do not use expired or uncalibrated BDV testers

Following proper testing procedures ensures reliable, repeatable results.

BEYOND BDV: COMPLETE TRANSFORMER OIL ANALYSIS

While BDV testing is essential, it tells only part of the story. For a complete transformer health assessment, combine it with:

At Oorja Technical Services, we offer complete transformer oil analysis through our NABL-accredited transformer oil testing laboratory — so you get the full picture.

INDUSTRIES WE SERVE IN INDIA

BDV testing services in India are required across:

Wherever there's a transformer, regular transformer oil testing is part of mandatory maintenance programs