Quality assurance
Our key services
Certified power transformers laboratory
Elprom Heavy Industries operates a dedicated certified power transformers laboratory, accredited under Certificate No. A243 / 29.07.2022, in accordance with ISO/IEC 17025. The scope of accreditation is defined in Order No. A39 / 29.07.2022.
The laboratory performs routine and special tests on power transformers and tap changers in line with international standards and specific customer requirements.
To support a wide range of testing procedures, the facility includes a generator room capable of providing test voltages at 50 Hz, 60 Hz, and 200 Hz.

Transformer testing capabilities:
- Turn ratio and phase displacement measurement
- DC resistance of windings
- No-load losses and harmonics in no-load current
- Short-circuit impedance and load losses
- Zero-sequence impedance
- Heat run test & power consumption of cooling systems
- Sound level and vibration measurements
- SFRA (Sweep Frequency Response Analysis)
- Watt balance test
- Capacitance and power factor (tan δ) measurements
- Insulation resistance
- Oil breakdown voltage
- Lightning impulse test (including chopped wave)
- Switching impulse voltage test
- Separate source AC withstand voltage test
- Induced overvoltage test
- Partial discharge measurements
- Transient voltage transfer analysis through windings
Tap changer testing capabilities:
The laboratory is also accredited for performing the following tests on transformer tap changers:
- Lightning impulse (LI)
- Chopped lightning impulse (LIC)
- Switching impulse (SI)
- Applied voltage (AV)
- Partial discharge measurement
Legacy and reliability




