• Electrical India
  • Mar 5, 2016

Advance Energy Efficient Transformers Testing

To prove that the transformer meets customer’s specifications and design expectations, the transformer has to go through different testing procedures in manufacturer premises...

D A Suthar


Electric transformers become a part and partial of all Modern industries, Smart manufacturing Industries, Automation Industries, Textile, Refrigeration, all Multi National Co as well as all process Industries. without transformer one can not Imagine their growth of over all Empire or Industries . No one can connect their Machine directly with National grid /power supply .or work directly on High Tension line or connect Equipments directly with Electrical Supply.

What is transformer?

     “The transformer is static part of apparatus by means of which an electrical power is transformed from one A.C circuit to another with the desired change in voltage and current, without any change in frequency”
Transformer manufacturer Offer Wide range of sophisticated High quality industrial grade single and three phase electrical transformers .with

• A Grade Quality having 97-99 % Efficiency,
• B Grade 90-95 % and
• C grade less than 85 % Efficiency as per demand of Customer at reasonable prices.


     The various range of products are Single-phase, Three-phase, Isolation transformers, Distribution transformers, Drive isolation transformers, Autotransformers, Motor-starting autotransformers, line reactors, Epoxy coated transformers. K-factor rated transformers, low temperature rise, low electromagnetic field emission transformers, Electrostatic shielded transformers, Special voltage transformers, and Epoxy sealed transformers. And widely popular Dry-type transformers with long and trouble-free life.

     Transformers are designed according to the required international standards such as DIN/VDE / IEC or IS. Furthermore, they fulfill all climatic, environmental and fire protection requirements. Basic surge level, the environmental protection requirements are taken into account in the design of Cast Resin Transformers. So customer should aware about which Types of transformer testing is necessary for his applications .



Tests done at Factory

• Type Tests
• Routine Tests
• Special Tests

Tests done at Site

• Pre Commissioning Tests
• Periodic/Condition Monitoring Tests
• Emergency Tests

Type test of transformer

     To prove that the transformer meets customer’s specifications and design expectations, the transformer has to go through different testing procedures in manufacturer premises. Some transformer tests are carried out for confirming the basic design expectation of that transformer. These tests are done mainly in a prototype unit not in all manufactured units in a lot. Type test of transformer confirms main and basic design criteria of a production lot.

Routine tests of transformer

     Routine tests of transformer are mainly for confirming operational performance of individual unit in a production lot. Routine tests are carried out on every unit manufactured.

Special tests of transformer

     Special tests of transformer are done as per customer requirement to obtain information useful to the user during operation or maintenance of the transformer.

Pre commissioning test of transformer

     In addition to these, the transformer also goes through some other tests, performed on it, before actual commissioning of the transformer at site. The transformer testing performed before commissioning the transformer at site is called pre commissioning test of transformer. These tests are done to assess the condition of transformer after installation and compare the test results of all the low voltage tests with the factory test reports.

Type tests of transformer includes

• Transformer winding resistance measurement
• Transformer ratio test
• Transformer vector group test
• Measurement of impedance voltage/short circuit impedance (principal tap) and load loss (Short circuit test)
• Measurement of no load loss and current (Open circuit test)
• Measurement of insulation resistance
• Dielectric tests of transformer
• Temperature rise test of Transformer
• Tests on on-load tap-changer
• Vacuum tests on tank and radiators

Routine tests of transformer

• Transformer winding resistance measurement
• Transformer ratio test
• Transformer vector group test
• Measurement of impedance voltage/short circuit impedance (principal tap) and load loss (Short circuit test)
• Measurement of no load loss and current (Open circuit test)
• Measurement of insulation resistance
• Dielectric tests of transformer

Tests on on-load tap-changer :

Oil pressure test on transformer to check against leakages past joints and gaskets.
That means Routine tests of transformer include all the type tests except temperature rise and vacuum tests. The oil pressure test on transformer to check against leakages past joints and gaskets is included.

Special Tests of transformer include:

• Dielectric Tests
• Measurement of zero-sequence impedance of three-phase transformers
• Short-Circuit Test
• Measurement of acoustic noise level
• Measurement of the harmonics of the no-load current
• Measurement of the power taken by the fans and oil pumps
• Tests on bought out components / accessories such as buchhloz relay, temperature indicators, pressure relief devices, oil preservation system etc.

Standard used:
IS 2026, IS 11171, IS 12012

Reference standards: IS 2026-5
   IEC 60076-5
   IEEE Std C57.12.90 (1999),
   IEEE Std C57.12.00 (2000)

Purpose: To verify the integrity for stresses, primarily mechanical, developed when a short-circuit current flows through the transformer.

TESTS PERFORMED For 1φ Transformers:

Following Routine test on transformers as per IS-2026.
• Resistance Test
• Insulation Resistance Test (MEGGER).
• No load test
• (Open ckt test)Short Circuit test. (Full Load Test).
• High Voltage Test.
• Temperature Rise.
• Vibration Test.
• Customer specific test.

Conclusion

Transformer manufacturer Offer Wide range of sophisticated High quality industrial grade single and three phase electrical transformers if customer asked for lower price Transformer they suffer after few years so always use energy efficient transformer.


D A Suthar Chif Project Executive, Advance Magnetronics