The Testing transformers depends on what you wish to know. If it has an iron-looking laminated core, it’s fair to assume it is made for use with horsepower. If it weighs less than one pound, you. might assume it works on 115 VAC.

If it is made with fine wire and wound around a ferrite core, it was made for higher frequency use. If you raise the voltage on the winding until the thing begins to warm up, you know what the maximum allowable voltage is, and you can measure the voltage on the other winding confirming the turns ratio. If you can see a fit for your needs, you can continue testing.

Now would be real-time to see for that. Is it best to line it aside and decipher what you wish? Go Transformer Manufacturer India and get what you wish or forge ahead!

What is the SFRA test of a transformer?

Sweep Frequency Response Analysis (SFRA) is to assess the mechanical integrity of a transformer. These changes can’t be detected through typical condition observation techniques.

Like Dissolved Gas Analysis, Winding Resistance mensuration, Capacitance, tan delta measurement, etc. Typically, even transportation while not correct precautions might cause some internal mechanical damages.

SFRA measurement, that is, signature analysis, provides essential data of the interior condition of the instrumentality so early correction action might be initiated.

What is the BDV?

BVD – Break Down Voltage

It might be any of the subsequent:

  • Dielectric BDV of transformer oil: this is often periodically done to check the insulator strength of used and filtered oil.
  •  Power Frequency BDV test:Here, you apply such a voltage per the relevant standards for a given electrical device winding. It ought to face up to that voltage (really, this is often referred to as Power Frequency face up to Voltage Test).
  • Impulse BVD test: Here, you take a look at the voltage face up to the capability of the Transformer Manufacturer Indiawinding with the 1.2 / 5 or (1.5 / 50 in the USA or 1 / 50 UK) impulse voltage of value specified as BIL ( Basic Impulse Insulation level) and therefore the insulation shouldn’t break down. (Really, this is often referred to as Impulse face up to Voltage Test).
  • Chopped impulse voltages will be applied and tested repeatedly.

For illustration, a 220 kilovolt / 100 and ten-kilovolt power transformer might influence frequency face up to the price of ( 220 / 1.732 )x F. F could also be regarding one, eight about to be designated from relevant standards. BIL could also be regarding 900kV, 1.2/ 50 wave, conjointly obtained Lightning Arrester rating, earthing status, etc.

Short circuit test of a transformer

A short circuit is finished in a transformer to search out the copper loss at rated load current if potential. The most current allowed to flow throughout the short is the rated current. Any winding may be shorted on paper; power, voltage, and current are measured within the alternative winding.

Note that voltage needed to pass rated current is regarding 5 to 10℅ of rated voltage.

How many varieties of tests are performed on transformer oil?

There are multiple tests for various purposes:

  • Insulating oil analysis (as per IS 1866:2000): In commission, electrical device insulating oil is subjected to deterioration because of varied service conditions. These changes affect each solid and liquid insulant that affects the functioning of transformer manufacturer Indiaand shortens the whole operating life.
  • BVD Breakdown Voltage: necessary to live the quality of insulating oil to resist electrical stress.
  • Interfacial tension: interfacial surface tension between oil and water detects the soluble polar contaminants.
  • Flash purpose: an occasional flash purpose indicates the presence of volatile flammable oil.
  • Dielectric Dissipation issue (DDF) & electrical resistance: It measures the outflow current through the oil.
  • Acidity and Neutralisation variety:Acidity of insulating oil ought to be allowed to exceed; otherwise, it will induce corrosion within the electrical device.
  • Water Content:It accelerates the deterioration of each insulating oil and paper insulation.
  • Sediments & Sludge:It contains insoluble oxidation or degradation products of insolent.
  • DGA Analysis: To sight the various inchoate fault conditions.
  • Furan Analysis: It is used to work out the condition of insulation paper.

Why is Indirect testing of massive transformers necessary?


As per transformer manufacturer India, the indirect testing of massive size transformer is necessary because:

  • For large transformers, actual conditions are severe and rigorous; if one thing is wrong (shorting) within the electrical device, in actual load, it’s going to cause an accident. To avoid such a scenario and to have safe and secured testing, indirect testing strategies are used.
  • It prevents loss like for energy meters. We tend to use phantom loading for testing that saves energy loss indirectly cash.
  • Technical issues are detected at early stages throughout indirect testing, which is designed consequently.
  • The cost/time of testing is additionally less.
  • No conclusion of power is needed in indirect testing.

What is the comprehensive testing of a transformer at substations?

Power transformer at the substations suggests that it’ll be a thirty-three / eleven kilovolt, or eleven / 440 kilovolt, or sixty-six / 132 kilovolt of various ranges of a hundred, 200, three hundred kVA then on, as per the wants of the electricity board. The subsequent examination tests to be conducted:

  • To test the wellbeing of the electrical device. To examine for any transit damages and if the outflow of electrical device oil. To examine the rigidity of terminals and to examine the general look of the transformer manufacturers in India.
  • To check the insulation resistance of each winding, it ought to be over two mega ohms.
  • Check the continuity of every set of the winding coils, and live the resistance of every winding.
  • To study the directions manual and nameplate details of the electrical device.
  • To check the proforma invoice issued by the provider and compare the norms whether or not they match what it’s mentioned on the plate details.


Transformers play a vital role in generating electricity, transmittal power, distribution, and utilization of electricity. Therefore, regular testing and maintenance of transformers are evident. These were a number of the test’s transformers. We hope this blog had all the answers you are in search of.


Please enter your comment!
Please enter your name here