The Brazilian standard (ABNT - NBR 5356) establishes that all transformers must undergo routine tests. Do you know what that means?

The use of dry-type transformers is commonly found in spaces that require medium or low voltage power adaptation, such as data centers, airports, hospitals, and commercial buildings. This is because they offer a series of benefits, as greater security, reduced space, and low maintenance levels.

The Brazilian standard (ABNT – NBR 5356) establishes that all transformers must undergo routine tests.

Routine testing
Routine tests are tests performed to ensure the proper functioning of a transformer.

Check below to see what these tests are: 

Turns ratio test
The purpose of this ratio is to ensure that the number of turns between windings conforms to the design, thereby ensuring that the input and output voltages remain within a range that does not deviate by more than +/- 0.5% and that the actual values fall within the specified range.

Ohmic resistance test of windings
The essay aims to compare calculated values with measured values and to check for loose connections and interruptions.

Insulation resistance test
Verify solid insulation levels of transformers between windings and ground. 

Applied Stress Test
It consists of applying a specific voltage to the equipment within the range determined by the standard, and there must be no insulation breakdown.

Induced Tension Test
The test consists of applying double the nominal voltage, at a frequency of at least 120Hz for the standardized calculated time. No disruptive discharges are allowed.

 No-load test and excitation current
Perform loss measurements through nominal voltage and frequency, and compare the obtained values with the design and standard.

Short-circuit Losses and Impedance Test
Measurements of losses are performed using nominal current and frequency, and the obtained values are compared with the design and the standard.

Partial discharge measurement
Fundamental test for verification of material and process variables during the manufacturing period.

The process requires strict control of productive activities and monitored follow-up.

The equipment is subjected to standard values and times. The results must be evaluated and compared according to ABNT NBR 5356.