What tests are carried out before the transformer leaves the factory

Before the transformer leaves the factory, the transformer manufacturer will conduct certain tests on the quality, function and service life of the transformer. The general transformer test includes two types, factory test and type test. The transformer type laboratory conducts a representative test to verify whether the transformer meets the specified technical conditions. So, what tests will be performed before the transformer leaves the factory?   Transformation ratio, group, direct resistance, no-load, load, capacity, power frequency withstand voltage, inductive withstand voltage, insulation resistance, dielectric loss, partial discharge, impulse voltage, etc. of the test items required for the transformer factory test.

What tests are carried out before the transformer leaves the factory

 What tests are carried out before the transformer leaves the factory    1. Voltage detection   Detect and test the online voltage and offline voltage of the transformer    Transformer voltage detection   2. Grounding resistance    Grounding resistance refers to the resistance generated when current flows from the grounding body into the soil. This is the ground resistance.   3. DC resistance    DC resistance is the resistance that the element exhibits when direct current is applied, that is, the inherent static resistance of the element. For example, when the coil is connected to direct current and alternating current, its resistance is different. When connected to alternating current, in addition to DC resistance, the coil also has reactance, which reflects the synergistic effect of resistance and reactance, which is called impedance.   4. Short-circuit resistance    It is a very important item in the transformer performance index. The deviation between the actual measured value and the specified value when leaving the factory is very strict.    Transformer short-circuit resistance    5. Output resistance    The output resistance test is mainly used to measure the important index of the amplifier’s influence on the signal source. The smaller the output resistance, the stronger the output capability of the amplifier.   6. ​​Withstand voltage test    can effectively find the overall defects of the insulation, such as moisture and dirt, through the relationship between the current and the leakage current can find the local defects of the insulation. Since the voltage is divided by the insulation resistance under DC voltage, it is more effective to find terminal insulation defects than AC voltage. 

What tests are carried out before the transformer leaves the factory

  7. No-load characteristics    No-load characteristic refers to the change curve of the generator stator voltage and rotor current when the load current is zero at the rated speed of the generator.    8. Transformation ratio test    is mainly used to test the transformation ratio of power transformers.   9. Load test    is mainly to ensure that the transformer can still operate normally when the load exceeds the expected load.   10. Heating test    is used to determine the adaptability of the product in storage, transportation and use under high temperature climate conditions. The severity of the test depends on the high temperature and exposure time.

The above are the 7 common common faults of oil-immersed transformers. If there are other problems or you are not sure, you can contact us in time: info@hengfengyou.com

Published by hengfengyou

Qingdao Hengfengyou Electrical Engineering Co., LTD., subordinate to Hengfengshuai Group, is an export-oriented enterprise with transmission and distribution industry as its main business, integrating product research and development, manufacturing and trade. Its main products include power transformers, medium and low voltage switch cabinets, circuit breakers and other power distribution equipment and power engineering services.

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