Test Standards And Precautions Related To Transformer Capacity Testers

The transformer capacity tester is a specialized device used to measure the actual capacity of a transformer quickly and accurately through low-voltage testing without the need for an external high-power power supply. It can also determine whether the transformer's capacity is consistent with the nameplate. Additionally, it can measure parameters such as no-load loss, load loss, and impedance voltage of the transformer.
Test standard
The transformer capacity and characteristic tests are mainly based on the following national and industry standards:
GB/T 1094.1-2013 "Power Transformers - Part 1: General Principles"
It stipulates the basic terms, definitions and general requirements for transformers.
GB/T 1094.5-2008 "Power Transformers - Part 5: Capacity for Withstanding Short Circuits"
Transformer Capacity Tester
The requirements related to short-circuit impedance.
GB/T 6451-2015 "Technical Parameters and Requirements for Oil-immersed Power Transformers"
It stipulates the standard values for the no-load loss, load loss and short-circuit impedance of transformers of various capacity levels. The built-in database of the capacity tester is precisely based on this standard.
GB/T 10228-2015 "Technical Parameters and Requirements for Dry-Type Power Transformers"
It stipulates the standard values for the no-load loss, load loss and short-circuit impedance of dry-type transformers of each capacity level.
DL/T 1256-2013 "General Technical Conditions for Transformer Short-Circuit Impedance Test Instruments"
Technical specifications specifically designed for such testing instruments.
Test Precautions for Transformer Capacity Tester
Safety first, prevent electric shock: It is necessary to ensure that the transformer is completely de-energized, isolated, and grounded. During the testing process, the transformer bushing and the test leads carry test voltage, although it is a safe voltage, vigilance is still required.
Correct wiring is crucial: Connect the current output to the high-voltage side, and the voltage measurement terminal to the low-voltage side while short-circuiting it. This is the standard wiring method for capacity testing. Incorrect wiring will result in completely wrong results.
Ensure good contact: The test clamp and the transformer bushing must be tightly connected to prevent the contact resistance from affecting the test accuracy.
Verify the connection group: The connection group set in the instrument must be consistent with the transformer nameplate; otherwise, the calculation results will be incorrect.
Environmental temperature: Record the ambient temperature during the test. The instrument needs to adjust the load loss to 75℃ based on this temperature.
Calibration of transformer capacity tester: Regularly send the instrument for calibration to ensure measurement accuracy.
Read the manual: The functions and usage details of different models of instruments vary. Before operating, be sure to carefully read the user manual provided by the manufacturer.