The test transformer can be used to generate power frequency high voltage, which acts on the insulation of the tested product to test the insulation. The insulation of the tested product is closely related to the normal operation of power equipment and power grid systems.

To choose a test transformer, you need to understand the type of test transformer:

Several factors need to be considered:

Voltage, according to the tested product, the voltage of the test transformer should be considered at the beginning. The selection principle is based on the rated voltage of the high-voltage side of the test transformer should be higher than the test voltage of the tested product. In addition, we must also consider whether the voltage on the low-voltage side of the test transformer can match the field test conditions. According to regulations, the voltage levels of test transformers include 5, 10, 25, 35, 50, 100, 150, and 300KV.

Current, the rated current of the output of the test transformer should be greater than the current required by the equipment under test. The magnitude of the current can be estimated based on the capacitance.

Capacity, the capacity of the test transformer can be determined according to the rated current and rated voltage of the test transformer and the formula P=UnIn. According to regulations, the capacity levels of our country's test transformers include 3, 5, 10, 25, 50, 100, 150, and 200KVA.

for example:

In terms of voltage level, the voltage level and capacity of the distribution transformer are 10kV, 1000kVA, and the test product is 10kV. Choose the test transformer of 50kV, 5kVA, because the factory test voltage of the 10kV, 1000kVA distribution transformer is 35kV, and the AC test The voltage is 30kV; the requirements of 10kV insulator, high-voltage switchgear test, and 10kV cable DC test can all be met.

In terms of test capacity, the capacity of the selected test transformer must be greater than the capacity corresponding to the capacitor current of the test product. It is generally believed that the capacity of the test transformer is 5‰ of the capacity of the test product (power transformer).