Induced Overvoltage Test Set for Longitudinal Insulation of Electromagnetic Equipment such as Instrument Transformers



The Induced Overvoltage Test Set is a core high-voltage test equipment specifically used to assess the longitudinal insulation (inter-turn, inter-layer, inter-section) and phase-to-phase insulation strength of electromagnetic equipment such as transformers and instrument transformers.

Unlike the "external applied voltage withstand test" (directly applying high voltage to the winding-to-ground) you mentioned earlier, the induced overvoltage test applies voltage on the low-voltage side and uses electromagnetic induction to generate high voltage on the high-voltage side. This method not only tests the main insulation but also effectively detects hidden defects such as inter-turn short circuits within the winding.

Here is an in-depth analysis of this device:

1. Why use "triple frequency"? (Core principle)

This is the most critical technical point of the induced overvoltage test.

Problem: According to the transformer formula

B is proportional.

If at power frequency (50Hz) the voltage is increased to 2 times the rated voltage (e.g., from 10kV to 20kV) to test the longitudinal insulation, the magnetic flux density