Analysis of Test Transformer Faults

In what scenarios are VLF, variable-frequency series resonant, and power-frequency withstand voltage tests respectively suitable?

How to Choose Between 30kV, 50kV, 60kV, 80kV, and 90kV VLF High-Voltage Generators？

Can VLF (Very Low Frequency) withstand voltage testing be used for 10kV and 35kV cables?

Why is an ultra-low frequency high voltage generator commonly used for voltage withstand tests on 10kV cables?

High-Precision CT Tester: 14 Specifications to Compare