“…The PD test platform used in this study comprises the voltage regulator, the test transformer, the protection resistance, the discharge sample, the high-frequency current transformer (HFCT), and the high-frequency oscilloscope, among other components, as depicted in Figure 1 . The HFCT, known for its exceptional sensitivity, straightforward setup, and strong anti-interference capabilities [ 43 ], is a widely used instrument for the online detection of PD signals, particularly when the ground conductor of the device under test is accessible. The circuit of the PD test platform is illustrated in Figure 2 .…”