How are surge protection levels classified on the power side of a power DTU?

The tiered design of surge protection on the power side of the DTU requires determining the protection level based on the application scenario. Level 1 protection (inlet) uses a 2R600L-8×6 gas discharge tube with a current carrying capacity of 20kA (8/20μs). Level 2 protection (front-panel) uses a 14D511K varistor with a current carrying capacity of 6.5kA. Level 3 protection (panel level) uses a TVS diode SMCJ24CA with a current carrying capacity of 100A. Each level is coordinated with a decoupling inductor (10μH) or resistor (10Ω) to ensure energy is discharged step-by-step. The design conforms to the IEC61643-11 standard, with a test waveform of 8/20μs. The actual measured system should pass the combined waveform test (6kV/3kA). This tiered design ensures equipment safety under lightning strikes or operational overvoltages.