How to protect against high-voltage DC power surges in data center switches?

Data center switches are gradually adopting 240V/336V HVDC high-voltage DC power supply, requiring surge protection to adapt to higher operating voltages. Based on IEC61000-4-5 Level 4 requirements, a TVS reverse withstand voltage VRWM of 1.2 times the bus voltage (336V × 1.2 = 403V) is selected. A 15KP440CA voltage regulator from Yinte Electronics (VRWM = 440V clamping voltage 713V peak pulse power 15000W) is connected in parallel to ground on the input line. A 2R600L-8X6 gas discharge tube (DC breakdown voltage 600V) and a 20D511K varistor (varistor voltage 510V) are connected in series to form a two-stage protection system. The measured residual voltage after a 4kV/2Ω surge is <650V, meeting the 800V withstand voltage requirement of the downstream DC-DC module. This solution has been applied to HVDC power supply systems in ultra-large data centers.