How can grounding in a power DTU system improve its immunity to disturbances?

Improving the immunity of a DTU system requires comprehensive optimization of grounding design and protection measures. A tiered grounding system is adopted: the primary ground is for safety, with a resistance <0.1Ω; the secondary ground is for signal grounding, isolated from the primary grounding via an isolation transformer or optocoupler. A common-mode inductor CML4532A-510T and a TVS diode SMCJ24CA are deployed in the signal grounding system. For radio frequency interference, shielded cables are used, and both ends of the shield are grounded (length <λ/20). The grounding system's response to interference is analyzed through simulation. In actual testing, the system should pass EFT ±4kV, surge ±2kV, and ESD ±8kV tests. Grounding optimization can improve system immunity by 20dB, resulting in more reliable communication.