How to minimize the grounding impedance of a power line carrier PLC?

Minimizing the grounding impedance of a power line carrier PLC requires optimization of grounding materials, connection methods, and paths. High-conductivity materials should be selected, such as copper busbars (resistivity ≤ 0.0175 Ω·mm²/m) or tin-plated copper strips, with the cross-sectional area chosen based on the current, typically ≥ 2.5 mm². Connection points should be welded or crimped to ensure contact resistance is less than 1 mΩ. Grounding paths should be as short and straight as possible, avoiding bends to reduce inductive effects. For high-frequency grounding, a multi-point grounding strategy should be used, arranging an array of grounding vias (0.3 mm diameter, 2 mm spacing) on the PCB to reduce ground plane impedance. System-level grounding should use a star topology, with all ground wires converging to a single grounding point. During testing, a four-wire milliohmmeter should be used to measure the grounding resistance, with a target value less than 0.1 Ω. Simultaneously, a network analyzer should be used to measure the frequency characteristics of the grounding impedance, with impedance less than 1 Ω in the carrier frequency band. Through optimization, grounding noise can be reduced by more than 20 dB.