How to suppress lightning overvoltage in frequency converters

Suppressing lightning overvoltages in frequency converters requires a multi-level protection and system grounding scheme. Lightning strikes generate enormous energy and can enter through power lines, signal lines, or through direct induced coupling.

Suppression measures include:

First-level protection: installing a surge protector at the building's power inlet.

Second-level protection: installing a suitable power surge protection module at the power inlet of the frequency converter cabinet, typically using voltage-limiting SPDs, such as varistors.

Third-level protection: installing TVS or varistors for fine protection at the DC bus or critical power inlets inside the frequency converter.

For signal ports, such as communication and control lines, signal surge protectors should be used, and their grounding must be reliable. All surge protectors must be grounded together to a low-impedance grounding system, with the grounding resistance as low as possible. The cabinet itself should be well grounded to provide a discharge path for lightning current. Optimize cabling by separating power lines and signal lines and avoiding parallel routing. Using shielded cables and proper grounding can reduce induced overvoltages. Verify the effectiveness of the protection scheme through simulated lightning strike tests. Yinte Electronics provides surge protection devices at all levels for frequency converter systems and complete protection solution design support.