Glossary · Automation fundamentals, platforms and components
Overvoltage protection
Also known as: Surge protection, Surge protective device (SPD)
German: Überspannungsschutz
In electrical engineering, overvoltage protection is the set of measures and devices, such as surge protective devices (SPDs), that limit transient overvoltages caused by lightning or switching operations to values the equipment can withstand.
- Automation components
In one sentence
Overvoltage protection limits transient overvoltages from lightning or switching to safe levels, typically using surge protective devices.
Example
Surge protective devices on the signal lines of a remote pumping station protect the PLC inputs after lightning strikes nearby.
How it applies
- Engineering: Protection concepts use coordinated SPD types at the building entrance, distribution boards and equipment, plus protection on data and signal lines. Equipotential bonding is a prerequisite.
- Maintenance: SPDs age with each surge; many have status indicators or remote signaling contacts and need periodic inspection.
- Documentation: Installation documentation should show where SPDs are installed, their type and connection. Maintenance manuals should include inspection intervals and replacement criteria.
- Operation: Remote signaling of SPD status lets operators replace worn protective devices before the next surge.
Overvoltage protection vs. overcurrent protection
Overcurrent protection (fuses, circuit breakers) disconnects when current is too high. Overvoltage protection limits voltage peaks, usually for microseconds, without interrupting supply. Both are needed and serve different purposes.