overspændingsbeskyttelsesudstyr

Overspændingsbeskyttelse, or overvoltage protection, encompasses devices and practices designed to limit transient overvoltages on electrical installations. The goal is to minimize damage to equipment, reduce downtime, and improve safety by keeping voltages within acceptable levels during surges such as lightning strikes, switching operations, or grid faults.

Common technologies include surge protective devices (SPDs). The main components are metal-oxide varistors (MOVs), gas discharge tubes (GDTs), and transient voltage suppression diodes (TVS). SPDs are chosen by their voltage protection level (the maximum surge voltage they let through) and energy rating. MOVs shunt excess energy to earth; GDTs provide rapid, high-energy discharge with a high isolation when not conducting; TVS diodes protect sensitive electronic circuits by clamping fast transients.

Categories and applications: Type 1 SPDs installed at service entrances to withstand external surges; Type 2 at distribution boards to protect downstream devices; Type 3 at point of use for sensitive equipment. Applications span residential, commercial, industrial, and data networks. Good practice includes proper grounding, coordinated protection, and regular testing to ensure functionality and compatibility with the installation.

Standards and maintenance: Standards such as IEC 61643-1 (general SPD requirements) and IEC 60364 for electrical installations, as well as UL 1449 in North America, define performance criteria and testing methods. The protection system should be sized for expected surge energy and the installed equipment’s vulnerability. SPDs can degrade over time and should be inspected; power quality issues and improper installations limit effectiveness.