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This post was last edited by Jibao NARI – Microcomputer Protection – Islanding Prevention – Zhang on 2020-2-20 at 19:17. What is an arc flash protection device? In China, in cases of short-circuit faults in medium and low-voltage busbars, arc flashes are the main cause of damage to critical equipment and injuries to personnel. However, most medium and low-voltage busbars in China do not have rapid busbar protection systems; instead, only simple arc suppression devices and transformer relay protections are used. These protections have lower intelligence levels and slower response speeds, which often prolongs the time required to eliminate faults. This further increases the extent of equipment damage, and may even lead to catastrophic accidents in which one failure triggers others, affecting the normal operation of transformers and compromising the safe functioning of the entire power grid. The solution is to use arc flash protection devices, with arc flash sensors being installed in various areas within the switchgear (typically in the busbar compartment and cable compartment to detect faults in the busbars and cables), thereby meeting the requirements for zone-based protection. The arc flash control system can indicate the location of the fault, allowing for rapid identification and handling of the problematic area. Scope of application: It is mainly applicable to the microcomputer-based protection for busbars and switching equipment at voltage levels below 110 KV. Arc flash protection is primarily used for the protection of medium and low voltage busbars within switchgear, the protection of feed cable connectors, the protection of box-type substations, and the protection of rectifier cabinets. The main functions of arc flash protection devices: 1. To reduce or minimize the harm caused by arc flashes to human beings ； 2. Reduce or minimize the damage caused by arc flash short-circuit faults to equipment ； 3. Prevent the transformer from suffering damage to its dynamic stability due to faults in the nearby busbars, thereby extending its service life ； 4. Reduce the time required to eliminate arc flash faults, thereby preventing damage to the station’s DC system and avoiding significant losses ； 5. Reduce the downtime of equipment caused by arc flash failures, and restore power supply more quickly.