MSENS voltage sensors (Low Power Voltage Transformers - LPVT) are specially designed to be installed in OEM busbar or feeder connection systems of MV cubicles and switchgears, allowing factory-installation and test avoiding in field installation concerns. Arc protection system is used to prevent short circuit by arc light for circuit breakers in medium & low voltage busbar and switch cabinet applications. There are no special requirements for primary equipment, and it can be used in. SEL combines light-sensing technology with fast overcurrent protection to provide high-speed arc-flash detection. SEL combines. The arc flash is one of the most dangerous incidents in electrical installations that could cause severe harm to people and equipment involved. They provide an accurate voltage.