Complementing an extensive portfolio of protection relays for distribution and industrial grids, the primary application for the Reyrolle 7SR46 is to provide overcurrent and earth fault protection in medium-voltage distribution transformer stations. Mounted in a ring main unit, the protection device detects cable faults on the network and operates quickly to disconnect the fault.
Due to their often remote locations, secondary substations do not always have a battery to provide power to electronic equipment, such as protection relays. With this in mind, the 7SR46 has been designed to operate using power from current transformers (CTs) when the line is live. Addressing scenarios whereby the line is switched off and there is already a fault on the line, or the earth connection has been mistakenly left connected, the 7SR46 has been specifically designed to power up quickly to provide protection in such circumstances.