3-phase bus differential relay
The REB 103 bus differential relay is a high-speed percentage restrained differential relay. The operating time for an internal bus fault is 1-3 ms and trip impulse is sent to the breakers within 6-9 ms. The high speed of operation ensures power system stability also for busbar faults with very high fault currents.
REB 103 is suitable for all types of bus configurations: 1, 2, 3 and 6-zones, with switching of CT secondary circuits. Full stability is guaranteed during the switching operations, owing to the method of reconnecting the circuits and, also, by the percentage operating and starting relay features.
Intermediate current transformers are used for adjustment of the CT-ratios, other relays can be inserted in the same CT-loop.
- Percentage restrained differential relay for phase-to-phase and phase-earth faults
- Very high E/F-sensitivity of the differential relay element in directly earthed networks
- High speed of operation, detecting an internal fault within 1-3 ms and sending an output trip signal within 6-9 ms
- Fully stable in the event of faults outside the protected zone