RAHL/RXHL - Compact overcurrent relays RXHL 4xx and line protection RAHL 4xx
The four overcurrent and earth-fault relays RAHL/RXHL 401, 411, 421 and 422 are intended for power system applications and as backup to e.g. the 650 or 670 series terminals at all system voltage levels including EHV. All time-curves are provided according to IEC 60225-3, the thermal replica overload function and the RI and a special logarithmic curve for earth-faults in EHV systems are also available. Intermittent phase- and earth-faults can be detected. The relays are also intended for retrofit and replacement of earlier electromechanical and static relay designs.
- Three stages for phase overcurrent I>, I>>, I>>> alarm and trip functions
- Three stages for earth-fault alarm and trip functions
- Supersedes RXIDK 4 and RAIDK 400
RXHL/RAHL 421 for high impedance earthed systems
RXHL/RAHL 422 for solidly earthed or low impedance earthed systems
- Three stages of two-phase time-delayed or instantaneous overcurrent protection, I>, I>>, I>>> alarm and trip functions
- Three-phase thermal overload protection, Q> alarm and trip functions
- Three stages of time-delayed or instantaneous directional or non-directional earth-fault protection for effectively earthed networks, IN>, IN>>, IN>>> alarm and trip functions. - Polarising voltage down to 0.5%. - Settable characteristic angle from 0° to 90°.
- Breaker failure protection, three phases and neutral current detection, selectable timing logic
- Pole disagreement function based on separate phase current level measurement
- Autoreclosing, up to 4 attempts (option)
- Extra I/O board with 4 optocoupled inputs and 4 relay outputs (option)