Protection Assemblies

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

• Three stages of three-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 earth-fault protection, IN>, IN>>, IN>>> alarm and trip functions
• Breaker failure protection, three phases and neutral current detection, selectable timing logic and retrip for single & three-pole trip applications
• 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)

RXHL/RAHL 421 for high 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 earth-fault protection, IN>, IN>>, IN>>> alarm and trip functions. - Neutral point voltage stage, enabling criteria for directional earth-fault stage. Definite time delay, serves also as back-up protection. - Uni- or bi-directional operating characteristic and manual or remote change of characteristic angle, 0° or -90°. Definite time delay.
• Neutral point time-delayed overvoltage function (one step)
• Logic for detection and clearance of intermittent faults
• 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)

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)

Common Features:

• Logic for detection and clearance of intermittent faults
• Two binary inputs for blocking or enabling functions and five configurable binary output relays
• Additional binary I/O module, 4 inputs and 4 outputs, for 411/421/422 (option)
• Self-supervision with output alarm selectable via relay contact
• Two setting groups selectable by binary input or HMI setting
• Very user friendly HMI-dialog
• Service value reading (primary or secondary values) and disturbance information through the fully graphic HMI
• Three LED's for In service, start and trip indication
• Test of binary outputs and inputs can be performed through the HMI
• Several mounting alternatives are available; 19" equipment frames, panel mounting cases and DIN-rail adapters 

The compact current relay RXHB 411 has a wide application range as an important part of the backup protection for feeders and lines, transformers, capacitor banks, electric boilers as well as for generators and motors.

Main Features:

• Three-phase compact numerical breaker failure relay
• Single- and three-phase breaker failure protection
• Pole disagreement protection

• Basic version
• Basic version together with overcurrent and earth-fault protection
• Basic version together with binary I/O option
• Basic version together with overcurrent and earth-fault protection and binary I/O option

• Phase overcurrent protection with two stages and definite time delay
• Earth-fault protection with two stages and definite time delay
• 4 additional inputs and 4 additional outputs 

RXEDA 1 is a microprocessor based time-overvoltage relay. The relay can be used for AC or DC. The AC input can be single- two- or three-phase, with or without neutral.

The relay may also be used as an instantaneous single-phase undervoltage relay. In case of three-phase undervoltage applications using one relay only, the relay will set required undervoltage in all phases in order to operate.

Since the relay does not need a separate auxiliary DC supply, it is suitable as a replacement for electromechanical relays.

RXEDA 1 has a built in timer and a LED indication of the time-delayed trip function. A starting output can be used as an alternative to having both outputs operated after the time-delay.

• Setting voltage ranges are 20-300 V DC and 15-210 V AC, 15-400 Hz
• Setting time range of 0-10 s definite time
• Two output change-over contacts; one for start and one for time function or both for time function
• High resetting ratio; > 97 %
• No auxiliary voltage required