RAPDK/RXPDK (Legacy)

Directional overcurrent protection is used for overcurrent or earth-fault protection when selectivity is required, e.g. due to parallel lines meshed networks or networks being supplied from a number of directions.

The RXPDK 21H is used for phase-overcurrent protection. The operating time can be set to be current independent (definite time) or current dependent using the available IEC inverse characteristics. The relay uses memory voltage for polarization when the voltage collapses due to the fault.

Assemblies for earth-fault protection in some solidly earthed networks may use the RXPDK 21H directional relay with independently set time delay. The polarizing voltage for RXPDK 21H must exceed 5 V in order to provide proper directional sense.

The RXPDK 22H is used for directional earth-fault protection in high-impedance earthed systems. The RXPDK 23H relay is intended for solidly grounded systems where expected polarizing voltages are below 5 V.

• Voltage polarised phase overcurrent relay
• Memory of polarizing voltage upon loss of voltage during faults
• Inverse or constant time characteristics selectable from front
• Low set stage and high set stage
• Characteristic angle settable -120° to +120°
• Two variants with wide setting ranges
• Low set stage programmable for various inverse or fixed time delayed characteristics

• Voltage polarized 0° or 90° earth-fault relay for isolated or high impedance earthed systems
• Enable setting of 5-30 V neutral point voltage
• Fixed time delay 0-10 s
• Undirectional or bidirectional setting feature
• Backup function included based on neutral point voltage with 8-20 s delay setting
• Replacement for RXPF 4
• Low set stage programmable for various inverse or fixed time delayed characteristics

• Voltage polarized earth-fault relay for solidly earthed systems
• Two variants with wide setting ranges
• Responds to absolute current value within the operating area 0-140°
• Low set stage programmable for various inverse or fixed time delayed characteristics