ABB UFC921A 3BHE024856P106 DC power module

In addition to protection, measurement, control, condition monitoring and general functions,

the REF 543 feeder terminals are provided with a large amount of PLC functions, 

which allow for several automation and sequence logic functions, needed for substation automation, to be integrated into one unit.

The data communication properties include the following communication standards: 

SPA bus, LON bus, IEC 60870-5-103. IEC 61850 via SPA-ZC 400. 

Profibus DPV1 via SPA-ZC 302. DNP 3.0 and Modbus communication with higher level equipment. 

Further, the LON communication together with the PLC functions minimizes the need for hardwiring between the feeder terminals.

Protection functions

The IED offers directional and non-directional overcurrent and thermal overload protection as

well as directional and non-directional earth-fault protection. 

Some standard configurations allow as an option admittance-based, harmonics-based or wattmetric-based earth-fault protection to be

used in addition to directional earth-fault protection. 

Further, the IED features sensitive earth-fault protection, phase discontinuity protection, transient/intermittent earth-fault protection, 

overvoltage and undervoltage protection, residual overvoltage protection, positive-sequence undervoltage 

and negativesequence overvoltage protection. 

The outstanding I/O capability in REC670 enables control of several bays with complete measurement with only one IED. 

For instance, one REC670 IED is capable of handling control of all apparatuses 

in one entire diameter in 1 ½ breaker arrangement including breaker failure protection for all breakers.

The REF 543 feeder terminal is designed for protection, control, 

measurement and supervision in medium voltage networks.

The REF 543 feeder terminal can be used with different kinds of switchgear, 

including single busbar, double busbar and duplex systems.

The protection functions also support different types of networks, such as, isolated neutral networks, 

resonant-earthed networks and partially earthed networks.