ABB REF545KM133BAAA feeder protects the terminal

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. 

The application area also covers medium-sized three phase asynchronous motors as well as 

protection and control of shunt capacitor banks used for reactive power compensation. 

REF542plus success story

„ Market launch 2000

„ Delivered units approx. 50,000

„ Applications ranging from low voltage to high voltage

„ In service worldwide

„ Many different protection and control functions

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. 

Event recording

All events are stored with a resolution of 1 ms in the central unit and in the BUs.

System, protection and test events can be generated.

Protection events refer to the protected busbar and include the changes in the disconnector and breaker positions,

trips, etc. Test events are recorded during testing with the test signal generator.

System events describe the diagnostic and fault messages of the NBP system as a whole.

Frequency protection, including overfrequency, underfrequency and frequency rate-of-change protection,

is offered in IEDs with standard configurations H and J. 

The IED also incorporates optional three-pole multi-shot auto-reclose functions for overhead line feeders.

Enhanced with optional hardware and software,the IED also features three light detection channels 

for arc fault protection of the circuit breaker, busbar and cable compartment of metalenclosed indoor switchgear.

The arc-fault protection sensor interface is available on the optional communication module.

Fast tripping increases staff safety and security and limits material damage in an arc fault situation.