ABB REF 541, REF 543 and REF 545Feeder terminals

Features

• Feeder terminal for protection, control, measurement and supervision of medium voltage networks 

 • New application areas for power quality measurement, protection, capacitor bank protection and control and motor protection 

 • Voltage and current measurement via con ventional measuring transformers or cur rent and voltage sensors 

 • Fixed man-machine interface including a large graphic display, or an external display module for flexible switchgear installation 

 • Extended functionality including protec tion, control, measurement, communica tion, power quality and condition monitoring 

 • Protection functions including e.g. non directional and directional overcurrent and earth-fault protection, residual voltage, overvoltage and undervoltage protection, thermal overload protection, CBFP and auto-reclosing 

 • Control functions including local and remote control of switching objects, status indication of the switching objects and interlockings on bay and station level 

 • Measurement of phase currents, phase-to phase and phase-to-neutral voltages, residual current and voltage, frequency, power factor, active and reactive power and energy, etc. 

 • Condition monitoring including circuit breaker condition monitoring, trip circuit supervision and internal self-supervision of the feeder terminal 

 • Additional functions including synchro check, frequency protection, capacitor bank protection and control, measurement of current and voltage harmonics 

 • RTD/analogue module for temperature measurement, current/voltage measure ment and mA-outputs 

 • Communication over two communication interfaces: one for local communication with a PC and the other for remote commu nication via a substation communication system 

 • Part of the ABB Substation Automation system

Application

The REF 541, REF 543 and REF 545 feeder terminals are designed to be used for protec tion, control, measurement and supervision of medium voltage networks. They can be used with different kinds of switchgear including single busbar, double busbar and duplex sys tems. The protection functions also support different types of networks such as isolated neutral networks, resonant-earthed networks and partially earthed networks. 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. In addition to protection, measurement, control and condi tion monitoring functions, the feeder termi nals are provided with a large amount of PLC functions allowing several automation and sequence logic functions needed for substa tion automation to be integrated into one unit. The data communication properties include SPA bus communication or LON bus com munication with higher-level equipment. Fur ther, the LON communication together with the PLC functions minimizes the need for hardwiring between the feeder terminals.

Design

The feeder terminals REF 541, REF 543 and REF 545 differ from each other regarding the number of digital inputs and outputs avail able. Please, refer to section “Ordering” for more details. These feeder terminals incorpo rate a wide range of feeder terminal func tions: 

 • Protection functions 

 • Measurement functions 

 • Power quality functions 

 • Control functions 

 • Condition monitoring functions 

 • General functions 

 • Communication functions 

 • Standard functions The function blocks are documented on the CD-ROM “Technical Descriptions of Func tions” (1MRS 750889-MCD).

Protection functions

Protection is one of the most important func tions of the REF 54_ feeder terminal. The protection function blocks are independent of each other and have their own setting groups, data recording, etc.

Either Rogowski coils or conventional cur rent transformers can be used for protection functions based on current measurement. Correspondingly, voltage dividers or voltage transformers are used for protection functions based on voltage measurement.

For further information about functionality levels and the protection functions included in them, refer to the table “Functionality lev els, protection functions” in section “Ordering”.

Measurement functions

The measurement functions include three phase currents, neutral current, three-phase voltages, residual voltage, frequency, active and reactive power and power factor. In addi tion, other measurement functions are avail able.

As a standard feature the REF 54_ terminal includes pulse counter inputs. The number of pulse inputs varies from 7 (REF 541) to 10 (REF 545) according to the REF variant.

Disturbance recorder

record 16 current or voltage waveforms and 16 logic digital signals. The sampling fre quency of the analogue inputs is 2 kHz at the rated frequency of 50 Hz and 2.4 kHz at the rated frequency of 60 Hz.

The user can set the length of a recording within a range determined by the number of analogue inputs used. The number of record ings depends on the sampling frequency, length of recordings and number of analogue inputs.