ABB REL551 1MRK002480-AE Line Differential Relay

The REM 545 machine terminals are used as the main protection system of generator and 

generator-transformer units in small and medium-power diesel, hydroelectric and steam power plants. 

The protection for large and/or important MV synchronous and asynchronous motors used, 

for example, in pumps, mills and crushers during start-up and normal run forms another application area.

The protection functions of REM 545 are designed for selective short-circuit and earth-fault protection of rotating machines. 

Unlike most other power system components, rotating machines also need protection against abnormal 

operating conditions such as over-current, unbalanced load, over-temperature, over-voltage, over and under-excitation, 

under-impedance, over- and under-frequency and generator motoring. 

For motor protection start-up supervision, there are also stall protection and cumulative start-up counter features.

Protection functions

Protection is one of the most important functions of the machine terminal. The

protection function blocks (e.g. NOC3Low) are independent of each other and have

their own setting groups, data recording, etc. The non-directional overcurrent

protection, for example, includes the three stages NOC3Low, NOC3High and

NOC3Inst, each with independent protection functions.

Either Rogowski coils or conventional current transformers can be used for

protection functions based on current measurement (overcurrent). Correspondingly,

voltage dividers or voltage transformers are used for protection functions based on

voltage measurement (overvoltage).

Relay Retrofit Program for REX 521 Product Guide 1MRS758962

Relay Retrofit Program for REX 521 Installation Manual 1MRS758961

Relay Retrofit Program for REX 521 Application Manual 1MRS758960

Relay Retrofit Program for REX 521 Cutting Tool Safety Guide 1MRS758975

Relay Retrofit Program for REX 521 Cutting Tool Operating Guide 1MRS758976

ABB CI850A Communication Interface Module

ABB CI850K01 CI850 Interface Kit, Non-Redundant

ABB CI850K01A CI850 Interface Kit, Non-Redundant

ABB IOR810 S800 I/O Gateway Module (For HN800)

ABB IOR810A S800 I/O Gateway Module (For HN800)

ABB IOR810K02 S800 I/O Gateway Kit, Redundant

ABB IOR810K02A S800 I/O Gateway Kit, Redundant

ABB IOR810N200A S800 I/O Gateway Mounting Base

ABB MB605 SCI200 Module Base, Non-Redundant

ABB MB605A SCI200 Module Base, Non-Redundant

ABB MB855 CI850 Module Base, Non-Redundant

ABB MB855A CI850A Module Base, Non-Redundant

ABB PDP800 Profibus DP V0/V1/V2 Master Module

ABB PDP800A Profibus DP V0/V1/V2 Master Module