ABB REM 54 Series, Technical Reference Manual

Page: 23 / 110

1MRS750915-MUM
REM 54_
23
Machine Terminal
Technical Reference Manual, General
4. Instructions
4.1. Application
The REM 54_ rotating machine terminals (referred to as “machine terminals”
further on) are designed to be used as the main protection system of generator and
generator-transformer units in small and medium-power diesel, hydroelectric and
steam power plants, etc. The protection of large and/or important MV synchronous
and asynchronous motors used e.g. in pumps, mills and crushers during start-up and
normal run forms another application area.
The functionality available for the machine terminals depends on the selected
functionality level (refer to section “Ordering Information” on page 95) and is also
tied to the hardware configuration. The desired functions can be activated from a
wide range of protection, control, measurement, condition monitoring, general and
communication functions within the scope of I/O connections, considering the total
CPU load. Compared to the traditional use of separate products, the combination of
desired functions provides cost-effective solutions and, together with the relay
configuration (IEC 61131-3 standard), allows the machine terminals to be easily
adapted to different kinds of applications.
By means of the graphic HMI display, the control functions in the machine terminal
indicate the status of disconnectors or circuit breakers locally. Further, the machine
terminal allows status information from the circuit breakers and the disconnectors to
be transmitted to the remote control system. Controllable objects, such as CBs, can
be opened and closed over the remote control system. Status information and control
signals are transmitted over the serial bus. Local control is also possible via the push-
buttons on the front panel of the machine terminal.
The protection functions of the machine terminals are designed for selective short-
circuit and earth-fault protection of rotating machines. Further, unlike most other
power system components, rotating machines also need protection against abnormal
operating conditions such as overcurrent, unbalanced load, overtemperature, over-
and undervoltage, over- and underexcitation, over- and underfrequency and
generator motoring. Also, underimpedance function is provided for line back-up.
Furthermore, stall protection and cumulative start-up counter are provided for motor
protection start-up supervision.
The machine terminals measure phase currents, phase-to-phase or phase-to-earth
voltages, neutral current, residual voltage, frequency and power factors. Active and
reactive power is calculated from measured currents and voltages. Energy can be
calculated on the basis of the measured power. The measured values can be
indicated locally and remotely as scaled primary values.
In addition to protection, measurement, control, condition monitoring and general
functions, the machine terminals are provided with a large amount of PLC functions
allowing several automation and sequence logic functions needed for substation
automation to be integrated into one unit. The data communication properties
include SPA bus, Modbus or LON
bus communication with higher-level equipment.
Further, LON communication, together with PLC functions, minimizes the need for
hardwiring between the machine terminals.