Design Description - ABB REU 523 Technical Reference Manual

1MRS 750942-MUM
4.2.
4.2.1.
Combined Overvoltage and Undervoltage Relay
Technical Reference Manual

Design description

Input/output connections
The energizing voltages are connected to terminals X1.1/1-3, X1.1/4-6 and
X1.1/7-9. The nominal voltage (100/110/115/120 V) of the matching transformers
has to be selected with SPA parameter V134 or via the HMI. The REU 523 can also
be used in single-phase applications by setting switch 1 in switchgroup SGF2.
The binary input X2.1/17-18 can be used to generate an external blocking signal, to
unlatch the output contacts or for remote control of relay settings. The requested
function is selected in SGB. The binary input can also be used as a trigger signal for
the disturbance recorder; this function is selected with SPA parameter V243.
The auxiliary voltage of the relay is connected to terminals X2.1/1-2. At dc supply,
the positive lead is connected to terminal X2.1/1. For details, refer to the description
of the auxiliary voltage. The permitted auxiliary voltage range of the relay is marked
on the front panel of the relay.
Output contacts PO1 and PO2 are heavy-duty trip contacts capable of controlling
most circuit breakers. The trip signals from the different protection stages are routed
to the output contacts with switches 1 and 2 of SGR1...SGR8. On delivery from the
factory, the trip signals from all the protection stages are routed to both PO1 and
PO2.
Output contacts SO1 and SO2 can be used for signalling on start and tripping of the
relay. The signals to be routed to output contacts SO1 and SO2 are selected with
switches 3 and 4 of SGR1...SGR8. On delivery from the factory, the start signals
from all the protection stages are routed to both SO1 and SO2.
Output contact IRF functions as an output contact for the self-supervision system of
the protection relay. The IRF relay is energized under normal operating conditions
and contact gap X2.1/13-15 is closed. When a fault is detected by the
self-supervision system or the auxiliary voltage is disconnected, the output contact
will drop off and contact X2.1/13-14 will close.
The following picture presents a rear view of the REU 523, showing three
connecting sockets: one for matching transformers, one for power supply and one
for serial communication.
REU 523
47