Connecting Analog Signals - ABB RELION REX640 Installation Manual

1MRS759115 E
5.3.2 Connecting protective earthing to local HMI
Connect the LHMI to earth using an earth lead of at least 6.0 mm
1.
2.
5.4

Connecting analog signals

A connection diagram is needed to connect the analog signals.
• Use the compression type for CT/VT terminals. The wires for the analog signals
can be connected to the CT/VT terminals before the connector is connected
to the protection relay. The connector features an automatic short circuit
mechanism for the current terminals. Therefore, detaching the connector from
the unit does not open the secondary circuit of the CT which otherwise could
cause dangerously high voltages. To avoid a mismatch between CT and VT
connections, the connectors are color coded. The light gray pairs with short
circuit facility are intended for CTs while the dark gray pairs without short circuit
facility are for VTs. The counterpart connectors on the module have the same
color coding.
REX640
Installation Manual
Loosen the protective earth screw T20 on the LHMI to connect a separate earth
protection lead.
Figure 63: Loosening protective earth screw T20
Tighten the protective earth screw to 1.5 Nm ±10% (1.1063 ft-lb ±10%).
Connecting
2
(AWG 10).
71