Connecting Analog Signals - ABB RELION REX640 Installation Manual

1MRS759115 A
5.4
REX640
Installation Manual
GUID-93E2EC7F-92D8-4AEE-8568-7508EF13D59B V1 EN
Figure 48: Loosening protective earth screw T20
2. Tighten the protective earth screw to 1.5 Nm ±10%.

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.
Section 5
Connecting
61