ABB RET670 - Connecting the Power Supply Module; Connecting to CT and VT Circuits

Use the main protective earth screw (1) for connection to the
stations earthing system. Earthing screws for PSM module (2) and
TRM module (3) must be fully tightened to secure protective earth
connection of these modules.
5.4.3 Connecting the power supply module
The wiring from the cubicle terminal block to the IED terminals (see figure 23 for
PSM connection diagram) must be made in accordance with the established
guidelines for this type of equipment. The wires from binary inputs and outputs and
the auxiliary supply must be routed separately from the current transformer cables
between the terminal blocks of the cubicle and the IED's connections. The
connections are made on connector X11. For location of connector X11, refer to
section "Rear side connectors".
5.4.4
Connecting to CT and VT circuits
CTs and VTs are connected to the 24–pole connector of the Transformer input
module (TRM) on the rear side of the IED. Connection diagram for TRM is shown
in figure
19.
Use a solid conductor with a cross section area between 2.5-6 mm
2
(AWG14-10)
or a stranded conductor with a cross section area between 2.5-4 mm
2
(AWG14-12).
If the IED is equipped with a test-switch of type RTXP 24 COMBIFLEX wires
with 20 A sockets must be used to connect the CT and VT circuits.
Connectors on TRM (for location see section "Rear side connectors") for current
and voltage transformer circuits are so called “feed-through IED blocks” and are
designed for conductors with cross sectional area up to 4 mm
2
(AWG 12). The
screws used to fasten the conductors should be tightened with a torque of 1Nm.
Connector terminals for CT and VT circuits, as well as terminals for binary input
and output signals, can be of either ringlug or compression connection type,
depending on ANSI/IEC standards, or customers choice.
Table 8: CT and VT circuit connectors
Connector type Rated voltage and current Maximum conductor area
Screw compression type 250 V AC, 20 A
4 mm
2
(AWG12)
2 x 2.5 mm
2
(2 x AWG14)
Terminal blocks suitable for
ring lug terminals
250 V AC, 20 A
4 mm
2
(AWG12)
1MRK 504 088-UEN C Section 5
Installing the IED
59
Installation and commissioning manual