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3-8 L60 Line Phase Comparison Relay GE Multilin
3.2 WIRING 3 HARDWARE
3
Figure 3–9: CONTROL POWER CONNECTION
3.2.4 CT/VT MODULES
A CT/VT module may have voltage inputs on Channels 1 through 4 inclusive, or Channels 5 through 8 inclusive. Channels
1 and 5 are intended for connection to Phase A, and are labeled as such in the relay. Channels 2 and 6 are intended for
connection to Phase B, and are labeled as such in the relay. Channels 3 and 7 are intended for connection to Phase C and
are labeled as such in the relay. Channels 4 and 8 are intended for connection to a single phase source. If voltage, this
channel is labelled the auxiliary voltage (VX). If current, this channel is intended for connection to a CT between a system
neutral and ground, and is labelled the ground current (IG).
a) CT INPUTS
VERIFY THAT THE CONNECTION MADE TO THE RELAY NOMINAL CURRENT OF 1 A OR 5 A MATCHES
THE SECONDARY RATING OF THE CONNECTED CTs. UNMATCHED CTs MAY RESULT IN EQUIPMENT
DAMAGE OR INADEQUATE PROTECTION.
The CT/VT module may be ordered with a standard ground current input that is the same as the phase current inputs (Type
8F) or with a sensitive ground input (Type 8G) which is 10 times more sensitive (see the Technical Specifications section for
additional details). Each AC current input has an isolating transformer and an automatic shorting mechanism that shorts the
input when the module is withdrawn from the chassis. There are no internal ground connections on the current inputs. Cur-
rent transformers with 1 to 50000 A primaries and 1 A or 5 A secondaries may be used.
CT connections for both ABC and ACB phase rotations are identical as shown in the Typical Wiring Diagram .
The exact placement of a zero-sequence CT so that ground fault current will be detected is shown below. Twisted pair
cabling on the zero-sequence CT is recommended.
CAUTION