Ct/Vt Modules - GE G30 Instruction Manual

CHAPTER 3: INSTALLATION
Table 3-2: Power supply LED on module
LED indication Power supply
Continuous on OK
On/off cycling Failure
Off Failure or no power
When using a G30 with a HardFiber system, before powering off the G30, save data in the compact flash memory
using Commands > Relay Maintenance > Save Non-Volatile Data. When not saved or the relay loses power, up to
the last two minutes of data is not saved to the compact flash memory.
When using an SH power supply module, after disconnecting power and powering up again, some measured values
displayed can change from that last displayed. This is because there is not enough time for the compact flash to store
data. Upon power up the last stored value displays.

3.3.4 CT/VT modules

The CT and VT inputs are analog current transformer and voltage transformer signals used to monitor AC power lines. The
UR-series relays support 1 A and 5 A CTs.
A CT/VT module can have current or 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 labelled as such in the relay. Likewise, channels 2 and 6
are intended for connection to phase B, and channels 3 and 7 are intended for connection to phase C.
Channels 4 and 8 are intended for connection to a single-phase source. For voltage inputs, these channels are labelled as
auxiliary voltage (VX). For current inputs, these channels are intended for connection to a CT between system neutral and
ground, and are labelled as ground current (IG).
Verify that the connection made to the relay terminals for nominal current of 1 A or 5 A matches the
secondary rating of the connected CTs. Unmatched CTs can result in equipment damage or
inadequate protection.
To connect to the module, size 12 American Wire Gauge (AWG) is used commonly; the maximum size is 10 AWG.
G30 GENERATOR PROTECTION SYSTEM – INSTRUCTION MANUAL
Figure 3-17: Control power connection
WIRING
3
3-17