6–50
350 FEEDER PROTECTION SYSTEM – INSTRUCTION MANUAL
S2 SYSTEM SETUP
CHAPTER 6: SETPOINTS
GROUND [SENS GND] CT PRIMARY
Range: [1 A to 600 A] 1 A to 6000 A
Default: 50 A
For the above configuration, the ground CT primary rating must be entered. To detect
low level ground fault currents, the sensitive ground input may be used. In this case, the
sensitive ground CT primary rating must be entered. The Sens GND CT primary range is
1 A to 600 A
The relay phase and ground CT types (5 A, 1 A) must match the feeder phase and ground
CT taps.
Voltage sensing
PATH
:
SETPOINTS > S2 SYSTEM SETUP > VOLTAGE SENSING
VT CONNECTION
Range: Wye, Delta
Default: Wye
The 350 provides three-phase VT inputs, that can be wired to either bus VTs or feeder
VTs. Select “Wye” connection, if phase-neutral voltages are wired to the relay VT
terminals. Select “Delta” connection, if phase-phase voltages from either Delta or Open
Delta VTs are connected to the three-phase VT terminals. See the VT connections per the
Typical Wiring Diagram in Chapter 2.
VT SECONDARY
Range: 50 V to 240 V
Default: 120 V
This setting defines the voltage across the VT secondary winding when nominal voltage
is applied to the primary. On a source of 13.8kV line-line voltage, with a VT ratio of
14400:120 V delta connection, the voltage to be entered is “115 V”. For a Wye
connection, the voltage to be entered is 115/
√
3 = 66 V.
VT RATIO
Range: 1:1 to 5000:1
Default: 1:1
This setting defines the VT primary to secondary turns ratio. For a 14400: 120 VT, the
entry would be “120:1” (14400/120 = 120).
AUX VT INPUT
Range: V
ab
VT, V
bc
VT, V
ca
VT, V
an
VT, V
bn
VT, V
cn
VT
Default: V
ab
VT
The 350 relay provides a voltage input (AUX VT INPUT), where a single feeder/line VT can
be connected. The aux. VT voltage can be used for setting up auxiliary under- and over-
voltage feeder protection. Select the phase-neutral, or the phase-phase voltage
connected to the Aux VT input terminals
AUX VT SECONDARY
Range: 50 V to 240 V
Default: 110 V
This setting defines the voltage across the VT secondary winding when nominal voltage
is applied to the primary. On a source of 13.8kV line-line voltage, with a VT ratio of
14400:120 V delta connection, the voltage to be entered is “115 V”. For a Wye
connection, the voltage to be entered is 115/
√
3 = 66 V.
