12-22
Installation
BE1-951
Notes:
°
1.
The neutral ground (I
N
) operates on internally calculated residual (3Io) current
2.
VTP connections shown are for H1 case. See Figure 12-13 for S1 case connections
3.
4-wire connection shown as typical. See Figure 12-20 for alternate VTP connections. The
4-wire connection provides negative and zero sequence voltage polarizing for ground faults;
3-wire connection provides negative sequence voltage polarizing.
4.
CT polarity connected to relay polarity, power flow from Bus to Line defined as power out
and = "+" watts; OC elements set for forward trip
5.
Current polarizing input to IG provides zero sequence polarization for ground faults
6.
VTX can be connected A-N, B-N, C-N or A-B, B-C, C-A. The relay automatically
compensates for phase angle difference between VTP and VTX. Voltage magnitude
between VTX and VTP must be matched external to the relay.
Figure 12-25. Directional OC Protection with Reclosing of a Transmission Line (Zero Sequence Current
Polarizing Source from Delta-Wye Transformer Connected to IG)