BE1-951
Installation
12-23
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.
7.
When tertiary is loaded, use 3 CT's inside Delta (3Io); When tertiary is unloaded, only 1 CT
(Io) is required
Figure 12-26. Directional OC Protection with Reclosing of a Transmission Line (Zero Sequence Current
Polarizing Source from Delta Tertiary Connected to IG)
