Hardware configuration – Siemens ISGS SG8158-00 User Manual
Page 25
Hardware Configuration
Siemens Energy & Automation, Inc.
19
Voltage transformers may be connected in either of two
ways:
Two VTs connected open delta-open delta
Three VTs connected wye-wye
For brevity, the open delta connection is referred to as L-L
(line-to-line), while the wye connection is referred to as L-N
(line-to-neutral). Wye-delta or delta-wye connection of VTs is
not allowed. Figure 4.7 shows the correct VT connections
and polarities.
Voltage transformers are specified with an input to output
voltage ratio (for example, 12000:120). The secondary volt-
age rating of the VTs can be set by the Secondary Voltage
Rating parameter (1203).
Before leaving the hardware configuration blocks, (only when
changing parameters, not when viewing) the ISGS relay dis-
plays the message END OF PASSWORD OPERATION?.
Press the No button to return to one of the configuration
blocks. The message PRESS ANY KEY TO CONTINUE
appears. Press any key to return to the screen displayed last
before the message prompt appeared. Press the Yes button
if you are finished with the configuration changes. The device
prompts you to save the settings.
Press the Yes button to save the settings. The relay
resets and displays the Power On and Power Meter On
displays.
Press the No button if you do not want to save the
changes The message SAVING PROCEDURE
ABORTED appears. Press Enter to return to the last
address block.
Note: For CT configuration, CTs on the neutral
must be the same rating as other CTs for
residual ground sensing, directional neutral
sensing, or direct ground sensing.
For VT connections, VTs must be either wye-wye
or delta-delta. Wye-delta or delta-wye connec-
tions are not permissible.
1200 VT Configuration
Address Parameter
Options
1201 Primary Rating
120-138,000 V (1 V steps)
1202 VT Connect
Line-to-Line or Line-to-Neutral
1203 Sec. VT Rating
100-120 V (1 V steps)
Figure 4.7 Voltage Transformer Connections
V1
1
2
3
ISGS
41
42
43
44
45
46
V2
V3
Wye-Wye VT Connection
V12
1
2
3
ISGS
41
42
43
44
45
46
V23
V31
Open Delta-Open Delta VT Connection
4
isv3o_1.bk : isv3ohw.frm Page 19 Wednesday, August 7, 1996 10:51 AM