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Hardware configuration – Siemens ISGS SG8158-00 User Manual

Page 25

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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

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