Siemens SG8158-00 manual Isgs

Hardware Configuration

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)

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.

1	2	3
		ISGS
		41
		V1
		42
		43
		V2
		44
		45
		V3
		46
		Wye-Wye VT Connection
1	2	3
		ISGS
		41
		V12
		42
		43
		V23
		44
		45
		V31
		46
	Open Delta-Open Delta VT Connection

4

Figure 4.7 Voltage Transformer Connections

Siemens Energy & Automation, Inc. 19