Siemens ISGS SG8158-00 - Manual (Page 24)

Hardware Configuration
18 Siemens Energy & Automation, Inc.
4.4 CT Configuration
The CT Configuration function allows you to set up the ISGS
relay to match the phase CT primary rating, the neutral or
ground CT primary rating, and the CT input’s normal power
flow setting of your system. For CT connections refer to
Figure 4.8.
The phase (1101) and neutral/ground (1102) CT primary rat-
ings are independently configurable. However, when a resid-
ual sensing method is used for ground fault protection, the
primary current ratings for the neutral CT and the phase CT
must be equal. The CT secondary ratings (1A or 5A) are set
at the factory and are not changeable from the front panel.
Power flow is also referred to as top feed or bottom feed. If
the power enters the polarity mark on the CTs, set the Power
Flow parameter (1104) to Normal. If power leaves the polarity
mark, enter Reverse. Figure 4.6 illustrates examples of nor-
mal and reverse power flow.
1100 CT Configuration
Address Parameter Options
1101 Phase CT Primary
Rating
5-8000 A (1 A steps)
1102 Neutral or Ground
CT Primary Rating
5-8000 A (1 A steps)
1104 Power Flow Normal or Reverse
Figure 4.6 Normal/Reverse Power Flow
4.5 VT Configuration
Use this address block to configure the ISGS relay to match
the VT primary rating and the VT connection setting for your
system. These settings are available only if the voltage input
option is installed on the relay.
ISGS
ISGS
Main Bus
Power Power
Normal Power Flow
(Into CT Polarity Mark)
Reverse Power Flow
(Out of CT Polarity Mark)
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