20
Instruction Booklet
IB022018EN
Effective July 2020
Instructions for the installation and
EATON
www.eaton.com
Figure 32. Example input voltage transformers.
NOTICE
DURING COMMISSIONING, IN ORDER TO PERFORM POWER FREQUENCY
WITHSTAND VOLTAGE (PFWV) TESTING, IT WILL BE NECESSARY TO
DISCONNECT THE VTS FROM THE CIRCUIT TO AVOID DAMAGE.
BECAUSE THE VT EARTHING SWITCH CAN CONNECT OR GROUND THE
VT, IT WILL BE NECESSARY TO GROUND THE VT WITH THE EARTHING
SWITCH, REMOVE ITS FUSE, AND RECONNECT THE VT WITH THE
EARTHING SWITCH FOR PFWV TESTING.
VT earthing switch
XGIS switchgear can be fitted with one VT earthing switch
mechanism.
Where main bus voltage transformers are furnished, whether fused
or unfused, the VT earthing switch is a tank-mounted three-pole
switch that connects each phase voltage transformer primary
to its phase bus or to ground. The main bus VT is mounted in a
compartment behind the main bus connection compartment, and
connects to the earthing switch through bushings mounted in the
tank top.
This switch can be operated either under load or no-load conditions.
The earthing switch operator is located in the XGIS low voltage
compartment, and connected by a linkage to the VT earthing switch
mechanism located in the tank.
Cable side VTs can also be fitted for the VT earthing switch, but only
when the VT is top mounted (in the compartment behind the main
bus connection compartment), and connects to the switch using
the same tank bushing.
shows the VT earthing switch
operator in the low voltage compartment, the linkage connecting
it to the switch mechanism, and the bushing where a VT can be
connected to the switch.
Figure 33. VT earthing switch mechanism.
Current transformers
XGIS switchgear can be furnished with or field modified to include
current phase current transformers for main bus phases or cable
side phases.
The XGIS switchgear line can include single or multiple CTs per
phase, depending upon the application. The maximum quantity of
CTs possible on any phase depends upon the required CT standard,
rating and design. In some cases, as many as three CTs can be
mounted on either the main bus phases or the cable phases. In
other cases, no more than one CT per phase can be furnished.
When furnished for the main bus side, the current transformers
must be installed during the system installation and commissioning
process, when the SSIS busbars are installed.
When furnished for the cable side, the current transformers can be
installed on the cable bushings during fabrication. In either case,
applied CTs are donut type sensors that encircle the main bus SSIS
conductors or the cable connection bushings or bus tie cones.
XGIS uses mounting brackets to hold the optional CTs in place.
These brackets differ with CT application, location, rating and type.
Since the XGIS switchgear can be furnished within two design
ranges, 1250 A or 2000 A / 2500 A, the main bus side (insert mount)
and the cable side (through mount) bracket designs with be different
for each design range.
Main bus CTs
Main bus CTs can be furnished on the horizontal bus in the space
above the gas tank, with the SSIS conductors passing through
the CTs before terminating at the tank bushings. Main bus CT and
bracket dimensions will differ depending upon the CT rating and
applicable standards.
