32
Instructions for the installation and
Figure 32. VDS grounding.
Prior to performing any voltage withstand test, the voltage
transformers and surge arresters must be isolated. Suggested
isolation methods are as follows:
1. Top-mounted VT installed and VT 3PS grounded, thereby
removing the VT circuit from the PFWV test.
2. Top-mounted VT is removed and an insulating plug is installed
in the VT port with the VT 3PS connected (see below for
information on how to plug the VT port).
3. Top-mounted VT installed, primary VT fuse is removed, low
voltage VT secondary circuit open (fuse removed or breaker
open), and VT 3PS connected. In this case, the PFWV cannot
exceed the field test level for the given service voltage (cannot
perform PFWV test at type test levels for this option).
4. Cable side VTs must be disconnected from the cable connector
tank inner cone and an insulating plug installed.
5. Surge arrestors must be removed and an insulating plug
installed.
Removing a top-mounted VT and installing an insulating plug
In order to satisfy the conditions of item 2. above, it will be
necessary to remove a VT from its VT port on top of the tank, then
plug the port with an insulating plug. To do this,
1.
Confirm that the equipment is de-energized
2. Loosen the four bolts holding the VT assembly to the tank VT
port.
3. Disconnect the VT wire harness from its VT receptacle.
4. Remove the VT from the VT port area.
5. Install an insulating plug, Eaton Catalog Number
83C3662G01
.
6. Secure the insulating plug to the VT port by tightening the bolts
to 13 Nm (115 in.-lb.) See
, below.
Figure 33. VT port with insulating plug installed.
5.2.2.2. Performing switchgear PFWV test
Power frequency withstand voltage tests should be performed at an
AC voltage not to exceed the field PFWV level. PFWV tests should
be performed with adequately rated AC hi-pot equipment.
PFWV tests can be performed directly on the Power Xpert IGX
switchgear by installing a voltage test cable (see
empty inner cone connection. Any power cables connected to a
load must be disconnected from the load prior to voltage withstand
testing. Empty (unapplied) terminations of any power cables that are
connected to the Power Xpert IGX switchgear must insulated and/or
isolated.
PFWV testing of the Power Xpert IGX switchgear can also be
performed using Hi-Pot cables. This test should be performed using
AC Hi-Pot testing equipment only. The voltage test should not
exceed 60 kV or 75% of the cable’s rated voltage, whichever is less.
5.2.2.3. Performing cable PFWV test
Power Xpert IGX switchgear is designed to allow the dielectric
testing of power cables while the power cables are connected to the
switchgear. Any cables under test should be isolated from the main
bus using the 3PS. Once isolated, cable testing can be conducted
with the main bus energized up to the rated nameplate value.
The power cables must be disconnected from any load prior to
testing. After disconnecting the cable from the load, Hi-Pot test
equipment can be used to perform the applicable PFWV test on the
entire cable run.