Megger IDAX 300, User Manual

Page: 23 / 46

AG033586EE ZP-AG03E IDAX 300/322/350 23
4 IDAX 5 SOFTWARE
4.2. Measurement using
Individual Temperature
Correction for single
material (ITC1)
This type of measurement is mainly intended
for bushing and current transformer condition
assessment.
Start the IDAX 5 software
1]
Press “New File” button to set-up the
measurement.
2]
Press “Single Test” tab and then “ITC1”
button.
3]
Select suitable “Test Object” template, e.g.
“Bushings” (transformer bushing).
4]
Enter mandatory temperature data
for ambient and object temperature
(highlighted). Object temperature (°C) refers
to insulation temperature. Top oil or winding
temperature is normally used as insulation
temperature for the transformer.
Note IDAX 5 software estimates bushing tempera-
ture as average between ambient and object
temperature.
5]
Select appropriate “Insulation Type” for
given bushing from dropdown menu.
6]
Press the green “Create” button.
7]
Select the folder where the measurement
will be saved and name the file.
The default name is composed of: “Location”
+ ”Designation” + ”Date + Time”.
Now you have a “File” with one “Test”, the C1
configuration by default, visible on the legend in
the left-hand side of the main window (see picture
below). On the top you have several “Tabs” showing
Nameplate, the Test (Named ITC1), Hook-up, Graph
(and table) and Settings.
8]
Press the “Hook-up” tab to show the cable
connections from the instrument to the
object.
There are two pictures showing the two versions of
IDAX 300, IDAX 300 delivered 2011 or earlier (to the
left) and IDAX 300 delivered 2012 or later.
Note
If you have an older IDAX 300 with two input
connectors for each channel, the SENSE input
must NOT be connected.
9]
Ensure that the safety ground cable is
connected to the IDAX 300 instrument and
to the station ground near the test object/
transformer. This cable acts as safety ground
AND test input lead.
10]
Make sure that all HV phase terminals and
any exposed neutral terminal are connected
together. While connecting together the
terminals with bare copper wire, the phases/
windings should be connected to ground.
11]
Make sure that all LV phase terminals and
any exposed neutral terminal are connected
together. While connecting together the
terminals with bare copper wire, the phases/
windings should be connected to ground.
12]
Connect the Generator cable to the high
voltage winding – according to the picture in
Hookup tab.
13]
Connect the Red input lead to the test pin
of the bushing – according to the picture in
Hook-up tab.
14]
Remove any grounding connection from the
windings before you start the measurement.
15]
Press the “Connect” button located on the
right-hand side of the main window or press
the “Start” button. This will connect to IDAX
300 if not connected yet.
16]
Press “Start” to initiate the measurement/test
Measurement
The measurement will start a routine initiation
procedure where the system measures all
capacitances, including stray capacitances in the
test object as well as the interference level. This
routine procedure sets up the instrument and the
model ensures the highest possible accuracy over the
selected frequency range.
Analysis
During the ITC1 test an automatic correction is
performed from the first point and results are
presented in the “Analysis results” section. The
analysis is complete when %DF values are presented
at all three frequencies.
Insulation assessment guidelines
The default limits of %DF at 20°C are based on
recommendations given in CIGRE TB 445, which gives
values for new and aged bushings at 50/60 Hz and
15 Hz. The materials covered are Resin Impregnated
Paper (RIP), Oil Impregnated Paper (OIP) and Resin