ISA T2000 User manual

DATE: 18/11/2009
DOC.MIE11110 REV.5
T 2000
APPLICATION GUIDE

DOC. MIE11110 Rev. 5
Page
2
of
110
REVISIONS SUMMARY VISA
NPAGE DATE
1All 25/04/2006 Issued Lodi.
242, 62-65 24/11/2006 Added the line
impedance test, notes
to PT ratio test
Lodi
348 -52 23/04/2007 Modified the dynamic
TAP changer test Lodi
423-27 31/7/2007 Added the very high
current booster Lodi
5All 18/11/09 Minor corrections Lodi

DOC. MIE11110 Rev. 5
Page
3
of
110
SHORT FOREWORD.......................................................................................................4
SAFETY AT WORK............................................................................................................5
INTRODUCTION................................................................................................................9
1 TRANSFORMER TESTSAPPLICATION EXAMPLES ............................................10
1.1 CURRENT TRANSFORMER TESTS.......................................................................11
1.1.1. CT tests : ratio, polarity voltage mode.............................11
1.1.2. CT tests : ratio, polarity and burden...................................16
1.1.3. CT tests : ratio, polarity with booster................................21
1.1.4. CT tests : burden, secondary side........................................36
1.1.5. CT tests : excitation curve..........................................................39
1.1.6. CT tests : winding or burden resistance...........................47
1.1.7. CT tests : voltage withstand.....................................................50
1.1.8. CT tests : polarity by impulses................................................54
1.2: VOLTAGE TRANSFORMERS TESTS..................................................................57
1.2.1: VT tests: ratio and polarity..........................................................57
1.2.2: VT tests: burden, secondary side...........................................61
1.2.3: VT tests: ratio, electronic transformers.............................63
1.2.4: VT tests: voltage withstand........................................................64
1.2.5: VT tests: secondary over-current protection.................66
1.3: POWER TRANSFORMERS TESTS......................................................................68
1.3.1: PT tests: ratio per TAP.....................................................................68
1.3.2: PT tests: resistance of LTC contacts.....................................72
1.3.3: PT tests: dynamic LTC test..........................................................76
1.3.4 PT tests: PT ratio test........................................................................84
2RESISTANCE TESTS.......................................................................................................86
2.1 MICROOHMMETER..................................................................................................86
2.2 EARTH RESISTANCE..............................................................................................90
2.3 SOIL RESISTIVITY..................................................................................................95
3LINE IMPEDANCE TESTS ..............................................................................................99
3.1 LINE IMPEDANCE MEASUREMENT......................................................................99
3.2 EARTH IMPEDANCE MEASUREMENT................................................................101
3.3 MUTUAL FACTOR MEASUREMENT.....................................................................103
APPENDIX: DYNAMIC TAP CHANGER TESTING...................................................107

DOC. MIE11110 Rev. 5
Page
4
of
110
SHORT FOREWORD
Dear T 2000 user,
I often wondered why the user’s manual is not very much used,
even if it includes valuable information. As me too I am a user of
such manuals, the answer I have given myself is that valuable
information are concealed somewhere in the thick thing, and I do
not have time to waste to find it. So, either the manual is actually
of help, or I ignore it.
This is why I decided to split the T 2000 manual in three:
specification, with all performance details; application manual, with
instructions about how to use it one its operation is understood;
introductory guide, with the device description and basic
information. The idea is that you may read once the device
description, while you need application examples more than once;
so, why not to split the manual in three?
Have a good work with T 2000!
Primo Lodi
Q&A Manager

DOC. MIE11110 Rev. 5
Page
5
of
110
SAFETY AT WORK
The Product hereafter described is manufactured and tested
according to the specifications, and when used for normal
applications and within the normal electrical and mechanical
limits will not cause hazard to health and safety, provided that
the standard engineering rules are observed and that it is used
by trained personnel only.
The application guide is published by the Seller to be used
together with the Product described in the corresponding
document. The Seller reserves the right to modify the guide
without warning, for any reason. This includes also but not
only, the adoption of more advanced technological solutions and
modified manufacturing procedures, and also the addition of other
features, not available in the first release.
The Seller declines any difficulties arising from unknown
technical problems. The Seller declines also any responsibility in
case of modification of the Product or of any intervention not
authorized by the Seller in writing.
The warranty includes the repair time and the materials necessary
to restore the complete efficiency of the Product; so, it does not
include other burdens, such as the transport and customs fee.
Under no circumstances the warrantee includes any cost that
the User may have suffered because of the Product unavailability
and downtime.
The Product is CE marked, and has been tested to operate
according to EN 61010-1, with the following operating conditions:
. Pollution degree 2: normally, non conductive pollution occurs;
. Measurement category 2, for measurement inputs;
. Altitude: less than 2000 m;
. Operating temperature: 0 to 50 °C; storage: -20 °C to 70 °C;
. Relative humidity : 10 -80% without condensing;
. Inputs/outputs protection: IP 2X: CEI 70-1 for all but high
voltage outputs; IP4X for high voltage outputs;
. The test set is portable, using the handles.

DOC. MIE11110 Rev. 5
Page
6
of
110
Would the test set be used beyond these limits, the safety of
the test set could be impaired.
Mains supply characteristics are:
. Voltage: 230 AC, 50-60 Hz;
. Power consumption: 1 kW maximum without overload; 4 kW at
600 A (5 s).
The Product generates voltages and currents that may be lethal
to the unadvertised user. Besides, in order to avoid any danger in
case of fault inside the Product, the device under test should
have the following characteristics:
. Connection cables must use safety sockets;
. Connection sockets must be isolated and not accessible;
. Input circuits must have an isolation degree at least equal to the
one of the product.
To this respect, the following symbols are used to alert the
operator about dangerous outputs:
. The symbols and are related to the HV
generation, up to 3000 V: the first one is located close to the
output connectors; the second one is located close to the
generation button, that must be pressed during HV generation.
. The symbol !is related to dangerous input or output,
and is located close to the following points:
-Output: main 0-250 V AC;
-Input: AC voltage measurement (up to 600 V.
. The symbol is located closet o the round socket.
. The symbol is located close to the mains supply
socket, that incorporates the protection fuse.
THE TEST SET CANNOT BE OPERATED IF NOT CONNECTED TO
GROUND: THIS PREVENTS POSSIBLE DANGERS TO THE
OPERATOR AND/OR FAULTS OF THE TEST SET.

DOC. MIE11110 Rev. 5
Page
7
of
110
The connection to ground is provided through the mains supply
cable; however, for added safety, the Product should be
connected to ground using the dedicated socket.
IF THE GROUND IS NOT AVAILABLE AT THE MAINS SUPPLY,
CONNECT THE TEST SET TO GROUND USING THE DEDICATED
SOCKET.
The following table lists a number of situations that are potentially
hazardous to the user and/or to the test set. Please consider this
list, and check the situation in case of doubt.
SITUATION CAUSE OF RISK CONTROL
Feeding the
transformer
during the test
In this situation very high
currents or voltages could be
applied to the test set, that
could be severely damaged;
also the operator would be
exposed to an high risk
Disconnecting
the transformer
during the test
A very hig
h voltage can be
generated by the inductance
of the transformer under
test.
Filtered mains
The AC voltage can be a
squared waveform rather
than sinusoidal; the test set
operates at the minimum
supply level, with low
efficiency.
Supply
waveform
Connection to a
live wire
The connection can be
dangerous to the user, to the
test set and even the plant.
Test before
connecting
Long generation
of all outputs Possible danger of over-
heating components,
specially with high ambient
temperature
Check burden
and duration

DOC. MIE11110 Rev. 5
Page
8
of
110
Of these points, the first two are very hazardous, both for the
user and the test set. THESE TYPES OF FAULT ARE NOT
COVERED BY THE WARRANTY.
The first hazard is very clear: while T 2000 is connected to the
transformer to be tested, there must be no connection of the
transformer itself to a voltage or current source. T 2000 outputs
are protected against transient spikes, but not against such a
situation.
In case of doubt, please contact your Seller. The Seller, and
Manufacturer, declines any and all responsibility due to improper
usage, or any usage outside the specified limits.

DOC. MIE11110 Rev. 5
Page
9
of
110
INTRODUCTION
T 2000 allows performing all the test to be performed on current
and voltage transformers.
At power-on, there is a message asking to wait for the self
diagnosis is completed. After this, the following menu is displayed.
The desired operation is accessed by the multi-function wheel.
The following chapters explain how to operate with the above
selections.
NOTE: WINDOWS is a trademark of MICROSOFT inc.

DOC. MIE11110 Rev. 5
Page
10
of
110
1 TRANSFORMER TESTS APPLICATION EXAMPLES
In this chapter we describe how to operate to test transformers.
The description of why we operate this way and of which are test
set features are given in the following chapters. So, read the
following chapters the first time you use T 2000, and then, once
learned about it, apply what you learned as follows.
The following examples include all information related to the test.
As a consequence, there could be some repetition passing from
one test to the next; however, we preferred to arrange the
manual so that it was not necessary to read other paragraphs
than the relevant one.
There are three types of tests available: CT’s; VT’s PT’s. At
power-on, the following screen is opened.
The selection is accessed by the multi-function knob (22).
On all tests, unless the over-current protection for VT, if the
adjustment knob (6) is not at zero when the test START button
(56) is pressed, the following message is displayed:
Press the OFF button (55), move the knob and start again.

DOC. MIE11110 Rev. 5
Page
11
of
110
The following paragraphs detail the operations following these
selections.
1.1 CURRENT TRANSFORMER TESTS
When this selection is performed, the following screen is displayed.
It is possible to select the tap number: this selection is reported in
the available tests.
1.1.1. CT tests : ratio, polarity voltage mode
When this test is selected, the following menu is displayed.
Purpose of the test is to measure the actual CT ratio and to verify
its polarity. This test is called voltage mode because these
parameters are verified by connecting the main AC voltage output
(high or low) to the CT secondary, and measuring the
corresponding voltage at the primary side. These parameters could

DOC. MIE11110 Rev. 5
Page
12
of
110
be measured also generating current; however, with this
connection it is also possible to test the excitation curve.
The following table explains the AC voltage output to be used as a
function of CT parameters.
Given:
. VA = VA rating;
. IS = secondary current;
. KN = overload factor,
compute:
VSM = VA * KN / IS
And then VSM/2, that is the maximum test voltage, so that we
keep away from saturation and the related errors. Note that at
the saturation there is usually 1 V per turn; more rarely 0.5 V per
turn.
The test voltage range is the following.
VSM/2 < 80 V 80 TO 220 V > 220 V
V RANGE 90 V 250 V 3000 V
The voltage input range is also selected as a function of the test
voltage and of the CT ratio.
Given:
. KCT = CT ratio;
. VP = voltage at primary,
Then, compute:
VP = VSM / (2 * KCT)
If VP > 10 V, then connect the CT’s primary to the 600 V
measurement input, else connect it to the 10 V measurement
input.
The connection diagram is the following.

DOC. MIE11110 Rev. 5
Page
13
of
110
NOTE: the drawing shows the output connection to 3000 V, and
the input connection to 10 V.
For the connection, use the following cables:
A) Output connection, 3000 V:
-N. 2 High voltage connection cables, 4 m long, 5 kV, with earth
screen. Terminated on both sides with HV connectors.
-N. 2 Clamps for the HV connection.
RED
S1
S2
RED

DOC. MIE11110 Rev. 5
Page
14
of
110
B) Output connection, other voltages:
-N. 2 Low current connection cables, 10 sq. mm, 4 m long.
Terminated on both sides with a 4 mm banana plug.
-N. 2 Clamps to connect low voltage or low current or
measurements.
C) Input connection, voltage less than 10 V:
-N. 1 Cable for low voltage measurement connection, shielded, 4
m long. Terminated on one side with the measurement connector,
and on the other side with two 4 mm banana plugs.
-N. 2 Clamps to connect low voltage or low current or
measurements.
D) Input connection, voltage more than 10 V:
-N. 2 measurement cables.
-N. 2 Clamps to connect low voltage or low current or
measurements.
HV cables shall be connected while T 2000 is powered-off. HV
clamps shall have a minimum clearance of 20 mm with respect to
all conductive surfaces, so to avoid discharges during operation.
After connections, the area around the HV clamps shall be
isolated, so that no accidental contact can occur. If something
goes wrong for any reason, power-off T 2000 before getting close
to HV connections.
Input in the screen the primary and secondary current, and the
selected output voltage range and input measurement range: the
screen displays the nominal ratio.
If the test is to be performed at 3000 V, press test START button
(56): the following message will be displayed.
The HV is generated only while the START button (56) is kept
pressed: this is an additional safety feature. The operator will
have both hands occupied: one for the knob (6), the other for the
button (56); however, this is much safer than starting the HV
generation, and then forgetting it in the ON state.
You have to turn ON the HV key (28), and adjust the VSEC
voltage to VSM/2 by the adjustment knob (6); the screen shows:
. the secondary voltage that you are generating;
. The corresponding primary voltage;

DOC. MIE11110 Rev. 5
Page
15
of
110
. The transformer ratio;
. The percentage ratio error with respect to the nominal;
. The polarity, as OK or KO. You will notice that the % error does
not change as a function of the test voltage.
When you are close to VSM/2, press SAVE: test result is saved,
and voltage is removed. Return to zero the adjustment knob (6),
and turn off the HV key (28).
Please remember that if the test current is more than 0.2 A aT
2000 V, the test duration will be limited, as per the following table.
VOLTAGE
OUTPUT
VOLTAGE
OUTPUT
CURRENT
OUTPUT
A
OUTPUT
POWER
VA
LOAD
TIME
Min
RECOVERY
TIME
min
3000
2500 0.2 0.6 600 1500 STEADY 1- 8
The one minute duration at 0.6 A is more than enough for the
test, so, it is no practical limitation. However, for higher currents
the duration could not be sufficient for the test.
If, when the test START button (56) is pressed, the HV key is
already ON, the following message is displayed:
In this instance, press the STOP button (55), turn OFF the HV key
(28), then press test START button (56).
If, during the test, you want to make sure that the applied
voltage is not such to cause the saturation of the transformer,
select EXCIT: the screen will become the following one.

DOC. MIE11110 Rev. 5
Page
16
of
110
Having verified that there is no saturation, you can return and
press SAVE to save the test result; then, slowly reduce the
voltage: the test can be stopped only after knob (6) is in its zero
position. This is because the transformer under test cannot be left
with some remaining magnetization. So, if the test is broken during
the generation, and the output has not been adjusted to zero
prior to stop, the following message is displayed.
In this instance, you have to start again the test, slowly reach
the same test value and slowly decrease to zero.
NOTE: if CT’s are located on the primary side and on the
secondary side of a power transformer, the test of the CT ratio
can be performed with the voltage mode, as follows:
. Connect the CT secondary to the test set voltage output;
. Connect the PT winding on which the CT is inserted to the low
voltage measurement input.
The PT winding is not crossed by any current, so the secondary
voltage can be measured on the PT terminals (primary or
secondary).
1.1.2. CT tests : ratio, polarity and burden
When this test is selected, the following menu is displayed.
Purpose of the test is to measure the actual CT ratio, to verify its
polarity, to measure the burden in terms of VA. This test is
performed applying current (and not voltage, as in the former

DOC. MIE11110 Rev. 5
Page
17
of
110
test) to the primary side, and measuring the secondary current
and voltage.
The connection diagram is the following.
For the connection, use the following cables:

DOC. MIE11110 Rev. 5
Page
18
of
110
A) Output connection, 800 A:
-N. 2 High current connection cables, 100 sq. mm, 4 m long.
Terminated on one side with the high current connector; on the
other side, it is possible to use one of the following three
connections.
. The male to male jumper, that allows closing the cable loop into
the hole of the current transformer.
. The high current clamp, that eases the connection to the bars,
but has a maximum current rating of 400 A. Do not go beyond
this value, as the heat can damage the clamp!
. The high current vice, that is a bit less easy to use than the
clamp, but that allows testing up to the maximum current rating.
However, with tests at 800 A, the burden of the 4 m cables can
impeach to reach this current. If the test current is not the
desired one, use the 1 m connection cables provided.
B) Input connection:
-N. 2 measurement cables, for the secondary current, plus N. 2
Clamps. In alternative, if desired: N. 1 Clip-on transformer, plus N.
2 measurement cables (to the clip-on transformer).
-N. 2 measurement cables (to the 600 V measurement), or N. 1
cable for low voltage measurement connection, shielded, 4 m long
(for the 10 V measurement; shown in the circuit diagram), plus N.
2 Clamps to connect the voltage measurement.
Primary clamps shall be well tightened on a clean surface, so that
contact resistance is negligible.
For secondary connection, it is possible to decide whether to
measure the secondary current by opening the circuit or by means
of the optional clip-on current transformer; to this purpose, the
clip-on transformer is more easily used, but it looses accuracy.
Secondary leads should be twisted to reduce stray flux influence.
Take care of current direction, else the polarity test will give
wrong result: the red socket (output or input) is the positive; with
the clip-on transformer, look at the arrow or at the red mark
(entering current).
Also for the measurement of the voltage you have to take care of
the polarity. You can use either the 10 V metering input or the

DOC. MIE11110 Rev. 5
Page
19
of
110
600 V input. The choice is performed considering the test current
IP and the VA rating. Given:
. KCT = CT ratio;
. IP = primary test current;
. VA = VA rating,
compute:
IS = IP / KCT
VS = VA / IS
If VS < 10 V, connect to the 10 V input, that has a better
resolution; else, connect to the 600 V input.
Now, input in the screen:
. The primary and secondary current;
. The secondary current metering method: if the current clamp is
enabled, the clamp’s ratio (1000 to 1 for our option);
. The secondary voltage measurement input.
BEFORE STARTING THE TEST, VERIFY THAT THE SECONDARY
CIRCUIT IS CLOSED: THE CT GENERATES HIGH VOLTAGE IF
THE PRIMARY CURRENT IS INJECTED AND THE SECONDARY IS
OPEN!
Press test start button (56), and adjust the primary current to the
desired value by the adjustment knob (6). There are two tabs to
select the measurement of ratio and polarity or burden. With the
selection RATIO, the screen shows:
. The primary current;
. The secondary current;
. The transformer’s ratio;
. The ratio percentage error with respect to the nominal;
. The polarity, as OK or KO. You will notice that the % error does
not change very much as a function of the test current.
Now select the BURDEN tap: the following screen is displayed.

DOC. MIE11110 Rev. 5
Page
20
of
110
The screen shows:
. The secondary current;
. The secondary voltage;
. The phase angle, in degrees, between current and voltage, with
the voltage taken as the reference. Usually this angle will be
negative, because the burden is inductive;
. The corresponding power factor;
. The VA burden at the nominal current IN. Also this
measurement will not change very much with the test current.
Remember that if you test with a current more than 100 A the
test will have a limited duration, as per the following table.
CURRENT
OUTPUT
A
OUTPUT
POWER
VA
LOAD
TIME
s
RECOVERY
TIME
min
I SUPPLY AT
MAX VA
A
100 600 STEADY -2.8
150 800 15 min 30 4.2
200 1000 4 min 15 5.6
400 1600 15 511.3
600 2000 5317
800 2000 1222.6
Keep the test duration as short as possible: if you exceed the
above table, the test set stops automatically the test, and you
have to wait until the recover time is elapsed. Also, consider that
you are sinking power from the mains supply: the supply cable
wires should have a cross section suitable for a current supply of
10 to 20 A. The table shows the full power current sink from the
mains as a function of the output current.