TD 5000 APPLICATION GUIDE

DATE: 05/05/2014
DOC.MIE13175
TD 5000
APPLICATION GUIDE
Rev 1.1.1
MIE13175 TD 5000 – Application Guide – Rev 1.1.1
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REVISIONS
N
PAGE
1.0.5
All
SUMMARY
VISA
DATE
18/01/2014
Issued
Lodi
1.0.6
04/02/2014
Complete Revision
Meneghin
05/05/2014
Added:
Hot collar test
Meneghin
1.1.1
All
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SHORT FOREWORD ............................................................................................. 5
INTRODUCTION................................................................................................... 6
1 SAFETY AT WORK ........................................................................................... 10
1.1 INTRODUCTION TO SAFETY ................................................................................... 10
1. 2 SAFETY SYMBOLS .............................................................................................. 12
1.3 RISKY SITUATIONS .............................................................................................. 12
2 TEST SET DESCRIPTION AND USE .................................................................... 14
2.1 THE FRONT AND SIDE PANELS ............................................................................... 14
2.2 LOCATING TD 5000 .......................................................................................... 15
2.2.1 Mounting the TD 5000 module.............................................................. 15
2.2.2 Mounting the STS module ..................................................................... 16
2.2.3 Mounting the cable wheels ................................................................... 16
2.2.4 Preparing for testing: modules connections .......................................... 17
2.2.6 Preparing for testing: test cables connection ........................................ 20
2.2.7 Preparing for testing: connection to the power transformer ................ 23
2.3 POWER SUPPLY ................................................................................................. 25
2.4 POWER-ON ...................................................................................................... 25
2.5 GENERATOR CHARACTERISTICS ............................................................................. 26
3 TAN(Δ) AND CAPACITANCE MEASUREMENT BASICS ...................................... 30
3.1 CAPACITANCE AND TD MEASUREMENT OF A GENERIC TEST OBJECT .............................. 32
3.1.1 Tests execution ...................................................................................... 33
3.1.2 View Results........................................................................................... 34
3.1.3 Save results ............................................................................................ 36
3.1.4 Open results ........................................................................................... 36
3.1.5 Software settings ................................................................................... 36
4 TEST MODES .................................................................................................. 38
5 POWER TRANSFORMERS ................................................................................ 41
5.1 TWO WINDINGS TRANSFORMER ............................................................................ 41
5.1.1 Test connections .................................................................................... 42
5.1.1.1 Capacitance and TD measurement of CH, CHL or CH+CHL .......................... 42
5.1.1.2 Capacitance and TD measurement of CL, CHL or CL+CHL ............................ 42
5.2 THREE WINDINGS TRANSFORMER .......................................................................... 43
5.2.1 Test connections .................................................................................... 43
4.2.1.1 Capacitance and TD measurement of CH, CHL, CH+CHL, CHT, CH+CHT,
CHL+CHT or CH+CHL+CHT........................................................................................ 43
5.2.1.2 Capacitance and TD measurement of CL, CHL, CL+CHL, CLT, CL+CLT,
CHL+CLT or CL+CHL+CHT ......................................................................................... 44
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5.2.1.3 Capacitance and TD measurement of CT, CHT, CT+CHT, CLT, CT+CLT,
CHT+CLT or CT+CHL+CHT ......................................................................................... 44
5.3 AUTOTRANSFORMER .......................................................................................... 45
5.3.1 Test connections .................................................................................... 45
5.3.1.1 Capacitance and TD measurement of CH .................................................... 45
5.4 AUTOTRANSFORMER WITH TERTIARY ..................................................................... 46
5.4.1 Test connections .................................................................................... 46
5.4.1.1 Capacitance and TD measurement of CH, CHT or CH+CHT.......................... 46
5.4.1.2 Capacitance and TD measurement of CT, CHT or CH+CHT .......................... 47
5.5 BUSHING ......................................................................................................... 48
5.5.1 Test connections, capacitance and TD measurement of C1 .................. 48
5.5.2 Test connections, capacitance and TD measurement of C2 .................. 49
5.5.3 Hot collar test ........................................................................................ 49
Disclaimer
Every effort has been made to make this material complete, accurate, and up-to-date. In
addition, changes are periodically added to the information herein; these changes will be
incorporated into new editions of the publication. ISA S.R.L reserves the right to make
improvements and/or changes in the product(s) and/or the program(s) described in this
document without notice, and shall not be responsible for any damages, including but not
limited to consequential damages, caused by reliance on the material presented,
including but not limited to typographical errors.
Copies, reprints or other reproductions of the content or of parts of this publication shall
only be permitted with our prior written consent.
All trademarks are the property of their respective holders.
Copyright 2012© ISA S.R.L. Italy – All rights reserved.
MIE13175 TD 5000 – Application Guide – Rev 1.1.1
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SHORT FOREWORD
Dear TD 5000 user,
I often wondered why user manuals are not very much used, even if they include
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 separate the TD 5000 manual from the STS family
manuals, so that all instructions related to this fundamental option of the STS
family are kept together. Therefore, you will find here the following information:
introduction to TD 5000 and the user guide.
Have a good job with ISA test sets!
Luca Biotti
Q&A Manager
NOTE: WINDOWS is a trademark of MICROSOFT inc.
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INTRODUCTION
The products of the STS family allow performing all tests foreseen by international
Standards on CTs, VTs, Power Transformers, and to measure the tan(δ), Power
Factor and capacitance of any device with the TD 5000 option. The use of STS
models is described in MIE12175 STS FAMILY – Application Guide.
The STS family is made of three models: STS 5000, STS 4000 and STS 3000 light. All
of them can operate with TD 5000; as there is no difference in the TD 5000
operation, in this document the STS family module will be called STS, without
specifying the model.
All test sets of the family are controlled locally, by keyboard, dedicated keys,
control knob and display, or by a PC, with the STS_Pro program, which is a part of
the TDMS software, which is provided with the test set. The STS module controls
completely the TD 5000 option, which has no local selection.
The capacitance and tangent delta measurement with TD 5000 can be performed
on CTs, VTs, CBs, PTs and bushings.
Tests are performed in accordance with the following IEC standards: EN 60044-1;
EN 60044-2; EN 60044-5; EN 60044-7; EN 60044-8; EN 60076-1, and also in
accordance with ANSI/IEEE C57.13.1.
The instrument is housed in a transportable aluminium box, which is provided
with removable cover and handles for ease of transportation. A foldable trolley is
also available.
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The following picture shows TD 5000.
On the test set are located three panels, with connectors.
The following one is located to the right: the BOOSTER INPUT must be connected
to the EXT. BOOSTER connector of the STS unit.
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The following panel is located to the left: the COMMUNICATION PORT is used to
establish the communication with STS and to supply the electronic boards of the
TD 5000 unit.
The two measurement input IN A and IN B are used for the sensing of a current
that can be involved or not in the capacitance or tan(δ) measurement, according
with the test mode (GSTg-A, UST-B, and so on).
In the following picture is shown the high voltage output
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The block schematic of the STS with TD 5000 operation is shown in the following:
Device Under Test
IN A
IN B
METERS
--------SWITCH MATRIX
HV
TRANSFORMER
CPU
GND
TD 5000
BOOSTER
CONNECTOR
COMMUNICATION
PORT
CPU
POWER
AMPLIFIER
DISPLAY
STS
GND
During the operation, the test is selected on the STS LCD screen through the
multi-function knob; then, STS sends instructions and power to TD 5000, which
generates the high voltage. The HV return connection passes through the
selection switches, which select the input A or B, and through the high accuracy
measures, where the current is measured. Measurements are sent to STS, which
computes the desired parameters, and displays them to the operator. Test results
are kept in the STS memory, and can be transferred to a PC at a later time, along
with settings.
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1 SAFETY AT WORK
1.1 INTRODUCTION TO SAFETY
The Product TD 5000 hereafter described is an option of the STS family of
products, including: STS 5000, STS 4000, and STS 3000. The following notes apply
to TD 5000 with any of the above STS models.
TD 5000 is manufactured and tested according to the specifications, and
when used for normal applications and within the normal electrical and
mechanical limits, it will not cause hazard to health and safety, provided that all
standard engineering rules are observed, and that it is used by trained personnel
only.
The User should carefully read the instructions and the examples of this manual
prior to operate the test set.
This application manual is published by the Seller, to be used together with TD
5000, as described in the corresponding introductory manual. 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 TD 5000, 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 TD 5000; 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 TD 5000 unavailability and
downtime.
TD 5000 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: - 10 to 55 °C; storage: -20 °C to 70 °C;
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. Relative humidity: 5 to 95 %, without condensing;
. Inputs/outputs protection: IP 2X: IEC 60529, for all but high voltage outputs;
IP4X for high voltage outputs;
. The test set is portable, using the handles.
Would TD 5000 be used beyond these limits, the safety of the test set could be
impaired, and the Seller would not be liable for any occurring problem.
TD 5000 has been tested to match the EMI/RFI standards, as requested by the
European Directive 2004/108/EC; Applicable Standard: EN61326 : 2006. However,
the User should not carry a pacemaker.
1.2 Prior to testing
TD 5000 generates a voltage that may be lethal to the unadvertised user.
ATTENTION
TD 5000 is used to test HV devices. During connections and disconnections, the
device must be grounded: follow the safety procedures!
When the test is in progress, DON’T TOUCH the terminals for any reason.
In case of doubt, press the EMERGENCY pushbutton with mechanical lock which
is located on the front face of STS!
In order to avoid any danger, the device under test should have the following
characteristics:
. Connection cables must be those provided with the test set;
. Connection points must be isolated and not accessible;
. Input circuits must have an isolation degree at least equal to the one of the
product.
. The test area should be clean of loose metal items.
. When performing HV tests, we recommend isolating the area, so
that nobody could accidentally touch the test item. For added safety,
we suggest to use the optional warning strobe light: it will keep on
flashing until the test is over. Anyway, the test set can be
programmed to generate a buzz.
. When performing HV test, an additional precaution is to drive the
START/STOP using the optional remote safety switch: with its 20 m long
cable, you can stay apart from TD 5000, STS and from the test item.
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. The use of isolation gloves is highly recommended.
. Perform all connections to the test item before powering-on the test set.
. At the end of tests, power-off and then disconnect the test set.
Further safety instructions are provided in the manual, for each test to be
performed. Before operating, read them carefully!
1. 2 SAFETY SYMBOLS
The following symbols, located on the test set, are used to alert the operator
about dangerous points.
The symbol is related to dangerous input or outputs, and it is located on
the TD 5000 connector panel, by the side of the current input sockets, of the HV
connector, and of the voltage Booster connector.
.
Also this symbol is related to HV generation, or to HV danger. On the TD
5000 connectors’ panel, the symbol is located by the side of the HV connector.
. The symbol
yellow socket.
is located on the connector’s panel, close to the green-
1.3 RISKY SITUATIONS

Never leave connection cables connected, even if the output is unused.
The TD 5000 HV connector is suited for HV isolation; instead, connection
cables have at their ends some accessible clip-on clamps. It is true that
HV generation is disconnected when not used; however, an error could
always occur.

Connect the cable to the test device before enabling the test. Here
again, a mistake is always possible. DO NOT CONNECT THE TEST DEVICE
WHEN THE TEST SET IS ON!

If, as the test is started, you understand that a clamp is not properly
closed, or that it has dropped down, power off the test set before
correcting!
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
Remember that, during these tests, the HV transformer is referred to
ground: this is why touching conductors is so dangerous.

In all tests, the generation is performed after having pressed the START
button. After the start, the test set generates a low voltage, and
measures the burden impedance: in case of high burden, including
short-circuit, the operation is stopped, and the user is alerted. After this,
the test set generates the full voltage, taking into account the voltage
drop, so that the actual voltage copes with the nominal test value.
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2 TEST SET DESCRIPTION AND USE
In this chapter we describe TD 5000, and inform about the HV generator
characteristic.
2.1 THE FRONT AND SIDE PANELS
The following pictures show the test set the side panels. All components are
marked; their function is explained in the followings.
In Appendix 1 are listed the standard components which are provided with the
test set. For each component it is described its characteristic, and the mode of
use.
(1) TD 5000 ground connection
(2) High voltage transformer
connector, must be connected to
the EXT. BOOSTER connector of the
STS unit
(3) STS communication port
(4) “IN A” measurement input
(5) “IN B” measurement input
(6) Ground connection for the HV
cable external shield
(7) HV generator’s connector
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2.2 LOCATING TD 5000

TD 5000, for the ease of transportation, is provided with front handles. It
is conceived and tested to be operated when mounted on the foldable
trolley, as shown in the following series of pictures.

NOTE. If the trolley is not available, locate horizontally STS, and
vertically TD 5000. Leave enough space around the test sets, so they are
not heated by other devices.
2.2.1 Mounting the TD 5000 module
There are two arms below: open them then put on TD 5000. After this, tie TD
5000 to the trolley with the stripe provided.
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2.2.2 Mounting the STS module
Open the upper arms of the trolley: they host STS.
Put on STS and tie it with the stripe.
2.2.3 Mounting the cable wheels
The HV cable wheel is located in the rear, and blocked with the mechanical lock.
The measurement cables are laid in the baskets. Now, for the ease of
transportation, lift the handle, removing the mechanical lock: the trolley is ready
to be moved around.
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2.2.4 Preparing for testing: modules connections
When you are at the test place, first lower the handle; then, connect the
communication cable.
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The Communication Port is a 15 pins connector. The housing is provided with two
screws: after inserting the cable, firmly tighten them.
Next, connect the BOOSTER cable.
The BOOSTER connector is a safety one: after fitting it in, you have to turn it
counter clockwise, until it stops: the mechanical lock prevents any unwanted
disconnection. To disconnect it, you have to slide the lock down and rotate
clockwise.
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Next, connect the ground cables.
Connections are as follows:
 The STS module is connected to the substation ground, by means of the
6 m long cable provided, and to the TD 5000 module, with the short
cable provided;
 The TD 5000 module is connected to the STS module and to the trolley,
with the short cable provided.
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2.2.6 Preparing for testing: test cables connection
The test set comes with the following clamps.
The four ones to the left are used for measurements, with a smaller (above) or
bigger (below) clamp opening, as a function of the thickness of the part you are
clamping it on.
The two to the right, with the 6 mm connector, are for the HV connection.
Measurement cables are screwed into the corresponding connectors as shown.
There can be one or two connections, according to the type of test to be
performed.
On the other side, the measurement cable is connected to one of the
measurement clamps.
MIE13175 TD 5000 – Application Guide – Rev 1.1.1
The HV cable comes with a protection on the HV connector.
The protection has to be unscrewed.
Pag. 21 of 54
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Now, it is possible to screw the HV connector to TD 5000. The following picture
shows the connector position when it is locked.
For safety reasons, don’t forget connecting to ground the external
shield!
The connector has a mechanical protection: when fitting it, you will hear a soft
click when the protection is armed. In this situation, the cable does not open
even if you pull it: this is important, because otherwise the cable weight could
cause the opening.
To the other end of the HV cable, connect one of the two HV clamps:
To remove the cable, push it some more, and then pull it open.
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2.2.7 Preparing for testing: connection to the power transformer
A fundamental general rule is that the power transformer should be
disconnected from the substation, and grounded before to start with test
connections.
In this example is shown how to prepare the setup for CH measurement of the
following 400 MVA autotransformer. The connections show how to perform a GST
measurement.
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First, the test set has been connected to ground with the tank.
Next, all bushings must be short-circuited together and then connect the HV cable
to one of the primary side bushing.
The use of STS software to execute the measurement is described in section 3.1.
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2.3 POWER SUPPLY
The power supply of the HV transformer is taken from the BOOSTER connections,
and the power supply for the electronic boards is taken from the communication
port.
Attention: THESE CONNECTIONS MUST BE DONE WHEN STS IS POWERED OFF!
Characteristics of the BOOSTER connection:




Output not isolated from the mains supply.
Output voltage: adjusted by STS from 0 to 220 V AC, as a function of the
test being developed.
Output power; STS supply 230 V: 1500 VA steady, 3600 VA during 2
minutes.
Output power; STS supply 110 V: 1360 VA steady, 2500 VA during 2
minutes.
The Ground connection is critical for some of the tests to be performed, and is the
main protection against errors. For this reason, TD 5000 is provided with a
dedicated ground connection cable, which shall be connected to ground as close
as possible to the test power transformer. STS will be connected to the same
ground by means of the short yellow/green cable provided.
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.
2.4 POWER-ON
When you are to operate the TD 5000 unit, before power-on, connect STS to TD
5000, as explained here before. As you power-on STS, also TD 5000 is poweredon.
As soon as STS is connected to the mains, the power supply goes to a standby mode, a diagnostic runs, and, in a couple of seconds, the test set can be
powered-on.
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Pressing the ON/OFF button powers-on the test set; pressing it again, the test set
is turned off.
After power-on, the test set will perform first a self-diagnostic sequence, and then
the display will confirm that TD 5000 is connected.
The TD 5000 connection status with STS is shown with the following icons on the
main window:
TD 5000 is communicating properly with STS
TD 5000 is not communicating or it’s not connected
TD 5000 is communicating but not properly
2.5 GENERATOR CHARACTERISTICS
The TD 5000 module, driven by STS, is a High Voltage electronic generator, with
the following characteristics, in the range of 50 to 60 Hz. Generator characteristics
are the followings.
MAX. OUTPUT
VOLTAGE
12000V
12000V
OUTPUT
CURRENT
300 mA
125 mA
MAX. OUTPUT
DURATION
>120 s
>1h
OFF/ON
RATIO
6.3
1.1
The ON/OFF ratio is the ratio of the time during which the generation is blocked,
after having generated high power. When the current generation is less than the
maximum output duration, the OFF time is the ON time by the OFF/ON ratio. For
instance, if the test at 300 mA lasted 20 s, the OFF time lasts:
TOFF = 20 * 6.3 = 126 s.
On this output there is no output or power limitation as a function of the supply
voltage.
The HV output decreases in amplitude below 45 Hz. The decrease is linear with
the frequency; at 15 Hz the amplitude is 40% of the one at 50 Hz.
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The HV output decreases also for frequencies above 200 Hz, but only at 300 mA.
The following diagram shows the test set behaviour.
120
100
[%]
80
60
< 125 mA
40
< 300 mA
20
15
40
65
90
115
140
165
190
215
240
265
290
315
340
365
390
0
Frequency [Hz]
The test set measures the current generated by the HV output, and the phase
shift of the current with respect to the voltage. These measurements don’t
change with the HV output range.
There are two current measurement ranges. Current ranges, resolution and
accuracy are shown in the next table.
INTERNAL
MEASURE
RESOL.
1V
1 mA
TYPICAL
ACCURACY
± % (rdg) ± % (rg)
± 0.2% ± 0.5 V
± 0.2% ± 1 mA
GUARANTEED
ACCURACY
± % (rdg) ± % (rg)
± 0.3% ± 1 V
± 0.5% ± 2 mA
12000 V AC
5 A AC
(@ inputs A or B)
10 mA AC
(@ inputs A or B)
0.1 µA
± 0.2% ± 0.1 µA
± 0.3% ± 0.1 µA
NOTE. When we speak of accuracy, the error has always two components: the
first one proportional to the reading (rdg), the second one proportional to the
range (rg).
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
Frequency range: 15 to 500 Hz. Frequency resolution: 10 mHz; accuracy
10 ppM.

Connections: by a double shielded HV connector, a Ground sockets, and
two measurement sockets (A and B).
From the measurements of V and I, the following measurements are derived.
 Capacitance:
 Measurement range 1, from 1 pF to 100nF. Resolution: 6 digits.
Accuracy, typical: ± 0.03% of the value ± 0.1 pF; guaranteed: ±
0.05% of the value ± 0.1pF.
 Measurement range 2, from 10 nF to 3 µF. Resolution: 6 digits;
accuracy, typical: ± 0.1% of the value ± 10 pF; guaranteed: ± 0.2% of
the value ± 10 pF.
 Tan(δ)(or dissipation factor DF):
 Measurement range 1: from 0 to 10% (capacitive). Resolution: 5
digits; accuracy, typical: 0.05% of the value ± 0.005 %; guaranteed:
0.1% of the value ± 0.005 %;
 Measurement range 2: from 0 to 100%. Resolution: 5 digits;
accuracy, typical: 0.3% of the value ± 0.01 %; guaranteed: 0.5% of
the value ± 0.02 %.
 Measurement range 3: over 100%. Resolution: 5 digits; accuracy,
typical: 0.5% of the value ± 0.03 %; guaranteed: 0.8% of the value ±
0.05 %.

Power factor PF (or cos(φ)):
 Measurement range 1: from 0 to 10% (capacitive). Resolution: 5
digits; accuracy, typical: 0.05% of the value ± 0.005 %; guaranteed:
0.1% of the value ± 0.005 %;
 Measurement range 2: from 0 to 100%. Resolution: 5 digits;
accuracy, typical: 0.3% of the value ± 0.02 %; guaranteed: 0.5% of
the value ± 0.02 %.

Power:
 Measurement ranges: 10 kW, 100 kW, 1 MW. Resolution: 0.1
mW; accuracy, typical: 0.5% of the value ± 1 mW; guaranteed:
1% of the value ± 2 mW.

Inductance:
MIE13175 TD 5000 – Application Guide – Rev 1.1.1


Pag. 29 of 54
Measurement range 1: from 1 H to 10 kH. Resolution: 0.1 mH;
accuracy, typical: 0.5% of the value ± 0.5 mH; guaranteed: 1% of
the value ± 1 mH.
Measurement range 2: from 100 H to 1 MH. Resolution: 1 H;
accuracy, typical:0.5% of the value ± 0.5 H; guaranteed: 1% of
the value ± 1 H;
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3 TAN(δ) AND CAPACITANCE
MEASUREMENT BASICS
The electrical model of a generic test object can be modeled as a capacitor with a
parallel resistor as shown in the following picture:
IC
ITOT
C
IC
R
IR
ITOT
d
IR
Applying an AC voltage to the test object, the total current flowing out from the
voltage source is divided into the capacitive and resistive part of the impedance.
The tan(δ) quantity, hereafter called TD, is defined as:
The parallel resistor represents how much the capacitor is not ideal, in other
words it is an indication of the dielectric losses: as small is the resistance, as bad is
the dielectric.
Accordingly to this concept, as good is the dielectric, as small is TD.
The TD measurement is used, for example, to understand how good is the
insulation of a bushing or the insulation between the HV and LV winding of a
power transformer. Since the resistive part of an insulator is very high, a very high
voltage source with very high power must be used in order to drive such a huge
resistive load and inject a small measurable current.
NOTE: TD can be called Dissipation Factor (DF), these two terms are considered
synonymous.
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From the two currents IC and IR is possible to derive another quantity called Power
Factor, hereafter defined as PF:
These two quantities have practically the same value when d is very close to zero;
if your test object has a very good insulation who leads to a very small TD value,
even PF has the same small value. But if the test object has a problem and TD
starts to increase, beyond few degrees of d angle, TD and PF starts to be slightly
different.
TD value should not change if the applied voltage changes; actually what’s
happen is that beyond a certain voltage level, the applied electrical field starts to
polarize the insulator’s atoms so the conductivity changes as well. This atoms
polarization effect leads to an increasing of TD values even if the insulator is not
damaged. Different materials give different response to the same voltage.
Even changing the applied frequency the TD values change, and the main reason
is that the capacitor impedance is a function of frequency.
TD [%]
TD [%]
1.5
15.0
1.0
10.0
0.5
5.0
1k
5k
10k
[V]
15
200
400
[Hz]
All physical phenomenon who interact and play a role in the TD value change are
various and their physical description and comprehension is complicated, so the
concept “as good is the dielectric, as small is TD” automatically lose of sense if it
is not related to the test conditions (voltage, frequency, temperature, etc…) and
to what kind of insulation (oil, paper, resin, porcelain, etc…) we are talking about.
What must be very clear to the operator is that a single value of TD or PF alone
cannot be used to state whether the insulation is good or damaged, what has
sense to do is to collect many values and do a comparison in order to see if there
is a worsening of the TD values’ trend over the time.
MIE13175 TD 5000 – Application Guide – Rev 1.1.1
Pag. 32 of 54
3.1 CAPACITANCE AND TD MEASUREMENT OF A GENERIC TEST OBJECT
In the STS main window, select the “Tangent Delta & Capacitance” icon (see
picture above) and press the knob.
The following windows will be opened:
(1) Test type. Select here where the high voltage output will be applied: in case
of a defined test object (CT, VT, PT or CB), the available options will be
displayed accordingly.
(2) Capacitance under test. In case of e defined test object (CT, VT, PT or CB),
the available options will be displayed accordingly.
(3) Generation mode. Select here if a single shot, a voltage sweep or a frequency
sweep must be performed.
(4) Test Mode. Select here the test mode accordingly with the connection
between TD 5000 unit and the test object. In case of a defined test object
MIE13175 TD 5000 – Application Guide – Rev 1.1.1
Pag. 33 of 54
(CT, VT, PT or CB), the most proper test mode will be automatically selected
accordingly with the selections (1) and (2). See section 4 for further details.
(5) Voltage/Frequency test table. Accordingly with selection (3), this table allows
to set different test voltages or frequencies.
(6) Nominal Values. Insert here the reference values of capacitance and TD. In
case of e defined test object (CT, VT, PT or CB), these values will be taken
from the related headers (see MIE12175 – STS FAMILY Application Guide).
The check-box allows including these parameters in Tests table.
(7) Temperature compensation. Capacitance and TD values changes with the
temperature: selecting the check-box, the “k” coefficient will be used to
compensate the measurements.
(8) Tests table. To add a test in the test table, highlight this table and press the
button “Add Test”; each row of this table contains the parameters selected
in (1) (2) (3) (4) (5) (6) (7).
(9) Results table. Here you find all measurements and calculations of the
selected row in the Tests table.
(10) Show graph. In case of a voltage or a frequency sweep, capacitance and TD
values are plotted in a graph.
3.1.1 Tests execution
Connect the TD 5000 unit to STS while STS is switched off, then switch on STS; the
TD 5000 unit is powered by STS.
Prepare all tests you want to perform and add rows in the Tests table (see section
3.1); in the following picture is shown an example of a voltage sweep:
MIE13175 TD 5000 – Application Guide – Rev 1.1.1
Pag. 34 of 54
Connect TD 5000 to the test object taking care of the selected test mode (e.g.
UST-A, GSTg-a, and so on).
Once all connections are done and all safety precautions has been respected,
press the START/STOP button
.
Each pair of voltage and frequency injection consists in a sequence of operations:
1.
2.
3.
Load evaluation
Calibration
Measurement
This sequence is performed in order to guarantee the maximum possible
measurement accuracy.
3.1.2 View Results
Once all tests are performed, the Results table contains all measurements. The
Results table changes every time a row of the Tests table is highlighted and
selected by pressing the knob. When a row in Tests table is selected, the focus is
automatically moved on the Results table and the window is displayed as in the
following picture:
MIE13175 TD 5000 – Application Guide – Rev 1.1.1
Press the button “Scroll”
table.
Pag. 35 of 54
and rotate the knob to scroll left-right the Results
With the button “Show graph”
, in the Results table will be shown the
corresponding graph of the measurements.
The following pictures are examples of capacitance and TD measured with a
frequency sweep:
MIE13175 TD 5000 – Application Guide – Rev 1.1.1
Pag. 36 of 54
Rotate the knob to highlight the graph and then press it: with this operation it is
possible to read the values of each point:
3.1.3 Save results
Press the save button
located to the left of the screen.
For more details, please refer to MIE12175 STS FAMILY – Application Guide.
3.1.4 Open results
Press the open button
located to the left of the screen.
For more details, please refer to MIE12175 STS FAMILY – Application Guide.
3.1.5 Software settings
MIE13175 TD 5000 – Application Guide – Rev 1.1.1
Pag. 37 of 54
Selecting the two icons above and the panel “Tandelta”, the following window
will be shown:
Power factor naming. Select if you want to consider TD or PF values.
Power factor value. Select if TD or PF values must be shown as an absolute value
or a percentage value (% value = abs value * 100).
Noise Reduction. Select how many measures will be taken to perform an
averaging and calculate the result.
Ground Shield Check. Enable the sensing of the HV shield cable’s connection.
Warnings. Enable external warnings devices during the execution of the test:
buzzer, siren or strobe light.
MIE13175 TD 5000 – Application Guide – Rev 1.1.1
Pag. 38 of 54
4 TEST MODES
There are two main test modes:
 GST - Ground Specimen Test
 UST - Ungrounded Specimen Test
The target is to measure the current that is flowing in a capacitor in order to
perform capacitance, tangent delta or power factor measurement.
When the test object is, for example, a two windings power transformer, the
equivalent circuit is composed by three interconnected capacitors, thus the total
current flowing out from TD 5000 will be divided into each branch of the circuit.
The only way to perform the measurement on a single capacitor is to filter out (or
to guard) the current that is flowing into the other branches.
Accordingly with the selected test mode, TD 5000 will automatically set-up the
internal architecture in order to guard the unwanted currents.
The following picture shows this principle on a two windings power transformer.
ITOT = I1 + I2
CHL
TD 5000
HV
output
I2
I2
CH
I1
CL
X
GND
IN A
IN B
SWITCH
MATRIX
Current
sensing
I1
I1
I2
CH measurement, test mode GSTg-A
If the capacitance CH must be measured, the only current that must be taken into
account is I1. Since CH cannot be disconnected from CHL and CL, the current I2
must circulate out of the current sensing unit; through the switch matrix a
different path is created and I2 is deviated to point “X”. Note that any current can
flow into CL because IN A creates a very low impedance node, so I2 is not divided.
The test mode here described is called GSTg-A.
MIE13175 TD 5000 – Application Guide – Rev 1.1.1
Pag. 39 of 54
With the same connection is possible to measure CHL and the sum CH+CHL, just
selecting different test modes, UST-A and GST respectively (see pictures below).
In case of UST-A the current that must be guarded is the one that is flowing in the
ground connection, while in case of GST all currents must be considered.
ITOT = I1 + I2
CHL
TD 5000
HV
output
I2
I1
CH
I1
CL
X
GND
IN A
IN B
SWITCH
MATRIX
Current
sensing
I1
I2
I2
CHL measurement, test mode UST-A
ITOT = I1 + I2
CHL
TD 5000
HV
output
I2
CH
I1
CL
X
GND
IN A
IN B
SWITCH
MATRIX
Current
sensing
I1+I2
I1
I2
CH+CHL measurement, test mode GST
To measure CL a different connection is needed:
MIE13175 TD 5000 – Application Guide – Rev 1.1.1
Pag. 40 of 54
ITOT = I1 + I2
CHL
TD 5000
HV
output
I2
I2
I1
CH
CL
X
GND
IN A
IN B
I2
Current
sensing
SWITCH
MATRIX
I1
I1
CL measurement, test mode GSTg-A
Same as CH, the capacitance CL can be measured with the GSTg-A test mode.
NOTE: the same tests can be performed using IN B instead of IN A as well, just
select test mode GSTg-B for CH and CL and UST-B for CHL.
The most complicated case is the three windings power transformer.
The third winding introduces three more equivalent capacitances: CT, CLT and
CHT. In the following picture is shown that both IN A and IN B must be used
together in order to measure CH: in this case only GSTg-A+B test mode can be
used.
ITOT = I1+I2+I3
CHT
I3
TD 5000
HV
output
CLT
CHL
I2+I3
X
GND
IN A
IN B
SWITCH
MATRIX
Current
sensing
I2
I1
CL
CH
I1
I2
I3
CH measurement, test mode GSTg-A+B
CT
MIE13175 TD 5000 – Application Guide – Rev 1.1.1
Pag. 41 of 54
5 POWER TRANSFORMERS
Select this icon on the STS main window, input all necessary header parameters
and select the “Tangent d” button in the test list. The use of STS software to
execute the measurement is described in section 3.1.
5.1 TWO WINDINGS TRANSFORMER
Before to start with any measurements the transformer must be taken out of
service, disconnected from the power system and the tank must be very well
grounded. All HV bushings must be short-circuited, as well as the LV bushings.
Once these operations are done, three equivalent capacitances must be
measured (see picture below):



CH: capacitance between HV winding and the ground
CHL : capacitance between HV and LV winding
CL: capacitance between LV winding and the ground
CHL
CH
CL
MIE13175 TD 5000 – Application Guide – Rev 1.1.1
Pag. 42 of 54
5.1.1 Test connections
5.1.1.1 Capacitance and TD measurement of CH, CHL or CH+CHL
HV cable's shield
To STS EXT. DEVICE port
CHL
CH
CL
To STS External
Booster socket
To STS ground
5.1.1.2 Capacitance and TD measurement of CL, CHL or CL+CHL
To STS EXT. DEVICE port
HV cable's shield
CHL
CH
To STS External
Booster socket
To STS ground
CL
MIE13175 TD 5000 – Application Guide – Rev 1.1.1
Pag. 43 of 54
5.2 THREE WINDINGS TRANSFORMER
Before to start with any measurements the transformer must be taken out of
service, disconnected from the power system and the tank must be very well
grounded. All HV bushings must be short-circuited, as well as the LV and tertiary
bushings.
The presence the tertiary winding complicates the equivalent circuits. In this case
there are six capacitances to be measured:






CH: capacitance between HV winding and the ground
CHL : capacitance between HV and LV winding
CL: capacitance between LV winding and the ground
CLT: capacitance between LV and tertiary winding
CT : capacitance between tertiary winding and the ground
CHT: capacitance between HV and tertiary winding
5.2.1 Test connections
4.2.1.1 Capacitance and TD measurement of CH, CHL, CH+CHL, CHT, CH+CHT,
CHL+CHT or CH+CHL+CHT
HV cable's shield
To STS EXT. DEVICE port
CHT
CHL
To STS External
Booster socket
To STS ground
CH
CLT
CL
CT
MIE13175 TD 5000 – Application Guide – Rev 1.1.1
Pag. 44 of 54
5.2.1.2 Capacitance and TD measurement of CL, CHL, CL+CHL, CLT, CL+CLT,
CHL+CLT or CL+CHL+CHT
HV cable's shield
To STS EXT. DEVICE port
CHT
CHL
To STS External
Booster socket
CLT
CH
CL
CT
To STS ground
5.2.1.3 Capacitance and TD measurement of CT, CHT, CT+CHT, CLT, CT+CLT,
CHT+CLT or CT+CHL+CHT
To STS EXT. DEVICE port
HV cable's shield
CHT
CHL
To STS External
Booster socket
To STS ground
CH
CLT
CL
CT
MIE13175 TD 5000 – Application Guide – Rev 1.1.1
Pag. 45 of 54
5.3 AUTOTRANSFORMER
Before to start with any measurements the transformer must be taken out of
service, disconnected from the power system and the tank must be very well
grounded. Since the autotransformer has a single winding, all HV and LV bushings
must be short-circuited together. Once these operations are done, there is only
one equivalent capacitance:

CH: capacitance between HV/LV winding and the ground
5.3.1 Test connections
5.3.1.1 Capacitance and TD measurement of CH
HV cable's shield
To STS External
Booster socket
To STS ground
CH
MIE13175 TD 5000 – Application Guide – Rev 1.1.1
Pag. 46 of 54
5.4 AUTOTRANSFORMER WITH TERTIARY
Before starting with any measurements the transformer must be taken out of
service, disconnected from the power system and the tank must be very well
grounded. All HV and LV bushings must be short-circuited together, as well as the
tertiary bushings.
This power transformer has two windings, so the equivalent circuit is the same of
a two windings transformer; the capacitances to be measured are:



CH: capacitance between HV/LV winding and the ground
CHT : capacitance between HV/LV and tertiary winding
CT: capacitance between tertiary winding and the ground
5.4.1 Test connections
5.4.1.1 Capacitance and TD measurement of CH, CHT or CH+CHT
HV cable's shield
To STS EXT. DEVICE port
CHT
CH
To STS External
Booster socket
To STS ground
CT
MIE13175 TD 5000 – Application Guide – Rev 1.1.1
Pag. 47 of 54
5.4.1.2 Capacitance and TD measurement of CT, CHT or CH+CHT
HV cable's shield
To STS EXT. DEVICE port
CHT
CH
To STS External
Booster socket
To STS ground
CT
MIE13175 TD 5000 – Application Guide – Rev 1.1.1
Pag. 48 of 54
5.5 BUSHING
A bushing has two equivalent capacitances to be measured:


C1: capacitance between the internal conductor and the Td tap
C2: capacitance between the Td tap and the ground
5.5.1 Test connections, capacitance and TD measurement of C1
HV cable's shield
CONDUCTOR
C1
To STS EXT. DEVICE port
To STS External
Booster socket
To STS ground
C2
Td TAP
MIE13175 TD 5000 – Application Guide – Rev 1.1.1
Pag. 49 of 54
5.5.2 Test connections, capacitance and TD measurement of C2
To STS EXT. DEVICE port
CONDUCTOR
HV cable's shield
C1
To STS External
Booster socket
C2
Td TAP
To STS ground
5.5.3 Hot collar test
For a correct use of the hot collar, the inner black side of the collar must be
placed directly in contact on the surface of the bushing under test. The green
colored other side of the collar is not so conductive; therefore the outer green
colored side is not a so suitable for an electrical contact.
In the next picture there is an example of a correct application of the collar.
MIE13175 TD 5000 – Application Guide – Rev 1.1.1
Pag. 50 of 54
As you can see, the inner black side of the belt is strictly wrapped around the
device under test.
In the picture the Device Under Test (D.U.T) is the lower part of the bushing of a
medium voltage breaker.
The HV is applied via the HV clamp; be sure that a good electrical contact is
present between the clamp and the black surface of the collar.
In the ISA's supplied hot collars, a metallic buckle is present to ensure a good
tensile force as well a good electrical contact.
MIE13175 TD 5000 – Application Guide – Rev 1.1.1
Pag. 51 of 54
Here above an example of a hot collar wrapped and fastened with the buckle.
In the following images, a sequence of the operations required for the hot collar
installation.
1) Wrap the collar around the bushing; then insert the free side of the collar
into the buckle as shown. Take some care to place the small part of the belt
which is “solid” with the buckle; place it just under the free part of the belt.
This will ensure a continuous contact all around the surface of the D.U.T
and the conductive side of the collar itself.
2) Once the operations above are executed, fasten and lock the belt into the
buckle.
MIE13175 TD 5000 – Application Guide – Rev 1.1.1
Pag. 52 of 54
3) If there’s enough free space around the wrapped collar; you can engage the
clamp directly on the buckle. Otherwise it is possible to hang the clamp to
the belt directly. In this case, be sure that the black side of the collar belt is
in electrical contact with the metallic part of the clamp. In both cases avoid
any contact of the not wrapped part of the collar with the objects around.
Don't leave it “floating” around. Wrap the remaining part on itself.
MIE13175 TD 5000 – Application Guide – Rev 1.1.1
Pag. 53 of 54
Of course, it is possible connect the HV using the 4 mm plug connected on the
collar as in the following image
If erroneously the collar is wrapped “upside down” (see below), that means with
the colored side attached to the DUT surface, you will be able anyway to perform
the test, but the measurements will be affected by this fact (see table below,
where are compared the results on the same D.U.T).
Results using the collar installed in the right way:
Vout [V] Iout [A] Freq. [Hz]
Cp [F]
Tδ
QF
Loss [W]
[W]@10k QTest [VA] STest
V
[VA]
Rp [Ω]
1
4992.4
24.4µ
35.0
22.2108p
8.5218m
117.3465
1.0370m
4.1606m
-0.1217
0.1217
24.0349G
2
4984.4
34.7µ
50.0
22.1851p
4.9392m
202.6650
0.8533m
3.4343m
-0.1731
0.1731
29.1485G
3
5007.9
94.3µ
135.0
22.1732p
4.2812m
233.5770
2.0208m
8.0578m
-0.4720
0.4720
12.4104G
4
5008.4
0.2m
220.0
22.1804p
4.8315m
206.9737
3.7111m
14.7943m
-0.7681
0.7681 6759.4389M
5
4983.4
0.2m
305.0
22.1535p
5.9287m
168.6721
6.2559m
25.1906m
-1.0552
1.0552 3969.7322M
MIE13175 TD 5000 – Application Guide – Rev 1.1.1
Pag. 54 of 54
Results using the collar “reversed” :
Vout [V] Iout [A]
Freq. [Hz]
Cp [F]
Tδ
QF
Loss [W] [W]@10kV QTest [VA] STest
[VA]
Rp [Ω]
1
4994.4
23.3µ
35.0
21.1884p
2.9884m
334.6243
0.3472m
1.3919m
-0.1162
0.1162
71.8720G
2
4987.2
33.2µ
50.0
21.1802p
1.9175m
521.6025
0.3170m
1.2743m
-0.1654
0.1654
78.6833G
3
4990.0
89.7µ
135.0
21.1877p
1.6289m
613.9007
0.7295m
2.9296m
-0.4478
0.4478
34.1361G
4
5008.5
0.1m
220.0
21.2090p
2.2410m
446.2352
1.6459m
6.5614m
-0.7345
0.7345
15.2424G
5
5001.8
0.2m
305.0
21.1932p
2.5988m
384.7918
2.6428m
10.5636m
-1.0169
1.0169 9466.6862M
6
4987.1
0.3m
400.0
21.1982p
2.8558m
350.1664
3.7829m
15.2102m
-1.3247
1.3247 6574.7039M

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