Megger tan Delta Test Attachment User manual

Mess- und Ortungstechnik
Measuring and Locating Technologies
Leitungsortung
Line Locating
Rohrleitungsnetze
Water Networks
Kommunikationsnetze
Communication Networks
Elektrizitätsnetze
Power Networks
Issue: 7 (08/2015) – EN
128311098
Operating Instructions
tan Delta Test Attachment

3
Consultation with Megger
The present system manual has been designed as an operating guide and for reference. It is meant to answer your
questions and solve your problems in as fast and easy a way as possible. Please start with referring to this manual
should any trouble occur.
In doing so, make use of the table of contents and read the relevant paragraph with great attention. Furthermore,
check all terminals and connections of the instruments involved.
Should any question remain unanswered or should you need the help of an authorized service station, please
contact:
Megger Limited Seba Dynatronic
Mess- und Ortungstechnik GmbH
Archcliffe Road
Kent CT17 9EN
T: [phone]
F: [phone]
E: [e-mail]
Dr.-Herbert-Iann-Str. 6
D - 96148 Baunach
T: [phone] – 0
F: [phone]
E: [e-mail]
Hagenuk KMT
Kabelmesstechnik GmbH
Megger USA
Röderaue 41
D - 01471 Radeburg / Dresden
T: [phone] – 0
F: [phone]
E: [e-mail]
Valley Forge Corporate Centre
2621 Van Buren Avenue
Norristown, PA 19403 USA
T: [phone]
F: [phone]
Megger
All rights reserved. No part of this handbook may be copied by photographic or other means unless Megger have before-hand
declared their consent in writing. The content of this handbook is subject to change without notice. Megger cannot be made
liable for technical or printing errors or shortcomings of this handbook. Megger also disclaims all responsibility for damage
resulting directly or indirectly from the delivery, supply, or use of this matter.

4
Terms of Warranty
Megger accept responsibility for a claim under warranty brought forward by a customer for a product sold by
Megger under the terms stated below.
Megger warrant that at the time of delivery Megger products are free from manufacturing or material defects which
might considerably reduce their value or usability. This warranty does not apply to faults in the software supplied.
During the period of warranty, Megger agree to repair faulty parts or replace them with new parts or parts as new
(with the same usability and life as new parts) according to their choice.
This warranty does not cover wear parts, lamps, fuses, batteries and accumulators.
Megger reject all further claims under warranty, in particular those from consequential damage. Each component
and product replaced in accordance with this warranty becomes the property of Megger.
All warranty claims versus Megger are hereby limited to a period of 12 months from the date of delivery. Each
component supplied by Megger within the context of warranty will also be covered by this warranty for the remaining
period of time but for 90 days at least.
Each measure to remedy a claim under warranty shall exclusively be carried out by Megger or an authorized service
station.
This warranty does not apply to any fault or damage caused by exposing a product to conditions not in accordance
with this specification, by storing, transporting, or using it improperly, or having it serviced or installed by a workshop
not authorized by Megger. All responsibility is disclaimed for damage due to wear, will of God, or connection to
foreign components.
For damage resulting from a violation of their duty to repair or re-supply items, Megger can be made liable only in
case of severe negligence or intention. Any liability for slight negligence is disclaimed.
Since some states do not allow the exclusion or limitation of an implied warranty or of consequential damage, the
limitations of liability described above perhaps may not apply to you.

5
Contents
1Safety Advices..................................................................................................................... 6
1.1 General Notes ......................................................................................................................... 6
1.2 General Cautions and Warnings.............................................................................................. 7
2Technical Description......................................................................................................... 8
2.1 Technical Priciples................................................................................................................... 8
2.2 Technical Data......................................................................................................................... 9
2.3 System Description................................................................................................................ 10
2.3.1 Scope of Delivery and Accessories.............................................................................. 11
2.3.2 Measurement Data Unit (MDU).................................................................................... 12
2.3.3 Termination Current Unit (TCU) ................................................................................... 13
3Setting Up the System ...................................................................................................... 14
3.1 Connecting the DRU or DRU-1 .............................................................................................. 14
3.2 Power Supply......................................................................................................................... 15
3.3 Electrical Connection ............................................................................................................. 16
3.3.1 Electrical Connection for Measurements without Leakage Current Compensation ...... 18
3.3.2 Electrical Connection for Measurements with Leakage Current Compensation ........... 20
3.4 Starting Up the Test Attachment and the Test Voltage Source.............................................. 22
4Performing Measurements............................................................................................... 23
5Concluding the Measurement.......................................................................................... 24
6Connection examples....................................................................................................... 25

6
1 Safety Advices
1.1 General Notes
Safety precautions This manual contains basic instructions on commissioning and operating the tan Delta
test attachment. For this reason, it is important to ensure that the manual is available
at all times to authorised and trained personnel. Any personnel who will be using the
devices should read the manual thoroughly. The manufacturer will not be held liable
for any injury or damage to personnel or property through failure to observe the safety
precautions contained in this handbook.
Locally applying regulations have to be observed.
Labelling of safety
instructions
Important instructions concerning personal, operational and technical safety are
marked in the text as follows:
Symbol Description
WARNING
Indicates a potential danger that may lead to fatal or serious injury.
CAUTION
Indicates a potentially hazardous situation which, if not avoided, may
result in minor or moderate injury or material damage.
The notes contain important information and useful tips for using the
system. Failure to observe them can render the measuring results
useless.
Working with products
from Megger
It is important to observe the general electrical regulations of the country in which the
device will be installed and operated, as well as the current national accident
prevention regulations and internal company rules (work, operating and safety
regulations).
Use genuine accessories to ensure system safety and reliable operation. The use of
other parts is not permitted and invalidates the warranty.
Operating staff This system and its peripheral equipment may only be operated by trained or
instructed personnel. Anyone else must be kept away.
The system may only be installed by an authorised electrician. DIN VDE 0104 (EN
50191), DIN VDE 0105 (EN 50110) and the German accident prevention regulations
(UVV) define an electrician as someone whose knowledge, experience and familiarity
with the applicable regulations enables him to recognise potential hazards.
Repair and maintenance Repairs and service must only be done by Megger or authorised service departments
of Megger. Megger recommends having the equipment serviced and checked once
per year at a Megger service location.
Megger also offers direct on-site support. Please contact our service office for more
information.

7
1.2 General Cautions and Warnings
Intended application The tan Delta test attachment can be used to measure the loss factor tanδ of cables
and transformers (see section 2.3).
Using the equipment for other purposes may lead to human danger and damage of
equipment of involved installations.
The limits described under technical data may not be exceeded.
Behaviour at malfunction
of normal operation
The equipment may only be used when working properly. When irregularities or
malfunctions appear that cannot be solved consulting this manual, the equipment
must immediately be put out of operation and marked as not functional. In this case
inform the person in charge who should inform the Megger service to resolve the
problem. The instrument may only be operated when the malfunction is resolved.
Five safety rules
The five safety rules must always be followed when working with HV (High Voltage):
1. De-energise
2. Protect against re-energising
3. Confirm absence of voltage
4. Ground and short-circuit
5. Cover up or bar-off neighbouring energised parts
Using cardiac pacemaker
Physical processes during operation of high voltage may endanger persons wearing a
cardiac pacemaker when near these high voltage facilities.
Fire fighting in electrical installations
•According to regulations, carbon dioxide (CO2) is required to be used as
extinguishing agent for fighting fire in electrical installations.
•Carbon dioxide is electrically non conductive and does not leave residues. It is
safe to be used in energized facilities as long as the minimum distances are
maintained. A CO2 fire extinguisher must be always available within electrical
installations.
•If, contrary to the regulations, any other extinguishing agent is used for fire
fighting, this may lead to damage at the electrical installation. Megger disclaims
any liability for consequential damage. Furthermore, when using a powder
extinguisher near high-voltage installations, there is a danger that the operator of
the fire extinguisher will get an electrical shock from a voltage arc-over (due to the
powder dust created).
•It is essential to observe the safety instruction on the extinguishing agent.
•Applicable is DIN VDE 0132.

8
2 Technical Description
2.1 Technical Priciples
Requirement Underground medium and high voltage cables are continuously subject to thermal,
electrical and mechanical stresses over the course of their use.
This fact inevitably leads - despite the use of durable materials - to increasing damage
or ageing of the cable, which in turn leads to dielectric losses.
One measure for these dielectric losses is the loss factor tanδ.
To prevent cable faults or detect cables with critical ageing, the measurement of tanδ is
a useful diagnostic method.
Physical background The dielectric losses are primarily determined by the conductivity losses in the cable
insulation. With mass-impregnated paper insulation cables, polarisation losses likewise
influence the loss factor.
The dielectric losses (tanδ) can be calculated as follows:
Shown as a vector diagram, this gives the following picture:
Put simply, the insulation resistance is inversely proportional to the tanδ. With a rising
proportion of active current IRan increase is consequently also seen in the tanδ.
Typical indicators of
aged cables
The most important age indicator for mass-impregnated paper insulation cables is
the decomposition of cellulose, which, in principle, acts to increase the moisture in the
paper insulation (through thermal and chemical processes). The moisture decreases
the insulation resistance and thus raises the cable insulation's loss factor tanδ.
Water that has penetrated the insulation from outside also has a considerable
influence on the loss factor.
For VPE cables, the absolute value of the loss factor is less decisive than the change
of the tanδ with increasing voltage (Δtanδ or “tip-up”). The dielectric properties of water
in water trees do not behave in a linear manner with increasing voltage and are thus
detectable using appropriate diagnostic methods.
Water trees are the most frequent age indicator for polymer cables and can definitely
lead to abrupt cable failures.
U
IC
2
I
δ
RCI
I
C
R
ω
δ
1
tan ==

9
2.2 Technical Data
The tan Delta test attachment is defined by the following parameters:
Parameter Value
Measuring range, tanδ 1 x 10-4 ... 1 x 100
Measuring accuracy 1 x 10-4
Resolution 1 x 10-5
Frequency 0.01 Hz … 1 Hz
(10 Hz with accuracy limitations)
Testable cable capacitance 2 nF ... 3 μF
(10 m … 15 km VPE cable for example)
Maximum voltage 54 kVPEAK
Measuring range, current
Measurement Data Unit (MDU)
Termination Current Unit (TCU)
1 μA .. 25 mA
1 μA .. 1 mA
Measuring range, insulation
resistance
1 MΩ … 10 TΩ
Power supply
MDU / TCU
Charger
battery-operated
90 V ... 240 V, 50/60 Hz AC (via power cable) or
12 VDC (via optional vehicle charging cable)
Operating time
Measurement Data Unit (MDU)
Termination Current Unit (TCU)
16 hours (for operation with TCU)
32 hours (for operation without TCU)
24 hours
Charging time 3.5 h
Interfaces
Measurement Data Unit (MDU)
Termination Current Unit (TCU)
Data Reception Unit (DRU)
optical interface (TOSLINK),
wireless connection (868/915 MHz)
optical interface (TOSLINK)
connection to PC via USB (DRU)
or Ethernet (DRU-1) connection to MDU via
radio link (868/915 MHz)
Operating temperature range -25 °C...+55 °C
Operating humidity +30 °C, 70 % relative humidity
Storage temperature range -40 °C...+70 °C
Weight
Measurement Data Unit (MDU)
Termination Current Unit (TCU)
System with case, tripod,
accessories and cables
2.6 kg
1.6 kg
12.25 kg
Protection rating
MDU, TCU, tripod
case (closed)
case (open)
(in accordance with IEC 60529)
IP52
IP62
IP30

10
2.3 System Description
Area of application Dielectric losses can be measured on cables with XLPE (Cross Linked Polyethylene),
PE (Polyethylene), PILC (Paper Insulated Lead Covered) and EPR (Ethylene-
Propylene Rubber) insulation.
The measurement results for mixed sections can only be conditionally interpreted. It is
possible, for example, to diagnose a PILC cable section with a small proportion of
XLPE cable (e.g. about 10%) according to the criteria for a regular mass impregnated
cable.
However, a XLPE/PE cable section with a certain proportion of PILC cable cannot be
evaluated according to the known criteria for XLPE/PE insulation. This is due to the fact
that measurements on even fault-free mass PILC cables show a considerably higher
dielectric loss factor.
Prerequisites In order to use the tan Delta test attachment to measure the loss factor, a VLF sine
wave voltage source (VLF Sinus test system) is required for applying a sinusoidal
voltage to the test object.
It does not matter if the VLF sine wave is used as a stand-alone system or as a
component of a measurement or diagnostics device.
It is only important that the version of the software used by this system is able to
analyse tanδ measured values. This is always evident in that a corresponding
operating mode is provided in the software.
If this is not the case, please contact your Megger sales representative.
The tan Delta test attachment has been developed and designed exclusively for
use with VLF sine wave systems of the Megger Group. If other test voltage sources
are used, no guarantee can be made for trouble-free functioning and correct
measurement results.
System components The tan Delta test attachment consists of three main components, which are
responsible for different tasks:
•Measurement unit
The “Measurement Data Unit” (MDU) is directly integrated in the HV link
between the sine wave source and test object and measures the object's
current and voltage. The measured data are transmitted to the software per
wireless signal via the E-Box.
•Termination Current Unit
(only if your product configuration includes leakage current compensation)
The task of the “Termination Current Unit” (TCU) is to record the leakage
current over the terminations and to transfer this information to the
measurement unit via the optical link.
•Data Reception Unit
The “Data Reception Unit“ (DRU) enables the exchange of control and
measurement data between the software and the measurement unit via
wireless signal and USB interface.

11
2.3.1 Scope of Delivery and Accessories
Scope of delivery In addition to the above described main components, the tan Delta test attachment’s
scope of delivery also includes the following components:
•Measurement unit (MDU)
•Data Reception Unit (DRU or DRU-1)
•Transport case / charging device
•Tripod
•1 x custom HV connection cable with “guard” connections, 1 m
•1 x power cable, 2 m
•1 x USB or Ethernet cable, 1 m (for connecting the DRU)
•1 x Ethernet cable, 1,5 m (for connecting the test voltage source)
•1 x Ethernet cable, 30 m on cable drum (only for test van installations)
•1 x earthing cables (green/yellow), 1.5 m
•2 x measurement cables, 5 m
•1 x operating manual
•Recovery CD
If the product configuration includes leakage current compensation, the package also
contains the following components:
•Termination Current Unit (TCU)
•2 x “guard” strips for leakage current measurement
•2 x fibre-optic cables (TOSLINK), 3 m
•1 x earthing cables (green/yellow), 1.5 m
•1 x soft tie for fastening the TCU
Optional accessories The following optional accessories can be ordered::
Item Description Order number
Longer Ethernet
cable
30 m on cable drum 820023868
Longer HV
connection cable
3 m pre-assembled HV connection cable
with “guard” connections
820020993
Connection set Provides adequate adapters for typical
connection conditions (see also chapter 6)
890017909

12
2.3.2 Measurement Data Unit (MDU)
The following illustrations show the connection and operating elements of the MDU:
Element Beschreibung
HV connection, VLF sine wave source, Ø 10 mm
HV connection test object, Ø 10 mm
On/off button
Status LED
lit in green: operational
lit in orange: charging
Communications LED
flashing green: Device is ready and awaiting activation (no high voltage
is applied yet)
flashing red: Processing of measurement data (high voltage on!)
flashing blue: Communication with TCU
„Guarding“ terminal
TOSLINK connection sockets (IN / OUT)
Tripod attachment with adjusting device and earth contacts
8
7
6
5
4
3
2
1
6
8
7
1
5
4
3
2

13
2.3.3 Termination Current Unit (TCU)
The following illustrations show the connection and operating elements of the TCU:
Element Beschreibung
Leakage current connection (guarding)
On/off button
Status LED
lit in green: operational
lit in orange: charging
Communications LED
flashing blue: Communication with MDU
Earthing connection
TOSLINK connection sockets (IN / OUT)
Holder (on both sides)
for fastening the TCU with the enclosed soft ties
9
10
11
12
13
14
15
15
14
13
12
11
10
9

14
3 Setting Up the System
3.1 Connecting the DRU or DRU-1
Introduction The Data Reception Unit is available in two different models, with the respective model
which best suits the system features being used.
The DRU, which features a USB port, is generally used in systems which are operated
using a laptop computer (e.g. diagnostic test vans, portable systems).
The DRU-1 model instead features a network connection, and is used in test van
systems with a central control unit (e.g. Centrix).
Both models are powered via the respective connection cable, and are activated and
deactivated by connecting the cable and disconnecting it.
Connecting the DRU For portable systems, the operator must connect the DRU manually prior to each
measuring assignment. This step is usually not required for built-in test van systems.
Connecting the DRU-1 In test vans which are operated via one central control unit, the Data Reception Unit
usually has a standing connection with the IPC and the test voltage source via a PoE-
capable (Power over Ethernet) network switch.
If the test van is located at a remote distance from the test object, e.g. in front of a
larger substation, problems could arise in the wireless connection between the DRU-1
and the MDU. This would be signalled by a fault message output to the screen.
In this case, a longer Ethernet cable (see section 2.3.1) should be used to connect the
DRU-1 to the switch. In this way, the DRU-1 can be brought closer to the MDU and a
continuous wireless connection can be ensured.
VLF Sinus
test system
Ethernet
to MDU
USB Ethernet
to MDU
VLF Sinus
test system

15
3.2 Power Supply
Both the MDU and the TCU have an internal, maintenance-free nickel metal hydride
battery. When the batteries are fully charged, both devices can be operated together
during measurements for up to 16 hours.
When the capacity is low, the respective status LED ( or ) begins to flash orange.
The affected device also emits a signal tone at regular intervals. During measurement,
the remaining capacity can also be seen in the software.
It is recommended to check both devices for sufficient capacitance before
connecting them.
To charge the devices, they need merely be placed in the position provided in the
transport case and then connected to the mains with the
supplied power cable
(90 V ... 240 V, 50/60 Hz AC).
Alternatively, an optional vehicle charging cable for connection to 12 VDC can be used.
The charging procedure takes about 3.5 hours. The status LED is lit in orange during
the charging. When the battery is fully charged, the LED lights up green.
11
4

16
3.3 Electrical Connection
WARNING
When performing the following listed work steps, the applicable safety regulations as
specified by VDE 0104 and the “five safety rules” must be followed when setting up
and operating high voltage testing systems (see section 1.2).
The test site and the forbidden area must be made safe, fenced off and equipped with
indicator lamps and warning signs according to the regulations.
WARNING
Before performing the actual electrical connection of the tan Delta test attachment,
the VLF sine wave test system must be brought into position, secured and earthed
according to the work steps described in the manual.
Connection of the VLF sine wave test system to the mains may only be done after the
installation of the tan Delta test attachment.
CAUTION
The measuring sensors were functionally tested for alternating currents of up to
40 kVRMS. To avoid damage, tests with higher alternating current or any other
operating mode (e.g. interval operation, DC tests) may not be performed with the test
attachment installed!
As a rule, the connection on the test object should be made free of partial discharge.
Partial discharges at the connection point could falsify the measurment results.
Versions of
measurement set-up
For a measurement of the loss factor, only the measurement unit MDU needs to be
installed - as described in the following section - in the HV path between test voltage
source and test object.
If, during the measurement, the leakage current over the terminations is additionally to
be recorded and considered in the measurement result, the TCU box must also be
installed in the immediate vicinity of the test object. Electrical connections must also be
made on the remote end (see section 3.3.2).
A measurement with leakage current compensation is always recommended, if small
tanδ values are to be expected. For example, this can be expected when measuring on
homopolymeric and copolymeric XLPE cables. In these cases, the leakage current
caused by dirty or moist cable terminations should not be neglected. If this is not
recorded and compensated for, the measurement results can be falsified which would
make the analysis more complicated.
If the terminations are obviously clean or if the measurement is performed on aged
paper-insulated lead covered (PILC) cables, leakage current compensation is not a
mandatory requirement.
To obtain comparable measurement results, repeat measurements must always be
undertaken with the identical measurement set-up.

17
Measures for improving
the measuring accuracy
The following factors can have unwanted influence on the measurement results and at
worst lead to false interpretations:
•Dirt on the test attachment, especially in the upper area of the stand. Soiling
due to grease, dirt and scratches are the main causes of falsified
measurement results.
•Condensation can appear if the tan Delta test attachment was stored in a cold
place (e.g. overnight in the test van) and the system is afterward set up in a
warm station. The condensation due to air humidity can be clearly seen and
felt.
•High air humidity (>70%), which can occur in certain regions.
Falsified measurement results carry more weight the more limited the measured tanδ
values. The measures described in the following should particularly be performed for
measurements of relatively new homopolymeric and coploymeric XLPE cables.
For measurements of aged XLPE cables, new and old PILC cables, as well as EPR
cables, the falsifications that appear can generally be ignored.
It is recommended, however, to adhere to the following rules for everyday handling of
the tan Delta test attachment:
•Try to avoid condensation in the system due to air humidity. Do not store the
test attachment in a cold place if the measurement will later be performed in a
warm station. If this is not possible, the devices (MDU on stand) should be set
up about 1-2 hours prior to the measurement in order to acclimatise them. It is
recommended to perform such an acclimatisation before every measurement.
•Try to avoid performing measurements with the test attachment on days with
clearly higher air humidity. High humidity affects not only the test attachment,
but also the test object and its terminations in particular. Increased humidity
typically results in lower than usual tanδ absolute values.
•Clean the upper part of the stand with a
dry cloth before beginning a
measurement. This will remove deposited dirt as well as any condensation due
to humidity.
area to be
cleaned

18
3.3.1 Electrical Connection for Measurements without Leakage
Current Compensation
Connection of the MDU The following is an idealised illustration depicting the electrical connection of the MDU
for measurements without leakage current compensation:
When connecting the MDU, proceed as follows:
Step Description
1 Place the tripod between the test voltage source and the test object.
Ensure that the tripod has solid and secure footing.
Set the height of the stand so that the orange portion of pipe rises
completely out of the tripod (see figure).
2 Connect the earthing point with the station earth. Use the supplied
earth cable and the measuring cable with banana plugs.
3 Connect the phase of the HV cable coming from the test voltage source
with the HV plug of the MDU (VLF) and the shield of the cable with
the laid earth line (station earth) from Step 2. Details of the procedure
can also be found in the operating manual for the test voltage source.
4 Connect the phase of the supplied HV connection cable (the end with the
fixed “guarding” lead) with the remaining HV plug of the MDU (test
object) and plug the “guarding” lead into the “guarding” terminal .
6
2
1
1
Cable under test
VLF Sinus
Lock below
this mark
1

19
Connection to the test
object
Connect the other end of the HV cable coming from the MDU to the phase of the test
object which is to be tested, as described in the operating manual of the test voltage
source. If measurements of multiple phases are planned, the numerically lowest phase
should always be connected first.
To ensure a connection free
of partial discharges, the appropriate connection
accessories from the kit should be used according to the connection requirements.
The shield of the HV connection cable, as indicated in the following example
illustration, is to be fastened in the upper area of the termination using the copper
band. The copper band should lie taut on the termination. It should lie as fully against it
as possible (without air gaps) so that it can compensate for all leakage currents.
A selection of other possible connection conditions, see chapter 6.
from the
MDU

20
3.3.2 Electrical Connection for Measurements with Leakage
Current Compensation
Connection of the MDU The following illustration depicts in a simplified manner the electrical connection of the
MDU for measurements with leakage current compensation:
For measurements with leakage current compensation, the MDU is connected the
same way as described in the previous section.
Additionally, the two fibre-optic cables supplied in the delivery must be inserted in the
TOSLINK connection sockets on the underside of the MDU and later connected
with the TCU (see next page).
When laying the cables, avoid kinks, twists, bending radiuses that are too tight and
mechanical deformations. The cables should not be subject to any chafing or
winding.
7
cable under test
VLF Sinus