Megger STX 40 User manual

1
STX 40
Portable Fault Location System
USER GUIDE
Issue: H (11/2022) - EN
Article number: 86883

2

Consultation with Megger
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 Megger Germany GmbH (Baunach)
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]
Megger Germany GmbH (Radeburg) 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 information in this document is subject to change without
notice and should not be construed as a commitment by Megger. 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.

Terms of Warranty
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.

Contents
5
Contents
Consultation with Megger...............................................................................................3
Terms of Warranty ...........................................................................................................4
Contents ...........................................................................................................................5
1Safety Instructions ...........................................................................................7
1.1 General Notes ....................................................................................................7
1.2 General Safety Instructions and Warnings.........................................................8
2Technical description ....................................................................................10
2.1 System description ...........................................................................................10
2.2 Technical data ..................................................................................................12
2.3 Display and operating elements.......................................................................14
2.4 Connection elements........................................................................................15
2.5 Safety devices ..................................................................................................16
2.6 Operation in vehicle..........................................................................................17
3Commissioning ..............................................................................................18
3.1 Electrical connection ........................................................................................19
3.1.1 Use of an external safety device (optional) ......................................................23
3.2 Switch on ..........................................................................................................24
3.3 High-voltage control .........................................................................................25
4Operation ........................................................................................................26
4.1 Screen layout ...................................................................................................26
4.2 Basics of control system...................................................................................28
4.3 Quick selection of operating modes – .......................................................30
4.4 On-line help – ............................................................................................30
4.5 Phase selection – ......................................................................................31
4.6 History database - .....................................................................................32
4.7 System settings - .......................................................................................35
4.7.1 Data menu - .................................................................................................37
4.7.2 Basic settings - ...........................................................................................38
4.7.3 Administration menu - (administration password required)........................39
4.7.3.1 Updating the software - ..............................................................................40
4.7.3.2 User administration - ..................................................................................41
4.7.3.3 Connection Cable Calibration - ....................................................................42
5Performing measurements............................................................................43
5.1 Good to know …...............................................................................................43
5.1.1 Propagation velocity .........................................................................................43

Contents
6
5.1.2 Pulse width .......................................................................................................44
5.1.3 Typical TDR reflectograms...............................................................................45
5.2 Standard functions ...........................................................................................46
5.3 Systematics of cable fault location ...................................................................50
5.4 Insulation test - ............................................................................................51
5.5 DC voltage test / breakdown detection ............................................................52
5.6 Sheath test and sheath fault detection.............................................................53
5.6.1 Perform sheath test - .................................................................................54
5.6.1.1 Pinpointing a sheath fault - .......................................................................56
5.7 Pulse reflection measurement (TDR) - .....................................................58
5.8 Pre-location of high-resistance cable faults - ..........................................60
5.8.1 Arc reflection measurement (ARM) - .........................................................60
5.8.2 Voltage decoupling (DECAY) - .................................................................64
5.8.3 Current decoupling (ICE) - ........................................................................66
5.9 Burning - ....................................................................................................69
5.10 Surge pinpointing - / ............................................................................70
6Completing the work......................................................................................72
7Transportation, storage and care .................................................................73
8Troubleshooting and maintenance ..............................................................74

Safety Instructions
7
1Safety Instructions
1.1 General Notes
This manual contains basic instructions for the commissioning and operation of the device
/ system. For this reason, it is important to ensure that the manual is always available to
the authorised and trained operator. He needs to read the manual thoroughly. The
manufacturer is not liable for damage to material or humans due to non-observance of
the instructions and safety advices provided by this manual.
Locally applying regulations have to be observed!
The following signal words and symbols are used in this manual and on the product itself:
Signal word /
symbol
Description
DANGER Indicates a potential hazard which will result in death or serious
injury if not avoided.
WARNING Indicates a potential hazard which may result in death or serious
injury if not avoided.
CAUTION Indicates a potential hazard which may result in moderate or minor
injury if not avoided.
NOTICE Indicates a potential hazard which may result in material damage if
not avoided.
Serves to highlight warnings and safety instructions.
As a warning label on the product it is used to draw attention to
potential hazards which have to be avoided by reading the manual.
Serves to highlight warnings and safety instructions that explicitly
indicate the risk of an electric shock.
Serves to highlight important information and useful tips on the
operation of the device/system. Failure to observe may lead to
unusable measurement results.
It is important to observe the generally applicable 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 directives (work, operating and safety
regulations).
After working on the system, it must be voltage-free and secured against reconnection as
well as having been discharged, earthed and short-circuited.
Use genuine accessories to ensure system safety and reliable operation. The use of other
parts is not permitted and invalidates the warranty.
Safety precautions
Labelling of safety
instructions
Working with products
from Megger

Safety Instructions
8
The system may only be installed and operated 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.
Anyone else must be kept away!
The product meets the following security requirements of the European Council
Directives:
•EMV Directive (2014/30/EC)
•Low Voltage Directive (2014/35/EC)
•RoHS Directive (2011/65/EU)
1.2 General Safety Instructions and Warnings
The operating safety is only guaranteed if the delivered system is used as intended (see
page 10). Incorrect use may result in danger to the operator, to the system and the
connected equipment.
The thresholds listed in the technical data may not be exceeded under any circumstances.
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. Earth and short-circuit
5. Cover up or bar-off neighbouring energised parts
Using cardiac pacemaker / defibrillator
Physical processes during operation of high voltage may endanger
persons wearing a cardiac pacemaker or defibrillator when near these
high voltage facilities.
Operating staff
Declaration of
Conformity (CE)
Intended application

Safety Instructions
9
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 CO2fire 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.
WARNING
Dangers when working with high voltage
Working on high voltage systems and equipment – especially in non-
stationary operation – requires particular care and safety-conscious
action on the part of test personnel. VDE regulations 0104 on setting up
and operating electrical test systems, as well as EN 50191 and national
standards and regulations must be strictly adhered to.
•The STX 40 generates a dangerous voltage of up to 40 kV during
measurement operation. This is supplied to the test object via a high-
voltage cable.
•The test system may not be operated without supervision.
•Never fail to use safety equipment or put it out of operation.
•Operation requires minimum two people whereas the second person
must be able to activate the emergency switch in case of danger.
•To prevent dangerous charge accumulation, earth all metal parts in
the vicinity of the high voltage equipment.

Technical description
10
2Technical description
2.1 System description
The fault location system STX 40 is a portable, multi-functional device suitable for outdoor
use for testing and locating faults on low and medium voltage cables.
It comes with the following features:
•Dedicated DC test and breakdown detection up to 40 kV
•Dedicated Insulation test up to 20 kV
•Prelocation of faults with well-established HV methods such as arc reflection
measurement (ARM), current decoupling (ICE), and voltage decoupling
(DECAY)
•Conversion of faults by burning with up to 850 mA
•Pinpointing of faults by surging/thumping with up to 2.000 J in multiple voltage
ranges
•Sheath test with up to 20 kV with automatic breakdown detection
•Pinpointing the location of sheath faults with up to 20 kV using the voltage
gradient method (step voltage method)
The STX 40 has an integrated time domain reflectometer, which eliminates the time-
consuming cabling work before locating faults and ensures a perfectly coordinated
temporal sequence of surge decoupling and pulse reflection measurement.
With its easy-to-read 10 inch display, the reflectometer simultaneously forms the central
control unit of the system and enables intuitive and fast selection and configuration of the
operating modes.
A well-established integrated safety system ensures the safety of the operator by
continuously monitoring the earthing and temperature conditions during operation.
Functional description

Technical description
11
The scope of delivery includes the following components:
Component Item number
Fault location system STX 40 1011497 (without 4 kV voltage range)
1013011 (with 4 kV voltage range)
Mains supply cable Varies by region
Earthing cable drum with earthing cable,
25 m
2013151
Separate earthing cable (5 m) for connection
between earthing drum and system
2013149
Reference earth wire (red, 5 m) for fault
voltage (FU) monitoring + metal earth rod
and hammer
820003013 (earth wire)
892479915 (earth rod)
892517507 (hammer)
High-voltage connecting cable, 25 m on
drum
2012308
Various connectors and terminals ---
Device key 2012515
Manual 86883
Check the contents of the package for completeness and visible damage right after
receipt. In the case of visible damage, the device must under no circumstances be taken
into operation. If something is missing or damaged, please contact your local sales
representative.
If the following optional accessories are not included in the scope of delivery, they can be
ordered through Sales:
Accessory Description Item number
External safety device For indicating the operating state and for
emergency shutdown or locking the high
voltage (in accordance with EN 50191)
2012574
Scope of delivery
Check contents
Optional accessories

Technical description
12
2.2 Technical data
The STX 40 is defined by the following parameters:
Parameter Value
Insulation test
•Measuring voltage
•Measuring range
1 … 20.000 V
100 … 650 MΩ
DC test
•Output voltage
•Leakage current measurement
0 … 40 kV ±1.5%
(adjustable in steps of 0.1 kV)
0 … 1A ±2%
TDR module
•Measuring range
(at v/2 = 80 m/μs)
20 m … 320 km
•Pulse width 20 ns … 10 μs
•Pulse amplitude (bipolar) 100 V
•Resolution 0.1 m at v/2 = 80 m/μs
•Accuracy 0.1%
•Timebase accuracy <50 ppm
•Data rate 533 MHz
•Propagation velocity As V/2 or NVP value
10 … 149.9 m/μs or 33 … 492 ft/μs
•Dynamic range 115 dB
•Output impedance 50 Ω
•Distance-dependant de-attenuation
(ProRange)
+40 dB, adjustable
•Number of traces Up to 6 traces simultaneously (e.g. for phase
comparison)
Surging
•Surge levels1
•Surge rate
0 … 8 / 16 / 32 kV with 2,000 J
0 … 4 kV with 1100 J (optional)
Every 3 seconds at 2000 J at 32 kV
Adjustable between 3 … 10 seconds or
single pulse
1If the system is connected to 120 VAC input voltage, surge power is limited to 1,600 W
(as per ANSI/NEMA 5)

Technical description
13
Parameter Value
Fault pre-location methods
•Inductive ARM Multishot Reflection measurement while the arc
caused by a fault flash-over at the fault
position is still burning. A total of 32 fault
traces are recorded per measurement.
•ICE Current decoupling from a traveling wave
caused by a fault breakdown
•DECAY Voltage decoupling from a traveling wave
caused by a fault breakdown
Burning Max. 850 mA in 5 kV range
Max. 400 mA in 10 kV range
Max. 200 mA in 20 kV range
Max. 100 mA in 40 kV range
Sheath test
•Output voltage
•Leakage current measurement
0 … 20 kV ±1.5%
0 … 1 A ±2%
Sheath fault pinpointing
•Output voltage
•Pulse ratio
20 kV
0.5:1, 1:3, 1:4, 1:6
Safety •FΩprotection device
•FU protection device
•Temperature monitoring
•Device key for high voltage locking
Input voltage range 110 … 230 VAC ±10%, 50 / 60 Hz
Power consumption 2.5 kVA
Display 10.1" colour TFT WXGA 1280x800,
capacitive touch screen, 1000 cd/m2, LED-
backlight
Memory 4 GB mSATA for program and data
Interfaces 1 x USB 2.0
Operating temperature −20 °C ... +55 °C
Storage temperature −40 °C ... +70 °C
Relative humidity 93% at 30 °C (non-condensing)
Dimensions (W x H x D) 74cm x 103cm x 65cm (with folded in handle)
Weight 124 kg (with 4 kV voltage range)
119 kg (without 4 kV voltage range)
Protection class (in accordance with
IEC 61140 (DIN VDE 0140-1))
I
Ingress protection rating
(in accordance with IEC 60529
(DIN VDE 0470-1))
IP43

Technical description
14
2.3 Display and operating elements
The following operating and display elements are located on the front panel of the STX 40:
Element Description
USB port
Emergency stop switch
On/off button
"HV ON" button
Display
Rotary encoder with tilt function
"HV OFF" button

Technical description
15
2.4 Connection elements
The following connection and fuse elements are located on the back of the STX 40:
Element Description
Protective earth connection
Reference earth connection for FU monitoring
Socket for connecting the device key or the external safety device
Fuses (2 x T16 A)
Mains socket
HV output

Technical description
16
2.5 Safety devices
In order to ensure sufficient earthing, the resistance between the operating and protective
earth is continuously monitored during operation (FΩ monitoring). This must not exceed
6 Ω.
In parallel, the FU safety device checks that the voltage difference between the device
and earth (reference earth) does not exceed 33 VDC or 40 VDC in order to protect the
operator from step voltage potentials.
If one of the two protective devices detects that the specified limit values have been
exceeded, any high-voltage operation is immediately interrupted automatically and the
test object is discharged via a discharge resistor. It is only possible to switch on the high
voltage again after the earthing conditions have been improved and the measured values
are within the tolerance levels.
For reasons of liability, it must be ensured that measuring devices that emit a hazardous
voltage are secured against unauthorised access. For the STX 40, this is done by means
of the device key, which must be screwed onto the socket at the rear of the device in
order to activate high voltage.
In the event that the device must be left unsupervised for a period of time, this key must
be removed and carried by the person responsible for the device.
High voltage preparation possible High voltage preparation locked
FΩ and FU monitoring
Device key
<150 kΩ
<33 VAC/40 VDC
<6 Ω

Technical description
17
2.6 Operation in vehicle
The device can also be operated in or on a vehicle if the following requirements are met:
•The vehicle chassis must be connected to the protective earth connection of
the device with the lowest possible contact resistance.
•Both earth connections and must be connected to suitable connection
points outside the vehicle (see page 19).
•The high-voltage output must be connected directly to the object under test
using a HV connection cable provided by Megger with a length of at least 25 m.
Connection via a patch panel is not permitted.
•If several individual devices are transported in or on the vehicle, only operation
outside the vehicle is permitted for safety and liability reasons!

Commissioning
18
3Commissioning
WARNING
General safety instructions for set-up and commissioning
•The safety guidelines for the operation of mobile testing systems
often differ from one network operator to another and are frequently
subject to national regulations (such as the German BGI 5191).
Before the measurement session, find out what the applicable
guidelines are and follow the rules set out therein precisely, in
respect of the organisation of work and the commissioning of the
mobile test system.
•Select a location that is sufficient for the weight and size of the
system and which ensures that it stands securely.
•The device may only be operated in upright position!
•When setting up or connecting the device, make sure that it does not
impair the functional capability of any other systems or components.
If other systems and components have to be modified, be sure to
reverse these measures once the work has been completed. Always
take the special requirements of these systems and components into
account and only carry out work on them after consulting and
obtaining approval from whoever is in charge of them.
•In the event of large differences in temperature between the storage
and installation locations (cold to warm) condensation may form on
components carrying high voltage (condensation effect). To avoid
any risk of damage to people and devices caused by voltage flash-
overs, the system must not be operated when in this condition. It
should rather be left in the new environment to acclimatise for
approximately one hour before putting it into operation.

Commissioning
19
3.1 Electrical connection
WARNING
Safety instructions for the electrical connection
•The system may only be connected to de-energized equipment. The
general safety instructions and, in particular, the five safety rules (see
page 7) must always be followed prior to connection to the test
object.
•Follow the specified connection sequence.
•All the cables at the measuring point that are out of operation and are
not to be tested must be shorted and earthed.
•Because the amount of voltage applied to the test object poses a
danger in the event of contact, the prohibition zone around live parts
as defined in DIN EN 50191 (VDE 0104) must be protected in a way
that it cannot be breached.
•The ends of the cables must be shielded to ensure that contact is not
possible. When doing so, be sure to take all branches of the cables
into account.
•The device should never be operated without the earth lead being
connected. The earth lead establishes the connection between the
device and protective earth and ensures that the device is touch-
proof. Eearthing provided through the earth contact of the mains
connection or an earth spike is not sufficient. An earthing tester can
be used to check the protective earthing. Unless reliable earthing can
be guaranteed, the entire measurement setup must be considered
live. In this case, follow the instructions of the sections related to live
working in EN 50110-1. When working under these operating
conditions, insulating protective gloves of class 1 (or higher)
according to EN 60903 must be worn!

Commissioning
20
The following figure shows the simplified connection diagram of the fault location system:
Connection diagram
Prohibited zone and test area according
to DIN EN 50191 (VDE 0104)
110 V to 230 V
50/60 Hz
Connection type for
cable testing
and cable fault location
Connection type for
sheath testing
and sheath
fault location
min. 25 m