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Här har vi samlat vårt utbud av olika applikationsnoter för att ge dig ökad kunskap och förståelse om hur du använder våra instrument för att säkerställa en pålitlig drift. (Merparten är skrivet på engelska).



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Circuit breaker diagnostic testing

The paper provides a simple explanation of vibration testing and the type of diagnostic information it can produce. Care must be taken in setting up and carrying out the tests if accurate and dependable results are to be obtained. Users should also be aware of electrical interference such as induction, which is always present in electrical substations.

ODEN primary current injection test system used to test MCCBs in situ

A US based nuclear power generator needed some particularly robust test equipment to cope with testing MCCBs. By working collaboratively with Megger, Diablo Canyon has saved significant costs in its testing regime

With extreme care and a suitably qualified person, circuit breaker test sets can perform online condition assessments.

First trip analysis is a crucial tool to anticipate faults before they become critical, and to minimise disruption. Today’s circuit breaker analysers are very versatile. They can be configured to suit specific requirements, ensuring that users never pay for features they don’t need.



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Battery Inter-cell Resistance Measurements

This document discusses the nuances of inter-cell connection measurements, as well as best practices for the entire measurement process. Included are diagrams outlining the measurement structure so that you get consistantly reliable results. 

Internal Impedance of Batteries - What it is and Why it Works

Impedance: it correlates to battery capacity

Testing for ground faults on storage batteries

Identifying faults in storage batteries can be problematic. Using a test signal frequency in the range 20 Hz to 30 Hz can minimise interruption from ‘phantom’ faults in batteries.

Using battery test equipment with asset management software

Lost data records can be a problem for major power utilities. Using the right test equipment with modern asset management software can help to ensure that consumers are never without power.

The batteries that radar UPS systems depend on need regular testing to ensure that the skies stay safe

Batteries play a crucial role in ensuring that air traffic control systems around the world can continue to operate reliably and safely even if there is a failure of the mains supply at the radar stations on which they rely. It is imperative, therefore, that those batteries should be maintained in good condition, with potential problems detected and remedied before they can develop into outright failures.



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No more cable cutting errors - Westnetz Case Study

Positive cable identification with suitable devices prior to work on underground cables is a compulsory requirement at Westnetz in Bad Kreuznach, as stipulated by the standard DIN VDE 0105 part 1. However, sometimes problems can arise, as it may not be possible to conclusively identify cables despite the strict compliance with regulations. Traditional cable identifiers work by relying on system properties with many fringe conditions that cannot always be complied with in practice. The cable identifier CI/LCI from Megger is the first to offer a user-friendly and safe solution.

Fault location in low voltage networks

Discover key strategies when conducting fault location on low voltage cables. Inluded are typical LV behaviours, advantages and disadvantages of LV testing, different test methods and best practices. 

Fault location on power cables

Gain insight into specialised fault location and pinpointing proceedures for high voltage power lines. Look at the construction of high voltage cables, as well as the methods and practices that are becoming new the standard, such as condition based preventative maintenance. 

Fault location with the ETF 3

The 3kV energy separation filter (ETF 3) is specially developed for fault location on symmetrical communication and pilot cables. This article covers the technology and best way to use the ETF 3, as well as field examples of the the system in use.

Pre-location ICE method

The four most effective impulse current (ICE) methods for high resistance and intermittent power cable faults are "Direct mode", "Comparison mode", "Differential-comparison mode", Loop-on/Loop-off mode". The following document discusses the the process of each method.

Pre-location pulse reflection process

Learn more about the interaction between pre-locaation and pinpointing to minimise fault location time. pre-location methods referrenced include TDR and HV methods. Additionally, this document discusses the values a fault must exhibit to be located by pulse reflection. 

Pre-location transient methods

Learn more about the behaviour of transiet waves when a breakdown occurs at a cable fault, and understand how to evaluate and measure these transients for a more efficient fault location process. This article covers both DECAY (voltage decoupling) and ICE (current decoupling)



Pre-location with ARM arc reflection technology

Understanding the most common fault types is critical to cable fault location. More than 80% of cable faults are high impedance faults. This document breaks down the properties of the high impedance fault, and discusses the most effective way to deal with them through Arc Reflection (ARM) technologies. 

Sheath testing for fault location

Water ingress caused by damaged cable sheaths is a leading cause of faults in plastic-sheathed cables. Proper cable maintenance through sheath testing can extend the life of the cable by preventing the long term damage caused by water ingress. This article covers best practices and best equipment to use when sheath testing.

Case study Botkyrka

Condition based replacement of medium voltage cables saves millions The method for diagnosis of water trees in XLPE cables based upon measurements of dielectric losses and capacitance as function of frequency has been verified. Based upon diagnostic measurements in 1996 a replacement strategy was decided upon for the Vattenfall 24 kV network of Botkyrka and the most severely degraded cables were replaced. This paper reports on the measurements made in 1996 and selective repeated measurements in 2002. The development of the ageing is analysed The failure statistics are reported and the effectiveness of the diagnostic method is proved. The costs savings using a replacement strategy based upon diagnostic measurements is presented.

By Roland Eriksson, SM, IEEE, Peter Werelius, Member IEEE, Lars Adeen, Peter Johansson and Henrik Flodqvist

Diagnostics of Water Tree Deteriorated XLPE Cables

IEEE Transactions on Dielectrics and Electrical Insulation

A high voltage dielectric spectroscopy system has been developed for diagnostics of water tree deteriorated extruded medium voltage cables. The technique is based on the measurement of non-linear dielectric response in the frequency domain. Today’s commercially available system is capable of resolving low loss and small variation of permittivity as a function of frequency and voltage. Experience from more than 200 field measurements was combined with laboratory investigations. Small samples were used in an accelerated ageing test to elucidate the correlation between water tree growth and dielectric response. Furthermore, field aged cables were investigated in the laboratory. It has been shown that the dielectric response of water tree deteriorated XLPE cables can be recognised and classified into different types of responses related to the ageing status and breakdown strength. The influence of termination and artefacts such as surface currents was investigated. The measurement method enables us to separate the response of the cable from the influence of accessories. Finally, two different field studies of the implementation of the diagnostic method are presented. The field studies show that the fault rate decreased significantly when replacement strategy was based on the diagnostic criteria formulated.

By Peter Werelius, Peter Thärning, Roland Eriksson, Björn Holmgren and Uno Gäfvert

Innovative Test and Diagnostic System for medium voltage cables – PD monitored withstand testing versus non destructive Partial Discharge (PD) diagnosis

For testing and partial discharge (PD) diagnostic purposes many different test voltage wave shapes and frequencies have been established over the past years. Their application is well proven and is guided by IEEE 400 norm. For
testing purposes the voltage need to produce enough stress to lead failures to breakdown. The very low frequency (VLF) waveforms turn out to be very effective and economical for that purpose. For PD diagnostic voltages are needed, with waveforms close to power frequency and in its application non destructive for the test object. VLF voltages could cause in case of long testing times during PD diagnosis unwanted breakdowns at weak spots, even if the applied voltage is not that high like it is used for withstand testing. Damped AC voltage (DAC), which is close to power frequency, is well proven to be very effective for partial discharge diagnosis and causes nearly no risk for breakdown due to the short excitation time even for critically aged cables. A new test and diagnostic system combining both, providing an effective test voltage for withstand testing and being non destructive for diagnostic measurements, is introduced recently. This paper describes the application and comparison of the new test and diagnostic system for partial discharge diagnosis by using DAC. Furthermore true VLF cosine rectangular withstand testing with accompanying PD monitoring is discussed. It is demonstrated that cosine rectangular VLF waveform delivers comparable results of PD parameter to judge the severity and to locate PD defects in MV cable systems.

By Daniel Götz, Frank Petzold,  Hein Putter Seba KMT Baunach, Germany,  Sacha Markalous, Marco Stephan Seba KMT, Radeberg, Germany and Henning Oetjen, Megger, Valley Forge, PA, USA

Investigations on a Combined Resonance/VLF HV Test System – Partial Discharge (PD) characteristics at VLF and DAC voltages

The necessity of HV cable testing is a given fact. So far two testing methods, 24 hour soak or resonance testing are commonly used. This paper describes a comparison of test  power demand dependent from voltage shape and test capacitance as well as the power consumption of test systems for different test techniques. Furthermore an optimised technology for combining advantages of resonance and VLF principle is described and case studies of field applications of this technology are discussed. Moreover this paper presents the results of investigations regarding the noise sources created by the HV equipment and the methods for successful reduction and suppression to levels below 10 pC, which is a relevant value for on-site PD measurements. Case studies from field application show a good comparability of PD measurement results obtained with DAC and the optimised resonance/VLF technology. The new test equipment demonstrates that withstand testing on test objects with capacitances up to 25 µF are very successful and monnitored PD testing as well as diagnostic PD testing are conclusive.

By F. Petzold, H.T. Putter, D. Götz, H. Schlapp, S. Markalous SebaKMT GmbH, Baunach/Radeburg, Germany



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CATIV instrument rating



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5 KV and 10 KV insulation testing

DELTA4000 12 kV Insulation Diagnostic System application guide

Diagnostic insulation testing digest 5 and 10 k V

Dielectric Discharge Test

Interfacing MIT525, MIT1025 to PowerDB

Electric and hybrid vehicles need a special testing regime

Insulation test instruments for use in garages on electric vehicles need to be both physically tough because of the environment in which they are used, and to provide accurate diagnostic information. Wireless data communication ensures that faults and critical trending information are diagnosed rapidly.

Interpreting long-term insulation resistance trends

Having good insulation on electrical equipment is rather like having a water tank in your loft that’s actually watertight. In both cases, the cost of repairing an actual fault – whether it’s poor insulation or a leaking tank – is likely to be much less than the cost of repairing the damage caused by the fault. Nevertheless, how many people actually take the trouble to look occasionally at their water tanks to check that they are in good order? Not many, I suspect, even though doing so could potentially save a lot of money and heart-ache.

Delta 4000: Voltage vs Frequency



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Stake-less earth/ground testing with DET14C and DET24C clamps

Earth leakage clamp applications

The “ART” of earth electrode testing - Megger DET3TC with ICLAMP option

Clamp On electrode testing methods - DET4TC and DET4TCR with ICLAMP and VCLAMP

Parallel Earth Paths

Working with Fault Monitors

Earth testers have undergone a fundamental redesign with users’ needs given priority

The latest earth testers were designed after intensive research, observing the challenges that field engineers have had to put up with. The critical issues have been addressed, and you can now get earth testers with increased user safety and providing huge savings in time and aggravation.



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How to set up an AVTS database

How to set up a Telnet session

How to set up communication using Bluetooth

How to update SMRT firmware using PC

How to update RTMS firmware using STVI

How to update RTMS for PC

How to update SMRT firmware using STVI

Set up communications in AVTS

Controlling the MPRT with an external source

Advice on the right time to buy a protective relay test set

The new generation of IEC 61850-ready test sets are designed to meet the needs of protection testing on the smart grid. The latest products are smaller, lighter and more powerful than previous generations and have been designed with increased productivity in mind



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TTR calibration and functionality tests

The note describes how to check the TTR calibration using the appropriate calibration box and standards, plus how to check that the different functional tests in the TTR are working.

Diagnostic insulation tests for condition assessment of electrical assets have been redesigned to eliminate the shortcomings of older test equipment

Portable high voltage diagnostic insulation testers feature automatic voltage dependence detection and are much lighter and easier to use than previously. They also provide comprehensive facilities for archiving, analysing and reporting results.

Predictive diagnostic testing of electrical apparatus including transformers

Electric apparatus sometimes fails because of insulation deterioration. A proactive approach using Tan delta/power factor diagnostic testing is the key to monitoring the integrity of the insulation system and preventing or at least anticipating such failures. Understanding the impact of these parameters will help in obtaining accurate measurements that can be relied upon in the decision making process.

SFRA testing on transformers

Dismantling a power transformer to determine its condition is hardly ever a practical possibility. By using the latest proven SFRA test techniques, it is possible to accurately assess transformer condition without dismantling it.The latest SFRA test sets make these techniques more accessible, more convenient and more dependable that ever.

Reliable transformer diagnostics are essential for efficient maintenance of ageing energy infrastructure

Dielectric Frequency Response (DFR/FDS) measurement is a technique for general insulation testing and diagnostics. In comparison with standard 50/60 Hz dissipation factor measurements, DFR measurements has many advantages.

Storing thermal images with asset maintenance information

Using asset management software together with thermal imaging cameras can result in more cost effective maintenance and fault finding on electrical equipment.

Transformer oil testing for dielectric strength

Vessel preparation and elimination of the effects of moisture and contamination play a major role in successful oil testing. This application note points to the precautions that need to be taken

Delta 4000 Voltage v frequency capacity/capability

This document will help end users better utilize the wide ranging frequency capability of the Delta4000.  The note clarifies how to get more concise voltage/current specifications at both the lower and higher end of the frequency range.

PowerOn TTSC June 2014

FRAX: Clamps and connections

Transport och övriga applikationer


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Wind turbine test leads for low resistance ohmmeter

Robust test leads have been specially designed for low resistance testing of wind turbines. The new leads lead to more accurate and repeatable results.

Electric and hybrid vehicles need a special testing regime

Insulation test instruments for use in garages on electric vehicles need to be both physically tough because of the environment in which they are used, and to provide accurate diagnostic information. Wireless data communication ensures that faults and critical trending information are diagnosed rapidly.

Using a TDR to find cable faults without applying a high voltage

Although you will still need a combination of test instruments including an insulation test set, in the right circumstances, a TDR can sometimes locate cable faults without the need to apply a high voltage to the cable.

Storing thermal images with asset maintenance information

Using asset management software together with thermal imaging cameras can result in more cost effective maintenance and fault finding on electrical equipment.

Electrical testing on rail systems is essential for safety and reliability

Standard ohmmeters are inadequate to accurately determine the resistance of high-current connections and a digital low resistance ohmmeter should be used. Modern TDRs can locate able faults at distances up to 20 km from the point at which the instrument is connected and some types feature dual channel operation, which allows faults between cables to be rapidly localised.


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