Access a wide range of product guides below, for insight into how to use your Megger instrument for specific applications.
There are many different tests that can be performed on a battery string. The question often arises which one should be performed.
After we gather the impedance data what do we do with it? How do we make sense of it? A battery string consists of more than just batteries. All aspects of it need to be examined.
A battery consists of a jar that can contain multiple cells. When performing battery testing, it is recommended to take measurement on the individual cell if possible. However, with most batteries it is only possible to take measurements on the jar. Since this is the smallest unit that can be replaced, this makes sense. Yet some batteries that have multiple cells also have multiple posts that allow for the measurements of the cells within the jar. For this reason we allow PowerDB to be configured for this application and this paper explains how to do that.
This paper looks at how to change graphs and charts when using the PowerDB LITE.
Each Megger BITE product can measure internal cell impedance, inter-cell connection resistance and DC voltage of cells and jars. This paper looks at how the BITE can be checked in the field for calibration validity to ensure quality of the data generated.
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.
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.
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.
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.
There has been much talk about whether impedance (and other internal ohmic tests) truly correlates to battery capacity. This paper endeavours to show you how it does.
There are multiple ways to find a cable fault in a low voltage network, but no one method works for all situations. It’s only by knowing the pros and cons of each method that you can determine the most effective one to use in any given scenario and pinpoint the fault in as little time as possible.
The use of T-branches in low voltage networks makes the evaluation of TDR traces considerably more difficult. Only through comparative measurements of fault-free and defective wires can possible results be achieved. The test pulses of the Teleflex are partially reflected at the T-joint with a negative algebraic sign, while test pulses that continue are simultaneously reduced in amplitude. The amount of reflection depends on the impedance in the main line and the continuing line.
Overview of low voltage cable fault location test methods
Low voltage cable faults are often unstable, so they can only be located when the cable is conducting live voltage. Testing under these conditions is extremely hazardous, so separations filters, as well as constructional safety methods, should be employed at all times.
Low voltage networks are a huge national investment, under daily pressure to give out power for hours at a time to a plethora of electrical appliances. It is therefore essential that their cables and transformers are tested often to prevent outage. To effectively test the components in low voltage networks, it’s important to know the different types of systems within them and how they are structured.
In branched low voltage networks, low-resistance faults, interruptions and large changes in impedance can only be located by comparing fault-free and defective cores.
Fault occurrences in medium voltage networks are usually covered by redundancy in the system which, with appropriate switching, usually ensures a relatively uninterrupted continuation of the supply for the customer. A lengthy wait until the fault can be corrected only results in the increased risk of a second failure in this area, creating a customer outage that cannot be restored by switching.
High voltage terminations are essential components in high voltage cable systems. Great reliability is provided by high manufacturing quality and company type testing. However, onsite installations represent a considerable uncertainty for successful service of the system. UHF PD Diagnosis has proven to be a valuable and effective method for measuring high voltage assets because this online measurement is performed at frequencies which are not affected by environmental noise.
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.
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.
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.
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)
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.
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.
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.
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.
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.
A cable replacement strategy and diagnosis method for water trees in XPLE cables has been developed at the Botkyrka 24 kV network. Measurement reports from 1996-2002 highlight improvements in age-analysis, overall effectiveness and cost.
A new dielectric spectroscopy system has been developed for testing medium voltage cables damaged by water trees. The dielectric response of XPLE cables with water tree damage can be recognised and classified by ageing status and breakdown strength. Field studies showed that fault rate decreased significantly when the replacement strategy was based on the new diagnostic criteria.
A new test and diagnostic system combining DAC voltage testing and PD testing provides an effective, non-destructive method of withstand testing for medium voltage cables. The new system also demonstrates that cosine rectangular VLF waveform diagnostics can effectively locate PD defects in MV cables, and measure the severity of the fault.
Currently, 24 hour soak testing and resonance testing are the two most common methods for carrying out HV cable testing. This paper compares the power consumption of the test techniques, and discusses the suppression of noise generated by the HV equipment. It also demonstrates the success of monitoring test objects with capacitances up to 25 µF.
This paper will illustrate common best practices that simplify the installation of transducers and will explain the minimum amount of information required for a test plan to obtain meaningful results.
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.
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.
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
Accurately determining the insulation condition in twisted copper cable pairs is an essential requirement in the CATV and telecommunications sectors. Selecting test equipment that is tough, easy to use and capable is now possible.
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.
The testing of earth systems has relied for many years on the tried and tested “Fall of Potential” and other related methods. These methods give reliable results, but can be time consuming. This paper looks at Megger's Attached Rod Technique as a new solution to the issue of earth testing.
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.
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.
Low resistance ohmmeter testing using Megger DLRO products
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.
Robust test leads have been specially designed for low resistance testing of wind turbines. The new leads lead to more accurate and repeatable results.
There is a great deal of importance placed on harmonics. We know that excessive harmonic distortion can cause power quality problems due to the heat generated. These power quality problems can include neutral wires, transformers, as well as motors overheating.
But what exactly are harmonics?
Recommendations for measuring inter-cell connections on battery strings. It is important to note that this is a relative measurement.
When equipment trips offline, telecom customers can lose their service, costing the telecom money every minute the equipment is offline. This paper looks into how power quality testing can prevent this from happening.
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
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.
Multifunction testers are extremely versatile. They were designed to meet the needs of electrical contractors – rapid, accurate measurements in a tough case – but are also of direct relevance to electrical engineers working in other industries.
The measurement of winding resistance is useful in detecting a number of types of fault in a transformer. This application note discusses this in detail.
An application note that looks at testing insulating oil.
The moisture content of oil paper insulation system assessment is an important link in transformer fault diagnosis. This paper looks into the methods of assessing the moisture content of oil paper insulation as well as the degree of insulation aging.
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.
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.
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.
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.
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.
Using asset management software together with thermal imaging cameras can result in more cost effective maintenance and fault finding on electrical equipment.
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