Sparks Electrical News June 2018

ENERGY MEASUREMENT AND SUPPLY

18

INVESTIGATING MULTIFUNCTIONAL IN TRANSFORMER DIAGNOSTICS

T he value proposition of off-line electrical testing, such as for transformer diagnostics, is strengthened as the costs associated with testing are reduced and the diagnostic reach of the information grows. Multifunctional instruments, whereby the testing capability of multiple instruments is included in one, are increasing in popularity because of costs savings; through easier usability, manageabil- ity and transportability, lower equivalent upfront costs, and the on-going savings of an associated switchbox that reduces test time for transformer diagnostics. Technical features of a multifunctional instrument also determine the magnitude of savings provided as well as the degree to which the value of the results

overbuilt, they must be adequate for the test at hand. Easy usability must be preserved while providing ample versatility. Megger’s TRAX, the main section of which weighs just 26 kg, excels in attaining this balance. The out- puts are pragmatic. The user interface of the TRAX, which utilises the latest color touch-screen technol- ogy, presents functions in the form of apps (‘virtual instruments’). When the user has decided what to measure and has selected the app/instrument to work with from the start screen, the display shows only those elements that are appropriate to that function. Guidance is provided in the form of con- nection diagrams and tables that provide the correct sequences of tests. The TRAX delivers a simple testing experience for the user, who will feel well supported across all of its functions. A multifunctional instrument’s switchbox pro- vides time savings and reduces fall hazards by minimising the overall number of ladder climbs to complete testing. Switchbox cables are connected initially to each bushing terminal. The switchbox is a ‘router’ between the test instrument and the test specimen that ‘determines which track the train is directed’ so connections to bushing terminals do not have to be moved after completion of each single phase test. It is desirable to maximise the number of tests a switchbox can facilitate (Meg- ger’s TRAX switchbox facilitates seven different transformer diagnostics) and, here too, maintain balance. Switchbox cables to each bushing ter- minal must be manageable, safe and affordable while the ratings of these leads remain practical for the intended tasks at hand (particularly for winding resistance measurements) lest negat- ing the ability to successfully complete a test and benefit from the conveniences of automated switching between tests. Not only is Megger’s TRAX an extraordinarily balanced multifunctional instrument, it is packed with technically differentiating features that boost asset condition awareness. True dynamic resist- ance measurements of load tap-changers, TRAX’s adaptive demagnetisation procedure, and elevat- ed insulation diagnostic capabilities through di- electric frequency response (DFR) measurements together with patented techniques for tempera- ture correction (ITC), and voltage dependence detection (VDD) so that you only perform power factor tip-up tests when necessary, are just a few examples of why TRAX is arguably the best trans- former test instrument available today. BMG has made a substantial investment at its BMG World facility in Johannesburg, to ensure assembly, stockholding and technical support are on a par with pristine global standards. Functional operations at BMG World include a 50 000 m³ product warehouse and distribution centre for the company’s entire product range of more than 300 000 line items and a manufacturing centre and general engineering workshop. There are also specialist assembly and repair workshops for drives, conveyors, hydraulics and pneumatics, as well as electric motors, electron- ics, gaskets, lubrication systems and filtration. This facility enables BMG to continue to provide high levels of operating efficiency and service delivery, in line with the continued growth of the business. A team of technicians, with extensive experi- ence in gearing, offers a technical advisory and support service, tailored to meet the precise specifications of contractors, designers and the end-user. BMG MOTOLINE SOLAR INVERTERS FOR PV WATER PUMPS Enquiries: www.megger.com

is enhanced. A potential misstep of a multifunctional instrument is losing ‘balance’ – sacrificing transport- ability, unrealistically compromising testing capability, or becoming difficult and confusing to use as more functionality combines. The Megger TRAX Transformer and Substation Test System instrument provides thirteen different testing capabilities for transformer diagnostics alone, as well as extensive test capacities for other system assets, such as capabilities to time and record mo- tion on circuit breakers, etc. Balance, in particular, is very important. Desirable outputs/sources must be provided while avoiding excessive instrument weight and size. While the power sources should not be

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Enquiries: +27 (0) 11 620 1538

SPARKS ELECTRICAL NEWS

JUNE 2018