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TDAcompact

The TDAcompact is a portable capacitance and tanδ analyzer. The focus of theinstrument's application is on the analysis of the epoxy-mica insulation of rotatingmachines. Besides this, the unit is applicable for oil-paper insulation systems andespecially for mass-impregnated cables.

Analyzing the dissipation factor (tanδ) isa traditional method to assess the con-dition of an insulation system. With theanalysis of the dissipation factor, empha-sis is more put on the overall health ofthe insulation system, whereas with par-tial discharge analysis, the focus is onindividual defects producing dischargeactivity. Therefore, the application of tanδmeasurements concentrates on insula-tion systems, which are relatively stableagainst partial discharge.

Most prominently, the health of an ep-oxy-mica insulation of a rotating ma-chine can be assessed using a tanδanalyzer. Especially, the presence of hu-midity within the winding, the surfacecontamination of field grading elements,or the polarization losses of improperlycured resin, can be detected. Thus, thetanδ analysis is still a good complementto the partial discharge testing.

Dissipation factor

Principle of OperationThe TDAcompact simultaneouslysamples the AC current drawn by thedevice under test and the current drawnby a reference capacitor. Subsequently,the two current traces are evaluated andthe capacitance, the tanδ, and the levelof the high voltage are calculated. Theunit continuously displays and refreshesthese results.

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Portable and accuratetanδ analysis

PD •

Power Diagnostix Systems GmbHVaalser Strasse 25052074 AachenGermany

Email: support@pdix.comWeb site: www.pdix.comTel: + 49 241 74927Fax: + 49 241 79521

Power Diagnostix 2012

Offering adequate resolution and accuracy as well as an unmatched portabil-ity, the TDAcompact is an excellent choice for field-type dissipation factormeasurements. Additionally, the TDAcompact can be used as a module of aflexible automated test system.

Therefore, the instrument does notrequire any user interaction as with thetraditional Schering Bridge, nor doesthe refresh of the display take that longas with automatic adjusting bridge-type analyzers. The basic resolutionof the tanδ measurement is 10-4,which fulfills the requirements for ro-tating machine testing as well as fortesting on mass-impregnated cables.

Stand-alone InstrumentThe TDAcompact is designed as astand-alone instrument. To measurethe two currents the basic configura-tion of the TDAcompact comes with astandard capacitor, that has a built-inshunt capacitor, in combination withan external shunt. Optionally, the unitcan be supplied with further shunt ca-pacitors.Generally, the TDAcompact is withdigital fiber-optic links to the precision

shunts, which allow operation on anypotential including the high voltageconnection of the device under test.The measuring frequency can varybetween 20 and 500 Hz or is fixed to0.1 Hz (VLF). Upon request, Power Di-agnostix can supply complete portabletanδ testers including the high volt-age transformer.

Modular ConceptBesides the stand-alone field test ap-plication of the TDAcompact, the in-strument can also become a part of alarger and automated test system.Using the software HVpilot, the instru-ment will be read according to a pre-programmed test sequence. Besidestanδ measurements, such automatedtest systems further include partialdischarge measurements and so-called step tests.