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ATTanalyzer

The Power Diagnostix ATTanalyzer is a simple and effective stand-alone tool toaid in commissioning tests of gas-insulated switchgear (GIS) systems and powertransformers. The ATTanalyzer reduces delays in commissioning and mainte-nance by locating flaws in GIS systems and transformers acoustically.

Gas-insulated switchgear systems oc-casionally contain flaws that go unno-ticed during installation or maintenancebut that lead to immediate breakdownwhen high voltage is applied. Theseflaws can include floating particles, gas-eous impurities, faulty insulator discs,sharp metal burrs, or other defects. If agas-insulated switchgear system con-tains such a flaw when brought on-line,sparking and breakdown occurs at theflaw, forcing de-energization and repair.Without diagnostic aids, location of theflaw can lead to costly delays and un-necessary opening of unflawed gaschambers bearing the risk of causingnew imperfections, while searching forthe chamber containing the flaw.Using the ATTanalyzer, the flaw can belocated by mounting acoustic sensorsto the outside of the GIS or transformertank in several locations. When highvoltage is applied to the GIS, if a break-down occurs, the acoustic sensors pickup the disturbance and transmit a cor-responding optical signal to theATTanalyzer acquisition unit. The

ATTanalyzer then compares the rela-tive travel times of the sound signals todetermine which sensor is the closestto the flaw.Following initial location of the break-

down’s origin, the acoustic sensors canoptionally be repositioned closer to theflaw to narrow the location further, towithin a few centimeters. Comparingthe resulting display with the display ofthe breakdown while using a hammerto trigger a similar pattern on theATTanalyzer, further helps to narrowdown the location of the flaw.

Fiber optic connectors of the ATTanalyzer

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PD •

Power Diagnostix Systems GmbHVaalser Strasse 25052074 AachenGermany

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

Power Diagnostix 2011

System ComponentsThe ATTanalyzer consists of a com-pact central acquisition unit, acousticsensors, and sturdy fiber optic cableto connect the sensors to the acquisi-tion unit.The stand-alone ATTanalyzer acqui-sition unit, mounted in a half-19-inchrack, receives and internally pro-cesses signals picked up by the sen-sors. The acoustic sensors for exter-nal mounting on the GIS system canbe easily attached and removed forreuse. Up to sixteen sensors can beconnected to the ATTanalyzer.Fiber optic cables, up to 200 metersin length, provide galvanically isolatedconnection of the sensors to theATTanalyzer acquisition unit.

FeaturesThe ATTanalyzer’s embedded LCDpanel displays the relative travel timesfrom the sensors as horizontal bars.Cursors and settings are manipulatedthrough pushbuttons and on-screenmenus.

The display screen also shows rel-evant quantities such as samplingrate, time between cursors, time anddate stamp, etc.Using simple menus, users can ad-just the sampling rate of the acquisi-tion unit appropriately depending onhow widely or closely spaced thesensors are to each another.TheATTanalyzer features storage of upto sixteen GIS fault events with timeand date stamps. Users can chooseone of three operating modes:AUTO This mode considerseach trigger event. Thus, the instru-ment's memory contains the mostrecent 16 events.NORM Using this mode, the unitchanges to the STOP mode after 16events captured. Therefore, thememory contains the first 16 events.SINGLE This mode changes aftereach captured event into STOPmode. Changing manually back intoRUN mode re-enables triggering.

Offering easy implementation and convenient data analysis, the PowerDiagnostix ATTanalyzer aids in cost-efficient location and repair of gas-in-sulated switchgear and transformer defects during commissioning tests.

ATTanalyzer monitors a long-term test on GIS spacers and insulators (SIEMENS)