1 / 5

How we saved a Process Plant from break-down

We saved a Process Plant from break-down<br><br>

systemprotection
Download Presentation

How we saved a Process Plant from break-down

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. ISO 9001:2015 ISO 45001:2015 (OH & S) Certified Company Case Study How we saved a Process Plant from break-down www.systemprotection.in +91-265-2225137

  2. Background : Findings : IntheearlierCaseStudy, wesawhowwe solvedaTransformermal-trippingissue duringourRoutineMaintenanceand Testingactivities. Wearepresenting herewithanothercasewhichdemonstrates whytheseactivitiesshouldbeentrustedto experts, whocanmakesuchroutinejobs moremeaningfulandsaveassets. ItwasthetimetotesttheTIEFeeder. Necessaryshut-downactivitieswerecarried outandpermitsobtained. AteamwascarryingoutRelayTestingand anotherteamwasperformingCTTesting. These6.6kVCTswerehavingaratioof 2500/1A. AswehaveseeninearlierCaseStudythat PrimaryInjectiontestingofCTishaving manylimitations, plusitdoesnotusually providetheDiagnosticsoftheCTs. Moreover, injectionandmeasurementsof suchhighcurrentsalsoposevarious challenges. Wewereappointedtocarryouttheroutine maintenanceandtestingofthe Switchgears, Relays, CTs & PTsinoneofthe CementPlantsinIndia, havingitsown PowerPlant. ThisPowerPlantcombined withGridSupplycateredtotheplantload. Usually, atgeneratingstations, wehaveTIE FeederswhichconnectsGeneratorandGrid tomaintainavailabilityofPowerincaseof variousPower-Flowscenarios. Inmostofthe cases, TIEFeederisaSynchronisingFeeder, whereGeneratorandGridsuppliesare synchronisedtocatertheplantload. It is THE mostimportantFeederofanyPlant, anyprobleminthiscancausetheentire plantblack-out. So, usually, weemployastate-of-the-artCT TestingInstrument, CTAnalyzerofOmicron Make, whichusesIEC61869-2standardand performsmodel-basedtestingwhichisfar moreaccurateandconclusive. DuringthisTesting, ProtectionCore (5P10) ofaCTwashavingaveryhighsecondary resistance, theinstrumentdisplayed “SecondaryWindingresistanceistoohigh”. CTAnalyzerdetermineswindingresistance byapplyingDCcurrentintoSecondary windingandchecksvoltagedropacross SecondaryTerminals. Usually, atgeneratingstations, wehaveTIE FeederswhichconnectsGeneratorandGrid tomaintainavailabilityofPowerincaseof variousPower-Flowscenarios. Inmostofthe cases, TIEFeederisaSynchronisingFeeder, whereGeneratorandGridsuppliesare synchronisedtocatertheplantload. It is THE mostimportantFeederofanyPlant, anyprobleminthiscancausetheentire plantblack-out. ThishighervalueofCTSecondaryWinding indicatesthatCTcouldbeopenandmay mal-operatetherelayincaseofvarious loadingscenarios. Weenquiredaboutany suchincidentinthepast, butthehistory wasclean, therewasnosuchtrippingand plantoperatednormally. Buttherewassomethingabnormalabout thisCTandwedecidedtochecktheCT physically. Andbelowisthephotographof whatwefound. www.systemprotection.in +91-265-2225137

  3. Damaged CT Found in Panel Aswecanseefromtheaboveimages, SecondaryWindingwithitsinternalconnectionis crackedandbarelyhanging, alittlenudgeanditseparated! Wecanalsoobserve hotspots/carbonisationallaround. Root Cause Analysis : Asitcanbeseenfromtheaboveimage, thereisaCTbase-plate, andCTsareusuallymounted inPanelbybase-plates, andusually, upsidedown. MainPrimaryBus-barofCTisconnectedwith mainPowerBus-barofpanel. 1.    UpwardforcebyFixedBase-plate 2.    DownwardforcebyMainPowerBus-bars CTwasinoperationunderstressedconditionforverylongtime. Overaperiod, Secondary Windingstartedgettingdisconnected, andduringtesting, itshowedhigherresistance. www.systemprotection.in +91-265-2225137

  4. Conclusion – how advanced technology can help predict the failure : Therecouldbemanyreasonsforsuch occurrenceandbehaviourofProtection Systemandcanbeaddressedoncase- to-casebasis. Toknowmore, youmay call/writetous. Noteworthyhereis, despitethisdamage, CTmighthavebeentransformingthe currentsfaithfully, astheCTtypewasa mouldedcast resin (arubberyfibrelike material), theleadssomehowremained connected. So, whentherewasprimary current, secondarycurrentcompleted thepathbypuncturingnearby insulation, thisgeneratedhighvoltages andthusthearcingspots - ascanbe seenintheimages. Ifthisremainedundetected, thissurely wouldhaveledtocompletebreak-down innearfuture. Andweallknowwhatit couldhavecostedintermsof productionandrevenue. Allourefforts areviewingtheproblemsfrom customers’ pointandresolvingthemin totality. Andifyouarelookingforadedicated agencythatunderstandsthedirectlink betweenyourassetsandyourrevenue, call/writetous, wewillbehappytoassist you. Aswe’veseenthatthisCTmighthave transformedtheCurrentsfaithfullyor withlittleerror. Therewasnotenough unbalancecurrenttotriptheRelay, so, theFeederdidnottrip, butitwasjuston thevergeoffailurewhenthiswas detected. www.systemprotection.in +91-265-2225137

  5. CONTACT INFORMATION 301/2/306, SilverlineComplex,OppositeBBC Tower,Sayajigunj,Vadodara - 390005, Gujarat, India. bdm@systemprotection.in www.systemprotection.in +91-265-2225137

More Related