Accidentia Transformatoris Principalis et Questiones Operationis Gas Luminis

1. Registri accidentis (XIX Martii, MMXIX)

Hora XVI:XIIX die XIX Martii, MMXIX, monitorium background reportavit actionem gas levis transformatoris principis numeri III. Conformiter Codex Operationis Transformatorum Electricitatis (DL/T572-2010), personale operationis et maintenance (O&M) inspectavit statum in situ transformatoris principis numeri III.

Confirmatio in situ: Panel non-electricus protectionis WBH transformatoris principis numeri III reportavit actionem gas levis phase B corpus transformatoris, et reset fuit inefficax. Personale O&M inspectavit relais gas phase B et cista sampling gas transformatoris principis numeri III, et fecit experimenta super currentem terrae nucleus et clamp corporis transformatoris.

Hora XVI:XXXVI, monitorium background substationis reportavit actionem trip gas gravis transformatoris principis numeri III, cum igne in corpore phase B. Systema extinctionis incendii spumantis fixum transformatoris activavit recte (imagines signorum disponibiles).

Medida pro hoc accidente:

• Elabora planum transformationis de gas leve ad trip: Organiza compilationem schematum technologicorum transformationis, arranga subsequentes planos intermissionis electricitatis, et clarifica measuras O&M ante transformationem.

• Inspectiones speciales et transformationes pro transformatoribus in servitio: Fac inspectiones directas super transformatores operantes secundum causam defectus, et formula measuras transformationis.

2. Processus tractandi alarmam gas leve

Codex Operationis Transformatorum Electricitatis (DL/T572-2010) praescribit ut relais gas transformatorum debeant esse equipati duobus setibus contactuum: gas leve et gas grave. In operatione normali, gas leve est configuratum ad modum alarmae, et gas grave ad modum tripi. Processus typicus pro alarmis gas leve transformatorum sequitur:

• Cum signal protectivum gas sit activatum, inspecta immediate transformator ut determines si causa sit aeris accumulationis, descensus olei, defectus circuiti secundi, vel defectus interni transformatoris.

• Si gas existat in relais gas, registra volumen gas, observa colorem et flammabilitatem gas, et collige samples gas et olei pro analysi chromatographica.

• Si gas in relais sit coloris nullius, sine odore, non-flammabilis, et analysi chromatographica identificet id ut aer, transformator potest continuare operationem, et defectus introitus aeris debet eliminari prompte.

• Si gas sit flammabile vel resultatum analysis gas dissoluti (DGA) sit anormalis, iudica comprehensiviter si transformator debet intermitteri.

Novae Measurae Anti-Accidentales (9.2.3.6) praescribunt: "Si transformator experiat duas alarmas gas leve consecutivas intra unum diem, applica immediate pro inspectione intermissionis electricitatis; pro transformatoribus (reactoribus) structurae non-circulationis forzatae olei et sine dispositivo extractionis olei et injectionis nitrogeni, applica immediate pro inspectione intermissionis electricitatis ad alarmam gas leve corpus."

Transformatores novi commissionis vel sub oleo treatmente propensi sunt ad alarmas gas leve in operatione initiali. Transformatores circulationis forzatae olei susceptibiles sunt ad introductum aeris propter effluvium olei in areis pressionis negativae; transformatores cum dispositivo extractionis olei et injectionis nitrogeni possunt habere gas captum in ductibus emissoris olei—ambae conditiones possunt causare alarmas gas leve. Parvum quantitatum gas normaliter emittitur in operatione transformatorum, sed duae alarmas gas leve consecutivas intra 24 horas indicant potentialem defectum severum.

3. Analyse statistica alarmarum gas leve transformatorum

Casus I: Alarma gas leve in substatione (VII Iulii, MMXV)

Phenomenon defectus: Monitorium background substationis ostendit "alarmam non-electricam corpus transformatoris principis numeri III" et "alarmam gas leve phase C corpus". Causa: Inspectio in situ reperit nivellum olei in relais gas phase C transformatoris principis numeri III esse bassum (volumen gas excessit 300ml; configuratio alarmae gas leve: 270±10ml) (phases A et B erant pleni). Ex resultatis inspectionis et conventu speciali, defectus fuit causatus ab objectis metallicis alienis, quae iudicabantur introducta esse in transportatione/installatione (non ex manufactura), quia monitoring non poterat cubire totum processum manufacturae. Dispositio: Transformator defectus fuit removit et substitutus cum phase standby. Workshop maintenance constructus fuit in substatione pro reparatione in situ per manufacturam; transformator reparatus conservatus est ut phase standby.

Casus II: Alarma gas leve in substatione (XXX September, MMXV)

Phenomenon defectus: Monitorium background reportavit "alarmam pressionis surge phase C transformatoris principis numeri II", "signal trip gas grave", et "signal alarmae gas leve"; actio protectionis electricae non occurrerat. Causa: Lacuna communicationis inter institutum designi et manufacturam duxit ad stressum excessivum in terminali summitate bushing; bushing habuit designum sealing weak; zona pressionis negativae in summitate conduitus currentis bushing causavit inhalationem aeris/aquae post failurem seal. Maximum offset horizontalis inter T-connector lead et bushing high-voltage attingit V. LXI m, ducens ad tensionem lateralem longam, deformationem terminalis et cover, failurem seal, et emissionem internam in winding high-voltage propter inhalationem aeris/aquae. Dispositio: Transformator defectus fuit removit et substitutus cum phase standby. Reparatio in situ completata est in 2016 post constructionem workshop maintenance, et transformator conservatus est ut phase standby.

Casus III: Alarma gas leve in substatione (XVIII Iunii, MMXVIII)

Phenomenon defectus: Alarma gas leve phase A transformatoris principis numeri I in substatione. Causa: Testes sampling olei et gas demonstraverunt gas non-flammabile et data olei normales. Relais gas ventus est in eodem die, et signal reset immediate. Tracking longum temporis accumulationis gas in relais non monstravit gas novum, confirmans alarma fuit causata ab accumulatione aerea longa.

Casus 4: Alarma pro levis gaso dum commissionamento

Phenomenon defectus: Alarma pro levis gaso de fase C del tertie principale transformator durante commissionamento. Causa: Defluxo de oleo ex le relais de flusso de oleo del transformator; la unitate de construction non complete evacuava gaso post substitution. Non fuit detectato acetyleno in le transformator. Disposition: Evacuar gaso ex le transformator.

Casus 5: Alarma pro levis gaso in station de conversion (20 novembrie 2018)

Phenomenon defectus: A 06:24:55, le background OWS de un station de conversion reportava "Alarma pro levis gaso de fase B de un transformator de conversion in un certo lato"; a 06:40:57, "Proteccion pro gravis gaso de fase B de un transformator de conversion in un certo lato" fuit reportata, e le circuit-breakers del transformator de conversion 01B/02B tripnavit triphase. Causa: Ruptura del vesica de conservatorio de oleo. Oleo entrava in le vesica, e un subito diminution de temperatura causava le vesica plena de oleo seder, obturando le pipeline de oleo e trappando gaso, conducente ad action del relais de gaso. Le vesica rupturava a causa de longe tempore de standby e acceleration de senectute in basse temperature. Disposition: Inspection in situ confirmava una laceration de vesica (plure oleo in le conservatorio entrava in le vesica). Le vesica fuit substitutate, e le transformator de conversion resumeva operation.

Casus 6: Alarma pro levis gaso in societate electric (2 januario 2017)

Phenomenon defectus: Le DC bipolar se trovava in cold standby in un societate electric; a 20:37, fuit reportata alarma pro levis gaso del transformator de conversion YYC de Pole 1, seguita per un trip pro gravis gaso a 20:42. Causa: Inspection in situ trovava defluxo de oleo ex le pompa de oleo del quartie circuito de refrigeration de fase C Y/Y del transformator de conversion de Pole 1. Le defluxo cessava post disconnection del potencia de pompa e claudition de valvulas in ambe finales. Le causa radical era mala qualitate de material de bollos e flanges de copertura de pompa, conducente a sever corrosion, rupture de bollos, slippage de corpore de pompa, e massive defluxo de oleo. Disposition: Substituer 4 pompas submersibil de oleo del transformator de conversion YYC de Pole 1, refarcir oleo, e conducir testes de maintenance. Synchronemente substituer o modificar le structura de bollos de 52 pompas submersibil de oleo in 13 altere transformators de conversion (inclusive 2 standbys).

4. Explication de configuration de levis gaso a alarma o trip

4.1 Introduction a relais de gaso

Relais de gaso opera per detection de gaso generate ex decomposition de oleo o surges de oleo causate per defectus interne del transformator, activante contactos de levis gaso (alarma) o gravis gaso (trip).

• Levis Gaso: Reflecte minor defectus (ex. supercarga de calefaction, calefaction local del nucleo, calefaction del tank ab leakage magnetic). Gaso decomposite ascende in le camera de collection de gaso del relais, diminuente le nivel de oleo e activante le reed switch de levis gaso pro enviar alarma. Ulterior diminution de nivel de oleo activa gravis gaso.

• Gravis Gaso: Reflecte sever defectus (ex. grounding de bushing, short circuit inter-turns). Generation rapida de gaso impelle oleo a impactar un baffle, attractente le reed switch de gravis gaso via un magnete pro tripnar le transformator.

4.2 Rationes pro configuration de levis gaso a alarma

• Transformators AC UHV: Cada principal e transformator de regulation de voltage ha solmente un relais de gaso; risers de bushing se connecta al relais corporal via pipes de collection de gaso. Solmente un contacto de alarma de levis gaso es disponibile, configure a modo de alarma sub normal operation (gravis gaso a trip).

• Transformators de conversion: Equipate con 1 relais de gaso (technologia Siemens) o 7+ relais de gaso (technologia ABB). Levis gaso es configure a modo de alarma (gravis gaso a trip) sub normal operation.

Relais de gaso de transformators de conversion habe solmente 1 o 2 contactos de alarma de levis gaso, propense a falsa alarmas causate per ingresso de aqua in boxas de junction de relais, gaso carrier de chromatographia de oleo entrante in le tank, o intake de aer a causa de pobre sealing corporal. Non es disponibile mesures anti-misoperation "duo ex tres". Si levis gaso es configure a trip, falsa alarmas pote causar trips de DC monopole (un singule gruppo de valvas), perdendo 1500MW o plus de potencia e minaciante stabilitate de grid. In addition, levis gaso provide un fenestra de responsion pro minor defectus (ex. calefaction mild del nucleo/isolation) ante activation de gravis gaso, meliorante disponibilitate de equipment. Isto, le 18 Major Grid Anti-Accident Measures e Code for Operation of Power Transformers (DL/T572-2010) stipula que levis gaso debe solmente esser configure a alarma.

Casus de Falsa Operation:

• 2003: Ingresso de aqua in un relais de gaso de reactor de smoothing de un transformator de conversion causava block de bipolar, perdendo 1281MW.

• 2019: Un outage temporari occurreva a causa de un defectus in le circuito de contact de un relais de gaso de transformator de conversion.

4.3 Proposition pro modification de levis gaso a trip pro transformators UHV

Dato le risko de defectus subite in transformators UHV minaciante securitate de personnel, se propose cambiar action de levis gaso de alarma a trip pro transformators UHV, pro le sequente rationes:

• Action precoce in sever defectus: Levis gaso pote activar ante gravis gaso durante defectus subite sever. Tripar su levis gaso pote rapide isolar le transformator defectose, preveniente major damage de equipment o casualties. (ex. 2016: Un reactor de shunt UHV explodiva post multiple alarmas de levis gaso; 2017: Levis gaso activava 32 secundas ante gravis gaso durante un defectus de bushing de transformator de conversion.)

• Robustez de grid: Le fortificated grid pote tolerar le perdita de un gruppo de valvas o transformator sine problemes de stabilitate.

• Reduction de risko de falsa operation: Management enhance de relais non-electric (ex. installation de covers contra pluvia, inspectiones regular de sampling, verificationes de insulation de circuito) ha significantemente reducite falsa alarmas. Statisticas monstran nulle falsa actions de levis gaso in stations de conversion (3 annos) e substations (5 annos); 6 actions registrate esse causate per gaso non-evacuate durante construction (non defectus de equipment).

Munus temporarium: Dum operatio instabilis transformatorum UHV, omnes contrectationes gas levis (eluviones capsae, commutator graduum, corpus) transformatorum converter, principium, et regulantis tensionis ad modum tripi configurare, ut salus hominum et instrumentorum tueatur.

4.4 Ratio executionis pro modificatione gas levis ad trip

• Transformatores converter: Per systematis DC controlis unici ablationem software mutare, ut signa gas levis in trip vertantur. Post modificationem test trip non opus est (circuits signorum annuatim probantur); implere durante intermissionibus planificatis (1 dies).

• Transformatores AC: In panellis protectionis cabulam mutare et tests transmissionis exercere (1 dies).