Technologia et Examen Unitatis Principalis Annularis Solido-Insulatae Medio-Voltus
1 Introductio
Communes methodi insulandi pro unitatibus principalibus medii tensus 10kV (RMUs) includunt insulamentum gas, solidum, et aeris.
• Insulamentum gasi saepe utitur SF₆ ut medium insulantem. Tamen, unum molecule SF₆ habet effectum hibernaculum 25,000 vices maiorem quam unum molecule CO₂, et SF₆ permanet in atmosphaera per 3,400 annos, praebens pericula environmentalia significativa. RMUs medii tensus sunt latissime distributae, faciens recuperationem SF₆ difficilem et costosam si geratur responsabiliter.
• Insulamentum aeris postulat maior spatia insulantia, impedens reductionem magnitudinis apparatorum significantem.
Cum rapido progressu rete distributionis urbis electricitatis, applicationes sicut edificia alta et transitus ferroviarius postulant meliora performance RMUs - requirunt minus spatium, altam securitatem/reliabilitatem, minima manutenctionem, et aptitudinem environmentaliam. RMUs medii tensus solid-insulati representant tendentiam crescendi.
RMUs solid-insulati 10kV utuntur technologia insulantis solida in loco gas SF₆. Eorum volumen est tantum 30% comparativi apparatus aer-insulati, offerens performantiam insulantiam fidelius et recipiens recognitionem constantem ab expertis et usoribus.
2 Materiales Insulantes et Design
Analyse costi demonstrat quod structura insulans occupat plus quam 40% pretii totalis RMUs solid-insulati. Selectio materialium insulantium, design rationalis structurarum insulantium, et determinatio methodorum insulantium convenientium sunt cruciales pro valore RMU.
Ex sua prima synthesis anno 1930, resina epoxy est continuata ad meliorandum cum additivis. Illa est celeberrima pro sua alta dielectrica fortitudo, alta mechanicam fortitudo, parva volumetrica contractio in tempore curing, et facilitas machinandi. Itaque, utimur ea ut materia insulans principali pro RMUs medii tensus, augmentata cum hardeners, toughening agents, plasticizers, fillers, et pigments formare resina epoxy alti-performance. Meliorationes in thermica resistencia, thermal expansion, et thermal conductivity provident retardantiam flammam et excellentes proprietates insulantias sub longa temporis operatio tensionis et brevis temporis overvoltages.
Structurae insulantiae RMU conventionales creant campos electricos non-uniformes. Solum incrementum spatiorum non sufficit ad augmentandum fortitudinem insulantiam in tali campis. Nos optimizamus structuram campi ad meliorandum uniformitatem. Fortitudo electrica resinae epoxy variat inter 22-28 kV/mm, significans tantum paucis millimetris spatii requiritur inter phases in structuris optimizatis, drastice reducendo magnitudinem producti.
3 Design Structurae RMUs Medii Tensus Solid-Insulati
Interruptores vacui, disconnectores, commutatores terrae, et omnes componentes conductivi ponuntur in formas. Resina epoxy alti-performance tunc integrally funditur uti technologia automated pressure gelation. Medium extinguens arcus est vacuum, cum insulamentum provisum ab resina epoxy.
Structura armarii adoptat design modulare pro facile standardizata mass production. Unusquisque RMU bay est separatus per septa metallica ad continendum arcus fault intra modulos singulos. Utilizantur busbar connectors integrati et contact connectors integrati. Busbar primarius consistit ex segmentis, clausis insulated busbars connectis per telescopic integrated connectors pro commoditate installationis et commissionis in situ. Ianiua armarii featuret design anti-arc interna et permittit clausuram, aperturam, et terram (tres-position operation) cum ianua clausa. Status switch visibilis per fenestras observationis, assecurans operationem securam et fidem.
4 Advantages et Analysis Test Typi RMUs Medii Tensus Solid-Insulati
4.1 Key Advantages:
(1) Utitur resina epoxy alti-performance pro insulamento fidelem et parvam partial discharge.
(2) Structura tota insulata et clausa sine partibus vivis expostitis. Non affecta per pulvis vel contaminantes. Aptus pro diversis ambientibus (alta/parva temperatura, alta altitudo, explosion/contamination-prone areas). Eliminat problemata sicut fluctuationes pressionis gas SF₆ in operatione alta temperature vel liquefaction in frigore extremo. Offert distincta advantage in littoralibus alta-salina.
(3) Absque SF₆ et absque gasibus periculosis - productum eco-friendly. Design impermeabilis eliminat manutenctionem regularem. Resistens explosione meliore fit pro locis periculosis. Structura tota insulata triphasica preventat defectus inter phases, assecurans securitatem et fidem.
(4) Occupat tantum 30% spatii requiritur per RMUs aer-insulati - solution ultra-compacta.
4.2 Analysis Test Typi
Ex his advantagiis, test typi comprehensiva fuerunt condicta, includens:
- Testes insulantiae (42kV/48kV tenere tensionem)
- Measurement partial discharge (≤ 5pC)
- Testes alti/parvi temperature (+80°C / -45°C)
- Test condensation (Class II pollution)
- Test arcus internus (0.5s)
Resultata testorum confirmaverunt productum plene respondere specificis, validantes omnia statuta advantagia.
Testes additionales standard nationalis fuerunt condicti:
- Test temperaturae incrementi
- Measurement resistance circuiti principis
- Testes tenere currentis peak nominati et currentis brevis temporis nominati
- Test capacity faciendi circuitus brevis nominati
- Test capacity rumpendi circuitus brevis nominati
- Test endurantiae electricae
- Test mechanicus
- Test fault terrae (phase-to-phase)
- Test commutationis currentis activi nominati
- Test commutationis currentis capacitive nominati
Omnia resultata conformantur standardibus nationalibus.
5 Key Construction Points
① Cum funditur concretum, prius funduntur trabes et columnae, deinde placae. Funduntur stratum per stratum secundum directionem tuborum formarum (nota: translatio adjustata pro claritate technica), distribuens concretum super formam CBM self-stabilizing ante vibrationem deorsum. Depositetur primus stratum concreti ad semper altitudinis formae, vibratur symmetrice in ambabus lateribus. Uti vibratoribus ≤35mm diametro (typice 30mm) pro penetratione et vibratione uniformi. Vitianda sunt lacunae, sub-vibration, vel contactus cum forma. Spatium ≤25cm, duratio ≤3s per punctum. Post confirmationem compactionis, iterum vibretur stratum superficiale cum screed vibrator ante setting initiale, sequitur nivellatio et compaction cum float lignea.
② Conduits aquae/electricitatis debent currere intra costas inter unitates formarum CBM self-stabilizing. Si transeunt per unitatem, uti formam minoris magnitudinis. In installatione formarum et funditione concreti, constructae sunt plateae operativae. Positionentur supports tubi pump concrete super has plateas. Personale non debet ambulare directe super formam, nec materies debent imponi directe super eam.
6 Engineering Performance of CBM Self-Stabilizing Formwork
① Increased Clear Height
Comparando ad systemata trabea-placa conventionalia, duo projecta utentes placas hollow-core reducerunt crassitudinem structuralis per planum per 30-50cm, incrementando altitudinem liberi. Forma CBM self-stabilizing est idealis pro structuris industrialibus/publicis grandis span et oneris gravis. Illa assecurat distributionem uniformem virium et permittit placementum flexibile partitionum murorum.
② Reduced Costs
Systema CBM hollow-core slab featuret grid-like orthogonal "I"-shaped lattice et hidden closely-spaced ribs, permitens transferentiam virium balanciatam. Ex duobus projectis, illud reduxit ferrum reinforcement per 27%, volumen concreti per 29%, et area formarum per 46% comparativis structuris RC frame conventionalibus. Costus constructionis totalis diminuti sunt per 26.3%.
③ Simplified Construction
Forma CBM offert fortitudinem altam, levetatem, resistentiam impactus, et frames support integratas pro facilis installatione. Cum beamis absconditis, fundus placa remanet planus, simplificans operationes formarum/shoring.
④ Lighter Weight, Optimized Performance
Placas hollow-core CBM reducunt pondus structurae proprium per 27.6% ex calculis, optimizantes design trabea, placae, columnae, et fundamenta.
7 Discussion on CBM Formwork Construction Issues
① Ensuring lower flange concrete compaction is challenging. Leakage in CBM hollow-core slabs is difficult to remedy.
Unlike conventional slabs where concrete is placed directly on a single surface, CBM slabs have upper and lower flanges. Achieving compaction in the lower flange requires meticulous vibration using small-diameter vibrators and external vibrators. After this, the hidden beams and top slab are poured, demanding great care and dedicated QC oversight.
Crack frequency in CBM slabs is comparable to or slightly lower than conventional slabs. However, leaks occurred in the basement roofs and roof slabs of both projects. Identifying the cause is difficult—potential sources include cracks in the upper flange, water seepage through adjacent formwork, or conduits within the ribs. Per leak, repair effort/cost is 5–8 times higher than for conventional slabs.
② Construction Joints & Expansion Strips Require Detailed Design
Structural expansion joint locations are typically specified by design codes. However, the dual-flange nature of CBM slabs complicates pouring if a joint abuts a formwork unit: ensuring bond between new/old concrete in the lower flange and containing grout is difficult. On-site, joint locations should be adjusted based on formwork layout to ensure joints fall within ribs between formwork units. Resizing adjacent units may be necessary.
With CBM slabs typically covering large areas, designers often overlook construction joint placement. To ensure proper bonding within the initial setting time, the site team must determine joint locations considering pour width limits and resource capabilities. Joints must meet code requirements and be placed within ribs.
③ Difficult Mitigation of Formwork Buoyancy
If formwork buoyancy occurs during pouring, the existing countermeasures (removing top reinforcement, clearing concrete, re-fixing formwork) are impractical and often ineffective. Currently, the only solution is breaking/removing the floated unit, placing additional reinforcement, and pouring solid concrete there. Rigorous onsite monitoring of formwork securing and anti-buoyancy measures is essential during construction.
