Liema huma l-essenzjali għal is-silġ u l-instabbiliment ta' 66kV Outdoor AIS Voltage Transformers?

Hey kollha! Jien James, profesjonal bl-ghaxija ta’ aktar minn 10 snin fit-tisjil tal-mutawwaqif tad-dinja. Il-ġimgħa, nixtieq nagħti s-silġ dwar is-silġ u t-tisjil tas-silġ tal-mutawwaqif tal-Air Insulated Switchgear (AIS) fis-silġ tal-66kV barra mill-immiss.

Dawn il-dispożitivi huma importanti għad-determinar u t-tibdil fil-sistemi tal-kurrent. Is-silġ u t-tisjil tagħhom jaffettwaw direttament is-sigurtà u t-tibta' tal-graġ tal-kurrent elektromagnetiku. Bl-evoluzzjoni tal-teknoloġija tal-graġ smart, il-mutawwaqif elektroniku tal-AIS qed jagħmlu l-għażla preferita. Huma joffru ħafna karatteristiċi intelligenti, iżda jinkludu wkoll rikjesti akbar għat-tisjil u l-manutenzjoni.

1. L-Fatturi Miġbura f’l-Għażla tal-Mutawwaqif tal-AIS

B’daqqs, ibdew mid-dinja u l-applikazzjoni — dan huwa l-konsiderazzjoni l-iżjed importanti meta tkun qed tagħżel mutawwaqif tad-dinja.

• Il-mutawwaqif tal-protezzjoni għandhom dinamika wiesgħa. Solitament, nagħżlu klasse ta’ preċiżjoni 10P b’kapacita nominata ta’ 5VA. Dan jgarantixxi t-trasferiment akkurat tal-segn Nawwafta liema mhux normali kif is-silġ qasir.

• Il-mutawwaqif tal-misur, inkontu, għandhom preċiżjoni ħafiża. Solitament, nagħżlu klasse 0.2S jew aktar, b’kapacita nominata ta’ 10VA jew aktar, biex isoddifaw ir-rekwesti tal-misur tal-enerġija u t-tibdil tas-sistema.

B’evoluzzjoni tal-graġ smart, il-mutawwaqif elektroniku qed jagħmlu popolari fis-silġ tal-66kV għall-kapaċità tal-output digitali, speċjalment fi l-ambjent li l-integrazzjoni mal-sistemi tal-protezzjoni digitali hija meħtieġa.

Nosta, nara d-dinja u l-forma strutturali. F’66kV, li jikksilt fl-każ medju-volt (3kV–110kV), huwa komuni l-użu ta’ strutturi monofasi jew trifasi.

• Għal sistemi prinniwa sempliċi, żewġ mutawwaqif monofasi mikonnessa fid-dinja bejn fasa jew V/V konnezzjoni jimpjagħu sew.

• Fis-silġ li l-monitorn tat-tibdil tal-insulazzjoni huwa neċessarju, huwa aħjar tiżgħa ma’ wieħed mutawwaqif trifasi bil-ċavetta tal-5 u tri avvolgimenti jew trej mutawwaqif monofasi bil-avvolgimenti trija mikonnessa fid-Y/Y-Δ konfigurazzjoni. Din is-silġ toħloq lil misur tal-dinja u ftit tal-dinja zero fl-avvolgiment tal-triangulu mitlaqt, monitorjando effiċjentement it-tibdil tal-insulazzjoni tas-sistema.

Meta nara l-tip ta’ insulazzjoni u l-selezzjoni tal-dieltika — fattur miġbur għal operazzjoni sigura barra. Il-mutawwaqif tradizzjonali tal-66kV solitament jiżgħu insulazzjoni immersa fl-oli jew cast resin, iżda l-modeli moderni tal-AIS jiġu preferiti designs insulati bl-aħwa.

Skond l-standard nazzjonali ġdid GB/T 20840.11-2025, għal mutawwaqif tal-AIS barra tal-66kV jew aktar, in-nuqqas mixta SF₆/N₂ hija ordat waħda insestead tal-aħwa pura SF₆. X’minhu? Meta l-aħwa SF₆ pura tista’ teffissi leġġeramenti f’ambjenti bassa temperatura, speċjalment taħt -25°C. Il-mixta tal-aħwa (solitament 20%–30% SF₆) tisolvi din il-problema waqt li tirridċi l-emissjonijiet tal-aħwa tal-serra.

Il-mutawwaqif insulati bl-aħwa għandhom jagħmlu użu minn tanqi ta’ aħwa tal-inox imweldji u strutturi tal-sealing O-ring doppja biex jagħti airtightness tajba Nawwafta l-kundizzjonijiet barra harsh. Konsidraw ukoll l-adattabilità tal-medju tal-insulazzjoni — xejn kif l-resistenza tal-lanġas u l-kontaminazzjoni — biex jaffrontaw diversi kundizzjonijiet tal-klima f’dak il-post.

2. Ir-Rekwesti Tekniċi għat-Tisjil tal-Mutawwaqif tal-AIS

Ora, nnoġġu għal tisjil — passjar oħra miġbura li trid ikollok attenzjoni strikta skond is-standards tekniki.

Meta tkun qed tagħżel l-lokali għat-tisjil, hawnhekk hi xi punti miġbura:

• Il-mutawwaqif għandu jitissil bejn l-equipament tal-high-voltage outlet u l-equipament tal-distribuzzjoni, assigurjando misur tal-dinja akkurata.

• Huwa għandu jiġi mittissil karibu mill-busbar jew l-outlet tal-transformator, iżda jagħmel ċert li jkollu spazju ta’ 1.5 metri minn disconnettiv, circuit breakers, etċ., biex jiviti l-interferenza elettromagnetika u l-vibrizzjoni mekanika.

• L-altitudni għandha tsegwi l-guidelines tal-design tal-silġ — solitament aqra mill-equipament madwarha biex tirdiċi l-buildup tal-kontaminazzjoni u tassigura ventilation bona, prevenendu l-overheating li jista’ jiġi l-insulazzjoni.

• Jekk hemm mutawwaqif tal-dinja multiopera parallel, assiguraw li huma isolati minn wieħed l-ieħor biex jiviti l-interferenza mutwal.

Nosta, l-configurazzjoni tal-grounding, li hija essenzjali għal tisjil sigur.

Is-sistema tal-grounding għal mutawwaqif tal-AIS barra tal-66kV għandha tfollows il-prinċipju tal-“single-point grounding”:

• Il-neutral point tal-primary winding għandha tkun grounded reliably — speċjalment f’konfigurazzjonijiet star-connected. Dan huwa fundamentali għal prevenzjoni tal-overvoltage u għal sigurtà tas-sistema.

• It-taljen sekondarja għandha tkun grounded tiktar b’punt — solitament fil-terminal block f’control room — biex jiviti l-circulating currents jew l-false trips magħmul minn multi-point grounding.

• Wieden tal-terminali tal-tertiary winding (open delta winding) għandha tkun grounded b’punt, u ma jistax jkun hemm device switchable inserted fil-grounding lead.

Għal mutawwaqif insulati bl-aħwa, special attention għandha tkun data lill-design tal-grounding tal-explosion-proof membrane. Użu materials anti-aging u corrosion-resistant, u assiguraw solid grounding biex jprevennu l-danni mill-accumulation tal-ilma jew frost heave. Ukoll, installa covers tal-xita fuq relays tal-density tal-aħwa SF₆ u assiguraw li jpermettu calibration bla disassembly, improved operational reliability.

Infine, l-għażla u t-tisjil tal-fuses għandha tkun match the equipment parameters.

• Il-primary side tal-66kV outdoor AIS voltage transformer għandha tkun equipped with an RW10-35/0.5 drop-out fuse, with a rated current of 0.5A and breaking capacity of 1000MVA. This protects the transformer from short-circuit currents.

• Install the fuse vertically or horizontally, making sure the fuse tube is tightly connected to the porcelain bushing to prevent poor contact due to looseness.

• The secondary side fuses should be selected based on load impedance, usually using standard fuses. However, avoid connecting any possible break points (like isolators) in the secondary circuit to prevent voltage feedback from damaging equipment.

For electronic AIS voltage transformers, additional considerations include fiber-optic loop protection — such as anti-vibration and moisture-proof measures — to ensure signal integrity.

3. Standards for Installation and Maintenance of AIS Voltage Transformers

Standardization of installation and maintenance is the foundation of safe operation.

According to GB/T 20840.11-2025, 66kV and above AIS voltage transformers must meet strict requirements for mechanical strength, temperature tolerance, and sealing performance. During transportation, 10g vibration sensors should be installed. For batches of more than 10 units, install two per vehicle; for fewer than 10, install one. Upon arrival, check the vibration data. If any sensor records exceed 10g or has fallen, return the unit for internal inspection.

For maintenance, regular preventive testing is crucial:

• Perform insulation resistance tests

• Conduct partial discharge measurements

• Carry out excitation curve tests

This ensures the equipment meets performance requirements. For gas-insulated transformers, regularly test SF₆ gas moisture content and perform live leak detection. In some cases, shorten the inspection cycle.

During the first month after commissioning, perform live inspections. After that, inspect quarterly to ensure gas quality meets standards.

When it comes to fault handling, follow standardized procedures:

• If a fuse blows, first check the secondary side fuse. If it blows again after replacement, it means there’s a serious fault in the secondary circuit — investigate thoroughly.

• If gas pressure drops suddenly, immediately take the unit offline for leak detection and repair, avoiding continued operation that could compromise insulation.

4. Summary

In summary, here are the key points to remember when selecting and installing AIS voltage transformers:

• Clearly define the function: Protective types use wide-range classes like 5TPE; measuring types use high-precision classes like 0.2S; electronic types should consider digital output compatibility.

• Choose the appropriate structure based on voltage level and system characteristics — V/V or three-phase five-leg core configurations — and ensure the neutral grounding method matches the system.

• Select suitable insulation media based on environmental conditions. For 66kV outdoor systems, prioritize SF₆/N₂ mixed gas insulation to avoid liquefaction risks with pure SF₆ in cold climates.

• Install near high-voltage equipment outlets, but keep at least 1.5 meters away from switches and breakers to ensure ventilation and mechanical stability.

• Follow the “single-point grounding” rule for primary, secondary, and tertiary windings to avoid circulating currents.

• Match fuses to equipment specs: RW10-35/0.5 for primary side, standard fuses for secondary side, and ensure secure installation.

As technology continues to evolve, so do AIS voltage transformers. Improvements in gas insulation, maturity of electronic sensing technologies, and the adoption of smart monitoring systems all contribute to safer, more reliable, and efficient solutions for 66kV outdoor substations.

Looking ahead, new materials and manufacturing processes will further enhance the performance of these transformers, making them more environmentally adaptable and smarter. As environmental regulations tighten, mixed-gas insulation and low-power passive transformers will become more widely adopted, pushing the power industry toward greener and more sustainable development.

I hope this article helps you better understand the essentials of selecting and installing AIS voltage transformers. If you have any questions or want to share your own experiences, feel free to leave a comment or send me a message. Let’s learn together and grow together!

— James