Me Kana Da Zan Iya Zabi Da Jirgi 66kV Outdoor AIS Voltage Transformers?
Salam mai duka! Ina James, mutanen da na da shiga tsari ga wani shekaru 10 a yi kwalba masu jirgin gaji. Yanzu, ina son sanin game da zabin da kuma kwalba Air Insulated Switchgear (AIS) masu jirgin gaji a gasar wasanni na gajiyar 66kV.
Wasu wannan makamako sun fi yawa don tattaunawa da inganci a cikin jerin ruwa. Zabin da kuma kwalban masu daidai suka tabbatar da dalilin daidaito da kalmomin kasa na gajiyar ruwa. Daga baya da fadada tattalin jerin ruwa na zamani, AIS masu jirgin gaji na kayayyaki suna zama zabe da ake so. Sun bayarwa da abubuwan kayayyaki masu ma'ana, amma haka haka ana buƙata hanyoyi masu daidai don kwalba da kudin sadarwa.
1. Mafi Tsawon Da Za A Bayar Don Zabin Masu Jirgin Gaji Na AIS
Ina basa ne tare da muhimmin abubuwan da za su iya sa shawarwarsa - wannan shine mafi tsawon a kan zabin masu jirgin gaji.
Masu jirgin gaji na inganci sun buƙata darajar ta hanyar da take da. Duk da haka, ana zaba accuracy class 10P tare da rated capacity yaɗuwar 5VA. Wannan yana tabbatar da aika mai kyau wajen tattaunawa saboda kalmomi kamar short circuits.
Amma masu jirgin gaji na tattaunawa, sun buƙata darajar ta hanyar da take da. Ana zaba 0.2S class ko kadan, tare da rated capacity yaɗuwar 10VA, don yaɗuwa energy metering da kuma tattaunawa na system.
Daga baya da fadada tattalin jerin ruwa na zamani, masu jirgin gaji na kayayyaki suna zama zabe da ake so a gasar wasanni na 66kV saboda abubuwan kayayyaki masu ma'ana, musamman a cikin yankunan da ke buƙata integration with digital protection systems.
Na bi, ina nemi karin mafarin voltage level da structural form. A 66kV, wanda yake cikin category na medium-voltage (3kV–110kV), an samun single-phase ko three-phase structures.
Don main wiring systems na biyu, akwai two single-phase transformers connected in phase-to-phase voltage or V/V connection.
A cikin gasar wasanni da ke buƙata insulation monitoring, ita ce da ake amfani da one three-phase five-core three-winding voltage transformer ko three single-phase three-winding transformers connected in Y/Y-Δ configuration. Wannan setup yana ba aiki da line voltage measurement da kuma zero-sequence voltage filtering through the open delta winding, wanda yake da shawarwari masu ma'ana don tattaunawa insulation condition na system.
Na bi, ina nemi insulation type da dielectric selection - mafi tsawon wadanda ke fi yawa don safe outdoor operation. Masu jirgin gaji na 66kV na farko suna amfani da oil-immersed ko cast resin insulation, amma models na AIS na zamani sun buƙata gas-insulated designs.
Daga baya da standard na GB/T 20840.11-2025, don outdoor AIS voltage transformers a 66kV da kuma uku, ana so SF₆/N₂ mixed gas insulation instead of pure SF₆ gas. Sabon haka? Saboda pure SF₆ zai iya liquefy a cikin environmental temperatures, musamman harkar -25°C. Mixed gas (usually 20%-30% SF₆) yana haɓaka wannan matsaloli wajen yaɗuwa greenhouse gas emissions.
Gas-insulated transformers yana buƙata stainless steel welded gas tanks and double O-ring sealing structures don yaɗuwa airtightness even in harsh outdoor conditions. Kuma ina nemi environmental adaptability of the insulating medium - things like weather resistance and pollution resistance - don yaɗuwa different climate conditions across regions.
2. Abubuwan Kayayyaki Wajen Kwalba Masu Jirgin Gaji Na AIS
Na bi, ina nemi kwalba - mafi tsawon da ke fi yawa don technical standards.
A kan zaba location for installation, akwai mafi girman abubuwan da za su iya sa shawarwarsa:
Voltage transformer yana buƙata a cikin high-voltage equipment outlet da distribution equipment, tare da yaɗuwa accurate voltage measurement.
Yana buƙata a cikin busbar ko transformer outlet, amma yana buƙata clearance of at least 1.5 meters from disconnect switches, circuit breakers, etc., don avoid electromagnetic interference and mechanical vibration.
Installation height yana buƙata guidelines na substation design - usually higher than surrounding equipment to reduce contamination buildup and ensure good ventilation, preventing overheating that could degrade insulation performance.
Idan multiple voltage transformers yana yi aiki a parallel, make sure they’re isolated from each other to prevent mutual interference.
Na bi, ina nemi grounding configuration, wanda yana fi yawa don safe installation.
Grounding system for 66kV outdoor AIS voltage transformers must follow the “single-point grounding” principle:
The neutral point of the primary winding must be reliably grounded - especially in star-connected configurations. This is fundamental for preventing overvoltage and ensuring system safety.
The secondary circuit must be grounded at only one point - usually at the terminal block in the control room - to avoid circulating currents or false trips caused by multi-point grounding.
One of the terminals of the tertiary winding (open delta winding) must also be grounded at a single point, and no switchable device should be inserted into the grounding lead.
For gas-insulated transformers, special attention must be paid to the grounding design of the explosion-proof membrane. Use anti-aging and corrosion-resistant materials, and ensure solid grounding to prevent damage from water accumulation or frost heave. Also, install rain covers on SF₆ gas density relays and make sure they allow for calibration without disassembly, improving operational reliability.
Finally, fuse selection and installation must match the equipment parameters.
The primary side of a 66kV outdoor AIS voltage transformer should be 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
