Fully Insulated SF₆ Switchgear: Advantages Komponente ug Expansion Solutions
1. Katangian sa Fully Insulated SF₆ Switchgear
1.1 Overview
Ang fully insulated SF₆ switchgear nagsakop sa mga functional units sama sa load switches, load switch-fuse combinations, disconnectors-circuit breakers, ug uban pa, tanang sealed sa stainless steel gas boxes nga gipuno og low-pressure SF₆ gas. Kini nga gas ang nagserbiha isip arc-quenching ug insulating medium. Ang switchgear gigamit og electric o manual spring-operated mechanisms. Bawat cabinet usa ka independent gas box, naa sa kapabilidad sa pag-expand pinaagi sa busbar connectors sa anumang direksyon. Ang mga unit niini dapit sa medium voltage distribution systems, labi na gamiton sa mga substations ug switching stations aron mapasabot sa uban pang power distribution tasks.
1.2 Special Components sa Fully Insulated SF₆ Switchgear
Ang key components mao ang:
Sealed Gas Box: Sa sulod sa sealed gas box adunay switchgear ug busbars, gipuno og SF₆ gas sa rated pressure nga 0.03 MPa. Ang advanced laser welding ug simultaneous vacuum helium leak detection sigurado sa superior sealing. Wala na kailangan og re-gassing o replacement samtang operational life, making it maintenance-free. Dependiente sa expandability, ang gas boxes mahimong shared o standalone; ang solo ang mga standalone boxes support expansion.
Pressure Relief Device: Ania sa bottom sa gas box, ang pressure relief channel mayda explosion-proof membrane. Sa kasong internal arc faults, ang rapid gas expansion moputos sa membrane, releasing pressure ug guiding SF₆ gas sa trenches aron masiguro ang safety sa operators ug uban pang equipment.
Cabinet Frame: Ang frame (excluding the gas box) serbisyo isip mounting base sa tanang components ug supports the gas box. Kasagaran adunay three main compartments: operating mechanism room, cable room, ug pressure relief channel.
1.3 Main Advantages sa Fully Insulated SF₆ Switchgear
Fully Sealed ug Insulated: Tanang high-voltage live parts sealed sa sulod sa gas box, minimizing environmental impacts. Ideal sa humid o polluted environments, especially suitable sa regions sama sa Pearl River Delta.
Compact Design: Pinaagi sa paggamit sa three-position load switches makareduce sa component count. Ang conductive parts gamit ang SF₆ insulation, resulta ngadto sa mas compact structure kon parehas sa air-insulated SF₆ semi-insulated cabinets.
Altitude Independent: Ang internal elements nahimutang sa pressurized enclosures, ensuring consistent performance bisan asa ang altitude.
Expandability: Bawat cabinet usa ka independent gas box ug equipped sa reserved expansion interfaces, possible ang expansion pinaagi sa busbar connectors. Ang connectors mayda three silicone rubber adapters installed horizontally sa inner cone bushings sa adjacent cabinets, connecting their busbars without compromising the seal integrity.
2. Analysis sa Expansion Solutions sa Fully Insulated SF₆ Switchgear
Pinaagi sa pag-add sa new cabinets sa existing fully insulated SF₆ ring main units (RMUs) naging challenge sa recent years tungod sa lack of standardized interface specifications sa uban-uban manufacturers. Below is an analysis based on a specific project:
Case Study X: Ang substation sa usa ka residential area kasagaran adunay tulo ka expandable fully insulated SF₆ RMUs gikan sa HD Switchgear Company, including one incoming line unit ug duha outgoing line units. Ang project requires adding another outgoing line unit ug extending a ZRC-YJV22-3×120 cable sa new outdoor switchgear serving new users. Several solutions were considered:
Complete Replacement: Pag-replace sa tanang tulo ka existing RMUs could potentially damage the connected cables if not carefully removed and reinstalled, leading to significant additional costs. Given that the current units have been in operation for less than two years, this option is wasteful.
Adding a New Cabinet: As switchgear is supplied by the power bureau, procuring a non-HD product might lead to compatibility issues due to varying busbar interface standards. Procurement through specialized bidding processes would also delay project timelines.
Using Semi-Insulated SF₆ Cabinets: Introducing a semi-insulated cabinet alongside a busbar riser cabinet to bridge the gap between fully and semi-insulated units poses challenges due to the absence of standardized connection components, requiring close cooperation from the original manufacturer.
Installing Additional Semi-Insulated Units: Adding a semi-insulated outgoing line unit and a busbar riser cabinet next to the existing incoming line unit allows for re-routing cables via the riser cabinet, effectively expanding capacity without disrupting existing installations. This solution was ultimately chosen for its practicality and effectiveness.
Ang ika-upat nga method gi-adopt, successfully addressing the expansion needs, ug ang project is now completed and operating smoothly.
3. Conclusion
In conclusion, ang fully insulated SF₆ switchgear offers clear technical advantages but faces challenges due to the lack of unified interface standards, complicating direct integration between products from different manufacturers. While the fourth method solved the immediate problem, future projects should prioritize using products from the original manufacturer, confirming their expandability, particularly avoiding shared-box structures which generally cannot be expanded. This approach ensures better compatibility and feasibility for system upgrades.
