SF6 Ring Main Units (RMUs): Kasinatang mga Para sa Pagsuministro sa Kuryente Karon, Pana sa Pagpuno, Pinakamahimong Balaod Kontra sa Metal-Clad Switchgear ug Mga Kasimpulan

Ang Kasamtangan nga Paraan sa Pagsuministro og Kuryente Gamit ang SF6 Ring Main Units

Arang-arang sa pag-improve sa performance sa grid, ang disenyo sa tradisyonal nga SF6 ring main units (RMUs) gipadako pa sa pag-optimizar. Ang usa ka pangunahan nga katangian sa ikaduhang henerasyon nga SF6 RMUs mao ang paggamit og grounded, enclosed epoxy resin housing, sama sa SF6 gas isip insulating medium. Duha ka three-position load switches ug usa ka three-position arc-rotating circuit breaker gipahimulos sa usa ka single sealed unit, gisugdan usab og pressure relief safety valve. Kon magkamali ang pag-quench sa arc, ang safety valve mogilay sa internal pressure gikan sa enclosure, sigurado nimo ang kaligtasan sa operator sa front sa cabinet.

Tungod sa mga advantage sama sa mas gamay nga numero sa moving parts sa sistema, gamay nga volume sa sealed gas chamber, compact structure, kompletong functionality, ug murang cost, ang mga RMUs kini gihatagan og wide usage sa dekada ug gitubag na og dako nga stability ug seguridad. Tungod sa monitoring ug remote control sa daghang key node RMUs sa open-loop distribution networks, makakapabilis ang mga user og pag-restore sa kuryente sa loob lamang og minuto human sa fault, nagreduce niini sa oras sa pag-identify ug isolation sa fault ug minimiza ang power loss sa users.

Development Prospects of the SF6 RMU Power Supply Method

Ang SF6 ring main power supply, isip prototype ug initial stage sa grid-based power distribution, naghatag og pundasyon alang sa pag-abot sa mas taas nga reliability sa power supply. Ang "grid-based" planning, batasan sa urban control detailed planning ug nag-aim sa pag-satisfy sa high-reliability user demands, representa usa ka bag-ong "bottom-up" model sa distribution network planning, construction, operation, ug management.

Tungod sa grid-based planning ug transformation, ma-increase ang average utilization rate sa distribution equipment, ug ma-establish ang directional transfer capabilities sa within ug between grids, busa maxima ang support sa lower-level grids sa upper-level grids. Importante kini sa scientific guidance sa distribution network construction, ensuring reliable power supply, promoting high-quality development sa distribution networks, ug pagbuild og robust ug intelligent distribution network characterized sa "grid-based layout, refined protection, ug convenient access."

II. Advantages of SF6 Insulated RMUs over Metal-Clad Switchgear in "Five Prevention" Interlocks

Sa power supply systems, ang "Five Prevention" (preventing erroneous switching, load switching, grounding under voltage, closing with grounding, ug entering energized compartments) interlock technology para sa high-voltage switchgear (specifically air-insulated metal-clad switchgear) gi-mature ug diversified. Ang methods include microprocessor-based interlocks using pre-programmed sequences, mechanical interlocks, mechanical sequence locks, o combinations thereof. Pero adunay tanang easily overlooked issues gihapon sa practice:

Misoperation Prevention for Earthing Switches in Incomer Cabinets of Metal-Clad Switchgear

Ang pipila ka metal-clad switchgear adunay earthing switches sa both outgoing ug incoming cabinets. Particular sa bottom-fed switchgear, ang risk sa misoperation sa earthing switch kasagaran neglected. Sa contrast, ang SF6 RMUs inherently avoid this issue tungod sa grounding interlocks ug logical interlocks sa incoming side.

Misoperation Prevention for Energized Transformer Compartments

Sa metal-clad switchgear gamiton sa containerized substations, ang operating power kasagaran derived from the transformer's low-voltage side. Kon energized ang transformer compartment, ang electromagnetic lock dili mobuka; kon de-energized, ang voltage presence indicator ug electromagnetic lock mawala ang power, still preventing opening. Kini requires a release key aron manu-man unlock, creating a safety hazard.

Ang SF6 RMUs replace the electromagnetic lock with a door limit switch. Ang normally closed contact sa switch connected in series sa trip circuit sa transformer cabinet, powered from the low-voltage side. Kon buka ang transformer compartment door, ang limit switch activates, immediately triggering a trip to cut off power, effectively preventing entry into energized compartments.

In summary, ang SF6 RMUs significantly reduce the design complexity sa "Five Prevention" interlocks ug minimize risks sa personal injury caused by oversights o interlock failures sa metal-clad switchgear. Combined sa inherent feature nga fully enclosed ug inaccessible ang high-voltage live parts, ang SF6 RMUs further highlight their superiority sa protecting both professional ug non-professional maintenance personnel compared sa metal-clad switchgear.

III. Operational Advantages of SF6 Insulated RMUs over Metal-Clad Switchgear

Fully Sealed Insulation, Maintenance-Free

Tanang primary live components (e.g., load switches, busbars) sa SF6 RMUs sealed within the SF6 gas chamber, immune sa external environmental factors sama sa humidity, salt fog, ug dust. Kini ensures high reliability ug personnel safety, truly achieving maintenance-free operation. Core components can last up to 20 years without maintenance, making them suitable for unattended distribution rooms.

Compact Structure, Space-Saving

Ang SF6 RMUs compact ug space-efficient, single cabinet width lang 325mm (696mm for metering cabinets), significantly reducing the footprint sa distribution rooms ug ideal sa space-constrained locations. Switchgear ug enclosures fully assembled sa factory with lifting lugs, allowing for easy on-site installation by simply positioning the enclosure.

Taking a typical 10kV distribution room project as an example (dual incoming lines, six outgoing lines, bus tie sectioning):

• Using KYN28 metal-clad switchgear: 10 units required, each 800mm wide ug 1500mm deep, main body area 12㎡; considering operation ug maintenance clearance (1500mm front, 600mm rear), additional area 16.8㎡; DC screen area approximately 2㎡; total area approximately 30.2㎡.

• Using SF6 RMUs: 9 bays required, each 325mm wide ug 750mm deep, main body area 2.20㎡; considering 600mm front maintenance clearance (also serving as inspection passage), additional area 1.75㎡; no additional DC screen needed (self-powered protection devices available); total area approximately 3.95㎡. Compared sa metal-clad switchgear, this saves 26.25㎡, demonstrating a significant advantage.

High Protection Rating, Strong Environmental Adaptability

Ang SF6 RMUs feature a fully sealed structure, eliminating the need for heaters ug preventing condensation. Cable terminations waterproof ug sealed, allowing operation even when submerged. The stainless steel gas chamber sa switchgear (including fuse bushings) achieves an IP67 protection rating ug has successfully passed international tests for 24 hours of energized operation underwater at a depth of 5 meters.

Sa contrast, ang metal-clad switchgear indoor equipment, integrated sa circuit breakers. An accident sa one unit often affects multiple devices ug can even escalate to a substation-wide outage. Recent circuit breaker failures, particularly sa 6–35kV levels, frequently linked sa insulation degradation sa humid environments, poor sealing, insufficient creepage distance, ug inappropriate materials. Ang SF6 RMUs, sa ilang fully enclosed, outdoor-suitable design, naturally avoid these issues ug maintain reliable power supply even under harsh conditions sama sa coastal typhoons ug heavy rain, demonstrating far superior environmental adaptability.

Excellent Electrical Performance, High Technical Parameters

Circuit breaker cabinets can achieve short-circuit breaking capacities up to 25kA; load switch mechanical life reaches 5,000 operations, far exceeding the national standard requirement of 2,000 operations.

Conclusion

Ring main units evolved from initial closed-loop structures to open-loop configurations, progressing through oil-immersed fuse RMUs to today's advanced SF6 fully insulated RMUs. Designs continuously optimized, ug stability steadily improved. Compared sa metal-clad switchgear, ang SF6 RMUs offer significant advantages sa safety, unattended operation, space saving, harsh environment adaptability, electrical performance, ug technical parameters. Widely used now sa municipal, metro, ug building power supply systems.