Busbars at Connectors sa mga Installation ng HV at EHV

Ano ang Isang Busbar na Elektriko?

Ang busbar na elektriko ay isang konduktor o set ng mga konduktor na disenyo para makolekta ang lakas ng kuryente mula sa mga pumapasok na feeder at ibahagi ito sa mga lumalabas na feeder. Sa aspeto ng paggawa, ito ay gumagamit bilang isang junction kung saan ang pumasok at lumabas na kuryente ay nagtatagpo, gumagana bilang sentral na hub para sa pag-accumulate at pagbahagi ng lakas.

Pag-install ng Busbar sa Labas

Sa mga sistema ng mataas na boltya (HV), extra-mataas na boltya (EHV), at labas na medium-boltya (MV), karaniwang ginagamit ang mga hubad na busbar at connectors, na may mga konduktor na magagamit sa tubular o stranded-wire configurations:

• Tubular Busbars: Sinusuportahan ng column insulators (karaniwang ceramic), ito ay nagbibigay ng mataas na mechanical strength at superior corona resistance.

• Stranded-Wire Busbars: Nakakabit gamit ang dead-end clamps, ideyal para sa mga pag-install na nangangailangan ng malaking-span flexibility.

(Mga halimbawa ng mga nabanggit na configurations ay ipinapakita sa Figure 1 at 2.)

Busbars para sa Pag-install ng Switchgear

Ang switchgear busbars ay karaniwang gawa sa copper, aluminum, o aluminum alloys (halimbawa, Al-Mg-Si series), na may pangunahing katangian ng mga hubad na busbar kasama ang:

• Geometric Parameters

• Tubular conductors: Outer diameter at wall thickness

• Stranded wires: Nominal cross-sectional area

• Mechanical Properties

• Tensile/compressive/bending strength

• Buckling resistance

• Section modulus and moment of inertia

• Current-Carrying Capacity

• Rated current: Determined by material resistivity and heat dissipation conditions.Since bare conductors rely on air insulation, rated voltage is not a primary selection criterion.

Teknolohiya ng Pagsambit ng Busbar

Ang dedicated connectors ay mahalaga para sa pagtapos ng busbars sa equipment, tulad ng ipinapakita sa Figure 3. Karaniwang configurations kasama ang:

• Bolted connections: Rigid joints secured by torque-controlled bolts, requiring contact resistance management to prevent overheating

• Expansion joints: Compensate for thermal expansion, mitigating structural stress concentrations

• Transition terminals: Address electrochemical corrosion between dissimilar materials (e.g., copper-aluminum interfaces)

Ang disenyo ng pagsambit ay dapat sumunod sa:

• Contact area standards for temperature rise (e.g., IEC 61439)

• Material compatibility treatments (e.g., tin-plating for copper-aluminum transitions)

• Mechanical stability under short-circuit electro-dynamic forces

Pagsasaalang-alang sa Inhenyeriya

Ang mga sistema ng busbar ng medium/high-voltage switchgear ay nangangailangan ng integrated design para sa:

• Thermal management: Optimized air convection or forced cooling to control temperature rise

• Dynamic stability: Structural integrity under short-circuit electrodynamic forces

• Environmental protection: IP3X or higher ingress protection matching operational environments

Ang mga sukat na ito ay nag-uugnay upang matiyak ang maasintado na pag-transmit ng lakas at mahaba ang serbisyo ng equipment.

Malawakang ginagamit sa data centers at industriyal na planta para sa high-current power distribution, ang mga sistema na ito ay nagbibigay ng flexible layout at madaling pag-expand sa pamamagitan ng modular design.
Para sa copper-copper connections, ginagamit ang bronze connectors; para sa aluminium-aluminium connections, dapat gamitin ang aluminium alloy connectors; at para sa copper-aluminium connections, kinakailangan ang bi-metallic connectors upang maiwasan ang corrosion dahil sa electrolytic effects.
Insulated Busbars & Trunking Systems
Sa indoor medium-voltage (MV) at low-voltage (LV) installations—lalo na kung may mataas na kuryente at limitadong lugar—ang mga busbar ay kadalasang nakakabit sa metallic casings para sa mechanical protection at insulation.Ang disenyo na ito ay binabawasan ang busbar heat dissipation dahil sa restricted air flow at radiation losses, na nagresulta sa mas mababang current ratings kaysa sa free-air installations. Ang ventilated enclosures ay maaaring gamitin upang minimize ang current derating.

Analisis ng Teknikal na Detalye

• Electrochemical Protection para sa Iba't Ibang Material Connections

• Copper-copper joints: Bronze connectors (tin bronze or aluminium bronze) enhance contact reliability via solid solution strengthening, preventing pure copper creep relaxation.

• Aluminium-aluminium joints: 6061-T6 aluminium alloy connectors undergo aging treatment to ensure oxide film stability.

• Copper-aluminium transitions: Bi-metallic connectors use explosive welding or brazing (e.g., copper-aluminium composite bars) to block electrochemical corrosion paths.

• Thermal Management Challenges in Enclosed Busbars
  Thermal resistance analysis: Air gaps formed by enclosures reduce thermal conductivity by 30%-50%.
  Compensation solutions:
  

• Forced air cooling: Internal fans increase current-carrying capacity by 20%-30%.

• Enclosure cooling fins: Enhanced surface area for natural convection.

• High thermal conductivity insulation: Silicone rubber coatings to reduce thermal resistance.

• Engineering Application Specifications
  

• Protection class: Typically IP54 for indoor environments, upgraded to IP65 in humid conditions.

• Short-circuit withstand: Compliant with IEC 61439 dynamic and thermal stability requirements.

• Expansion compensation: Expansion joints every 30-50 meters to accommodate thermal deformation.

Malawakang ginagamit sa data centers at industriyal na planta para sa high-current power distribution, ang mga sistema na ito ay nagbibigay ng flexible layout at madaling pag-expand sa pamamagitan ng modular design.

Isolated Busbars

Ang isolated busbars ay karaniwang binubuo ng copper o aluminium flat bars (isa o higit pa bawat phase, na may sukat ayon sa mga requirement ng kuryente), na may bawat phase na nakakabit sa hiwalay na earthed sheath. Ang dulo ng sheath ay konektado ng short-circuit rated bars na kayang dalhin ang buong fault currents.Ang sheath ay pangunahing nagpaprevent ng inter-phase short circuits. Bukod dito, ito ay kanselado ang magnetic fields na nilikha ng mga conductor currents: isang equal at opposite na kuryente na induced sa sheath neutralizes ang electromagnetic field halos kompleto.Kasama sa mga common insulating media ang air at SF₆.

LV Busbar Trunking Systems

Sa low-voltage installations, ang busbar trunking systems ay nagbibigay ng cost-effective na solusyon para sa power distribution, na nagbibigay ng multiple devices at interconnecting switchboards o transformers, tulad ng ipinapakita sa Figure 5.

Busbar Trunking Systems

Ang busbar trunking system ay isang pre-assembled configuration na naglalaman ng flat-bar conductors (phase at neutral) sa loob ng single metallic enclosure.Sa feeder trunking systems, ang power tap-off ay nakuha sa pamamagitan ng standardized tap-off units, na konektado sa predefined positions sa trunking. Ang mga unit na ito ay nagbibigay ng power extraction sa pamamagitan ng compatible protective devices.

Advantages Over Cable Systems:

• Cost-Effectiveness & Installation Efficiency

• More economical for high-current applications: Eliminates the need for parallel single-core cables to meet current ratings, voltage drop, and dip requirements.

• Reduces overheating risks: Avoids heat buildup in cable bundles that can lead to short circuits.

• Mechanical Superiority

• Long-span stability: Requires minimal fixings, reducing installation time.

• Eliminates cable support structures: Minimizes metalwork requirements.

• Space & Maintenance Benefits

• Accommodates post-installation power changes (within trunking ratings).

• Enables easy repositioning of distribution points.

• Facilitates system expansion.

• Reduces switchboard termination space.

• Eliminates cable joints: Lowers contact resistance and failure points.

• Flexible tap-off design:

• Additional Advantages

• Aesthetic appeal in visible areas.

• Reusability: Can be dismantled and relocated.

• Enhanced fire resistance: Metal enclosures contain fire spread.