SF₆ Ring Main Units (RMUs) da Urban Grid Renovation

Overview​
A cikin tarihin da suka da na'ura, hanyar kungiyar abubuwa suna da muhimmanci a zama tsakiyar. Kafin abubuwan da aka samun wani abu a zan iya canzawa, ana iya amfani da SF₆ Ring Main Units (RMUs) mai kyau don in gudanar da shiga da abubuwa.

Daga baya, kungiyar abubuwa ta yi nasara a cikin tarihin da suka da na'ura, domin hukuma tushen bayanai da sauki masu tattalin arziki. RMUs mafi girma, mafi gudummawa, ba su kan lafiya, da kuma mai kusa da kyakkyawan su ne suka zama daya daga cikin kayayyakin da za su iya amfani da su don in gudanar da shiga da abubuwa a cikin tarihi.

​1 Types and Structural Features of SF₆ RMUs​

​1.1 Types of SF₆ RMUs​
RMUs mafi girma suna da nau'in biyu a cikin tsakiyar: Common Tank Type da Modular Unit Type. RMUs na Common Tank Type suna da wata inlets, loops, da outlets, wanda suke da yiwuwar ruwa. Amma, daga baya, wadannan abubuwan suna da kyau da Modular Unit Type, wanda ya samu karfin da yake da 10 MVA.

RMUs mafi girma suna da nau'in biyu a cikin tsakiyar: Cable Type, Fuse Type, da SF₆ Circuit Breaker Type:

• ​Cable Type:​​ Ana amfani da ita don cable inlets/outlets. Kyautar da aka sanya shi shine 630A.
• ​Fuse Type:​​ Ana amfani da ita don transformers. Kyautar da aka sanya shi shine 200A. Amma, saboda yanayin fuses, ana iya amfani da ita don transformers da suka da 1600 kVA a cikin tushen bayanai.
• ​SF₆ Circuit Breaker Type:​​ Ana amfani da ita don in magana da transformers da suka da 1600 kVA. Ya kamata ya yi protection da overcurrent da instantaneous trip. Kyautar da aka sanya shi shine 630A, da kuma lokacin da aka sanya shi shine 95ms.
  Tsakiyar da ke ciki a nan suna nufin cewa RMUs mafi girma suna da tsakiyar da ke ciki.

​1.2 Structural Features of SF₆ RMUs​
Common Tank Type SF₆ RMU suna da gas tank, operating mechanism compartment, da cable connection compartment. Modular Unit Type suna da busbar connection compartment.

SF₆ RMUs suna da tsakiyar da ke ciki:

1. ​Gas Tank:​​ Wannan shine wuri mai muhimmanci a cikin RMU. Gas tank yana da load switch, busbars, switch shaft, da SF₆ gas.
• Load switch yana da 3-position switch, da isolating knife switch da arc chute.
• Moving contact na knife switch yana da Nichrome alloy, wanda yana da dry lubrication da kuma yana da hoton da yake da ƙwarewa da short-circuit currents.
• Arc chute yana da deionizing plates, wanda suke da energy da metal vapor da SF₆ decomposition products.
• Busbar yana da fixed contact, wanda yana da rated current capacity da dynamic/thermal stability requirements.
• Switch shaft yana penetrate gas tank da kuma yana connect to operating mechanism compartment, wanda yana da double-seal structure.
• Annual leakage rate na SF₆ gas shine 0.0035%.
• Gas tank yana da Aluminum Oxide (Al₂O₃), wanda yana da SF₆ gas regeneration da kuma yana da desiccant.
• Gas tank yana da stainless steel plate, da double-sided welding.
2. ​Operating Mechanism Compartment:​​ Operating mechanism yana connect to load switch da earthing switch via switch shaft. Yana da position indicator da mechanical interlocks.
• Position indicator yana nuna state da ke ciki.
• Mechanical interlocks yana da anti-misoperation functions.
• Load switch da earthing switch yana da quick-make/quick-break mechanisms.
• Switches with fuse protection (TS Type switchgear) yana da automatic trip device, da total fault interruption time da 35ms.
• Padlocks yana da operating levers.
• Gas pressure gauge yana nuna status da ke ciki.
• Voltage indicator yana nuna circuit energization da phasing.
3. ​Cable Connection Compartment:​​ Yana da height da 1220mm, wanda yana da space da ke ciki.
• Cable connections yana da AFTS ko AWK silicone rubber cable accessories.
• Copper ko aluminum cable cross-sections yana da 25–240 mm² (for Fuse Type switchgear) ko 35–400 mm² (for Cable Type switchgear).
4. ​Busbar Connection Compartment (Modular Units):​​ Yana da bushings a step-up configuration, wanda yana da space da ke ciki.
• Bushings yana da hollow conductive type, wanda yana da copper tube busbars.
• Silicone rubber-insulated copper tube busbars yana da current-carrying capacity da phase spacing (only 110mm).
• Connections between busbars da bushings yana da E-type terminal connectors da T-type extension connectors.
• Front of the busbar compartment yana da grounded steel plate.

​2 Technical Parameters and Applications of SF₆ RMUs​

​2.1 Technical Parameters​

​2.2 Applications of SF₆ RMUs​
SF₆ RMUs suna da applications a cikin facilities, high-rise buildings, residential complexes, da urban grids. Suna da compact size, maintenance-free nature, da high reliability, wanda yana da operating costs da footprint.

• ​3-Unit Common Tank Type:​​ Dimensions only 980mm × 635mm × 1050mm, wanda yana da kiosk transformers da outdoor applications.
• ​Modular Cable Type:​​ Yana da switching tap-off boxes, wanda yana da configurations up to one incoming da three outgoing feeders.
• ​Modular Fuse Type:​​ Yana da locations far from substations, wanda yana da local transformer control.
• ​Circuit Breaker Type Switchgear:​​ Yana da overcurrent da instantaneous trip protection. Yana da transformer protection unit, incoming unit, ko busbar section unit. Yana da electromagnetic trip coil da power supply.
  ​Motorized Operation:​​
• Yana da electric motor da control box, wanda yana da local push-button operation.
• Yana da Automatic Transfer Switch (ATS) device, wanda yana da automatic switching between two incoming supplies.
• Electric motors yana da voltage levels (220V AC, 220V DC, 110V DC, 48V DC, 24V DC).
• Yana da short-circuit fault indicator, wanda yana da signals transmitted to a remote control room.
• Yana da low-voltage through-core Current Transformers (CTs) for current measurement.
• Yana da surge arresters for RMU protection. Distribution automation functions yana da Data Acquisition, Monitoring & Control, Fault Isolation & Service Restoration, Geographic Information System (GIS), da Data Statistics & Reporting.
• Yana da primary equipment da motorized operating mechanisms da Feeder Terminal Units (FTUs) ko Remote Terminal Units (RTUs).
• Yana da fiber optic cable, wanda yana da communication protocols like IEC 870, DNP 3.0, ko TCP/IP.
• Yana da SCADA software platform, wanda yana da multi-tasking da multi-user capabilities, like UNIX.
• Yana da database, wanda yana da stable processing capacity, like Oracle. Wannan solution yana da kyau a cikin RMUs da suka da outdoor da far from low-voltage power sources, wanda yana da simultaneous operation of two 150W motors over 50 times.

​3 Lifecycle​
Lifespan na SF₆ RMUs shine 25–30 years, wanda yana da retrofitting with distribution automation equipment. Don haka, SF₆ RMUs yana da kyau a cikin urban grid renovation projects.