Ang Pagkuha sa mga Box-type Transformers sa mga Distribution Networks

Prinsip Elektrikal ug Estruktura sa Pad-Mounted Substations

Ang elektrikal nga schematic diagram sa pad-mounted substation makita sa Figure 1.

Estruktural nga Komposisyon:

Ang American-style pad-mounted combined substation gikan sa pad-mounted transformer, estrukturado sa front ug rear sections:

• Front Section (Wiring Cabinet): Naglakip sa high/low-voltage terminal blocks, high-voltage load switch, plug-in fuses, high-voltage tap changer operating handle, pressure gauge, oil level gauge, oil thermometer, etc.

• Rear Section (Oil Tank and Radiators): Naglaman sa core, windings, high-voltage load switch, ug plug-in fuses sa fully sealed oil tank. Ang core sa transformer kaasabya adunay three-phase five-leg core design, mahimong wound core o laminated core gihimo sa high-quality cold-rolled grain-oriented silicon steel sheets o high-efficiency amorphous alloy sheets. Ang low-voltage windings gamit ang foil structure, naghimo og dako nga resistance sa short circuits, lightning impulses, ug overloads. Ang connection group mao ang Dyn11.

• Sealed Structure: Ang fully sealed design sa tank nagprotekta. Ang oil-immersed load switches adunay daghang klase aron masatisfy ang requirements sa radial o ring main distribution systems.

Proteksyon ug Estruktura sa American - style Pad - mounted Substations

Ang American - style pad - mounted substations protektahan pinaagi sa series connection sa backup fuse protector ug plug - in fuse. Ang backup fuse protector mogamit lang kung may fault sa pad - mounted substation, protektando ang high - voltage line. Ang plug - in fuse, uban sa dual - sensitive fuses, magblow kung may short - circuit faults, overloads, o excessive oil temperatures sa secondary side. Kini nga estilo sa proteksyon ekonomical, reliable, ug easy to operate.

Ang high - voltage terminals sa pad - mounted substation equipado sa bushing sockets, single - pass bushing connectors, ug elbow (bent) - type cable connectors capable of handling a 200 A load. Ang live parts sealed sa insulators, naghimo og fully insulated structure diin ang terminal surface walay kuryente, ensuring personal safety. Kasagaran, isipgihatagan usab sa plug - in composite - insulated metal - oxide arrester sa elbow - type insulator bushing. Kini nga arrester fully shielded, fully insulated, ug plug - and - play, ensuring safety ug facilitating easy installation. Mga accessories sama sa live indicators ug fault indicators mahimong giadto.

Characteristics sa Pad - mounted Transformers

Ang pad - mounted transformers, usa ka bag-ong tipo sa transformers wide na gamiton sa recent years, characterized sa reliable power supply, reasonable structure, rapid ug flexible installation, convenient operation, small size, ug low cost. Mahimong gamiton sa outdoor ug indoor, ug wide applicable sa various scenarios sama sa industrial parks, residential communities, commercial centers, ug high - rise buildings. Sa pagkumpara sa domestic pad - mounted substations, ang American - style pad - mounted substations adunay sumala nga mga advantages ug characteristics:

• Compact Size: Ilahang volume approximately one - third sa domestic pad - mounted substations sa same capacity.

• Fully Sealed ug Insulated: Fully sealed ug insulated structure, wala na need sa insulation clearances, ensuring personal safety ug suitable for underground power distribution environments.

• Versatile Application: Gamiton sa both ring - main ug terminal applications, convenient conversion, enhancing power supply reliability.

• Strong Overload Capacity: Makapigay sa overload nga 2 times sa rated value sa 2 hours o 1.6 times sa 7 hours without affecting ilahang service life.

• Low Loss: Mas baba ang losses kaysa sa domestic S₉ - type transformers.

• Flexible Cable Connectors: Ang cable connectors capable of handling a 200 A load current. Sa emergency situations, mogamit usab isip load switches ug characteristics sa disconnect switches, providing convenient ug flexible operation.

• Dual - Fuse Protection: Ang uso sa dual - fuse protection molabay sa operating costs. Ang fuses sa plug - in fuses dual - sensitive (sa temperature ug current).

• High - Flash - Point Oil: Using high - flash - point oil (R - TEMP oil with a flash point as high as 312°C), makaputlo sa buildings without the risk of fire hazards.

• Corrosion Resistance: Ang body sa transformer designed sa anti - corrosion ug treated sa special paint, making it suitable for various harsh environments, such as areas with frequent storms ug high pollution.

• Superior Electrical Performance: Thanks sa Δ/Υ connection ug three - phase five - limb structure, adunay outstanding advantages sama sa high voltage quality, stable neutral point, no heating sa body, low noise, ug good lightning protection performance.

• Land - Saving: Usually placed sa green belts, nakalihok sa space na gamiton sa building power distribution rooms, effectively improving land utilization.

Applications sa Pad - mounted Transformers
Selection sa Pad - mounted Transformers

• Capacity Selection: Determining ang capacity involves factors sama sa load, investment, losses, ug service life. Generally, based sa meeting sa maximum load with a margin, economic ug technical comparison made among transformers sa similar capacities sa selection sa distribution transformer sa lowest total cost of ownership. Ang rated capacities sa American - style pad - mounted substations include 150, 225, 300, 500, 750, 1000, 1500, ug 2000 kVA.

• Type Selection: Ang pad - mounted substations classified sa terminal type ug ring - main type, mainly determined sa type sa load switch.

• Installation Location: Adunay duha ka types sa insulating oil sa pad - mounted substations. Usa common mineral oil, sama sa domestic No. 25 transformer oil; ang uban R - TEMP oil (high - flash - point oil with a flash point of 312°C). Ang pad - mounted substations filled sa R - TEMP oil (with a clear mark sa low - voltage side) makaputlo sa buildings, while ang filled sa common oil dili.

• Customization sa Low - Voltage Side: Ang American - style pad - mounted substations generally wala gyud sa low - voltage branch protection ug metering. Pero branch protection switches, metering instruments, ug compensation devices maadto sa low - voltage side according sa user requirements.

Engineering Application Example

Ang usa ka unit sa Kunming urban area, na adunay newly built residential buildings ug office buildings, selected ang pad - mounted transformer gikan sa American COOPER Company. Ang model sa transformer mao ang PMT - LO - 500, rated capacity 500 kVA ug rated voltage 10 kV/0.4 kV. Sa low - voltage side, added ang three current transformers, one voltmeter, three ammeters, ug four - way load - outlet air switches according sa requirements sa users ug power supply department. Ang COOPER's fully insulated, maintenance - free cable branching boxes nga can withstand any harsh environment ug allow load - break plugging ug unplugging installed sa both sides sa pad - mounted substation aron maghatag og power sa tanang building. Ang pad - mounted substation ug branching boxes placed sa green belt, harmonizing well sa environment. After more than a year sa operation, both ang power supply department ug users reported good results.

Precautions sa Use

Sa pag-select ug use sa pad - mounted substations, atensyon sa type sa pad - mounted substation, type sa load switch, ug user requirements sa low - voltage meters.

• Types sa Pad - mounted Substations: Adunay ring - main type ug terminal type. Sa ring - main type pad - mounted substations, ang load switch ma-switch sa supply high - voltage power sa other end.

• Types sa Load Switches: Ang load switches divided sa 2 - position type, 3 - position type, ug 4 - position type. Each position type adunay daghan nga forms. For example, ang 4 - position type includes T - type ug Y - type, both usable sa dual - power supply. Ang T - type usable sa ring - main pad - mounted substations, while ang Y - type usable sa terminal pad - mounted substations.

• Inspection sa Plug - in Fuses sa Newly Installed Pad - mounted Substations: Sa inspection sa plug - in fuses sa newly installed pad - mounted substations, important na tingnan kung ang pressure gauge sa pad - mounted substation indicates zero. Kung dili zero, toggle ang exhaust valve aron exhaust air first before plugging or unplugging the fuses. Otherwise, possible nga spray out ang transformer oil.

Conclusion

Ang pad - mounted transformers essential electrical equipment sa urban power grid renovation, real - estate development, ug residential power supply construction. Ang American - style pad - mounted substations naging first choice sa urban power distribution transformers tungod sa ilang unique features ug prices comparable sa domestic counterparts. Convenient ug numerous advantages, nakadawat sila og high praise gikan sa society ug users, ug naging development direction sa small - scale urban substations.