Tủ điện trung thế: Các thành phần và cách lựa chọn

Một sự rõ ràng thiết bị đóng cắt trung thế quyết định bắt đầu từ thiết kế mạng đã được phê duyệt, không phải một thông số kỹ thuật danh mục riêng lẻ. Hướng dẫn này giúp bài viết tập trung vào các câu hỏi của dự án nhằm xác định phạm vi khả thi và hướng các quyết định chi tiết hơn đến các bài viết kỹ thuật liên quan.

Part 1. Use the one-line diagram to define the duty

Medium-voltage switchgear is an assembly that switches, protects, isolates, and controls circuits above low-voltage distribution levels. Selection starts with the system voltage, earthing method, continuous current, prospective short-circuit current, feeder roles, and operating philosophy. A voltage label alone does not establish the required assembly duty.

Part 2. Understand the components as one coordinated system

Typical sections combine busbars, circuit breakers or load-break switches, disconnecting and earthing functions, instrument transformers, protection relays, cable compartments, and interlocks. Their ratings and clearances must be coordinated. The equipment schedule should state what is included in each incomer, feeder, bus section, and metering panel.

Part 3. Choose the insulation and construction for the installation

Air-insulated, gas-insulated, and metal-clad designs solve different footprint, environmental, and maintenance problems. Indoor rooms require attention to access, cable routing, ventilation, and safety clearances. Outdoor or compact installations add enclosure and environmental considerations. Confirm the actual construction in approved drawings rather than inferring it from a generic category name.

Part 4. Separate protection design from hardware selection

Relays, CTs, VTs, breaker operating times, and the protection philosophy must be aligned with the network study. Protection settings are not universal values that can be copied between projects. Coordinate them with upstream utility equipment and downstream transformers or feeders before commissioning.

Part 5. Make factory and handover records part of procurement

Ask for approved GA drawings, wiring diagrams, nameplate information, routine-test records, relay documentation, and operation instructions. Factory tests should be witnessed or reviewed according to the contract. Site commissioning then verifies cable identification, interlocks, earthing, protection logic, and the latest settings file.

Part 6. Use the product page for initial scope alignment

For 12kV or 24kV project discussions, the published Tủ điện trung thế KYN28-12 can provide a catalog starting point. Product recommendation boundary: fault duty, internal-arc requirements, relay scheme, and utility interfaces must be confirmed by project engineering.

Để đọc chi tiết liên quan, xem KYN28 Gas Insulated Switchgear Buyer Guide và Ring Main Unit Selection Guide và 11kV Vacuum Circuit Breaker Selection. Xem xét tổng thể hơn Danh mục nguồn điện Thâm Hằng khi so sánh các họ danh mục và gửi các đầu vào dự án đã được phê duyệt qua Liên hệ Điện lực Thâm Hằng dành cho một cuộc thảo luận kỹ thuật.

Câu hỏi thường gặp

What does medium voltage switchgear do?

It switches, protects, isolates, and controls medium-voltage circuits according to the system design.

What should be defined before requesting a quotation?

Provide voltage, current, fault duty, insulation level, feeder schedule, protection requirements, site conditions, and required documentation.

How are AIS and GIS selection decisions made?

Compare footprint, environment, maintenance approach, project standards, and the required electrical duty rather than choosing by label alone.

Why are interlocks important?

They support safe operating sequences, but the required interlock scheme must match the approved single-line diagram and operating procedure.

What documents are needed before commissioning?

Use the approved drawings, test records, relay settings, cable schedule, manuals, and commissioning procedure.

When should an RMU be considered instead of a larger lineup?

Use the network layout, feeder functions, protection needs, and site constraints to determine whether an RMU is appropriate.

Tài liệu tham khảo

• Các ấn phẩm của IEC
• Hiệp hội Tiêu chuẩn IEEE