Description
Our medium voltage panels receive incoming power and distribute it safely to transformers, motors and outgoing feeders. Each line-up is configured from your single-line diagram, then assembled, wired and routine-tested in our Hangzhou factory.
High-Voltage Switchgear Cabinet Overview
In industry, “high voltage” switchgear usually means medium voltage equipment from about 3.6 kV to 40.5 kV. These panels switch and protect circuits under normal load and during faults, isolate equipment for maintenance, and measure current, voltage and energy. A typical line-up includes incoming, metering, bus-coupler and outgoing feeder panels connected by a common busbar.
Key Features
- Vacuum circuit breakers – reliable interruption with long mechanical and electrical life and low maintenance.
- Compartmented construction – separate breaker, busbar, cable and low voltage compartments in metal-clad designs, limiting the effect of internal faults.
- Mechanical interlocks – prevent unsafe operations such as racking a closed breaker or opening a live compartment.
- Digital protection relays – overcurrent, earth-fault, transformer and motor protection with event recording.
- Remote monitoring – breaker status, alarms and metering available to SCADA over standard protocols.
- Flexible configurations – incomer, feeder, metering, PT, bus coupler and capacitor panels in one line-up.
Panel Types We Supply
| Type | Typical use |
|---|---|
| Withdrawable metal-clad (e.g. KYN28-12) | Main substations in factories, mines, water plants and buildings |
| 35 kV withdrawable panels (KYN61-40.5 type) | 35 kV incoming substations and renewable collector systems |
| Fixed-type panels | Simpler distribution where cost and space are priorities |
| Ring main units | Secondary distribution rings and prefabricated substations |
Typical Ratings to Specify
- Rated voltage, for example 12 kV or 40.5 kV
- Rated normal current of busbars and feeders, for example 630 A to 3150 A
- Rated short-time withstand current and duration, for example 25 kA or 31.5 kA
- Internal arc classification and enclosure protection degree
- Protection functions, CT and VT ratios and communication protocol
Ratings are confirmed for each project against your network data; we do not supply equipment outside its tested ratings.
Applications
- Factory and industrial park substations
- Mines, mineral processing and metal plants
- Water and wastewater treatment works
- Commercial buildings, hospitals and data centres supplied at medium voltage
- Solar and wind collector substations
Standards and Testing
Medium voltage switchgear is designed to the IEC 62271 series, including IEC 62271-200 for metal-enclosed switchgear and IEC 62271-100 for circuit breakers. Every panel is routine-tested before shipment, and full documentation — single-line diagram, general arrangement, wiring diagrams, test reports and manuals — is included.
What to Send for a Quotation
- Single-line diagram and panel list
- System voltage, rated current and short-circuit level
- Protection requirements and preferred relay brand
- Cable entry, room dimensions and site altitude
Read what high voltage switchgear is and how it differs from low voltage switchgear, or request a quote.
How to Choose the Right Configuration
Start from the single-line diagram. The incoming panel must match the utility or generator supply and carry the full load current; outgoing feeders are sized for each transformer or motor. The short-circuit rating of the whole line-up must be at least the prospective fault level at the point of connection, which the utility or your consultant can provide. Where two supplies are available, a bus coupler and interlocking scheme allow one supply to feed both sections during maintenance or a supply failure.
Protection is selected for each feeder: overcurrent and earth-fault protection for cables, differential or thermal protection for transformers and large motors, and voltage and frequency protection where generators are connected. Selectivity studies make sure the breaker closest to a fault trips first, so the rest of the plant keeps running.
Installation and Room Requirements
- Front and rear clearances for breaker withdrawal and cable work, as shown on the general arrangement drawing.
- A level floor or steel base frame, and cable trenches or raised floor sized for the incoming and outgoing cables.
- Ventilation and a defined path for arc gases from pressure-relief flaps, especially for internal-arc-classified panels.
- Auxiliary power for protection relays, motor operators and heaters, usually from a DC battery system or UPS.
- Earthing connections to the substation earth grid.
Maintenance
Medium voltage switchgear needs little routine attention, but planned maintenance every three to five years keeps it reliable: cleaning and inspection, torque checks on busbar joints, breaker timing and contact resistance tests, relay secondary injection and an infrared scan under load. Our after-sales team can provide spare parts, training and maintenance support for the full service life of the equipment.
Why Buy From Danli
We design and build medium voltage panels together with low voltage switchboards, motor control centres and automation systems, so protection settings, interlocks and communication are coordinated across the whole substation. Panels are assembled and tested in our own factory, documentation is supplied in English for export projects, and our engineers support installation, commissioning and long-term maintenance. Our certifications are listed on the qualifications page.
Frequently Asked Questions
What voltage range do you supply?
We build medium voltage switchgear for common distribution voltages from 3.6 kV up to 40.5 kV, including 6, 10, 20 and 35 kV systems. The exact ratings are confirmed for each project.
Which type of switchgear is right for my project?
Withdrawable metal-clad panels such as KYN28-12 suit most industrial 6–10 kV substations. Fixed-type panels and ring main units suit simpler or secondary distribution. We recommend the type after reviewing your single-line diagram.
Which protection relays can you fit?
We fit digital protection relays from major international and Chinese brands, configured for overcurrent, earth-fault, transformer and motor protection as required.
What tests are carried out before delivery?
Each panel receives routine tests including power-frequency withstand, main circuit resistance, mechanical operation and secondary wiring checks. Test reports are supplied with the equipment.
