Medium Voltage Switchgear & Distribution Panels
When it comes to primary power distribution, absolute reliability and operator safety are non-negotiable. Our Fixed-Type Air Insulated Switchgear (AIS) is a heavy-duty, metal-enclosed switchboard designed to handle high currents and massive short-circuit faults in substations and heavy industrial plants.
Unlike withdrawable switchgear, this fixed-type design mounts the Vacuum Circuit Breaker (VCB) directly within the cubicle. This eliminates the moving parts of a withdrawable chassis, resulting in a simpler, highly robust, and incredibly durable structure. Built to strictly comply with IEC 62271-200, it provides a cost-effective yet rugged solution for main incoming feeds, large motor starting, and heavy-load distribution.
Core Engineering Advantages
• Heavy-Duty Performance: Engineered for primary networks. It easily handles rated currents up to 3150A and extreme short-circuit breaking capacities up to 40kA, making it ideal for the backbone of your power grid.
• Fail-Safe Mechanical Interlocking: We take safety seriously. The switchgear features a comprehensive, forced mechanical interlocking system. This prevents operational errors, such as closing the earthing switch while the circuit breaker is live, or opening the cabinet door when the busbar is energized.
• Visible Isolation Gap: Equipped with top and bottom rotary disconnectors (isolating switches). When maintenance is required, operators can visually confirm the physical break in the circuit through the inspection window, guaranteeing 100% safety before starting work.
• Robust & Low Maintenance: The fixed-type architecture means fewer moving contact alignments and no truck-racking mechanisms to maintain. Once it is installed and bolted down, it delivers decades of stable operation even in vibrating or dusty industrial environments.
• Compartmentalized Design: The metal-enclosed structure is divided into separate compartments (Busbar, VCB, Cable, and Low Voltage) with grounded metallic partitions (PM class), effectively localizing any potential internal faults.
Technical Specifications
Applicable Standards | IEC 62271-200, IEC 62271-100, IEC 62271-102 |
Rated Voltage | 12kV / 24kV |
Rated Frequency | 50Hz / 60Hz |
Insulation Medium | Dry Air |
Rated Current (Busbar & VCB) | 630A / 1250A / 2000A / 2500A / 3150A |
Short-Circuit Breaking Capacity | 25kA / 31.5kA / 40kA |
Short-Time Withstand Current | Up to 40kA for 3s / 4s |
Internal Arc Classification (IAC) | IAC A-FLR up to 40kA / 1s |
Partition Class | PM (Metallic Partition) |
Main Applications
• Utility Substations: Main incoming and feeder panels for primary distribution grids.
• Heavy Industry: Steel mills, cement plants, and petrochemical refineries requiring large motor control and high-current distribution.
• Mining & Minerals: Rugged environments where equipment must withstand dust, vibration, and continuous heavy-duty cycles.
• Power Generation: Auxiliary power distribution systems in conventional and large-scale renewable power plants.
Q1. What are the primary applications for Fixed-type AIS Primary Switchgear?
A: Fixed-type AIS is a high-reliability solution for primary distribution in substations, industrial power plants, and large commercial complexes. It is ideal for applications where a compact footprint and cost-effectiveness are required without the need for frequent breaker withdrawal.
Q2. What does "Air Insulated Switchgear" (AIS) signify in this design?
A: AIS uses atmospheric air as the primary dielectric medium between phase-to-phase and phase-to-earth conductors. Our design ensures optimized clearance distances and utilizes high-quality insulators to provide stable performance up to 12kV or 24kV, depending on your project specifications.
Q3. How is isolation achieved in a "Fixed-type" configuration?
A: In fixed-type switchgear, the circuit breaker is bolted to the frame. Isolation is achieved through a separate Disconnector (Isolating Switch) and an Earthing Switch. This combination ensures a visible break in the circuit, allowing for safe downstream maintenance.
Q4. What types of Circuit Breakers are integrated into these panels?
A: We typically integrate high-performance Vacuum Circuit Breakers (VCB) or SF6 Gas Circuit Breakers. For fixed installations, these breakers are known for their long electrical life, minimal maintenance requirements, and high breaking capacities (up to 40kA).
Q5. What are the Rated Voltage and Current parameters for your AIS?
A: Our standard Primary AIS supports a rated voltage of 12kV or 24kV, a rated main busbar current up to 4000A, and a rated short-time withstand current (Icw) of 25kA, 31.5kA, or 40kA for 3 or 4 seconds.
Q6. How does the "Mechanical Interlocking" system ensure safety?
A: Even in a fixed design, safety is paramount. Our switchgear features a strict logic interlock system:
The Disconnector cannot be operated while the Circuit Breaker is closed.
The Earthing Switch cannot be closed if the Disconnector is in the "Service" position.
The compartment door can only be opened when the Earthing Switch is closed.
Q7. What materials are used for the switchgear enclosure?
A: The enclosure is constructed from 2mm or 2.5mm Alu-Zinc coated steel (Galvalume) or high-quality cold-rolled steel with an electrostatic powder coating. This provides exceptional mechanical strength and superior resistance to corrosion in humid or industrial environments.
Q8. Is the Fixed-type AIS suitable for harsh environmental conditions?
A: Yes. For projects in coastal or high-pollution areas, we offer enhanced creepage distance insulators and anti-condensation heaters. We also provide various Ingress Protection (IP) ratings, typically IP4X for indoor utility rooms.
Q9. Can the switchgear be integrated into an automated SCADA system?
A: Absolutely. The low-voltage compartment is equipped with Intelligent Microcomputer Protection Relays. These devices support IEC 61850, Modbus-RTU, or Profibus protocols, allowing for remote monitoring, fault recording, and automated grid management.
Q10. What documentation is provided for international shipping from your Shanxi factory?
A: Every unit is shipped with a comprehensive technical package in English, including:
Single Line Diagrams (SLD) and wiring schematics.
Factory Acceptance Test (FAT) Reports.
Type Test Certificates (covering temperature rise, dielectric, and short-circuit tests).
Installation and Maintenance Manuals.
