Air Insulated Ring Main Unit
1. SF₆-Free & Eco-Friendly Solution: Uses nitrogen/dry air insulation and vacuum interruption, eliminating SF₆ and ensuring a greener, environmentally sustainable power distribution solution.
2. High Safety & Reliability: Fully sealed stainless steel gas tank, internal arc tested design, and pressure relief system ensure maximum protection for both personnel and equipment.
3. Maintenance-Free & Long Service Life: Ultra-low gas leakage rate (≤0.01% per year) and high mechanical life (up to 10,000 operations) ensure stable, maintenance-free performance for up to 40 years.
4. Compact & Flexible Modular Design: Space-saving structure with modular configurations and flexible expansion options, ideal for various applications and easy system upgrades.
KLH-12 Series Nitrogen / Dry Air Insulated Ring Main Unit (RMU)
The KLH-12 series nitrogen/dry air insulated ring main unit is newly developed based on the introduction and absorption of advanced international technologies, as well as years of experience in designing and manufacturing fully gas-insulated switchgear. It adopts dry air insulation and vacuum arc extinguishing technology.
With an innovative design concept and world-leading manufacturing processes, the product reflects energy-saving and environmentally friendly principles throughout its entire lifecycle—from production and operation to end-of-life recycling.
Featuring compact size, maintenance-free operation, simple handling, high performance, and strong safety and reliability, it can effectively replace SF₆ insulated switchgear and solid insulated switchgear, making it an ideal green solution for power distribution network construction and upgrading.
Advantages & Features
All high-voltage live parts are fully sealed in a stainless steel gas tank. Dry air is used as the insulation medium between phases, phase-to-ground, and isolation gaps, ensuring that the entire switchgear is unaffected by external environmental conditions. Circuit breakers, load switches, and earthing circuits all adopt vacuum interrupters. The traditional load switch + fuse combination is replaced by a vacuum circuit breaker unit, enabling rapid fault isolation at an early stage. A dedicated pressure relief channel safely releases high-temperature and high-pressure gases outdoors, ensuring safer and more reliable operation with lifetime maintenance-free performance.
Fully automatic nitrogen leak detection and gas filling equipment are used to test and fill the gas tank, ensuring a leakage rate of less than 0.01% per year and a service life of up to 40 years.
The mechanical life of vacuum circuit breakers and vacuum load switches reaches up to 10,000 operations, while the three-position switch (isolation/earthing) reaches 5,000 operations. The combination of earthing switch and vacuum circuit breaker allows unlimited short-circuit making operations beyond the conventional two-time limitation.
Compact structure and small footprint, suitable for installation in space-limited environments.
Modular design with multiple unit configurations. It supports both single gas tank units and shared gas tank combinations. Side expansion and top expansion options are available and can be used independently or in combination. The fully enclosed extension busbar is coated with conductive paint and grounded, ensuring safety and reliability.
Equipped with advanced temperature rise and density monitoring devices, as well as current and voltage monitoring systems. Integrated automation solutions enable unattended substation operation and full remote control (telemetry, telecontrol, telesignaling, teleadjustment, and telemetering).
The gas tank is made of 3 mm thick 304 stainless steel, processed by laser cutting and laser welding. It can withstand internal gas pressure up to 0.3 MPa, ensuring safety of personnel and equipment during internal arc faults, while maintaining excellent sealing performance and aesthetic appearance.
Combined mechanical and electrical interlocking systems effectively prevent misoperation.
Clean workshop environment, fully automated assembly lines, and comprehensive factory testing equipment ensure product consistency and high quality.
Basic Parameters
Rated Voltage | kV | 12 |
Rated Frequency | Hz | 50 |
Rated Current | A | 630 |
Power Frequency Withstand Voltage | kV | 42/48(across isolating distance) |
Lightning Impulse Withstand Voltage | KV | 75/85(across isolating distance) |
Mechanical Life | operations | 10000 |
Rated Short-Circuit Breaking Current | kA | 20 |
Rated Making Current | kA | 50 |
Rated Short-Time Withstand Current of Main Circuit (4 s) | kA | 20 |
Rated Peak Withstand Current of Main Circuit | kA | 50 |
Internal Arc Classification | AFLR,20kA,1s | |
Enclosure Protection Degree | IP4X | |
Gas Tank Protection Degree | IP67 | |
Annual Gas Leakage Rate | ≤0.01% |
Project Showcase
We have carried out construction projects in more than 20 countries and regions, supplying a wide range of medium and low voltage switchgear solutions. Guided by our philosophy of “Professional Manufacturing, Dedicated Service,” and driven by our core values of integrity, innovation, safety, efficiency, and win-win cooperation, we are committed to delivering high-quality products and services to customers worldwide.
About Us
We operate a 36,000 m² production facility with a team of 200 dedicated employees. We specialize in the R&D, manufacturing, sales, and power engineering installation of complete switchgear systems ranging from 0.22kV to 35kV, serving industries such as industrial and mining, public infrastructure, real estate, stadiums, commercial centers, and healthcare, with a strong focus on stable production and strict quality control.
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