Medium Voltage Switchgear & Distribution Panels
The HXGN-12(SF6) AC High-Voltage Metal-enclosed Ring Main Unit (RMU) is an indoor, box-type, fixed switchgear that uses SF6 gas as the insulation and arc-extinguishing medium. It is primarily used in distribution systems with a rated voltage of 12kV and frequency of 50Hz for ring main power supply and terminal distribution. Known for its compact structure, flexible operation, reliable interlocking, easy installation, and wide applicability, it is an ideal power distribution solution for urban power grids, industrial and mining enterprises, various buildings, and infrastructure projects.
The HXGN-12 (SF6) AC Metal-Enclosed Ring Main Unit is an indoor, modular, and sealed switchgear designed for 12kV medium-voltage distribution networks. It uses SF6 gas as the insulation and arc-extinguishing medium, ensuring superior safety, compact structure, and long-term reliability. Ideal for urban power grids, substations, industrial and mining enterprises, commercial buildings, and infrastructure projects, this RMU supports both ring main and terminal power supply configurations.
Parameter Category | Technical Specifications |
Rated Characteristics | Rated Voltage: 12kV |
Insulation Level | 1min Power Frequency Withstand Voltage: Phase-to-Phase & Phase-to-Ground 42kV, Isolating Distance 48kV |
Short-circuit Parameters | Rated Short-time Withstand Current (3s): 20kA, 25kA |
Control Circuit | Voltage: DC 110V/220V, AC 110V/220V |
Protection Degree | Enclosure: IP3X; SF6 Gas Chamber: up to IP67 |
Dimensions (W×D×H) | Common: 500mm × 1000mm × 1850mm; Others like 420×840×1600(1800), 500×840×1600(1800), 750×840×1600(1800), 375×940×1650(1850), etc. |
Compliance Standards | GB 3804, GB 3906, GB/T 11022, IEC 298, IEC 60420 |
1. Excellent Electrical Performance and Insulation Reliability
Utilizes SF6 gas for high insulation and efficient arc extinction.
Main components are sealed within epoxy resin-filled SF6 chambers (IP67), ensuring long-term, maintenance-free operation.
Supports making and breaking of rated load currents and transformer no-load currents, with fuse combinations interrupting high short-circuit currents up to 31.5kA.
2. Safe and Reliable Design and Construction
High-strength enclosure made from aluzinc or stainless steel, offering corrosion and oxidation resistance.
Comprehensive five-prevention interlocking system to avoid incorrect operations and ensure operator safety.
Internal arc-resistant design with pressure relief channels to safeguard personnel in case of faults.
3. Flexibility and Modular Design
Compact and modular design allows easy expansion and integration into existing systems.
Supports multiple operation types — manual and electric mechanisms.
Compatible with different switch types such as SF6 load switch, SF6/Vacuum circuit breaker, and load switch-fuse combinations.
4. Environmental Adaptability and Long Service Life
Stable operation under high humidity, pollution, salt-fog, or altitude conditions (up to 2000m or more).
Sealed SF6 system with leakage rate ≤0.01%/year, ensuring a service life of over 30 years.
Low maintenance and long-term reliability for demanding environments.
Urban Power Grids: Distribution network construction and renovation, switching stations.
Industries and Enterprises: Industrial and mining enterprises, small secondary substations.
Buildings and Communities: High-rise buildings, residential complexes, shopping malls, schools, hospitals, parks.
Infrastructure: Packaged substations, cable branch boxes, public utilities like water treatment plants.
Terminal Distribution and Ring Main Supply: Serving as ring main units and for terminal distribution.
Main Switch Options: SF6 load switch (e.g., FLN36-12D), SF6 load switch - fuse combination, Vacuum circuit breaker (e.g., VS1 type).
Operating Mechanisms: Manual operating mechanism, Electric operating mechanism.
Extended Functions: Equipped with PTs (Voltage Transformers), CTs (Current Transformers), FTUs (Feeder Terminal Units), communication devices for distribution automation; Adding capacitive voltage indicators, auxiliary contacts, trip coils, etc.
Special Environments: Configurations available for higher protection degrees (e.g., IP4X) or special environments (e.g., high altitude, high humidity).
Enclosure Dimensions and Combination: Various width, depth, and height options available, can be combined in multi-cabinet arrangements or used alongside other switchgear types.
Q1. What are the primary applications for the HXGN-12 (SF6) Switchgear?
A: The HXGN-12 is a compact, metal-enclosed Ring Main Unit (RMU) designed for AC 50/60Hz, 12kV distribution systems. It is widely used in urban residential areas, high-rise buildings, industrial parks, and wind/solar farm substations for receiving and distributing power while protecting the transformer.
Q2. How does the SF6 gas insulation benefit the system?
A: SF6 (Sulfur Hexafluoride) gas has superior dielectric strength and arc-extinguishing properties. By using SF6, the HXGN-12 achieves a highly compact footprint, which is ideal for space-constrained urban environments or integrated box-type substations.
Q3. What is the standard configuration of the HXGN-12 unit?
A: The unit typically integrates a load break switch (LBS), an earthing switch, and high-voltage fuses (for transformer protection) or a vacuum circuit breaker (VCB). The entire high-voltage live part is enclosed in a stainless steel tank or a robust metal cabinet to prevent accidental contact.
Q4. What are the Rated Voltage and Short-Circuit parameters?
A: Our standard HXGN-12 supports a rated voltage of 12kV, a rated current up to 630A, and a rated short-time withstand current (Icw) of 20kA or 25kA (4s). These parameters ensure high stability during grid faults.
Q5. How do you ensure the gas tightness and safety of the SF6 tank?
A: Safety is our priority. Each unit is equipped with a pressure gauge (SF6 density monitor) with alarm contacts. The gas tank is made of high-quality stainless steel and undergoes a rigorous helium leak test at our factory to ensure a service life of over 30 years without gas refilling.
Q6. What kind of "Five-Prevention" interlocking does it feature?
A: The HXGN-12 includes a comprehensive mechanical interlocking system (Five-Prevention) to prevent:
1.Closing the switch with the door open.
2.Opening the door with the switch closed.
3.Closing the earthing switch when energized.
4.Closing the load switch when the earthing switch is closed.
5.Accidental entry into energized compartments.
Q7. Can the HXGN-12 be upgraded for Smart Grid automation?
A: Yes. We can equip the HXGN-12 with Motorized Operating Mechanisms and an FTU (Feeder Terminal Unit). This allows for remote signaling, measuring, and control via a SCADA system, enabling rapid fault isolation and power restoration.
Q8. What is the Ingress Protection (IP) rating for the enclosure?
A: The standard enclosure is rated at IP3X or IP4X. The internal primary high-voltage components are sealed within the gas tank, which effectively reaches an IP67 equivalent, protecting them from dust, moisture, and small animals.
Q9. What testing standards do your RMUs comply with?
A: Our HXGN-12 sets are manufactured and tested in accordance with IEC 62271-200 (AC metal-enclosed switchgear and controlgear for rated voltages above 1 kV and up to and including 52 kV) and carry the necessary Type Test Reports from authorized laboratories.
Q10. How does your factory in Shanxi handle the shipping of high-voltage equipment?
A: High-voltage equipment requires specialized handling. We use heavy-duty vacuum plastic packaging and reinforced plywood crates. We also provide clear instructions for gas pressure verification upon arrival and offer remote video guidance for the installation of the busbars and cable terminations.
