Huanghua Group Co., Ltd. 
HRM6-40.5 Gas-Insulated Metal-Enclosed Switchgear (C-GIS)
The HRM6-40.5 series gas-insulated metal-enclosed switchgear (C-GIS) is a new generation of gas-insulated switchgear developed by Huanghua Group. Metal-armoured and hermetically sealed, it uses low-pressure SF6 gas at 0.04 MPa as the insulating medium. All HV components are waterproof and dustproof and unaffected by ambient conditions or altitude, making the switchgear completely maintenance-free. A permanent-magnet or spring operating mechanism combined with solid-sealed pole vacuum interrupters greatly reduces the number of parts.
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HRM6-40.5 operates reliably in harsh environments such as basements, plateaus, frozen soil and coastal areas with high altitude, humidity and salt spray, meeting the needs of new energy, plateau, metro, high-speed rail and urban distribution projects where land is scarce. It features high reliability, maintenance-free operation, strong environmental adaptability and a small footprint. An intelligent control and protection unit provides powerful control, protection, measurement and communication functions, fully meeting distribution network automation requirements. It is mainly used in power plants, small and medium-sized power stations, substations, high-rise buildings, industrial and mining enterprises, metros and electrified railways to control, receive, distribute, protect and monitor power supply systems and electric energy.
Type Designation
Key Highlights
| Highlights | Customer Value |
| Fully sealed & insulated: laser-welded stainless-steel gas tank, IP67, maintenance-free HV components | Immune to humidity, salt spray, dust and altitude — lowest lifecycle O&M cost |
| Minimal footprint: only 600/800 mm wide and 1600 mm deep, saving around 50% floor space versus AIS | Ideal for urban substations, prefabricated housings and compact substations |
| High ratings: 40.5 kV, 630–2500 A, Icw 31.5 kA / 4 s, Ip 80 kA | Covers mainstream 40.5 kV distribution and renewable collection duties |
| Three-position disconnector/earthing switch, 3,000 mechanical operations; VCB 10,000 operations | Dependable operating sequence, safe earthing, short outages |
| Solid-sealed pole vacuum interrupter with permanent-magnet or spring mechanism and far fewer parts | Fewer failure points, high mechanical reliability, long service life |
| Comprehensive interlocking: five-function mechanical interlock, under-voltage lockout and anti-pumping (standard) | Mis-operation proof, passes utility and EPC compliance audits |
| Outstanding environmental capability: altitude ≤5000 m, -25 °C to +50 °C, 24 h average humidity 95% | Directly deployable on plateaus, frozen soil, coastal sites and in basements |
| Modular and extensible: single or dual gas compartment, side-expandable busbar connectors, plug-in external PT and surge arresters | Flexible configuration, expansion without de-gassing, easy component replacement |
Product Features
| Features (EN) | Description (EN) |
| Compact Design | Indoor gas-insulated construction, 600/800 mm wide, 1600 mm deep and 2400 mm high, significantly saving valuable urban floor space — suitable for basement switchrooms, prefabricated housings and containerised substations. |
| Maintenance-Free Gas Compartment | All primary components are enclosed in a gas compartment welded from stainless-steel plate and filled with SF6 at 0.04 MPa as a shielding and insulating medium. The IP67 rating effectively isolates the switchgear from external climate conditions, giving maintenance-free performance. |
| Safe & Reliable Five-Function Interlock | A reliable five-function mechanical interlock prevents mis-operation. All HV components — cable terminations, surge arresters, current and voltage transformers — are enclosed in metal housings, achieving touch-safe condition. |
| Modular Structure, Easy Installation | A modular design offers flexible configuration and user-friendly operation. Cabinets are connected on side faces via side-by-side busbar connectors for simple installation. Voltage transformers and surge arresters are plug-mounted externally to the gas compartment for convenient installation and replacement. |
| Single or Dual Gas Compartment Options | Dual-compartment version: the vacuum circuit breaker is housed in one gas compartment while the busbars and three-position disconnector occupy a separate one. Single-compartment version: the breaker and three-position disconnector share a compartment made of non-magnetic stainless-steel plate by laser cutting and welding, with O-ring gaskets at all non-welded joints. |
| Inner-Cone Cable Socket & External CT | The breaker gas compartment is fitted with an inner-cone cable connection sleeve allowing parallel connection of multiple cables as well as connection of voltage transformers, surge arresters and other accessories. The ring-core current transformer is sleeved onto the cable and fastened to the switchgear frame. |
| Three-Phase Common Tank & Modular Layout | Three-phase common-tank modular design comprising gas-filled compartments for the circuit breaker, three-position disconnector and busbars, a low-voltage compartment (instrument compartment, operating mechanism compartment) and a cable compartment — clear functional segregation for independent maintenance. |
| Pressure Relief & Personnel Safety | Pressure-relief devices are installed at the upper section of the three-position disconnector and busbar gas compartment and at the rear of the circuit-breaker gas compartment. When internal pressure exceeds the specified threshold, the devices open automatically to release gas for the safety of personnel and equipment. |
| Solid-Sealed Pole Vacuum Interrupter | The solid-sealed pole vacuum interrupter encapsulates the interrupter and main conducting circuit by integral casting, resisting pollution, condensation and mechanical shock with stable breaking performance. Combined with a permanent-magnet or spring mechanism, the number of parts is greatly reduced. |
| Outstanding Environmental Adaptability | Altitude ≤5000 m (special instructions required above 1000 m); ambient temperature -25 °C to +50 °C (24 h average ≤35 °C); 24 h relative humidity average 95%, monthly average 90%. It operates reliably in basements, plateaus, frozen soil and coastal areas with high salt spray. |
| Intelligent Control & Protection | An intelligent control and protection unit delivers powerful control, protection, measurement and communication functions, supporting telemetry, remote signalling, remote control and integration with distribution automation masters — fully meeting distribution network automation requirements. |
| Standardised Operation & Interlock Logic | Energising sequence: open the circuit breaker → move the three-position switch from earthing to isolated position → from isolated to closed position → close the circuit breaker. De-energising reverses the sequence, verifying that the cable-side circuit is dead before earthing — a standardised, trainable and auditable procedure. |
Technical Parameters
1.Basic Data
| Item | Data | Unit |
| Product Name | Gas-insulated metal-enclosed switchgear (C-GIS) | — |
| Model | HRM6-40.5（HRM6(GIS)-40.5） HRM6-40.5 (HRM6(GIS)-40.5) |
— |
| Rated voltage (Ur) | 40.5 | kV |
| Rated frequency (fr) | 50 | Hz |
| Rated current (Ir) | 630 / 1250 / 2000 / 2500 | A |
| Rated short-circuit breaking current | 31.5 | kA |
| Rated short-circuit making current | 80 | kA |
| Number of short-circuit breaks | 30 | times |
| Rated operating sequence | O-0.3s-CO-3min-CO | — |
| Rated single capacitor bank breaking current | 630 | A |
| Rated back-to-back capacitor bank breaking current | 400 | A |
| Rated cable-charging breaking current | 50 | A |
| Operating mechanism | Permanent-magnet or spring mechanism | — |
| Rated supply voltage of auxiliary circuit | AC380 / AC220 | V |
| Rated supply voltage of control circuit | DC110 / DC220 / AC220 | V |
2.Rated Insulation Level
| Item | Data | Unit |
| Power-frequency withstand voltage (phase-to-phase, to earth, across vacuum gap) | 95 | kV |
| Power-frequency withstand voltage (isolating gap) | 118 | kV |
| Power-frequency withstand voltage (control & auxiliary circuits) | 2 | kV |
| Lightning impulse withstand voltage (phase-to-phase, to earth, across vacuum gap) | 185 | kV |
| Lightning impulse withstand voltage (isolating gap) | 215 | kV |
| Insulating medium | SF6 gas (0.04 MPa) | — |
3.Short-time & Peak Withstand
| Item (EN) | Data | Unit |
| Short-time withstand current — main circuit | 31.5 / 4 | kA/s |
| Short-time withstand current — earthing switch | 31.5 / 4 | kA/s |
| Short-time withstand current — earthing circuit | 27.4 / 4 | kA/s |
| Peak withstand current — main circuit | 80 | kA |
| Peak withstand current — earthing switch | 80 | kA |
| Peak withstand current — earthing circuit | 69.6 | kA |
4.Mechanical Life & Gas Data
| Item | Data | Unit |
| Mechanical life — circuit breaker | 10000 | ops |
| Mechanical life — three-position switch (disconnector/earthing) | 3000 | ops |
| SF6 rated filling pressure (20 °C, relative) | 0.04 | MPa |
| SF6 minimum functional pressure (20 °C, relative) | 0.02 | MPa |
| SF6 annual relative leakage rate | ≤0.01 | % |
| Gas monitoring | SF6 density monitor (optional) with alarm and lockout contacts | — |
5.Construction & Dimensions
| Item | Data | Unit |
| Construction type | Three-phase common-tank modular; single or dual gas compartment optional | — |
| Width W | 600 / 800 | mm |
| Depth D | 1600 | mm |
| Height H | 2400 | mm |
| Protection degree — sealed gas enclosure | IP67 | — |
| Protection degree — switchgear housing | IP4X | — |
| Functional units | Circuit-breaker gas compartment, three-position disconnector & busbar gas compartment, LV compartment (instrument & mechanism), cable compartment | — |
| Busbar connection | Side-expandable busbar connectors between cabinets (plug-in) | — |
| Cable connection | Inner-cone cable socket for parallel cables; ring-core CT sleeved onto cable | — |
| Pressure relief | Pressure-relief devices at the upper part of the disconnector/busbar compartment and the rear of the breaker compartment | — |
6.Service Conditions
| Item | Data | Unit |
| Altitude | ≤5000 | m |
| Ambient temperature | Maximum +50, minimum -25; 24 h average ≤35 | ℃ |
| Ambient humidity | 24 h relative humidity average 95%; monthly average 90% | % |
| Installation environment | No explosive or corrosive gas in the surrounding air; no frequent severe vibration or impact at the installation site | — |
| Beyond normal service conditions | If the conditions exceed those specified in GB3906 or IEC62271-200 and this manual, please contact our technical department | — |
| Applicable places | Indoor; basements, plateaus, frozen soil, coastal salt-spray areas, prefabricated housings and compact substations | — |
7.Standards & Certification
| Item | Data | Unit |
| Main standard | IEC 62271-200 — AC metal-enclosed switchgear and controlgear for rated voltages above 1 kV and up to and including 52 kV | — |
| Circuit-breaker standard | IEC 62271-100 — Alternating-current circuit-breakers | — |
| Disconnector & earthing switch standard | IEC 62271-102 — Alternating current disconnectors and earthing switches | — |
| Common specifications | IEC 62271-1 — Common specifications for alternating current switchgear and controlgear | — |
| Supplementary GIS standard | IEC 62271-203 — Gas-insulated metal-enclosed switchgear for rated voltages above 52 kV | — |
| Sealing test standard | ISO 20456 — Sealing tests for SF6 gas in high-voltage switchgear and controlgear | — |
| Sealing test standard | IEC 60529 — Degrees of protection provided by enclosures (IP Code) | — |
| Sealing test standard | GB 3906, GB/T 11022, DL/T 404 (China national & power industry standards) | — |
| Sealing test standard | IEC 62271-103 — Switches for rated voltages above 1 kV and up to and including 52 kV | — |
| Sealing test standard | 24 kV platform: TÜV SÜD certified (type test + factory surveillance); 40.5 kV: third-party type-test report available, same ISO 9001 QA system with identical laser-weld and helium-leak workflow | — |
8.Module Combinations & Options
| Item | Description | Applicability |
| C module — Load break switch | Ring in/out with three positions (close–isolate–earth) | ring unit |
| F module — Switch-fuse combination | Transformer protection with current-limiting fuse | transformer feeder |
| V module — Vacuum circuit breaker | Feeder or transformer protection, 31.5 kA breaking, with numerical relay | feeder/incomer |
| De module — Disconnector / earthing | Isolation and maintenance earthing | maintenance isolation |
| PT module — Voltage transformer | Plug-mounted externally to the gas compartment for metering and protection voltage | metering/protection |
| Surge arrester (plug-in external) | Plug-mounted externally to the gas compartment for overvoltage protection | overvoltage protection |
| Inner-cone socket on breaker compartment | Allows parallel connection of multiple cables and connection of PTs, arresters and other accessories | cable connection |
| Ring-core current transformer | Sleeved onto the cable and fastened to the frame for easy installation and replacement | protection/metering |
| Side-expandable busbar connector (extensibility) | Plug-in side connection between cabinets, extensible without de-gassing | extension |
| SF6 density monitor (optional) | Temperature-compensated type with alarm and lockout contacts | gas monitoring |
| Internal arc class IAC A-FLR (optional) | With pressure-relief ducts, per IEC 62271-200 Annex AA | Situations with high personal safety requirements |
| Eco-gas option (on request) | N₂ / dry-air blend replacing SF6 (subject to confirmed supply capability) | Low emission requirements market |
| IP54 enclosure (optional) | Gasketed door with rain louvre and filter, for dusty or outdoor coastal sites | outdoor/dusty |
| Intelligent control & protection unit | Integrated control, protection, measurement and communication supporting distribution automation | distribution automation |
