Huanghua Group Co., Ltd. 
KYN61-40.5(Z) Metal-Clad AC Enclosed Switchgear, Withdrawable Type
Product Overview
The KYN61-40.5(Z) metal-clad AC enclosed withdrawable switchgear (“switchgear”) is Huanghua Group’s next-generation medium-voltage assembly for 40.5 kV power transmission and distribution systems. Rated voltage 40.5 kV, rated current up to 2,000 A (2,500 A on request), rated short-circuit breaking current 20 / 25 / 31.5 kA, designed and type-tested to IEC 62271-200. Its armoured, four-compartment, centrally-mounted withdrawable truck design is widely used in power plants, substations, industrial plants and renewable energy stations for power receiving and distribution, providing control, protection and measurement.
Suitable for power receiving, distribution, and the control and protection of motors, transformers and capacitor banks in 40.5 kV systems of power plants, substations, industrial and mining enterprises, rail transit, and renewable (wind / PV / BESS) step-up substations.
Type Designation
Key Highlights
| Highlight | Description |
| IEC-Compliant Metal-Clad Design | Fully armoured with four segregated compartments (VCB / busbar / cable / instrument), separated by metallic partitions with pressure-relief ducts, meeting IEC 62271-200 for metal-enclosed switchgear. |
| Reliable Vacuum Interruption | Fitted with the ZN85-40.5 vacuum circuit breaker: mechanical endurance 10,000 operations, opening time ≤0.07 s, spring-mechanism closing time ≤0.15 s, operating sequence O-0.3 s-CO-180 s-CO. |
| Five-Prevention & IEC Interlocks | Five-prevention interlocking (mis-operation, on-load racking, earthing on live circuit, energising with earthing switch closed, access to live compartment) plus all mandatory interlocks of IEC 62271-200. |
| Generous Creepage & Insulation Margin | Phase-to-phase / phase-to-earth creepage ≥720 mm (pollution degree III), 95 kV / 1 min power-frequency withstand, 185 kV lightning impulse withstand, 2,000 V / 1 min on auxiliary and control circuits. |
| Three-Position Truck, Easy Maintenance | VCB truck offers Connected – Test – Disconnected positions, front-operated racking in/out, fully interchangeable trucks of the same rating; maintenance without de-energising adjacent circuits. |
| Comprehensive Schemes & Customisation | More than 24 single-line schemes (001–024+) covering overhead and cable in/outgoing feeders, left/right bus-tie, PT and metering; customised high-altitude, low-temperature (-25 to +45 °C), higher IP and internal-arc (IAC A-FLR) designs available. |
Product Features
| Feature | Detailed Description |
| Armoured Withdrawable Architecture | Enclosures are built from CNC-processed aluminium-zinc coated sheet or quality steel plate, assembled with bolts/rivets for high strength, corrosion resistance and dimensional stability; the circuit breaker is a centrally-mounted withdrawable truck. |
| Four Segregated Compartments | VCB, busbar, cable and instrument (LV) compartments are independent, separated by metallic partitions with dedicated pressure-relief ducts, confining any internal arc to a single compartment. |
| VCB & Operating Mechanism | Equipped with the ZN85-40.5 (VS1 series) vacuum circuit breaker with either electromagnetic or spring operating mechanism, electrical and manual emergency operation; mechanical endurance 10,000 operations. |
| Five-Prevention Mechanical Interlock | Mandatory mechanical interlocks and key-exchange procedures between truck, circuit breaker, earthing switch and door eliminate the five categories of mis-operation. |
| High-Creepage Insulation System | Tin-plated electrolytic copper busbars on SMC/DMC insulators and epoxy post insulators, phase-to-phase / phase-to-earth creepage ≥720 mm, suitable for pollution degree III. |
| Earthing Switch & Earthing System | The cable compartment earthing switch provides both maintenance earthing and fault-making capability; the frame PE bus is continuous and bonded to the substation earth grid. |
| Secondary & Intelligent Interface | The instrument compartment accommodates numerical protection relays, energy meters, live-line indicators and SCADA interfaces; secondary wiring runs in dedicated ducts with clear marking for easy commissioning. |
| IP Rating & Internal Arc | Enclosure degree of protection IP3X, IP2X with compartment door open; higher IP ratings and internal-arc classification to IEC 62271-200 Annex AA (IAC A-FLR, 1 s) available on request. |
| Installation & Maintenance Convenience | Front operation and maintenance, generous bottom cable-entry space, well-laid-out CTs, surge arresters and live-line indicators; standard foundation drawings simplify on-site lineup. |
| Scheme Flexibility & Customisation | Selectable schemes 001–024+ for incomer, outgoing, bus-tie, tie, PT/metering and capacitor circuits; special versions for low temperature, high altitude, salt mist and higher ingress protection. |
Technical Parameters
1.Switchgear Panel Parameters
| Parameter | Unit | Data | Standard & Remark |
| Rated voltage | kV | 40.5 | IEC 62271-200；Um = 36kV（IEC 62271-1） |
| Rated frequency | Hz | 50（ 60 Hz customised） | GB/T 11022；50/60Hz |
| Rated current of main busbar | A | 1250，1600，2000，(2500) | values in brackets: customised |
| Rated current of matched VCB | A | 1250，1600，2000，(2500) | higher ratings on request |
| 1 min power-frequency withstand voltage (rms) | kV | 95 | type-tested value |
| Lightning impulse withstand voltage (peak) | kV | 185 | BIL 185kV, insulation coordination with 40.5kV transformer |
| Power-frequency withstand voltage of auxiliary & control circuits | V / 1 min | 2000 | Secondary circuit insulation level |
| Rated short-circuit breaking current | kA | 20 / 25 / 31.5 | IEC 62271-100（VCB） |
| Rated short-time withstand current / duration | kA / 4 s | 20 / 25 / 31.5 | Icw 4s |
| Rated peak withstand current | kA | 50 / 63 / 80* | *80kA subject to configuration |
| Rated short-circuit making current | kA | 50 / 63 / 80* | *80kA subject to configuration |
| Rated voltage of control circuit | V | DC 110 / 220；AC 110 / 220 | as specified in order |
| Degree of protection — switchgear enclosure | — | IP3X | IEC 60529； higher IP optional |
| Degree of protection — compartments (door open) | — | IP2X | IEC 60529 |
| Creepage distance (phase-phase / phase-earth) | mm | ≥720 | pollution degree III |
| Internal arc classification | — | IAC A-FLR（on request） | IEC 62271-200 31.5kA 1s |
| Compartmentalisation | — | Four compartments: Circuit breaker/Busbar/Cable/Instrumentation | 4 compartments: VCB / busbar / cable / instrument |
| Interlocking | — | Five-proof mechanical interlock + IEC forced interlock | Five-prevention (GB 3906) + IEC mandatory interlocks |
| Enclosure material & construction | — | Aluminized zinc plate / high-quality steel plate assembly | Al-Zn coated sheet or steel plate, CNC-assembled |
| Typical panel width | mm | 1400 (Standard) / 1680 (KYN61A Wide Type) | subject to outline drawing |
| Typical panel depth | mm | 2800 | subject to outline drawing |
| Cable / busbar entry | — | Overhead incoming/outgoing lines / Cable incoming/outgoing lines / Busbar connections | Overhead or cable in/outgoing, bus-tie |
2.Vacuum Circuit Breaker Parameters (ZN85-40.5)
| Parameter | Unit | Data |
| Rated voltage | kV | 40.5 |
| Rated current | A | 1250，1600，2000，(2500) |
| Rated frequency | Hz | 50 |
| Rated short-circuit breaking current | kA | 20 / 25 / 31.5 |
| Rated short-circuit making current | kA | 50 / 63 / 80 |
| Rated peak withstand current | kA | 50 / 63 / 80 |
| Rated short-time withstand current / duration | kA / 4 s | 20 / 25 / 31.5 |
| 1 min power-frequency withstand voltage (rms) | kV | 95 |
| Lightning impulse withstand voltage | kV | 185 |
| Power-frequency withstand voltage of auxiliary & control circuits | V / 1 min | 2000 |
| Mechanical life (endurance) | operations | 10000 |
| Closing time — electromagnetic mechanism | s | ≤0.2 |
| Closing time — spring mechanism | s | ≤0.15 |
| Breaking (opening) time | s | ≤0.07 |
| Rated operating sequence | — | O-0.3s-CO-180s-CO |
| Truck positions | — | Connected / Test / Disconnected |
3.Normal Service Conditions
| Item (EN) | Unit | Data |
| Ambient air temperature | ℃ | -15 ~ +40 |
| Altitude | m | ≤1000 |
| Relative humidity — daily average | % | ≤95 |
| Relative humidity — monthly average | % | ≤90 |
| Water vapour pressure — daily average | kPa | ≤2.2 |
| Water vapour pressure — monthly average | kPa | ≤1.8 |
| Earthquake intensity | — | magnitude 8 |
| Installation location | — | Indoor |
| Special environments | — | Customised |
4.Applicable Standards & Testing
| Standard / Test | Code | Scope | Remark |
| AC metal-enclosed switchgear and controlgear | IEC 62271-200 | Cabinet design, type testing and mandatory interlocking | main product standard |
| High-voltage alternating-current circuit breakers | IEC 62271-100 | ZN85-40.5 Vacuum Circuit Breaker | Breaking and closing test basis |
| AC metal-enclosed switchgear 3.6–40.5 kV | GB 3906 | Five-prevention interlocking and domestic engineering acceptance | for domestic projects |
| Common specifications for HV switchgear | GB/T 11022 | Ratings and General Technical Requirements | Corresponding to IEC 62271-1 |
| Degrees of protection provided by enclosures | IEC 60529 (IP code) | IP3X / IP2X Authentication | Dustproof probe ϕ1mm test |
| Power transformers (matching equipment) | IEC 60076-1 | Insulation coordination with 40.5kV transformer | transformer side |
| Low-voltage switchgear assemblies (matching) | IEC 61439-2 | When supplied as a complete set with low-voltage switchgear | matching equipment |
5.Type Tests & Routine Tests
| Test Item | Type | Test Condition | Remark |
| Dielectric test | Type | Power-frequency 95 kV / 1 min; lightning impulse 185 kV (peak) | Applied to earth, between phases and across the open break as required by the standard |
| Short-circuit making and breaking test | Type | 31.5 kA (40 kA on request) | Per IEC 62271-100, carried out with the rated operating sequence O-0.3 s-CO-180 s-CO |
| Short-time and peak withstand current test | Type | 31.5 kA / 4 s (busbars, branch connections and joints) | Verifies dynamic (peak) and thermal withstand of main and earthing circuits |
| Temperature-rise test | Type | Full-load cyclic duty; temperature rise at contacts and joints ≤65 K | Confirms continuous current-carrying capability with stable contact resistance |
| Mechanical endurance (mechanical operation) test | Type | VCB 10,000 operations; withdrawable truck 1,000 operations | Mechanical endurance class C2 (M2 / E2 subject to order confirmation) |
| Internal arc test | Type (on request) | IAC A-FLR, 31.5 kA / 1 s | IEC 62271-200 Annex AA; assesses accessibility type for front, lateral and rear |
| Verification of the degree of protection (IP code) | Type | IP3X (φ1.0 mm test probe, no ingress) | IEC 60529; IP2X with the compartment door open |
| Power-frequency voltage withstand test (each cubicle) | Routine | 85 kV / 1 min (to earth) | Performed on every cubicle before delivery |
| Measurement of the resistance of main and earthing circuits | Routine | DC voltage-drop method; measured value not exceeding the design limit | Performed on every cubicle to verify joints and contacts |
| Mechanical operating and timing (travel) tests | Routine | Opening / closing times, pole synchronism ≤2 ms; travel and clearance | Performed on every cubicle; characteristic curves retained |
| Functional check of interlocks and five-prevention | Routine | Interlocks between truck three positions, circuit breaker, earthing switch and door | Includes IEC 62271-200 mandatory interlocks and GB 3906 five-prevention |
| Inspection of auxiliary wiring, appearance and tightening torque | Routine | Wiring correctness, ferrule marking, tightening torque and overall finish | Performed on every cubicle; critical torque points marked for traceability |
Engineering & Design Excellence
1 Gas Medium & Dielectric Design (the core differentiator)
Unlike SF₆ (εᵣ ≈ 1.002, excellent arc-quenching), dry air / N₂ has lower relative permittivity and arc-quenching capability, requiring compensated design:
Slightly elevated filling pressure (1.4–1.5 bar abs vs. 1.3–1.4 for SF₆) to maintain same Pf / BIL coordination
Enhanced creepage design: creepage ≥ 720 mm (pollution degree III), silicone-based coating on insulators optional for coastal/high-humidity
VCB as primary breaking element (not LBS-alone for feeder duties): dry air/N₂ has weaker arc-quenching than SF₆, so V-module (VCB 31.5 kA) is recommended for transformer/fault protection rather than relying on LBS+fuse alone in high-fault-current sites
Gas composition: dry air (filtered, dew point < –40°C) or N₂ blend — GWP < 1, zero SF₆, zero PFC
Professional nuance: IEC 62271-214 explicitly acknowledges that alternative gases (dry air, N₂, blends) require higher design pressure and/or enhanced contact/insulator geometry vs. SF₆-filled counterparts at same Ur. Huanghua’s 40.5kV eco-gas inherits the 12kV XIHARI-certified pressure-boundary welding + helium-leak workflow, then scales creepage, BIL coordination, and VCB rating per 40.5kV.
2 Welded Stainless-Steel Gas Tank (platform-pedigree shared with 12kV eco-gas & 24kV SF₆ RMU)
304L stainless, laser-welded longitudinal + circumferential seams — same regime as XIHARI-certified 12kV eco-gas
Helium leak test per tank (≤ 0.5% / yr equivalent) — critical because dry air/N₂ leakage = insulation level drop (no SF₆ self-healing effect)
Pressure Relief: Non-rupturable diaphragm, vented to cabinet top
Gas Density Monitor: Temperature-compensated, alarm + lockout at 0.9 / 0.8 bar abs — dry-air/N₂ density directly correlates to dielectric strength, so density monitoring is even more critical than SF₆
3 Switch & Breaking (VCB-prominent architecture)
| Element | Application | Breaking Capacity |
| Load Break Switch (LBS) | C-module (ring in/out), De (earthing) | Load make-break; fault withstand via fuse coordination (F-module) |
| Vacuum Circuit Breaker (VCB) | V-module | 31.5 kA / 25 kA breaking, C2 class (10,000 ops) — recommended primary for transformer protection in eco-gas version |
Three-position LBS: Close – Open – Earth, single handle + mechanical interlock
VCB: VS1 domestic / VD4-compatible, spring mechanism
4 Busbar, Cable & Earthing (architecture inherited from RMU platform)
SF₆-free tank internals: busbars, LBS, VCB, fuse-carrier, ES — all dry-air/N₂ insulated
Extensible via plug-in silver-plated finger contacts, bellows-sealed, field-expandable without de-gassing adjacent bays
Bottom cable entry, CT/PT built-in, De-module earthing per bay
5 Enclosure & Environmental
Outer cabinet: galvanized steel, powder-coated RAL 7035
IP54 outer cabinet on request (coastal / dusty)
Anti-condensation heater (cabinet compartment)
Operating temperature: –40°C to +70°C (tank); cabinet electronics –25°C to +55°C (heater-assisted)
