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ZCW Series 72.5kV / 126.5kV Outdoor SF6 Hybrid Switchgear (Open-Type)
Product Overview
The ZCW Series Outdoor SF₆ Hybrid Switchgear (Open-Type) is a highly integrated high-voltage switchgear solution designed for 72.5kV and 126.5kV three-phase AC transmission and distribution systems. Utilizing air as the external insulation medium and SF₆ gas for arc extinction, it combines multiple primary switching components into a compact outdoor assembly for reliable power system control and protection.
The ZCW Series integrates the SF₆ circuit breaker, disconnect switch, earthing switch, current transformer (CT), busbar, and support structure into one complete switching bay. Compared with conventional air-insulated substations (AIS), it significantly reduces installation space while maintaining excellent accessibility and operational flexibility.
It is widely used for line switching, transformer protection, bus couplers, capacitor bank switching, and substation automation, making it an ideal solution for urban compact substations, industrial power systems, renewable energy projects, and mountain substations where installation space is limited.
Model Designation
ZCW□-72.5 (126.5)/T3150-40
| Code | Description |
|---|---|
| ZC | SF₆ Hybrid Switchgear |
| W | Outdoor Type |
| □ | Design Series |
| 72.5 | Rated Voltage (126.5kV Optional) |
| T | CT26 Spring Operating Mechanism |
| 3150 | Rated Current: 3150A |
| 40 | Rated Short-Circuit Breaking Current (Standard: 31.5kA) |
Key Features
Highly Integrated Hybrid Switchgear Design
The ZCW Series combines multiple primary electrical components into a single compact switching bay, including:
SF₆ Circuit Breaker
Disconnect Switch
Earthing Switch
Current Transformer (CT)
Busbar System
Steel Support Structure
Compared with conventional AIS layouts, the integrated design reduces substation footprint to 30–50%, significantly lowering civil construction costs while simplifying installation.
Factory-Assembled Modular Construction
Each switching bay is completely assembled, tested, gas-filled, and factory commissioned before shipment.
Advantages include:
Factory-tested quality
Reduced on-site assembly
Minimal commissioning work
Shorter project schedules
Lower installation costs
Only foundation fixing, cable connection, and secondary wiring are required on site.
Reliable SF₆ Switching Technology
The circuit breaker utilizes advanced SF₆ arc-extinguishing technology to provide:
Excellent dielectric insulation
High short-circuit interruption capability
Stable switching performance
Long electrical endurance
Reliable capacitor bank switching
No restrike during capacitive switching
The optimized interrupter design ensures dependable operation under severe transmission system conditions.
Maintenance-Free Primary Components
The breaker interrupter and disconnect switch contacts are designed for long-term maintenance-free operation.
Additional reliability features include:
Factory-installed self-supporting busbars
Sealed SF₆ gas chamber
Annual leakage rate below 0.5%
Online gas density monitoring
Reduced maintenance workload
Flexible Substation Configuration
The modular structure supports various substation layouts, including:
Single busbar systems
Double busbar systems
Bus coupler arrangements
Transformer feeder bays
Transmission line bays
The circuit breaker can be removed as a complete assembly, allowing maintenance or replacement in as little as three hours, greatly reducing outage duration.
Technical Specifications
Electrical Ratings
| Item | Specification |
|---|---|
| Rated Voltage | 72.5kV (126.5kV Optional) |
| Rated Frequency | 50Hz |
| Rated Current | 3150A |
| Rated Short-Circuit Breaking Current | 31.5kA (40kA Optional) |
| Rated Short-Circuit Making Current (Peak) | 80kA |
| Rated Short-Time Withstand Current | 31.5kA / 4s |
| Rated Peak Withstand Current | 80kA |
| First-Pole-to-Clear Factor | 1.5 |
| Out-of-Phase Breaking Current | 8kA |
| Line Charging Switching Current | 10A |
| Operating Sequence | O–0.3s–CO–180s–CO |
| Main Circuit Resistance | Factory Tested |
| Mechanical Life | 10,000 Operations |
| Radio Interference Voltage | ≤500μV |
Insulation Performance
| Item | Specification |
|---|---|
| Power Frequency Withstand Voltage (to Ground) | K × 160kV |
| Power Frequency Withstand Voltage (Across Open Contacts) | K × 200kV |
| Lightning Impulse Withstand Voltage (to Ground) | K × 350kV |
| Lightning Impulse Withstand Voltage (Across Open Contacts) | K × 410kV |
| Power Frequency Withstand Voltage at Zero SF₆ Pressure | K × 84kV |
| Creepage Distance (Across Contacts) | 2585mm |
| Creepage Distance (to Ground) | 2248mm |
Altitude Correction Factor
| Installation Altitude | K Factor |
|---|---|
| 2000m | 1.13 |
| 3000m | 1.28 |
SF₆ Gas Characteristics
| Item | Specification |
|---|---|
| Rated Gas Pressure (20°C) | 0.5MPa |
| Alarm Pressure | 0.45±0.03MPa |
| Annual Leakage Rate | <0.5% |
| Moisture Content | ≤150×10⁻⁶ (V/V) |
| SF₆ Gas Weight | 10kg |
CT26 Spring Operating Mechanism
| Item | Specification |
|---|---|
| Auxiliary Voltage | DC110V / DC220V |
| Closing & Trip Coil Voltage | DC110V / DC220V |
| Energy Storage Motor | AC110V / AC220V / DC110V / DC220V |
| Motor Operating Voltage | 85–110% Rated Voltage |
| Motor Power | 600W |
| Charging Time | ≤15s |
| Heater Voltage | AC220V |
| Auxiliary Contact Rating | 10A |
| Auxiliary Contacts | 10 NO + 10 NC |
Mechanical Performance
| Item | Specification |
|---|---|
| Pole Spacing | 1200mm |
| Contact Stroke | 120±3mm |
| Contact Travel | 25±2mm |
| Opening Speed | 4.2–5.0m/s |
| Closing Speed | 2.2–3.0m/s |
| Opening Time | ≤40ms |
| Closing Time | ≤100ms |
| Total Breaking Time | ≤60ms |
| Close-Open Time | ≤80ms |
| Open-Close Interval | 300ms |
| Three-Phase Opening Synchronism | ≤2ms |
| Three-Phase Closing Synchronism | ≤3ms |
Installation Data
| Item | Specification |
|---|---|
| Total Assembly Weight | 1500kg |
| Wind Load Area | 4.5m² |
| Pole Spacing | 1200mm |
| Mounting Holes | 4 × Φ18mm |
| Foundation | Standard Reinforced Concrete Base |
The operating mechanism cabinet is mounted on one side, while the circuit breaker, disconnect switch, earthing switch, and built-in CT are integrated into a compact outdoor structure.
Typical Applications
The ZCW Series Outdoor SF₆ Hybrid Switchgear is ideal for:
Compact urban substations
Utility transmission substations
Industrial substations
Renewable energy substations
Wind and solar power plants
Mountain and remote substations
Bus coupler applications
Transformer feeder bays
Capacitor bank switching
Grid modernization and substation expansion projects
Why Choose the ZCW Series?
Highly integrated SF₆ hybrid switchgear combining circuit breaker, disconnect switch, earthing switch, CT, and busbar
30–50% smaller footprint than conventional AIS switchgear
Factory-assembled modular design for faster installation
72.5kV and 126.5kV voltage options
Rated current up to 3150A
Short-circuit breaking current up to 40kA
Mechanical life of 10,000 operations
Annual SF₆ leakage rate below 0.5%
Fast maintenance with complete breaker replacement in as little as 3 hours
Flexible configuration for single-bus, double-bus, and transformer feeder applications
Ideal for space-constrained substations and modern transmission projects
Customization Services
Weisho Electric offers complete customization services for utility and EPC projects, including:
72.5kV or 126.5kV voltage ratings
Rated current and breaking capacity options
CT ratios and accuracy classes
Auxiliary and control voltage configurations
Single-bus or double-bus layouts
Anti-pollution insulation options
OEM and private labeling
FAT testing and complete technical documentation
Engineering support for IEC, ANSI, and project-specific standards
The ZCW Series provides a compact, reliable, and cost-effective solution for modern high-voltage substations requiring superior performance, reduced footprint, and simplified maintenance.
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