Product Overview
The FZW28-12 outdoor high-voltage vacuum load break switch is engineered for 12kV, 50Hz three-phase AC power distribution systems. It reliably handles normal load currents, overload conditions and short-circuit faults, making it ideal for substations, industrial plants, rural grid protection and automated distribution networks requiring frequent switching. Built with a vacuum interrupter integrated into a sealed control unit via aviation connectors and control cables, it accurately detects and isolates both interphase and zero-sequence fault currents – whether local or downstream – ensuring robust performance across diverse outdoor environments and neutral grounding configurations.
Product Display
Model Designation
Model format: FZW28-12/T 630-20
- FZW: Outdoor Vacuum Load Break Switch
- 28: Design Sequence Number for the Product Series
- 12: Rated Voltage (kV)
- /T: Spring-Operated Mechanism
- 630: Rated Current (A)
- 20: Rated Short-Time Withstand Current (kA)
Service Conditions
- Ambient Temperature: -40 degC to +45 degC
- Altitude:
- Relative Humidity:
- Pollution Degree: Class III
- Installation Environment: Outdoor, no explosive or corrosive gases, no severe vibration or shock
Construction
The FZW28-12 features automatic locking upon phase-to-phase short-circuit faults: after a substation breaker or recloser trips due to a downstream fault, the switch trips and locks out, enabling rapid isolation of the faulty branch and fast reclosing of the main feeder to restore power to healthy sections; it also supports quick fault location through user outage reports and handheld diagnostic tools.
For single-phase ground faults on user branch lines, the switch instantly isolates the affected segment while maintaining continuity for the rest of the network. Its rugged, sealed design ensures reliable operation under various neutral grounding schemes – including solidly grounded, resistance grounded and ungrounded systems.
Technical Data
| Parameter | Value |
|---|---|
| Rated Voltage | 12 kV |
| Rated Frequency | 50 Hz |
| Rated Current | 630 A |
| Rated Short-Circuit Breaking Current | 20 kA |
| Rated Short-Time Withstand Current (3s) | 20 kA |
| Rated Peak Withstand Current | 50 kA |
| Power Frequency Withstand Voltage (1 min) | 42 kV (between phases and earth); 48 kV (across open contacts) |
| Lightning Impulse Withstand Voltage (peak) | 75 kV (between phases and earth); 85 kV (across open contacts) |
| Mechanical Life | >=10000 operations |
| Electrical Life (at rated current) | >=10000 operations |
Standards
The FZW28-12 is designed and type-tested to IEC 62271-103 and GB/T 16926 for high-voltage alternating-current load break switches, covering making and breaking capacity, insulation level and mechanical endurance.
Installation & Dimensions
Installation Diagram
The FZW28-12 is designed for pole-mounted installation using standard brackets. Adequate clearance must be maintained around the unit to ensure safe operation and ease of maintenance. All electrical connections must comply with local utility standards and national electrical codes.
| Dimension | Value (mm) |
|---|---|
| Total Height | 1320 |
| Width (phase spacing) | 300 |
| Depth | 580 |
| Mounting Hole Spacing (vertical) | 400 |
| Mounting Hole Spacing (horizontal) | 220 |
| Weight | 85 kg |