Overview
The ZW32-12G is a three-phase 12kV, 50Hz outdoor high-voltage vacuum circuit breaker engineered for urban and rural overhead distribution networks. It reliably interrupts load, overload and short-circuit currents and, with its integrated isolating switch (G), provides a visible break point for safe maintenance isolation and frequent operation.
The vacuum interrupter is combined with a spring operating mechanism (T) for manual and electric operation, and can be paired with a controller to form an automatic recloser with remote control, measurement, signalling and fault isolation. The compact, maintenance-free, fire- and explosion-free design suits harsh outdoor duty from -40 degC to +40 degC and altitudes up to 3000 m.
Model Designation
- ZW: Outdoor Vacuum Circuit Breaker
- 32: Design Sequence Number
- 12: Rated Voltage (kV)
- G: With Isolating (Disconnector) Switch
- T: Spring Operating Mechanism
- 630: Rated Current (A)
- 20: Rated Short-Circuit Breaking Current (kA)
- S / D: Manual / Electric Operation
Construction
Each phase uses a vacuum interrupter with outdoor-grade insulation mounted on a hot-dip galvanised common frame, driven by a spring mechanism that supports both automatic and manual operation. The built-in isolating switch gives a clear visible break, while an overcurrent release (5 A, +/-10%) and control/auxiliary circuits rated DC220/AC220 with 2000 V power-frequency withstand enable intelligent protection and remote automation on 10kV overhead lines.
Technical Parameters
Service Conditions
- Ambient Temperature: -40 degC to +40 degC
- Altitude: <=3000 m
- Wind Pressure: <=700 Pa (equivalent to wind speed 34 m/s)
- Air Pollution Degree: <=IV
- Ice Cover Thickness: <=10 mm
- Installation Site: No fire, explosion, chemical corrosion or severe vibration
Technical Data
| No. | Item | Unit | Parameter |
|---|---|---|---|
| 1 | Rated voltage | kV | 12 |
| 2 | Rated frequency | Hz | 50 |
| 3 | Rated current | A | 630 |
| 4 | Rated short-circuit breaking current | kA | 12.5 / 16 / 20 |
| 5 | Rated short-circuit making current (peak) | kA | 50 |
| 6 | Rated peak withstand current | kA | 50 |
| 7 | Rated short-time withstand current (4 s) | kA | 20 |
| 8 | 1 min power-frequency withstand voltage | kV | Dry 42 (phase-to-phase/earth), 48 (across open contacts); Wet 34 |
| 9 | Lightning impulse withstand voltage (peak) | kV | 75 (phase-to-phase/earth), 85 (across open contacts) |
| 10 | Rated operating sequence | – | O-0.3s-CO-180s-CO |
| 11 | Closing / opening time | ms | 25~50 / 15~50 |
| 12 | Number of rated short-circuit breaking operations | times | 30 |
| 13 | Mechanical life | times | 10000 |
| 14 | Control & auxiliary circuit 1 min power-frequency withstand | V | 2000 |
| 15 | Rated operating / auxiliary circuit voltage | V | DC220 / AC220 |
| 16 | Overcurrent release rated current / accuracy | A / % | 5 / +/-10 |
Installation & Wiring
Installation Diagram
The ZW32-12G is designed for standard pole-mounted outdoor installation on a hot-dip galvanised frame, with the isolating switch operating links and mechanism accessible for manual operation. Adequate clearance must be maintained around the unit for safe switching and maintenance, and all primary and secondary connections must comply with local utility standards. The certified outline and mounting dimension drawing is supplied with each unit.
Outline Dimensions
| Dimension | Value |
|---|---|
| Total height | 760 mm |
| Total width (incl. bushings) | 990 mm |
| Base / frame width | 920 mm |
| Phase spacing (adjacent poles) | 340 mm |
| Overall depth (side view) | 790 mm |
| Mounting hole span (W × D) | 460 × 225 mm |
| Bushing flange width | 160 mm |
| Insulator mounting span | 360 mm |
| Pole-mounting bolt holes | 4 × Φ13 mm |
Selection & FAQs
Selection Guide
- Confirm a 12kV, 50Hz three-phase overhead network and the 630A rated current after load assessment.
- Select the breaking rating (12.5 / 16 / 20 kA) above the prospective fault current and verify the matching making and withstand ratings.
- Decide whether the isolating switch (G) and spring mechanism (T) are required for visible break and frequent operation.
- Specify manual (S) or electric (D) operation, control voltage DC220/AC220, and the controller for reclosing and four-remote automation.
- Check outdoor duty: -40 to +40 degC, altitude <=3000m, wind pressure <=700Pa, pollution degree <=IV and ice thickness <=10mm.
Frequently Asked Questions
Q1: What is the ZW32-12G used for?
It is a 12kV outdoor pole-mounted three-phase vacuum circuit breaker for switching and protecting overhead distribution lines; the G adds an integrated isolating switch that gives a visible break point for safe maintenance isolation.
Q2: What ratings are available?
Rated current is 630A with a rated short-circuit breaking current of 12.5, 16 or 20kA, a 20kA 4s short-time withstand current, and 50kA peak making and withstand currents.
Q3: What does the G in the model mean?
G indicates an integrated isolating (disconnector) switch. It provides a clear visible break in addition to the breaker contacts, improving safety during line inspection and sectionalizing.
Q4: Can it work with a controller for automation?
Yes. Paired with a controller the ZW32-12G forms an automatic recloser offering remote control, measurement, signalling and automatic fault isolation, supporting three-phase protection on 10kV lines.
Q5: What insulation level does it provide?
The 1-minute power-frequency withstand voltage is 42kV dry (48kV across the open contacts) and 34kV wet, and the lightning impulse withstand voltage is 75kV (85kV across the open contacts).
Q6: What are the service conditions?
Ambient temperature from -40 degC to +40 degC, altitude up to 3000m, wind pressure up to 700Pa (34m/s), air pollution degree up to IV and ice thickness up to 10mm.