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The ZW8-12 Vacuum Circuit Breaker guide is a high-performance outdoor switchgear designed for AC 50Hz, 10–12kV three-phase power systems. As a key component in modern power distribution networks, it provides reliable load switching, overload protection, and short-circuit interruption. Engineered to operate efficiently in harsh outdoor environments, the vacuum circuit breaker is ideal for applications in power utilities, rural substations, industrial grids, and smart distribution systems.
Compliant with IEC 62271-100, the ZW8-12 series supports modular enhancements such as disconnector integration, surge protection, automatic reclosers, and power electronics PT modules for intelligent automation and remote control.

Key Features of ZW8-12 Vacuum Circuit Breaker
- Vacuum Interruption Technology: Provides fast, arc-free switching for load and fault currents.
- Modular Upgrade Options: Compatible with surge arresters, isolators, reclosers, automation metering, and dual power switching devices.
- Wide Operating Range: Can operate in extreme outdoor temperatures, up to 2000 meters altitude, with high wind and seismic resistance.
- Intelligent Variants: Versions like ZW8-12/C, ZW8-12/PT, and ZW8-12/ePT offer smart fault detection, recloser functionality, and energy-autonomous operation.
- Long Service Life: Rated for 10,000 mechanical operations and 50 short-circuit breaking cycles.

Application Scenarios
The ZW8-12 Vacuum Circuit Breaker is used across various utility and industrial sectors:
- Rural and urban medium-voltage distribution networks
- Pole-mounted outdoor breaker stations
- Renewable energy and small hydropower grid connections
- Smart grid automation and fault isolation
- Substations and ring main units requiring recloser functionality

Technical Parameters of ZW8-12 Vacuum Circuit Breaker
Item | Unit | Parameter |
---|---|---|
Rated Voltage | kV | 12 |
Power Frequency Withstand Voltage (1 min) | kV | 42 |
Lightning Impulse Withstand Voltage (Peak) | kV | 75 |
Rated Frequency | Hz | 50 / 60 |
Rated Current | A | 630 / 1250 |
Rated Short-Circuit Breaking Current | kA | 20 |
Rated Short-Time Withstand Current (RMS) | kA | 20 |
Rated Peak Withstand Current | kA | 50 |
Rated Short-Circuit Closing Current | kA | 50 |
Capacitor Bank Breaking Current (Single/Back-to-Back) | A | 630 / 400 |
Short-Circuit Duration | s | 4 |
Short-Circuit Breaking Times | Times | 50 |
Main Circuit Resistance | μΩ | ≤120 (≤200 with isolator) |
Operating Voltage | V DC | 220 |
Mechanical Life | Times | 10,000 |
Overcurrent Setting Range | A | 1–10 |
Quick-Break Current Range | A | 6–20 |
Delay Time Range | ms | 40–850 |
Remote Control Distance | m | >30 |
Reclose Times | Times | 0–3 |
Operating Sequence | – | O-0.3s-CO-180s-CO |
ZW8-12 Product Variants
ZW8-12/T Type
The standard model with a spring operating mechanism. It can be combined with isolators and lightning arresters. The silicon rubber jacket provides weather resistance and anti-corrosion. Ideal for grid protection in challenging environments.
ZW8-12/C Type
Intelligent recloser type, equipped with a controller for automatic power recovery after transient faults. Supports single or multiple reclosing operations, inrush current control, and short-circuit fast breaking. Suitable for radial or ring power systems.
ZW8-12/PT Type
Includes a voltage transformer drawing power from the high-voltage line, supplying 220V/110V/100V for the breaker or other devices. Perfect for small hydro stations and rural substations with autonomous operation.
ZW8-12/ePT Type
Equipped with electronic PT and battery charging via CTs. Supports operation during power loss, integrates inrush control, overcurrent, and short-circuit protection. Allows wired or wireless remote control and is ideal for smart grid deployments.
The ZW8-12 Vacuum Circuit breaker guide offers a robust, modular, and intelligent solution for outdoor medium-voltage power protection. With multiple variants and upgrade options, it meets the needs of modern power distribution systems requiring fast fault clearing, automation, and long-term durability. Whether used in basic overload protection or full-featured smart grid applications, this vacuum circuit breaker ensures safety, reliability, and operational flexibility in all weather and load conditions.