ZN28A-12/630A, ZN28-10kV/630A Indoor High Voltage Vacuum Circuit Breaker | 12kV Indoor High Voltage Switchgear

Overview

ZN28-12 Series Vacuum Circuit Breaker is an AC high voltage indoor switchgear with rated voltage 12kV, three-phase AC 50Hz, compliant with GB1984-89 standard. The overall structure of this product is available in two forms: switch body and operating mechanism integrated installation, or switch body and operating mechanism separate installation. The integrated structure is the ZN28-12 basic type; the separate structure is the ZN28A-12 type, suitable for various fixed-type switchgear such as GG-1A(Z), XGN2A10(Z), etc.

ZN28A-12/630A, ZN28-10kV/630A Indoor High Voltage Vacuum Circuit Breaker can be matched with CD17, CD10A DC electromagnetic operating mechanisms and CT17, CT19 spring charging operating mechanisms.

Service Environment Conditions

• Altitude: 2000m and below (2500m for plateau type);
• Ambient temperature: upper limit +40degC, lower limit -15degC (allowed for storage and transportation at -30degC);
• Relative humidity: daily average ≤95%, monthly average ≤90%; daily average water vapor pressure ≤2.2kPa; monthly average water vapor pressure ≤1.8kPa; condensation may occur during rapid temperature drops in high humidity periods;
• Surrounding air is not significantly polluted by dust, smoke, corrosive and flammable gases, steam or salt spray;
• Seismic intensity not exceeding 8 degrees;
• No fire, explosion, severe pollution or severe vibration at the place of use.

Model and Meaning

Product Structure and Working Principle

◆ This product itself does not come with an operating mechanism; a suitable operating mechanism must be used during operation.

This product is equipped with a center-sealed axial magnetic field vacuum interrupter, main shaft, opening spring, oil buffer and other components installed in the frame. The rear end of the rack has mounting holes for fixing the circuit breaker. Six large creepage distance insulators are horizontally installed on the front of the rack. The upper insulator fixes the stationary support, and the lower insulator fixes the moving support. The front part of the stationary and moving supports also serves as incoming/outgoing terminals. The vacuum interrupter is installed between the stationary and moving supports. The main shaft is connected to the moving rod of the vacuum interrupter through insulating rods and crank arms. A large creepage distance insulating rod is also installed between the stationary and moving supports, connecting them together and improving overall rigidity.

◆ Working Principle

The vacuum circuit breaker is equipped with a center-sealed axial magnetic field vacuum interrupter. When the moving and stationary contacts are opened under voltage by the operating mechanism, a vacuum arc burns in the contact gap and extinguishes at current zero crossing. Due to the special contact structure, an appropriate axial magnetic field is generated in the contact gap during arcing. This magnetic field can distribute the arc evenly on the contact surface, maintain a low arc voltage, and give the vacuum interrupter a high post-arc dielectric strength recovery speed, low arc energy and low electrical erosion rate, thereby improving the circuit breaker's short-circuit current breaking capacity and electrical life.

Main Technical Parameters

Outline and Installation Dimensions