Overview
The ZN85-40.5 series indoor high-voltage vacuum circuit breaker (hereinafter referred to as the circuit breaker) is suitable for three-phase AC 50Hz power systems with a rated voltage of 40.5kV, used in industrial mines, power plants and substations for switching load current, overload current and fault current. The circuit breaker and its operating mechanism adopt a vertical arrangement, effectively reducing the depth of the breaker. The three-phase arc-extinguishing chambers and associated live parts are isolated by three independent epoxy-resin insulation tubes, forming a composite insulation structure that meets the air clearance and creepage distance requirements under normal operation and effectively reduces the breaker size. The main conductive circuit, vacuum interrupter and fixed/moving conductive connections are installed inside the insulation tubes, making the phase pitch only 300mm. All main-circuit electrical connections adopt fixed connections, giving high reliability. The insulation tubes are mounted above the breaker frame. The spring operating mechanism specially designed for this new breaker is installed inside the frame; its structural features suit the vertical arrangement and form an integral part of the breaker. The mechanism is simple, and its output curve and performance better match the characteristics and requirements of the 40.5kV vacuum circuit breaker. The overall layout is rational, elegant and concise, with a compact size, flexible operation, reliable electrical performance, long service life, easy maintenance and a maintenance-free mechanism. This ZN85-40.5 vacuum circuit breaker is suitable for frequent-operation and harsh-condition sites.
Type Designation
Outline and Mounting Dimensions
The main technical parameters of the ZN85-40.5 vacuum circuit breaker are listed in the table below. The ZN85-40.5 vacuum circuit breaker is rated 40.5 kV with rated currents of 1250 A, 1600 A and 2000 A, a 4 s rated short-time withstand current of 25/31.5 kA and a rated peak withstand current of 63/80 kA, with a 1 min power-frequency withstand voltage of 95 kV and a lightning impulse withstand voltage of 185 kV.
| Item | Unit | Data |
|---|---|---|
| Rated voltage | kV | 40.5 |
| 1 min power-frequency withstand voltage (r.m.s.) | kV | 95 |
| Lightning impulse withstand voltage (peak) | kV | 185 |
| Rated frequency | Hz | 50 |
| Rated current | A | 1250,1600,2000 |
| Rated short-time withstand current | kA | 25,31.5 |
| Rated peak withstand current | kA | 63,80 |
| Rated short-circuit duration | s | 4 |
| Rated short-circuit breaking current | kA | 25,31.5 |
| Rated short-circuit making current | kA | 63,80 |
| Rated operating sequence | O-0.3s-CO-180s-CO | |
| Breaking time | ms | <80 |
| Number of rated short-circuit breaking operations | times | 20 |
| Single capacitor-bank breaking current | A | 630 |
| Back-to-back capacitor-bank breaking current | A | 400 |
| Rated operating voltage | AC110,220;DC110,220 | |
| Mechanical endurance | times | 10000 |
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