Structural Features
The circuit breaker, disconnecting switch, grounding switch, current transformer, busbar, and other components are organically combined on a grounded steel frame, resulting in a compact structure. It occupies only 30%-50% of the space compared to a separate-type configuration, offering significant advantages such as land savings and reduced construction costs.
The entire compartment is prefabricated in the factory, with assembly and all commissioning completed before shipment, allowing for transportation as a complete unit to the installation site. This greatly shortens the installation period. The design utilizes highly proven, high-performance arc-extinguishing chambers and disconnecting switches, which require minimal maintenance and have high reliability.
The self-supporting busbar, prefabricated in the factory, eliminates the need for the user to build a frame. The layout is flexible and can accommodate various wiring configurations. The circuit breaker can be fully lowered for maintenance or replacement. In the event of a failure, the downtime can be reduced to less than 3 hours, minimizing power outages.
Main Technical Parameters of Circuit Breaker
| No. | Name | Unit | Parameter |
| 1 | Rated voltage | kV | 72.5 |
| 2 | Rated power frequency withstand voltage (1 Minute) – Grounded | kV | 160 |
| Rated power frequency withstand voltage (1 Minute) – Contact gap | kV | 200 | |
| 3 | Rated lightning impulse withstand voltage – Grounded | kV | 350 |
| Rated lightning impulse withstand voltage – Contact gap | kV | 410 | |
| 4 | Power frequency withstand voltage of SF6 gas at zero gauge pressure (5 min) | kV | 84 |
| 5 | Rated frequency | Hz | 50 |
| 6 | Rated current | A | 3150 |
| 7 | First level coefficient | 1.5 | |
| 8 | Rated short-circuit breaking current | kA | 31.5 |
| 9 | Rated short-circuit making current (peak value) | kA | 80 |
| 10 | Rated short-circuit withstand current | kA | 31.5 |
| 11 | Rated peak withstand current | kA | 80 |
| 12 | Rated short circuit duration | s | 4 |
| 13 | Rated out of step breaking current | kA | 8 |
| 14 | Short-range fault breaking current | kA | 90%Ik, 75%Ik |
| 15 | Rated line charging switching current | A | 10 |
| 16 | Rated operating sequence | 0-0.3s-CO-180s-CO | |
| 17 | Main circuit resistance | µΩ | ≤ 40 |
| 18 | Rated sulfur hexafluoride gas pressure (20°C gauge pressure) | MPa | 0.5 |
| 19 | Alarm/minimum function pressure (20°C gauge pressure) | MPa | 0.45±0.03 |
| 20 | SF6 gas annual leakage rate | <0.5% | |
| 21 | Gas moisture content (V/V) | ≤150×10⁻⁶ | |
| 22 | Mechanical life | Times | 10000 |
| 23 | Radio interference level | µV | ≤500 |
| 24 | Creep distance – Contact gap | mm | 2585 |
| Creep distance – Grounded | mm | 2248 | |
| 25 | Weight of each unit filled with SF6 gas | kg | 10 |
| 26 | Weight of each circuit breaker | kg | 1300 |
