| Brand | ROCKWILL |
| Model NO. | SF6 Gas Insulated Switchgear for transmission systems-420kV |
| Rated voltage | 420kV |
| Rated normal current | 4000A |
| Series | ZF |
The ZF-420/4000-63 GIS is a high-voltage SF6 gas-insulated switchgear designed for 420kV transmission systems. Composed of standard modules with flanged joints, it enables flexible substation optimization through modular combinations. It saves space and conforms to applicable technical requirements.
The horizontal circuit breaker structure facilitates inspection and emergency maintenance while reducing ground impact. The GIS achieves a phase spacing of 670mm and a standard bay spacing of 2050mm, with three-phase integrated transport capability. Its technological innovation level is domestically leading.
The circuit breaker, disconnector, and earthing switch each have a mechanical life of 10000 operations, driven by a mature pure spring operating mechanism. The basin insulators feature aluminum flanges with double sealing structure. Key components and production equipment are sourced from international suppliers.
| NO. | Items | Units | Parameter value | |
|---|---|---|---|---|
| 1 | Rated voltage | kV | 420 | |
| 2 | Rated current | A | 4000 | |
| 3 | Rated 1 min power frequency withstand voltage (1min RMS) | Phase-to-phase,phase-to-ground | kV | 650 |
| Across the isolating distance | kV | 650+165 | ||
| 4 | Rated lightning impulse voltage (peak) | Phase-to-phase,phase-to-ground | kV | 1425 |
| Across the isolating distance | kV | 1425+240 | ||
| 5 | Rated short circuit breaking current | kA | 63 | |
| 6 | Rated short-time withstand current/rated duration of short-time | kA/s | 63/3 | |
| 7 | Rated peak withstand current | kA | 170 | |
Due to the excellent insulation performance, arc extinguishing performance and stability performance of SF6 gas, GIS equipment has the advantages of small footprint, strong arc extinguishing ability and high reliability, but the insulation ability of SF6 gas is greatly affected by the uniformity of the electric field, and it is easy to have insulation abnormalities when there are tips or foreign objects inside the GIS.
GIS equipment adopts a fully enclosed structure, which brings the advantages of internal components without environmental interference, long maintenance cycle, low maintenance workload, low electromagnetic interference, etc., while also having problems such as complex single overhaul work and relatively poor detection methods, and when the closed structure is eroded and damaged by the external environment, it will further bring a series of problems such as water ingress and air leakage.
The insulating property of SF₆ gas relies on its stable molecular structure, which makes electron escape and collision ionization difficult under normal operating voltages, ensuring high insulation resistance. In GIS, insulation is precisely maintained by controlling gas pressure, purity, and electric field distribution to guarantee a uniform and stable electric field between high-voltage conductors and the grounded enclosure.
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