The explosion-proof design of a fully insulated gas-filled fuse cabinet effectively withstands the internal pressure surges generated during a short circuit. This protection stems from a systematic design logic of "active suppression + passive load bearing + controlled release" tailored to the characteristics of short-circuit pressure. This multi-dimensional protection system, spanning the pressure source to the pressure-bearing terminals within the cabinet, ensures that the sudden internal pressure surge during a short circuit does not cause the cabinet to rupture or pose a safety risk.
When a short circuit occurs, arc discharge within a fully insulated gas-filled fuse cabinet generates significant heat. This heat rapidly heats the insulating gas (such as SF6 or dry air) within the cabinet, causing the gas volume to expand dramatically and generate transient high pressure. This pressure surge is characterized by a rapid rise rate, high peak pressure, and is accompanied by high temperatures and arc erosion. Without specialized explosion-proof design, ordinary cabinets are likely to be unable to withstand the pressure, resulting in weld cracking, door collapse, or even cabinet explosion. This can also lead to secondary risks such as insulating gas leakage and arc leakage. The explosion-proof design of a fully insulated gas-filled fuse cabinet begins by optimizing the source of pressure. Its internal structure is specifically designed to target arc generation and diffusion pathways. For example, dedicated arc channels are provided to guide short-circuit arcs toward pre-defined "pressure buffer zones," preventing them from directly impacting vulnerable areas within the cabinet. Furthermore, the insulating gas within the cabinet possesses excellent arc-extinguishing properties, quickly extinguishing arcs and shortening the duration of heat release, thereby reducing the magnitude of pressure peaks and ultimately minimizing the intensity of pressure shocks.
At the passive load-bearing level, the cabinet structure of a fully insulated gas-filled fuse cabinet has been reinforced to withstand pressure. The cabinet's main frame will be constructed of high-strength metal or composite insulation materials. These materials not only offer excellent mechanical strength but also maintain structural stability in high-temperature environments, preventing material softening and reduced load-bearing capacity caused by short-circuit heat. Key connections (such as door-to-body joints, weld seams, and gas line connections) will be reinforced with thicker panels, multiple sealed welds, or recessed joints to minimize deformation or cracking in these areas, which are prone to pressure breaches. Furthermore, the cabinet's overall design avoids sharp corners or weak protrusions, employing curved transitions or integral molding to evenly distribute pressure across the cabinet surface and avoid localized stress concentration. When internal pressure acts on the cabinet, this evenly distributed force allows the entire cabinet to bear the pressure, rather than concentrating it at a single point, significantly improving the cabinet's impact resistance.
More importantly, the explosion-proof design of the fully insulated gas-filled fuse cabinet incorporates a "controlled pressure release" mechanism, a key component in addressing high-voltage short-circuits. The cabinet is equipped with a dedicated pressure relief device, such as a rupture disk or pressure relief valve, in a pre-set safe location (usually away from personnel operating areas and away from critical equipment, on the side or top). These devices are set to trigger pressures based on the cabinet's rated pressure capacity. When a short circuit causes internal pressure to rise to the set value, the rupture disk will precisely rupture, or the pressure relief valve will automatically open, rapidly discharging excess high-pressure gas from the cabinet through a pre-set channel. This release process is controllable. Firstly, the direction of the release channel is carefully designed to ensure that the discharged gas does not rush into personnel areas or adjacent electrical equipment, thereby preventing secondary damage from airflow shock or gas leakage. Secondly, the opening pressure of the release device is precisely calibrated to prevent false triggering from minor pressure fluctuations during normal operation and to activate promptly before short-circuit pressure reaches a dangerous threshold, preventing pressure from exceeding the cabinet's load capacity. Furthermore, some explosion-proof designs incorporate filters or buffer structures within the release channel to reduce the risk of high-temperature particles or arc debris carried by the discharged gas, further minimizing the risk of leakage.
Furthermore, the explosion-proof design of a fully insulated gas-filled fuse cabinet also considers long-term operational reliability. For example, the pressure relief device is constructed of ageing- and corrosion-resistant materials to prevent seal failure or loss of triggering accuracy due to long-term use. The cabinet's welds and joints undergo rigorous pressure testing and fatigue strength verification to ensure structural integrity even after repeated short-circuit shocks. Some products also incorporate internal pressure monitoring sensors, linked to the explosion-proof device. If internal pressure shows an abnormal upward trend, an early warning signal is issued, allowing maintenance personnel time to intervene.
The explosion-proof design of a fully insulated gas-filled fuse cabinet is not a single "pressure-resistant" measure. Instead, it integrates multiple elements, including optimizing arc paths, strengthening the cabinet's load-bearing capacity, and implementing controllable pressure relief devices. This creates a comprehensive protection chain against short-circuit pressure shocks. This effectively prevents damage to the cabinet from transient high pressure while controlling the pressure release process within a safe range, avoiding secondary risks and thus ensuring the safety of equipment and personnel in the event of a short-circuit fault.
