Analysis of the key points of prefabricated cabin substation product structure

Regarding the design of the base load-bearing capacity, prefabricated cabin-type substations typically consist of three main components: a high-voltage chamber, a transformer chamber, and a low-voltage chamber. The total weight of the transformer is mostly over 5 tons, which will put considerable pressure on the load-bearing capacity of the cabin. Therefore, the base structure is very important. It needs to have a good load-bearing capacity to meet the high reliability requirements in various aspects such as fixing and hoisting. The prefabricated cabin-type substation uses H-shaped steel as the skeleton in the main support structure of the base. Compared with ordinary I-shaped steel, H-shaped steel has better flatness, which can reduce deformation during the welding process to a certain extent, and it is also convenient to drill screw holes for fixing on it. Similarly, the same brand of H-shaped steel is also selected for the corresponding part of the transformer chamber to distribute the heavier weight of the transformer throughout the base, thereby improving the load-bearing rigidity.

In terms of sealing design, the cabin of the prefabricated cabin-type substation must meet the IP54 protection level. For structural design, the sealing structure of the movable door body is the most important. A double-sealed structure is often used to block foreign matter or water droplets from the outside of the door body.

In terms of corrosion-resistant structural design, because most prefabricated cabin-type substations are installed in harsh on-site environments, corrosion protection both inside and outside the cabin is crucial. For example, to ensure suitability for marine environments, square tubes must be welded together to create a truly enclosed structure. This prevents corrosion from spreading from the inside and potentially causing the exterior coating to fail. Dacromet fasteners are primarily used on the cabin's exterior, meeting corrosion requirements while avoiding the "seizure" that can occur with the extensive use of stainless steel fasteners.

The busbar support design, connecting the busbar between the high-voltage compartment and the transformer compartment, generates electrodynamic forces during operation, which can deform or damage conductors and equipment. When current flows through a conductor, it generates a magnetic field around it. This magnetic field can act on other conductors, generating attractive or repulsive forces, known as electrodynamic forces. If the electrodynamic forces between two parallel conductors are too large, they can cause the conductors to vibrate or even touch, damaging equipment and affecting the stability of power transmission. Calculating electrodynamic forces involves considering multiple factors, including the magnitude and direction of the current, busbar specifications, spacing, and environmental conditions. To prevent the problems caused by electrodynamic forces, the design incorporates connectors at the top of the busbar that are both easily adjustable and reinforced, as shown in Figure 4. Testing has shown that these connectors effectively eliminate the adverse effects of electrodynamic forces.

The transformer room utilizes a forced ventilation system to maintain a stable temperature rise within a specified range. The appropriate air volume is calculated based on the heat dissipation power of the main indoor equipment, the actual operating conditions of the transformer, and user requirements, with sufficient design margin. Within the transformer room, clear air ducts must be strategically arranged to ensure unobstructed air flow. Ventilation design also considers material selection, layout and installation, maintenance and cleaning, and noise control requirements to ensure the safety, stability, and efficiency of the entire ventilation system.