The enclosure doors of prefabricated substations should open outwards and have handles, concealed latches, and locks. The latches and locks should be rust-proof. The transformer room should primarily rely on natural ventilation, and a curve showing the relationship between the internal temperature and transformer output should be provided. The transformer room may be equipped with a room temperature monitoring device and a self-starting ventilation and cooling system as needed to ensure the transformer operates at full load under specified environmental conditions. The transformer should be accessible through the top or side door of the enclosure. The noise level of the prefabricated substation should not exceed the specified transformer noise level. Regardless of whether the enclosure is made of metallic or non-metallic materials, the metal frame of the enclosure should have good grounding, a grounding terminal, and a clearly marked grounding symbol.
Prefabricated substations primarily rely on natural air circulation for cooling. Therefore, no unauthorized materials should be piled up around it, especially the transformer room door should not be blocked, and any adhering materials on the louvered ventilation openings should be regularly cleaned to ensure that all electrical equipment does not exceed the maximum permissible temperature. After a low-voltage circuit breaker trips, the cause of the trip should be investigated before attempting to restore power. If restoration is unsuccessful, the cause of the fault must be thoroughly investigated and eliminated before power can be restored to prevent the accident from escalating. Zinc oxide surge arresters should be installed in the high-voltage distribution room of a prefabricated transformer. The installation method must facilitate testing and easy replacement.
The grounding and neutral wires of a prefabricated substation share a common grounding grid. The grounding grid is generally constructed by driving grounding stakes at the four corners of the foundation and then connecting them together. The prefabricated substation and the grounding grid must have two reliable connections. After the prefabricated substation is put into operation, the grounding connections should be checked regularly to ensure they are not loose or corroded. The grounding resistance should be measured periodically and should not exceed 4Ω. Ring network switches, transformers, surge arresters, and other equipment in the high-voltage distribution equipment of the prefabricated substation should be inspected and maintained regularly. Any defects should be repaired promptly, and regular insulation preventative tests should be conducted. If a prefabricated substation has been out of service for more than 3 months, a full range of preventative tests should be performed before re-commissioning. When replacing a high-voltage fuse without breaking capacity, the transformer must be de-energized. During operation, the mechanical interlocks must be properly released, and an insulated operating rod must be used. All cable entry and exit holes in the prefabricated substation should be sealed to prevent small animals from entering and causing accidents.
The prefabricated substation should be placed on a higher ground, not in a low-lying area, to prevent rainwater from entering the box and affecting equipment operation. When pouring the concrete platform, gaps should be left on the high and low voltage sides to facilitate the laying of cables. When excavating the foundation, if the ground is composed of garbage or rotten soil, it is necessary to dig down to the solid soil, then backfill with better soil and compact it, and then fill with rammed earth or road ballast to ensure the foundation is stable.