The installation site for an outdoor prefabricated substation should be selected in an area free from severe vibration or mechanical shock, and situated away from the interference of large-scale electromagnetic induction equipment. The environment must be dry and well-ventilated; the equipment should be installed horizontally, with any inclination kept within a limit of 5 degrees. Furthermore, the site must be free of explosive hazards, as well as corrosive gases or liquids. Grounding conductors must be made of copper material with a cross-sectional area of no less than 30 mm²; the grounding grid should be buried at a depth of at least 1 meter below ground level, and vertical grounding electrodes should be added to reduce resistance. Upon completion of the grounding system installation, the grounding resistance must be tested during clear weather conditions; if the results fail to meet specifications, additional grounding electrodes should be installed.
Box-type substations typically do not require continuous manual supervision, resulting in lower operating costs.
Common faults include overheating issues, which can lead to insulation aging, loose connections, internal short circuits, and fire hazards. Consequently, dust and debris within the substation enclosure should be removed regularly, and temperature monitoring protocols should be strictly enforced.
Failures in on-load tap changers are typically attributed to prolonged service life, insufficient mechanical strength of components, or substandard manufacturing quality; therefore, on-load tap changers should be subjected to rigorous selection and quality control during the manufacturing process.
Tripping of low-voltage switchgear may be caused by busbar faults or inadvertent switch operation. A thorough inspection of the box-type substation is required; specifically, if an overcurrent protection event occurs on the low-voltage side of the main transformer, the associated equipment must be immediately inspected and secured. This process aims to rule out the possibility of a false switch trip and to facilitate further investigation of the busbars and feeder lines.
