American-style prefabricated substations require virtually no maintenance after installation and use. However, domestically produced substations necessitate regular maintenance due to various reasons.
Due to limitations in the surface treatment technology of the casing, it is crucial to regularly inspect for rust. American-style substations typically use FR3 insulating oil in their tanks. This oil has a flash point of 312℃ and possesses excellent electrothermal properties, high insulation strength, good lubricity, strong arc-extinguishing ability, and is non-toxic and biodegradable, thus minimizing environmental and health hazards. Unlike traditional mineral oils, FR3 insulating oil does not form sediment, while most domestically produced American-style substations use 25# ordinary mineral oil. Furthermore, American-style substations generally have an inert gas filling the upper part of the tank to prevent moisture from the air from entering the oil. Domestic manufacturers may not yet be implementing this feature, leading to a deterioration in oil performance over time.
Combined with insufficient sealing performance (not meeting the 7 Psig requirement), regular oil changes are essential.
American-style prefabricated substations lack oil temperature protection; they only have a thermometer to display the oil temperature. When the oil temperature is too high, protection is provided by a plug-in fuse, and a pressure relief valve is used to release excessive pressure within the tank. Therefore, it is essential to regularly check whether the fuse is functioning properly under these two conditions and whether there is any oil leakage from the casing.
Because the oil tank of an American-style prefabricated substation is exposed, it should be inspected frequently to prevent damage from external impacts that could cause oil leaks.
