Oil-filled transformers serve to cool and insulate internal components. If there is a fire, the oil can explode, spill and/or produce hazardous smoke. Any substation fire should be treated as a hazardous materials response.
Circuit breakers automatically test and re-energize circuits multiple times. Even if a circuit fails, it could potentially become live again due to the activity of automatic circuit breakers. For safety’s sake, always assume that substation equipment is energized.
Control buildings house equipment for controlling and monitoring substation batteries and other equipment. Never enter a control building unless you have the assistance of qualified personnel.