It must be converted into a useable voltage before we can plug in our computers, televisions and kitchen appliances. That's where the transformer in the green box comes in. It reduces, or “steps down,” higher-voltage power to lower-voltage power that can be safely used in homes and. Mobile Substation Definition: A mobile substation is a portable power distribution system used for temporary or emergency power supply. Components: Includes transformers, cooling systems, switchgear, metering systems, protection relaying systems, auxiliary power supplies, surge protection, and. The definition of contingency transformers and reactors may vary across customers, manufacturers, and even from one part of the world to another. With the rapid popularization of distributed photovoltaics and new energy vehicle charging facilities, traditional split-type substations are gradually unable to meet demands due to large floor space, long installation cycles, and complex maintenance. Why. Our definition of a mobile substation is a completely self-contained trailer mounted unit comprised of transformer, cooling equipment, high voltage and low voltage disconnects and power circuit protection (fuses or breakers/switchers), metering, relaying (communication optional), AC and DC.