Underground equipment eletric power system without an external power source

An underground electric power system without power source comprising:

• a box having an open upper portion;
• a cover part inserted into the box and covering the upper portion;
• and an air conditioning unit that is disposed in the cover part and ventilates or seals an inner space of the box according to inflow of external water, the air conditioning unit configured to:
• seal, by a lower surface of the cover part, the inner space of the box;
• exchange heat, by a heat exchange unit, between rainwater and the inner space when the rainwater is introduced is disposed at a location different from an arrangement location of the air conditioning unit in the cover part;
• include, by the cover part, an upper surface exposed to an outside;
• dispose the heat exchange unit below the cover part;
• provide stable radiating heat in an internal space of the underground electric power system to the outside without a separate power when external waster is not introduced;
• and spaced an upper surface of the heat exchange unit apart from the upper surface of the cover part and configured such that external water introduced into the cover part from the outside is introduced into a first space between the upper surface of the heat exchange unit and the upper surface of the cover part.