A method for operating a sealed for life compact secondary substation including a transformer, a high voltage side and a ring main unit arranged at the high voltage side and connected to a primary side of a the transformer, a secondary side of the transformer is connected a low voltage switch gear. An enclosure includes watertight material capable of withstanding corrosion at least for a life time of the compact secondary substation. The compact secondary substation is cooled with a cooling system that includes a heat exchanger. The compact secondary substation is protected with an extended arc eliminator. The compact secondary sub-station is connected to a remote control for surveillance and operation, which remote control is communicating with a fault protection equipment.