Depending on the size of the unit and on the transport conditions, the transformer may be dispatched completely or partly assembled. Larger transformers have to be dispatched with bushings, a conservator and a cooling equipment and all minor accessories have to be disassembled. Many transformers have to be transported without oil and are filled with dry-air. The transformer oil is transported in specially treated barrels or by tanker. The weight and size of large transformers require careful planning and preparation for transport and installation. ABB has extensive experience in delivering all types of transformers to all parts of the world. The combination of highly qualified technicians, local expertise and high quality equipment enhances the speed and efficiency of this vital operation.