Small and medium-sized transformers are transported to the users in an assembled state. The assembled state refers to the state where all components and parts of the transformer are installed and filled with insulating oil. However, the characteristics of large-capacity transformers are the transformer main body and the complete set of components are large size, large in mass, large in volume of insulating oil that equipped with a cooling system for strong oil circulation with a sealing device that isolates the insulating oil from surrounding media.
Large transformers are transported to the designated place. When transporting, either the oil supply is not provided but the nitrogen supply device or sealing device is installed, or the oil is filled to a height of 150-200 mm from the tank cover.
The installation of these transformers includes a complex combination of core inspection, assembly and commissioning which must be performed in accordance with certain procedures. Before the transformer installed, a work plan should be prepared and the installation site, equipment, tools and materials should be prepared.
The installation of complete sets of components on large transformer tanks should be performed on the basis of the transformer itself on a dedicated installation site or in a transformer repair shop.
Before and during the installation of the transformer, make a comprehensive judgment and inspection of its insulation and determine whether the transformer can be put into operation without drying. When the transformer insulation is wet, it needs to be dried or dried. In order to facilitate the installation of the complete set of components, a hanging assembly rack or a detachable work rack is used. The rack should be provided with railings and covered with reliable pedals to ensure work safety. Most transformer oil tanks have a device specifically designed to hold a hanging mount.
When installing high bushings, you need to open the cover plate and drain the oil out of the transformer. Vacuum and vacuum insulation and oil before and during filling. Some new structure transformers do not need to drain oil from the fuel tank when installing high voltage bushings. Preparations for installing the buried regulator should be performed after the transformer is vacuum-filled.
The installation of the hanging voltage regulator performed during the transformer sealing period or after the fuel tank is filled with oil. While installing the cooling system on the transformer tank and prepare and install the remaining complete components. After the transformer is finally filled with oil that connect the cooling system to the transformer and fill it with oil. The cooling system is also allowed to be vacuum-filled with the transformer tank.
After the assembly work is completed, the test before putting into operation is required. According to the completion of the assembly work, the installation and commissioning files are arranged. Then the transformer is tested at the rated voltage and put into operation.