In the past, it was always believed that the temperature rise of the measured winding was low, and it was naturally associated with the strong overload capability of the transformer. This is not true. The super-nameplate operating capability of dry-type transformers (usually referred to as overload capability) is stipulated by the standard and is mandatory. There is no strong or weak problem. The measured temperature rise of the winding under rated operating conditions is low, which only indicates whether the transformer design is reasonable. The temperature is different. The beneficial side is that the actual operating temperature is lower than the reference temperature, the load loss is low, and there is a large thermal margin. The disadvantage is that the material utilization rate is low, especially the material with high insulation heat resistance is difficult. To play its due function, the same problem exists with the allowable current carrying capacity of the wire. Therefore, dry-type transformers with different insulation and heat-resistance grades should have different load loss standards determined by optimized design, and it is reasonable to consider all aspects.
　　As with oil-immersed transformers, any dry-type transformer should have the necessary super-nameplate capability, which is what we usually call overload operation. It should be carried out in accordance with the dry transformer load guidelines. The guidelines stipulate that the dry-type transformer super-nameplate operation capability is controlled according to the winding hot spot temperature and reflects the six-degree rule of insulation life compensation. However, dry-type transformers are generally only used as distribution transformers. Unlike oil-immersed transformers, which also divide power and distribution transformers, they have different considerations. However, no matter what the requirements are, under the condition of the super nameplate specified in Guideline 0, all electrical components shall be able to withstand the corresponding overcurrent impact and operate under the overcurrent multiple specified here. The dry transformer will not cause any Electrical insulation failure.