Abstract: High-voltage/low-voltage prefabricated substation is short for“box substation”，its nature of saving

energy has been widely researched. The research have been from choosing components to optimizing structure. A

great of improved products have swarmed into market. But there is neither a set of method to test loss of box

substation nor a set of standard to evaluate in the inspection and testing field. In order to supplement the lack of

technique，loss test and optimization methods of box substation were studied and verified. There are some problems in the process of research and verification to be expect to solved in the future.

     Key words: high-voltage/low-voltage prefabricated substation；energy conservation；loss test method