午夜欧美大片免费观看,欧美激情综合五月色丁香,亚洲日本在线视频观看,午夜精品福利在线

GB 50057-2010 and GB 50343-2012 are the main standards about the design and installation of coordinated SPDs protection for the electrical systems within structures, but there are big differences between the two standards about the SPD.An analysis is made of the definition, location, discharge current and coordination of SPDs. The results show: (1) The explanations of SPD definitions are different, but the physical meanings are consistent. (2) The requirements of SPD location are more accurate in GB 50343, and the regulations about the discharge current of SPD in GB 50057 are reasonable. (3)The calculation methods of SPD levels are different in GB 50057 and GB 50343.