电气工程设计人员,一般习惯于采用单相二线的照明干线,给办公楼、教学楼、居民楼等供电。如果改用三相四线作为照明干线,把一栋楼的用电负荷按单元或楼层均匀地分配到三相上,就不仅对平衡三相负荷、减少三相负荷不对称所引起的损耗有利,而且还可以直接减少输电干线上的损耗,具有显著的节电效果。 Electrical engineering designers are generally accustomed to using single-phase secondary lighting trunks to supply power to office buildings, teaching buildings, and residential buildings. If three-phase four-wire lines are used as lighting trunks, even if the power load of a building is evenly distributed to three-phase units or floors, it will not only be beneficial to balance the three-phase load and reduce the loss caused by the three-phase load asymmetry. , And can also directly reduce the loss of the mains, has a significant power-saving effect.