Abstract
The main content of this graduation is to design the primary side of a 10kV substation. The electric power system plans to use 10kV inlet line. Through the main transformer, voltage can be transformed to 380V to provide electrical power for workshop. After to analysis raw data，I found that most workshop equipment were three class load, only a small part was two class load and with the nearby chemical plants have a contact line. Through calculating and looking up a lot of relevant information, finally, the number of transformers have been identified .The line of main transformer to workshop is the single bus section of the wiring. Various workshops wiring used radiation-Connection. According to calculate current, the right equipment can be selected, and at the same time checking through short-circuit current and voltage loss, the final design can be completed.
Keywords：primary side; load calculation; check short-circuit; current protection
