XIE Chao，XV Zheng
（College of Electrical Engineering，Zhejiang University，Hangzhou 310027，China）
Abstract：Most existing HVDC applications focus on system simulation and don't have the package design ability. They are mostly basedon process-oriented development approach and difficult to extend and maintain. Aiming at those problems，the functional requirements ofHVDC design software were analyzed and the modular design method was proposed. According to the access way of system transmissionequipment，the layered HVDC transmission software architecture was presented，which was on the basis of the object-oriented software
design methods. Then，the device class with inheritance was designed，the relevant device object was declared，the graphic system wasdesigned with Windows Forms，the database system was designed with Microsoft Access. The results indicate that this object-orientedprogramming（OOP） method can not only meet the needs of engineering design software，but also be modular，reusable and easy tomaintain.
Key words：HVDC transmission；object-oriented programming（OOP）；software design