Abstract: Aiming at the problem that existing research mainly focuses on the identification of electrical components in the secondary circuit of substations and neglects the determination of connection relationships,a method for jointly analyzing CAD electrical drawings using bitmap and vector graphics is proposed. Firstly, YOLOv8 object detection algorithm is used to identify electrical drawings in bitmap format,obtain the categories and positions of electrical components in the drawings, and then the vector graphic characteristics of CAD drawings are used to pick up the line segment information between connecting component symbols,generating a topology map with wires as nodes and wire connection points as edges. Finally,a depth first search method is used to traverse the topology map to determine the connection relationships between component symbols. This method combines the advantages of extracting component symbols from bitmap using object recognition methods and extracting line segments using vector graphics, resulting in high accuracy in electrical component recognition and accurate recognition of connection relationships.

Key words: YOLOv8, CAD drawing recognition, deep learning, connection relationship analysis