The topology analysis is decomposed into many units, each of which is modeled with a coloured Petri net, where a token represents a bus, and the token color represents the nodes connected to the bus. 把整个电网拓扑分析问题分解为若干个基本分析单元,提出了基本分析单元的有色Petri网模型,用令牌表示母线,用令牌的颜色表示连接在同一母线上的结点。