As the challenges associated with delivering reliable electrical power in the world are increasing, the mixture of 'fast response time' and 'distributed data sources' may cause scalability issues with the traditional approach that mostly uses centralized communication infrastructure. Due to tremendous demand growing in the future, the centralized approach will become less efficient. Therefore, this paper presents multicast-based Publisher/Subscriber communication models based on IEC-61850 standard for the smart grids. Models are proposed with regards to digital substations indicating the use of the emerging digital communication standards offered by IEC-61850 over typical Wireless Local Area Network. Simulation models are developed using the OPNET simulator. Therefore, the dynamic performance issues of the smart grid could be studied conveniently during the planning stage in advance of field trials.