The hierarchical protection & control system in new generation smart substation aims at realizing optimal protection & control strategy based on different intervals and different substations. Sharing information and high-reliable network scheme are the important supporting technology. This paper dissects architecture and function location of hierarchical protection & control system, analyzes network flow and time delay in its communication system, and puts forward an optimal network communication scheme in new generation smart substations. This scheme bases on a measurable network message time-delay technology. This technology overcomes the limits that desynchronized message cannot implement networking transfer, makes the protection devices realize protection function independent of uniform time hack, and advances information sharing and network transmission technology of new generation smart substation.