SUMMARYBecause of the capacity of satisfying the quality of service requirements of each traffic service in smart distribution networks, Ethernet passive optical network (EPON) technology is one of the primary technologies for establishing communication systems in smart distribution networks. This paper presents an improved weighted interleaved polling with adaptive cycle time (IW-IPACT) algorithm according to the quality of service requirement of different traffic classes, especially the requirement of the new protection and control technique. During a polling cycle, a virtual weighted buffer queue that meets the bandwidth requirements of the EPON was constructed. Thus, strict priority scheduling was used for the expedited forwarding service, and the weighted fair queuing scheduling was applied for the other services. In addition, to evaluate the real-time performance of the IW-IPACT algorithm, the upper bound for the packet delay of each traffic class was derived by using the network calculus method. The evaluation results indicate that the bandwidth utilization of the EPON was improved by using the IW-IPACT algorithm. In addition, the calculus and OPNET simulation results also show that the EPON can meet the real-time requirements of relay protection.