To solve load balancing problem of Power Line Communication (PLC) network in Smart Grid (SG), an adaptive opportunistic routing protocol named LBORP (Load Balancing Opportunistic Routing Protocol) was proposed. All the candidate forwarding nodes receiving a packet in LBORP had the opportunity to participate in packet forwarding. As a result, packet forwarding was no longer limited to one routing path, which avoided load imbalance caused by traffic with only one link for traffic to pass. And forwarding priority of the candidate forwarding nodes considered not only the distance from forwarding nodes to destination node, but also instability of PLC links and change of traffic. Besides, an implicit acknowledgment scheme was adopted in LBORP, further reducing the end-to-end delay of the proposed protocol. In simulation experiment, compared to PLC-TR (Power Line Communication-Tree Routing) and PLC-OR (Power Line Communication-Opportunistic Routing), LBORP reduced delay by 19.7% and 45.8% respectively and reduced packet loss rate by 23.4% and 32.5% respectively. Experimental results show that LBORP can achieve network load balancing, improve network reliability and reduce end-to-end delay.

To solve the traffic load-imbalance problem in electric power communication networks based on Open Shortest Path First (OSPF) protocol, an efficient Two-Step Optimized OSPF Protocol (TSO-OSPF) algorithm was proposed to balance the traffic in intra-area and inter-area of OSPF respectively. The bandwidth utilization and delay were adopted as link weights, the inward and outward traffic of a router was considered, the overloaded branches were decomposed into multiple routers to minimize the maximum traffic flow, thus the traffic-imbalance problem of internal and boundary router in the electric power communication networks was solved. The simulation results show that the TSO-OSPF algorithm can effectively balance the traffic in the network and reduce the packet loss rate by about 10% compared with the OSPF algorithm.

To solve the fault localization problem in electric power communication network, the large-scale connected area fault alarms caused by device or link faults were investigated, and a fault localization algorithm based on fault propagation model and supervised learning method was proposed. First, an improved fault propagation model was used to obtain an initial result with the minimum faults. Then the fault localization problem was transformed into a supervised classification problem by fault alarm vector decomposition to localize the faults within the fault warning areas. Finally, conjectural fault devices and links were added to improve the location results of previous two steps and increase the accuracy. The simulation results show that accuracy of fault localization of the proposed algorithm reaches 84%-95%, which achieves high reliability in fault location.

In electric power communication networks, load balance can reduce overloading on bottlenecks and improve the reliability and utilization of network resources. According to structure and flow characteristics of electric power communication network, a load balanced routing protocol combined with deterministic routing and opportunistic routing was proposed. Each node determined candidate sets to relay data packets from an area centered by it. Each candidate according to the precise local cost and the estimated remaining cost, and the forwarding probability was determined based on the priority. Compared with Load Balance Advanced-Open Shortest Path First (LBA-OSPF) protocol, the proposed routing protocol can reduce the average load by 32.3% and reduce the end-to-end delay by 50.3%.