Internet of Energy is promoting the deep integration between power grid and communication technologies, while the production, operation and service mode of the power grid are undergoing great evolutions. The expanded services need to be carried by efficient electric power communication network (EPCN). Aiming at releasing the bottleneck problem of link capacity in EPCN, we propose a pre-cross-connected trail (p-Trail)-based protection algorithm with load balance (TPLB) in this paper. First, we introduce the current statue and developing trend of EPCN and analyze traffic flow characteristics of various electric communication services. Then the protecting principles and implementing steps of the proposed TPLB algorithm are described in detail, in which an efficient load balancing algorithm is designed to groom the traffic flow. Finally, the validity and efficiency of TPLB is verified and analyzed in a real EPCN topology from a city of Jiangsu Province, China. It is demonstrated from the simulation results that compared with the existing algorithms, the proposed TPLB can further decrease the network redundancy and blocking probability, and improve the utilization of wavelength resources.