Study The Real-Time And Reliability Of The Communication Network Of Smart Substation Based On IEC 61850

Smart substation is the core important node of the smart grid and the communication network is the physical path of all kinds of information in substation, and its real-time and realibility performance determines the normal operation of substation. Therefore, it’s necessary to research on the real-time and reliability modeling analysis of communication network in smart substation.This dissertation analyzes the composition of transmission delay of messages based on the general transport protocol, and its non-determinism are researched. The data flow of substation is divided into five categories according to the data message sender and receiver. The transmission process of different categories data stream are analyzed.The substation communication network real-time model is established on the OPNET simulation platform. This paper has studied packet transmission real-time influence factors of the process-level network through transformer interval model simulation. These factors include communication network bandwidth, switch packet switching rate, merging unit sampling rate. The communication time delay of station-level network is researched under normal and fault condition through constructing the model of medium-sized substation. The results show that the end-to-end delay increases by 23% with CPU utilization rising to 90% in 100M Ethernet and that the influence of the CPU utilization becomes obvious in the case of the abundant network bandwidth. The communication time delay of different networking mode and the real-time influence of the application of virtual local area network (VLAN) technology are studied through constructing independent networking and unified networking models of D2-1 substation. The results show that independent networking is superior to the unified network in case of real-time performance; VLAN technology reduces the gap of different network mode in the aspect of real-time performance.A novel reliability assessment method which is called goal-oriented (GO) methodology is introduced to the field of reliability modeling of smart substation. The single star, double star, single ring and double ring type topology structure reliability models of communication network in D2-1 Substation are established. And the system reliability parameters of these topology structure models are calculated based on component reliability parameters. The results show that the reliability of the single star is worst; The reliability of double star and double ring using all IEDs redundant mode is best, but all kinds of components consume the most in this way; The core switch redundancy double star structure are superior to single ring type structure in terms of reliability and real-time performance. Finally, the component importance analysis in reliability of substation is conducted according to the global reliability parameters expressions derived by GO method. Component importance analysis is useful for the allocation of substation communication network reasonably and the determination of maintenance priority, and can provide theoretical basis for improving reliability of substation communication network.