A Communication Simulation Study On IEC 61850 Digital Substation

Smart equipments such as ECT/EVT, intelligent switchgear and etc. are gradually applied in practical project. The standard of substation communication network and system IEC61850 provides complete criterion for communication of digital substations. All above makes it possible for the construction of digital substation. Comparing with conventional substation, great change has occurred in both aspects of network framework and message transmission mode in digital substation automation system. So the dynamic performance of communication network in digital substation is necessary to be studied. Electric Power and Communication Synchronizing Simulator (EPOCHS) is an effective tool for simulation study on IEC 61850 substation communication network.The research status of IEC61850 standard is described in this paper. The main characteristics of IEC61850 digital substation and the communication simulation study of substation are summarized. According to the substation communication networks performance requirements, the network building schemes in digital substation based on the IEC 61850 standard are discussed. The messages transmission delay in substation Ethernet and its influencing factors are adequately researched, and methods which can improve the real-time performance are presented. The simulation process of IEC61850 main packet transmission is explained based on EPOCHS. For the communication simulation of IEC61850 digital substation, EPOCHS platform is extended as follows: The single physical subnet structure is changed and linkage among physical subnets is implemented in Network Simulator version 2 (NS2); Virtual LAN multicast protocol which is set originally in single switch is extended to substation communication network. IEEE 802.1Q buffer queue with multi-priority based on the end_node and switch is designed , and the message transmitted with priority tag is realized.The communication model of digital substation is set up on the extended EPOCHS platform . The experiment is carried out for internal unique network framework. Message delay and delay jitter are compared under different conditions. The factors affecting communication network real-time transmission are quantitatively analyzed based on simulation experiment result.