Assessment of Data Flow Control Methods and their Performance on IEC61850 based Digital Substation

Abstract

Data flow control methods are deployed to avoid network traffic congestion and achieve the best data flow maximizing reliability and availability performance of the IEC 61850 based digital substation These methods include First in First out (FIFO), Priority Queuing (PQ), and Weighted Fair Queuing (WFQ). This paper presents the substation automation system (SAS) performance evaluation and comparison studies for these three different data flow control methods. A National Grid (NG) typical 400kV substation is simulated by using OPNET Modeler, communication network simulation software. Three different data flow control methods are applied to the process bus and station bus in the substation respectively. The message (i.e. SV, GOOSE, MMS) delay, packet loss probability, and other network performance are investigated and analysed under different case scenarios. Results shows PQ control method has the best performance respect to time critical messages during the feeder fault conditions, followed by WFQ, and FIFO respectively. In addition, PQ has a smaller network delay than WFQ and FIFO. However, some packets with lower priority class can be delay even lost under traffic queuing condition. Therefore, the simulation results can be used to help power utilities and industries to improve and achieve the data flow management, also for substation expansion in the future.