Performance Evaluation and Optimization of Asynchronous Time-Sensitive Networking in Substation Automation Systems

Current Ethernet switches use a scheduling strategy based on strict priority queuing, which can lead to in unpredictable latency in power-system protection and operation within intelligent substations. Therefore, time-sensitive networking (TSN) has received widespread research attention due to its deterministic transmission characteristics. Based on the asynchronous traffic shaping (ATS) defined by the IEEE 802.1Qcr standard in TSN, we propose a method that evaluates and optimizes the performance of asynchronous TSN in substation communication networks (SCNs). Based on a port-connection model of an SCN, we propose a method that calculates the bandwidth and message distribution of traffic flows at each switch port. Then, we propose an optimization model for shaper parameters of the ATS strategy to minimize the end-to-end delay of traffic flows. The model is solved using the interior-point algorithm, which allows for the configuration of optimized shaper parameters. Subsequently, the shaped traffic flows are scheduled based on their eligible transmission time and priorities, with detailed implementation provided. Simulation results demonstrate that the ATS-based SCN ensures deterministic low-latency transmission for critical communication services, such as sample value and generic object-oriented substation event in substation automation systems, even in the presence of abnormal high-priority traffic.