Using Communication Reports for Troubleshooting OT Protocols

This Application Note serves as a guide for utilizing communication reports to troubleshoot Operational Technology (OT) protocols in substations. It outlines the characteristics of communications protocols in OT environments, emphasizing the fixed nature of devices, ports, protocols, and traffic paths. The document details the process of collecting data from protective relays, including the use of COMTRADE or Compressed Event files for analyzing power system disturbances. It explains the limitations of SEL protective relays in automatically recording communication troubleshooting reports and introduces the SEL Flex parsing protocol for querying real-time data. The guide highlights the Communication Monitor tool within the ACSELERATOR RTAC software, which captures and saves reports for analysis. Additionally, it discusses the use of Wireshark for network troubleshooting and the importance of manually capturing .pcap files during unexpected behaviors. The note concludes by recommending the collection of .pcap files for further analysis by technical support teams.