Protection engineers are generally familiar with different faults and events in power systems. While some events are straightforward, others present challenges and demand unique approaches for analysis, especially when protection schemes fail to operate correctly. In such instances, it is crucial to identify root causes and implement corrective actions. Event analysis can be very challenging and encounter many obstacles, making it essential for protection engineers to develop a deep understanding of power system fault characteristics, primary equipment behaviors, CTs and PT/CCVT behaviors, the design and algorithms of various relays, among other factors.
When faced with unusual events where conventional analytic tools fall short, protection engineers must adopt unique and creative strategies. This paper discusses a few distinct and initially puzzling events, most of which caused protection schemes to misoperate. Through the application of novel and unconventional analytical tools, protection engineers were able to identify the root causes and implement proper corrective actions accordingly.