Line Differential Protection with Synchrophasor Data in WAMPAC System in Control Room

Wide area monitoring system (WAMS) installed in Croatian Transmission system operator (HOPS) control center collects and process synchrophasor data in real time. There are ongoing activities on continuous, incremental and gradual upgrading of existing WAMS with new protection functions and control algorithms towards WAMPAC system. This paper describes line differential protection based on synchrophasor data and implemented on PDC server running in control room. In the first phase, the algorithm was applied to historical synchrophasor data. That check revealed that estimation block in PMUs at both line ends must implement the same estimation technique. Because of this finding, only lines with the same PMU type on both ends were selected for real-time performance test in the second phase. Several months long performance test successfully confirmed a soundness of concept and its implementation. It was proven in practice that new algorithm can be used as an effective tool for validation of basic protection performance and a solid foundation for development and implementation of backup protection.