Multi-ended line differential protection communication and time synchronization with HSR and PTP

The increasing integration of distributed power sources, particularly inverter-based generations like wind and photovoltaic, has introduced significant challenges to traditional power grid protection schemes. This paper introduces a multi-ended line current differential protection scheme to enhance fault detection and isolation reliability within complex power grid topologies. Time synchronization, analogue values, and control signals are managed in parallel by the LineDiff data flow using different frame types over a common physical interface. The scheme utilizes High-Availability Seamless Redundancy (HSR) to ensure communication redundancy and employs the Precision Time Protocol (PTP) to achieve precise time synchronization among protection relays, with one relay designated as the master clock. The implementation of these protocols allows sub-microsecond synchronization without reliance on external clocks and reducing communication delays. The direct connection communication methodology using HSR and the establishment of a PTP time domain for multi-ended line current differential protection is also discussed in this paper. Following this, the resampling method aligns sampled values across different clocks enabling the utilization of data across various time domains. Finally, test results from time synchronization test, data synchronization test and operate time test are detailed, demonstrating that the LineDiff system meets all requirements.