A novel identification scheme of lightning disturbance in HVDC transmission lines based on CEEMD-HHT

For high-voltage direct current (HVDC) transmission systems that use overhead transmission lines, the lightning disturbance is the main reason for the line protection mal-operation. To avoid the impact of lightning disturbance on the safety and stability of DC line protection, the model of HVDC transmission system including lightning strokes is constructed. On this basis, the complementary ensemble empirical mode decomposition (CEEMD) and Hilbert transform are combined as a time-frequency analysis method to calculate the energy distribution of the signals. Then the low-to-high-frequency energy ratio of the 1-mode voltage signal in a 3 ms data window after the protection startup is used as the protection criterion for identifying lightning disturbance, and that of the current signal in 1 ms is used as the criterion to further distinguish lightning and non-lightning faults. Verified through simulation tests, the scheme appears good adaptability and accuracy in different situations.