Detection and classification of MMC-HVDC transmission line faults based on one-terminal transient current signal

To quickly and accurately detect MMC-HVDC transmission line faults and identify the fault types, a new transient protection scheme based on one-terminal transient current signal is presented. MMC has the attenuation characteristic to the high frequency transient current components. By using empirical mode decomposition (EMD) and intrinsic mode function (IMF) energy entropy, the energy distribution of transient current in frequency domain is quantified. The IMF energy entropy is employed as a fault detection criterion to distinguish DC line faults from AC faults. Meanwhile, the trend of transient current, which can be extracted by using the moving average filter (MAF), is obviously dissimilar for different types of DC line faults. DC line faults can be classified into various categories based on this feature. RTDS test results demonstrate that the proposed scheme is able to detect and classify MMC-HVDC transmission line faults under different fault conditions.