A Novel Fault Identification Method for HVDC Converter Station Section Based on Energy Relative Entropy

The ac line fault could lead to the operation of converter station protection for high voltage dc (HVDC) systems. In order to avoid the false operation of converter station protection, a novel fault section identification scheme based on energy relative entropy is proposed. The fault characteristics of internal and external for converter station section are analyzed, and it is found that the difference of forward current traveling wave and backward current traveling wave is obvious when the fault occurs in different section. The difference between the forward and backward current traveling wave is represented by the S-transform energy relative entropy. The S-transform energy relative entropy for the external ac line fault is smaller than that of the internal fault of converter station. The performance and effectiveness of the proposed section identification method are evaluated and verified based on simulation and experiment. Finally, the adaptation is studied by considering the fault position, fault type, fault initial angle, transition resistance, and noise. The proposed method can accurately identify the fault of ac system from the converter station and effectively prevent the converter station protection from incorrect operation.