Research Of The Protection Principles For EHV Transmission Line Based On Hilbert-huang Transform

Transient based protection uses transient fault compoents to realize the protection. It can do well in settling the conflict between speediness and reliability in traditional protection for EHV transmission line. Started from theory of Hilbert-Huang and transient protection, several aspects of transient protection are displayed in this thesis, this paper discusses HHT principle and improving methods and its applications in transient signal. The transient current generated by the internal and external faults in EHV transmission lines contains different high frequencies because of the line traps and bus-bar capacitance. The difference is detected by the characteristics of the energy function of HHT in this paper. Based on analyzing the characteristics of modulus current components on different types faults occurred in EHV transmission lines, construct a novel non-unit transient current protection scheme. The schemes and algorithms mentioned above were proved to be correct and effective by lots of simulations in this paper.