The Application Study On Transient Protection For EHV Transmission Line Based On Wavelet Entropy

The reliability of HV/EHV transmission line protection is important to the security of the power system, The conflict between speediness and reliability exit in traditional protection for EHV transmission line, while transient based protection uses transient fault components to realize the protection, and it has a high speed, It can do well in settling the conflict. Transient signal analysis is the basis of realizing transient based protection, in order to ensure protectors correct operation, it is necessary for finding an appropriate right quantum to detect and determine kinds of faults. While the wavelet energy entropy is the combination of wavelet transform and entropy, It has the characteristic of multi-resolution analysis and has strong ability of characterizing information, neither can achieve the goal of information fusion, and can analysis transient signal more effectively. With the theory of wavelet entropy and transient protection, this paper proposes a method of transient current signal analysis and fault determination based on wavelet entropy. Many simulations show: this protection criterion calculate easily, have the characters of real-time, can distinguish internal fault and external fault rapidly and accurately, and it won't be affected by faulty location, faulty types, transition resistance or faulty time, so it will have a good adaptability.