Characteristic Analysis and Selection of Wavelets Applicable for Ultra-High-Speed Protection

To minimize insecurity and instability of rapid developing power systems, the ultra-high-speed protection schemes are demanded. However, the application of the ultra-high-speed protection techniques suffers relatively low reliability and feasibility by its limitations such as lack of effective signal processing tools. The advent of the wavelet transform (WT) method, which possesses capabilities of providing accurate transient information in both time and frequency domain, gives a great impetus to investigating the possibility of improving ultra-high-speed protection. There are many mother wavelets we can use and these mother wavelets exhibit different attributes and performance criteria when applied to specific applications. Among them the best choice is a wavelet, which most strikingly exhibits the phenomena to be studied. In which, the key problem is how to choose proper wavelets to achieve ultra-high-speed protection algorithms. This paper analyzes the various characteristics of classical wavelets. Finally, on the basis of protection requirements and wavelet characteristic analysis above, this paper presents the selection criteria of wavelets for ultra-high-speed protection