Security assessment of several distance protection algorithms based on the wavelet transform

In this paper three new variations of the two main distance relay algorithms which are based on Discrete Wavelet Transform (DWT) are introduced. Typically, distance relay algorithms based on DWT are designed to have faster tripping time relative to those which are based on the Discrete Fourier Transform (DFT). In this paper an investigation into how improvements in tripping time affect the security of fault detection is presented by comparing the number of maloperations occurring when each algorithm is used.