An adaptive PMU based fault detection/location technique for transmission lines part I: Theory and algorithms

An adaptive fault detection/location technique based on Phasor Measurement Unit (PMU) for an EHV/UHV transmission line is presented in this two paper set. This paper is Part I of this set. A fault detection/location index in terms of Clarke components of the synchronized voltage and current phasors is derived. The line parameter estimation algorithm is also developed to so lve the uncertainty of parameters caused by aging of transmission lines. Th is paper also proposes a new Discrete Fourier Transform (DFT) based algorit hm (termed as Smart Discrete Fourier Transform, SDFT) to eliminate system n oise and measurement errors such that extremely accurate fundamental freque ncy components can be extracted for calculation of fault detection/location index. The EMTP was used to simulate a high voltage transmission line with faults at various locations, To simulate errors involved in measurements, Gaussian-type noise has been added to the raw output data generated by EMTP . Results have shown that the new DPT based method can extract exact phasor s in the presence of frequency deviation and harmonics. The parameter estim ation algorithm can also trace exact parameters very well. The accuracy of both new DFT based method and parameter estimation algorithm can achieve ev en up to 99.999 % and 99.99 % respectively, and will be presented in Part I I, The accuracy of fault location estimation by the proposed technique can achieve even up to 99.9 % in the performance evaluation, which is also pres ented in Part II.