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A new fault detection/location technique with consideration of arcing fault discrimination based on phasor measurement units for extremely high voltage/ultra-high voltage transmission lines is presented in this two-paper set. Part I of this two-paper set is mainly aimed at theory and algorithm derivation. The proposed fault detection technique for both arcing and permanent faults is achieved by a combination of a fault detection index |M| and a fault location index |D|, which are obtained by processing synchronized fundamental phasors. One is to detect the occurrence of a fault and the other is to distinguish between in-zone and out-of-zone faults. Furthermore, for discriminating between arcing and permanent faults, the proposed technique estimates the amplitude of arc voltage by least error squares method through the measured synchronized harmonic phasors caused by the nonlinear are behavior. Then, the discrimination will be achieved by comparing the estimated amplitude of are voltage to a given threshold value. In addition, in order to eliminate the error caused by exponentially decaying dc offset on the computations of fundamental and harmonic phasors, an extended discrete Fourier transform algorithm is also presented. Index Terms--Arcing fault discrimination, extended discrete Fourier transform (EDFT), fault detection, fault location, phasor measurement unit (PMU).

Part I of this paper set sets forth theory and algorithms for adaptive fault detection/location technique, which is based on Phasor Measurement Unit (PMU). This paper is Part II of this paper set. A new timing device named 'Global Synchronism Clock Generator, GSCG' including its hardware and software design is described in this paper. Experimental results show that the synchronized error of rising edge between the two GSCGs clock is well within 1 ps when the clock frequency is below 2.499 MHz. The measurement results between Chung-Jeng and Chang-Te 161 kV substations of Taiwan Power company by PMU equipped with GSCG is presented and the accuracy for estimating parameters of line is verified. The new developed DFT based method (termed as Smart Discrete Fourier Transform, SDFT) and line parameter estimation algorithm are combined with PMU configuration to form the adaptive fault detector/locator system. Simulation results have shown that SDFT method can extract exact phasors in the presence of frequency deviation and harmonics. The parameter estimation algorithm can also trace exact parameters very well. The SDFT method and parameter estimation algorithm can achieve accuracies of up to 99.999% and 99.99%, respectively. The EMTP is used to simulate a 345 kV transmission line of Taipower System. Results have shown that the proposed technique yields correct results independent of fault types and is insensitive to the variation of source impedance, fault impedance, and line loading. The accuracy of fault location estimation achieved can be up to 99.9% for many simulated cases. The proposed technique will be very suitable for implementation in an integrated digital protection and control system for transmission substations. Index Terms--Discrete Fourier transforms (DFT), fault detection/location index, phasor measurement unit (PMU).

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 solve the uncertainty of parameters caused by aging of transmission lines. This paper also proposes a new Discrete Fourier Transform (DFT) based algorithm (termed as Smart Discrete Fourier Transform, SDFT) to eliminate system noise and measurement errors such that extremely accurate fundamental frequency 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 DFT based method can extract exact phasors in the presence of frequency deviation and harmonics. The parameter estimation algorithm can also trace exact parameters very well. The accuracy of both new DFT based method and parameter estimation algorithm can achieve even up to 99.999% and 99.99% respectively, and will be presented in Part H. The accuracy of fault location estimation by the proposed technique can achieve even up to 99.9 % in the performance evaluation, which is also presented in Part II. Index Terms--Fault Detection/Location Index, Discrete Fourier Transforms (DFT), Phasor Measurement Unit (PMU).

The theory and algorithms of the proposed technique have been presented in Part I of this two-paper set. In Part II of this two-paper set, the proposed technique is evaluated by considerable simulation cases simulated by the Mattab/Power system Blockset simulator. For the proposed fault detector, the trip time achieved can be up to 3.25 ms and the average value of trip times is about 8 ms for both permanent and arcing faults on transmission lines. For the proposed fault locator, the accuracy can be up to 99.99% and the error does not exceed 0.45%. Moreover, the proposed arcing fault discriminator can discriminate between arcing and permanent faults within four cycles after fault inception. It has proven to be an effective tool to block reclosing on the permanent faults in the computer simulations. The simulation results also demonstrate that the presented extended discrete Fourier transform algorithm eliminates effectively the error caused by exponentially decaying dc offset on fundamental and harmonic phasor computations. Finally, a test case using the real-life measured data proves the feasibility of the proposed technique. [ABSTRACT FROM AUTHOR]