Assessment of Two Double-end Data Fault Location Algorithms in Transmission Grids using ATP simulations MARCEL ISTRATE 1 , MIHAI GAVRILAŞ 1 , CRISTIANA ISTRATE 2 , RADU URSULEAN 3 1 Power Engineering Department, 2 Management and Production Engineering Department, 3 Electrotechnics Department Technical University “Gheorghe Asachi” of Iaşi Dimitrie Mangeron Bd., No. 51-53, 700050, Iaşi ROMANIA mistrate@ee.tuiasi.ro http://www.ee.tuiasi.ro Abstract: - The increased accuracy into the fault’s detection and location make an easier task for maintenance and, implicitly, for a faster restoration of the grid, this being the reason to develop new possibilities to a precise estimation of the short-circuits’ location. The paper presents the results of the implementation of two fault location algorithms in an ATP-EMTP program. These two algorithms are double-end data type, one of them processing the synchronized power frequency phasors of the voltages and currents and the other one processing only the power frequency phasors of the voltages. Some ATP-MODELS modules were associated to the ATP model of different transmission grids, these modules being developed on the basis of the previous mentioned double-end data algorithms, both of them processing positive-sequence phasor quantities on both transmission lines’ terminals. Discrete Fourier Transform and A3 type filters were used to calculate the power frequency phasors of the transient voltages and currents. There are presented some simulations’ results, the considered parameters of the presented analysis being: line’s load, fault’s resistance and position along the overseen line, precision into the calculation of line’s propagation parameters. Key-Words: - ATP simulation, double-end data algorithm, fault location, synchronized phasors, transmission lines, unsynchronized voltages. 1 Introduction The rapid removal of transmission lines’ faults is one of the best measures used to improve the power systems’ stability. At the same time, the rapid fault restoration on transmission lines is faced with the quality of the utility’s power service, so, following the occurrence of a fault, the utility tries to restore power as quickly as possible. To aid rapid and efficient service restorations, an accurate fault location estimation technique is needed. Without neglecting the economical losses induced by a fault occurrence, the increased accuracy into the faults’ location estimation also makes an easier task for inspection, maintenance and repair. Nowadays, the trend is to locate faults quickly and without human intervention. This is made directly possible by utilizing fault-generated signals, the fault producing a wide spectrum of signals that contains information on the fault distance. These signals are the power frequency component and the transients. In the case of widely used power frequency based algorithms, the IEEE guide for determining fault location on AC transmission and distribution lines, named IEEE Standard C37.114, considers one-ended measurement techniques as well as two-terminal data methods to estimate faults’ locations [1]. The single-end data algorithms carry some errors especially due to the variations of sources’ power, fault’s inception angle, lines’ asymmetry, presence of shunt installations, the combined effect of the load current and fault resistance and the uncertainty into the lines’ zero-sequence impedance estimation [1]-[3]. At the same time, these algorithms have the merit of simpler equipment especially because no data transmission channels between line’s terminals are necessary. The actual technologies in the measurements and in data-transmission make the development of the wide area monitoring feasible and, thus, the possibility to use the information from both transmission lines’ ends [1], [3]-[7]. The errors of two-terminal type algorithms are significantly smaller than the errors of single-terminal data algorithms. At the same time, the double-end algorithms minimize the effect of fault resistance, loading and charging currents, but their precision can be affected by the presence of the harmonics and the frequency deviation [1], [3], [5]. The majority of double-end data fault location techniques use complex devices, as are the phasor measurement units, and the processed quantities are synchronized. The IEEE Synchrophasor Standard, C37.118-2005, sets out criteria for measurement requirements, the majority of applications using as Proceedings of the 9th WSEAS/IASME International Conference on ELECTRIC POWER SYSTEMS, HIGH VOLTAGES, ELECTRIC MACHINES ISSN: 1790-5117 109 ISBN: 978-960-474-130-4