Plenary Lecture

Assessment of Power-Frequency Based Algorithms for Fault Location in Power Grids

Professor Marcel Istrate
Vice Dean of the Electrical Engineering Faculty
Technical University "Gheorghe Asachi" of Iasi
Romania
E-mail: mistrate@ee.tuiasi.ro

Abstract: The complexity of the actual power grids implies dynamic operative structures leading to more frequent and dynamic changes of the fault currents' levels and, as a consequence, the sensitivity and selectivity of an entire population of relays must be frequently verified and adjusted. At the same time, these changes into the operating schemes of the power grids, eventually as a result of the distributed generation using unconventional sources, give an increased importance to the detection and the location of the grids' lines faults, not only in the long transmission lines but in the distribution ones, too.
Nowadays, the trend into the power grids' operation is that of the quick faults' location, 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 components and the transients. Traveling wave based fault location techniques need a high sampling frequency, special transducer and sophisticated electronic devices, becoming more expensive and not as developed as the power-frequency based fault location techniques.
This paper presents the state of the art of the fault location techniques based on power frequency phasors estimation, together with a mathematical model of a fault locator processing only transient voltages, result of the investigations conduced by the author.
A section of the paper will be dedicated to the algorithms used for power frequency phasors estimation and the results obtained on the basis of in-site registered results. A special section of the paper will be dedicated to the implementation of the phasor estimation and of the fault location algorithms into ATP-EMTP software, results of the author's research. The very flexible programs, obtained by these means, will be used to identify the influence of some grid's parameters on fault locating error. The parametrical analysis and, thus, the assessment of the fault location accuracy will refer to the following parameters: sources' power, fault's inception angle, fault's position along the grid's lines, lines' asymmetry, the combined effect of the load current and fault resistance, the uncertainty into the lines parameter's estimation, the presence of the harmonics and the frequency deviation.

Brief Biography of the Speaker:
Marcel ISTRATE was born in Suceava, Romania, on the 5th of September 1960. He graduated in Electrical Engineering at the Technical University "Gheorghe Asachi" of Iasi, Romania, in 1985. Between 1985 and 1988 he worked as an electrical engineer for design and maintenance of low and medium voltage grids and equipment in a water supply company. In 1988 he joined the Technical University "Gheorghe Asachi" of Iasi, Romania. At present, he is a professor in the Power System Department of the Faculty of Electrical Engineering. In 1996 he received the Ph D degree in power systems from the Technical University "Gheorghe Asachi"of Iasi and in 2003 and 2009 he has attended postdoctoral studies in energy efficiency and in educational management, at the same university. In 1999, he visited the Ecole Superieure d'Ingineurs de Poitier, France, and Escuela Tecnica Superior de Ingenieros Industriales, Valladolid, Spain. Since 2004 he is Vice Dean of the Electrical Engineering Faculty. He is conducting lectures on High Voltage Engineering, Electromagnetic Transients and Pollution Control of the Power Plants. His scientific and educational experience is disseminated, as author or coauthor, in 13 books, over 120 papers in the area of power systems, published in international journals and conference proceedings (11 papers in ISI and other indexing international databases) and 17 patents (all available in ISI web of Science). He also has a valuable project management experience, being project manager or member in a research team of over 45 research grants sponsored by national research organizations or by different companies. He is member of CIGRE since 2005, member of the National Romanian Committee of World Energy Council and member of the editorial advisory board of the Environmental Engineering and Management Journal. His main research interests are directed towards computer assisted analysis of the transients, fault location in power grids, protection against lightning strokes and against overvoltages, modeling and simulation of power grids' protection systems.