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

The increased accuracy of the faults’ location is a very actual request of the power grids’ operation and management, reason to develop new and as precise as possible techniques for the estimation of the shortcircuits’ location. The actual fault locating techniques use algorithms based on power frequency quantities or on traveling waves principles, both categories of such fault locators being divided into so-called single, double or multi-ended, depending on the number of the measurement points and, implicitly, on the power grids’ operational structure. Irrespective of the type of the locating technique, the algorithms that derive from traveling waves principles are less affected by the high frequency transients than those based on power frequency quantities but, at the same time, they need high sampling frequencies, special transducer and sophisticated electronic devices. Due to these extra costs, the power frequency based algorithms attract attention, being superior when it comes to the commercial point of view. Consequently, the state of the art of the fault location techniques based on power frequency algorithms and results of power frequency phasors estimation based on in-site registered data and on simulations’ results are presented. A special section of the paper is dedicated to the implementation of the phasor estimation and of the fault location algorithms into the ATP-EMTP software, results of the author’s research. The obtained very flexible programs are 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 refer to the following parameters: 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. Key-Words: ATP simulation, fault location, power-frequency based algorithms, power grids