A new method to locate faults in power networks based on Electromagnetic Time Reversal

Abstract

The paper presents a new method based on the Electromagnetic Time-Reversal (EMTR) for locating faults in power systems. The applicability of the EMTR to electromagnetic transients associated with traveling waves in transmission lines originated by the fault is theoretically demonstrated. A new fault location technique is then proposed and illustrated for a simple case of a singleconductor transmission line, for which the performance of the proposed technique in terms of location accuracy is discussed. The use of the EMTR technique appears to be particularly promising for locating faults in passive and active electrical distribution networks in view of their radial structure.

An efficient method based on the electromagnetic time reversal to locate faults in power networks

“…In this section, we examine the properties of the transmissionline wave equations under time reversal [2]. The time-reversal operator corresponds to the change of the sign of the time,that is, to the following transformation:…”

“…The voltage wave equation for a multiconductor, lossless transmission line reads (2) where is a vector containing the phase voltages at position and time , and and are the per-unit-length matrices of the inductance and capacitance of the line, respectively. Time reversing (2) yields (3) Therefore, if is a solution of the wave equation, then is a solution too.…”

“…As summarized in [1] and [2], various procedures for fault-location assessment have been proposed for transmission and distribution power networks and, in this respect, two main cate- gories can be identified: 1) methods that analyze prefault and postfault voltage/current phasors (e.g., [3]- [5]) and 2) methods that analyze fault-originated electromagnetic transients of currents and/or voltages, (i.e., travelling waves generated by the fault itself, for example, [6]- [14]). As discussed in [2], with reference to the case of distribution networks, typical methods used these days are based on the estimation of the postfault impedance observed in measurement points usually located in primary substations.…”

“…As discussed in [2], with reference to the case of distribution networks, typical methods used these days are based on the estimation of the postfault impedance observed in measurement points usually located in primary substations. With the hypothesis of having a fully passive power system, such an estimation could provide useful information to locate the fault when compared with the line impedance.…”

“…In a previous study [2], the authors of this paper have presented a preliminary discussion on the applicability of the EMTR technique to locate faults in a single-conductor transmission line using multiple observation points. This paper aims at extending the applicability of such a fault-location technique to the case of a single observation point and multiconductor, inhomogeneous transmission lines (for example, composed of a number of overhead lines and coaxial cables).…”