Improved fault location through analysis of system parameters during auto-reclose operations on transmission lines

This paper describes a novel single-ended impedance-based fault-location method for transmission lines, which is based upon the analysis of voltage and current during discrete system states that arise during the operation of single- and three-phase autoreclose schemes. A fault-location estimation algorithm, using the data measured during various system states and is capable of locating the fault types involving one fault resistance (i.e., single-line-to-ground fault or line-to-line fault), is developed and presented. The proposed fault-location technique is shown to have high accuracy; results are presented and compared with the well-established Takagi method and the performance of the algorithm is analyzed and discussed. The proposed technique can reduce or negate limitations associated with conventional single-ended methods and can also estimate other factors associated with the fault (e.g., fault resistance and remote source impedance). In addition, it is a potentially economic solution, since it is relatively straightforward to implement on a standard protection relay hardware platform. The proposed method is demonstrated using Electromagnetic Transients Program/Alternate Transients Program simulation models for a variety of different cases. This paper concludes with an overview of ongoing and future work that has the intention of moving the work forward toward implementation within commercially available relay hardware