Faulted Section Identification in Mixed Conductor Circuits Using Traveling Wave Magnitudes

A faulted section identification method for mixed conductor circuits is proposed in this paper using magnitudes of current traveling waves available at the line terminals. The ratios of initial aerial-mode magnitudes are used to identify the faulted section. The attenuation and transmission properties of traveling waves are utilized to formulate the proposed method. The method does not require data synchronization. The effectiveness of the proposed method is assessed for faults simulated on a 400 kV transmission network with variations in fault parameters. Accurate identification of faulted sections as well as junctions is achieved by the proposed method, even with the uncertainties in line parameters and traveling wave magnitude estimation. Comparative assessment results show that the proposed method is more accurate compared to the available methods for faulted section identification of mixed conductor circuits.

I. Introduction

Mixed conductor circuits (MCCs) with multiple overhead transmission line (OTL), underground cable (UGC) and subsea cable (SSC) sections are increasingly being used as transmission networks nowadays for offshore wind farms, crossing populated localities and terrains for environmental and aesthetic reasons [1]. The transient nature of over 80% of OTL faults enables autoreclosing (AR), which increases system stability and reliability. Reclosing should be prevented for UGC faults, which are permanent, to prevent further damage. This calls for selective AR operations in MCCs, to reclose only for OTL section faults [2]. Therefore, accurate faulted section identification becomes vital in MCCs.