Abstract-Multi-tapped lines are common in integrated power systems and microgrids which supply variable loads between the main source and the main load. Adopting a cost effective and efficient method for fault location is important for fast power recovery and improving system reliability. A method requiring measurements only at the ends of the main distribution line is proposed in this paper to solve the issue of locating faults on the tapped lines as well as on the main line without any measurement required from the taps. A combination of singleended and double-ended algorithms based on higher frequency impedance estimation are utilized to locate the faults within the tapped line. The study considers different fault types in different locations as well as various fault inception angles. The presented results shows the efficiency and the accuracy of the suggested technique with maximum error less than 3% of the total line length.Index Terms-Fault location, impedance estimation, integrated power systems, protection and tapped lines.

The penetration of Distributed Generation (DG) into electricity distribution systems or the integrated power system such as ship or aircraft power systems present a challenge to fault location techniques. This paper investigates the influence of inverter based DG on a single-ended fault location scheme which uses impedance measurement made from the high frequency content of fault transient. The additional non-fundamental frequency current components contributed from the DG will influence the accuracy of this type of impedance based fault location technique. A single-ended impedance based fault location technique that utilizes the high frequency content (up to 3 kHz) is studied.The study shows that the single-ended method is still able to locate faults with maximum error of 4% compared to the case without DG (which showed a percentage error up to 1%). The study also showed that the DG location has a small influence on the accuracy of the scheme.

The double-ended impedance-based fault location technique (DEFLT) uses the wideband frequency content of the transient generated by the fault to determine the impedance from the point of measurement to the fault. This paper evaluates and develops the DEFLT experimentally for a Shipboard Power System (SPS) to determine its robustness to source impedance, the presence of interconnected loads (“tapped” loads) and tapped lines. Results demonstrate that the estimated impedance (and therefore distance to the fault) is influenced by the presence of tapped loads when the source impedance is large, or when the tapped load is comparable to the rated load of the system. Therefore, a scheme is proposed that compensates for any tapped load without requiring any additional measurements. Using the proposed scheme, the maximum error is significantly reduced from 92 to 13%. Simulation and experimental results show that a high accuracy for the estimated fault location can be achieved.