A new impedance-based fault location scheme for overhead unbalanced radial distribution networks

- New impedance-based fault location approach is proposed for overhead distribution systems using only one end voltage and current measurements..
- The approach compensates various aspects of distribution systems: tapped laterals, time varying loads, and unbalanced operations.
- One quadratic formula is introduced with two groups of constants for estimating location of all fault types.
- The proposed approach is extensively tested using MATLAB simulations on a typical real 11 kV distribution system to ensure its effectiveness.
- The proposed approach has proved robustness to overcome the challenges of network topology change and non-homogenous network sections.

This paper proposes an analytical impedance-based fault location scheme for distribution systems. The approach is based on voltage and current measurements extracted at only one-end feeding substation. Modal transformation is implemented to decompose the coupled three phase equations due to mutual effects into decoupled ones, and hence directly calculating fault distance in each section without iterative processes. The proposed approach considers various aspects of distribution systems: intermediate loads along the feeder, tapped laterals and sub-laterals at various nodes, time varying loads, and unbalanced operations. The proposed algorithm is extensively investigated on a typical real 11 kV distribution system, South Delta electricity sector, Egypt using MATLAB environment. Different cases are studied considering various loading conditions, varied fault resistance values and different fault types. The achieved results ensure the effectiveness of the proposed fault locator irrespective to fault conditions. Besides, the robustness of the proposed scheme against unbalanced loading, network topology change and non-homogenous network sections is also confirmed.