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In compensated distributed networks (CDN), minimizing the asymmetry in the shunt parameters of the power lines is a key factor for avoiding excessive neutral voltages which is necessary not only for safety but also for improving the sensitivity of detecting ground faults, particularly when bush-fire mitigation is a major concern. This paper offers a comprehensive analysis and modeling of the asymmetry of the power lines in CDN. Unlike the existing analyses which assume the asymmetry can be lumped in one phase, the proposed analysis is based on more practical assumption by considering the asymmetry in all of the phases of the power lines. The proposed analysis is used to develop an equivalent circuit for asymmetrical CDN which then used to develop a new method for calculating the per-phase asymmetries in the shunt parameters. The proposed method has been validated based on simulations of real networks. [ABSTRACT FROM AUTHOR]

This paper presents a decentralized fault detection technique for power distribution systems with resonant grounding. The aim of this paper is to detect single phase to ground faults and identify the faulty feeder within three cycles of the fault occurrence. In the proposed technique, faults are first detected based on the neutral voltage displacement. The pre-fault and post-fault voltages (phase to ground) are then used to identify the faulty phase. Finally, the faulty feeder (as well as the faulty area of a long feeder) is identified from the relationship between the initial transient of the zero-sequence current and the faulty phase voltage just after the occurrence of faults. A signal processing tool called mathematical morphology is utilized to identify the faulty feeder. To identify the faulty feeder, it is also required to know the fault occurrence time that is estimated using the slope of the neutral voltage. The main feature of the proposed scheme is that this technique only uses voltage and current signals from the corresponding voltage transformers and current transformers. Therefore, it does not require communication among protection devices in the same or different feeders to identify the faulty feeder. The proposed technique also has the ability to distinguish the nature of faults, i.e., whether the faults are permanent or temporary. The effectiveness of the proposed scheme is tested, on an IEEE test system as well as on a practical test system, using MATLAB/SimPowerSystems. Simulation results show that the proposed technique can quickly detect the single phase to ground faults in a resonant grounding power distribution system and identify the faulty feeder. It is also capable of distinguishing faults from other disturbances. Moreover, it works under different compensation levels as well as for different fault inception angles. [ABSTRACT FROM AUTHOR]