Stray current control is essential in direct current (DC) mass transit systems where the rail insulation is not of sufficient quality to prevent a corrosion risk to the rails, supporting and third-party infrastructure. This paper details the principles behind the need for stray current control and examines the relationship between the stray current collection system design and its efficiency. The use of floating return rails is shown to provide a reduction in stray current level in comparison to a grounded system, significantly reducing the corrosion level of the traction system running rails. An increase in conductivity of the stray current collection system or a reduction in the soil resistivity surrounding the traction system is shown to decrease the corrosion risk to the supporting and third party infrastructure.

Future distributed transactive energy markets are envisioned to integrate multiple entities located mainly at the distribution level of the grid, so that consumers and prosumers can trade power either directly with the upstream wholesale energy market or through local pricing mechanisms (e.g. through "peer-to-peer" contracts or by forming "energy communities"). In such market environments, a transparent loss allocation framework is required to guarantee economic efficiency and fairness. Nevertheless, the unbalanced power flow nature associated with the distribution networks should be fundamentally integrated in the loss allocation process. To this end, this paper presents a graph-based loss allocation framework that harmonizes the physical attributes of the distribution grid with the underlying financial transactions in distributed market settings. The latter is achieved via representing distribution networks as multi-layered radial graphs. The proposed loss allocation framework is tested on an actual LV feeder that is experiencing rapid growth in DG applications.

This study is directed toward furnishing stray current modeling on dc traction systems to cope with the variability of a number of influencing parameters. To this end, the archival value of this study is gained by virtue of two new modeling techniques. These new techniques, first, include a Monte-Carlo-based approach to take into account the variability of the dominant factors influencing the conductance per unit length between the track and the earth. Second, a simulation technique that can provide a more robust representation of the conductance per unit length between the track and the earth coupled with uniform and non-uniform soil models is presented in an attempt to comprehensively assess the levels of stray currents leaving a floating dc traction system.

The tunneling construction in underground DC Metro Systems is mainly based on the bored tunnel method and the cut-and-cover method. Therefore, the stray current assessments and mitigation actions should be tailored according to which method of tunnel construction is used. This paper presents a topologically accurate model for assessing the dynamic stray current picture in cut-and-cover sections of DC metro systems. The dynamic stray current evaluation can provide an indication to the extent of the corrosion problem in the supporting and third-party infrastructures of the system. In this paper, the dynamic evaluations are based on a combination of various ideal and realistic train operation scenarios.

The development of large-scale photovoltaic (PV) plants in rural areas is constantly increasing. However, the knowledge of performing and installing lightning and surge protection in large-scale PV plants is still premature. The main objective of this paper is to provide a method for assessing the external lightning protection and earthing designs that may be installed in large-scale solar applications. Consequently, the method and models presented in this paper may assist engineers to perform a comparison between the use of isolated and nonisolated lightning protection systems, and second to select suitable surge protection equipment.

The production of stray currents by DC light rail systems leads to the corrosion of the supporting and third-party infrastructure in close proximity to the rail system. This paper simulates two parallel tracks that are occupied by two trains: one on each track. This type of modeling constitutes a case study that is utilized to investigate the effect of soil topologies on the corrosion performance of a floating DC light rail system focusing on the supporting and third-party infrastructure. The modeling technique used involves the accurate computation of the shunt and series parameters for use in a resistive-type model using a commercially available software package. The results demonstrate the importance that soil resistivity has on the corrosion risk to traction system and third-party infrastructure. Such information could ultimately be used to vary the level of stray current protection across a light rail system to ensure a consistent lifetime across the whole system.