In this paper, the performance of a lightning protection system (LPS) on a grid-connected photovoltaic (PV) park is studied by simulating different scenarios with the use of an appropriate software tool. The aim of this paper is to highlight the importance of an LPS and optimize its design for the protection of equipment and personnel in case of a direct lightning strike. In particular, developed potential due to lightning strikes is examined considering isolated and non-isolated external LPS. Moreover, the effect of the separation distance on the lightning performance of the PV installation is investigated for different soil structures and grounding systems. The extracted results are expected to support the design and implementation of a secure PV park and endorse its uninterrupted operation considering techno-economically balanced protection measures.

The connection of electric vehicles to distribution networks has been an emerging issue of paramount importance for power systems. On one hand, it provides new opportunities for climate change mitigation, if electric energy used for charging is produced from zero emission sources. On the other hand, it stresses networks that are now required to accommodate, in addition to the loads and production from distributed generation they are initially designed for, loads from electric vehicles charging. In order to achieve maximum use of the grid without substantially affecting its performance, these issues have to be addressed in a coordinated manner, which requires adequate knowledge of the system under consideration. It is advantageous that electric vehicle charging can be controlled to a certain degree. This research provides better understanding of real distribution networks’ operation, proposing specific operational points through minimizing electric vehicle charging effects. The probabilistic Monte Carlo method on high performance computers is used for the calculations.

The decision-making process during system planning of power systems is something that requires integrated tools that evaluate technical parameters, environmental impact, and overall costs and benefits with various performance indicators (i.e., key performance indicators KPIs). Several cost–benefit analysis approaches have been presented worldwide, providing analytic procedures to quantify the impact and practical effects of specific electricity projects. The implementation of innovation technology into the electricity networks play a critical role to optimizing overall costs. The targets set by the Clean Energy Package have been the main driver for the disruption occurring in the electricity sector, setting electrification of sectors and digitalization as additional emerging challenges. In the present paper, an evaluation approach for the flexibility benefits of smart grid innovations will be presented, as it has been developed and implemented in the context of the Horizon 2020 Research and Innovation project FLEXITRANSTORE. Flexibility is a prerequisite in an effort to achieve an electrical system of low CO₂ emissions. Moreover, flexibility contributes to the increase of renewable energy sources penetration, to the network investments deferral and to the enhancement of the efficiency of the system operation, avoiding generation capacity oversizing. Thus, flexibility has been the scope of many projects lately. FLEXITRANSTORE pilot projects are implemented in various sites across Europe and are briefly presented and the respective technologies are propagated on system level approach, evaluating the respective benefits on a specific use case for the power system of Cyprus, where the one of the pilots is located. The paper tries to show the big picture of the project and presents system study use case to highlight the system impacts of the technologies. To this direction, the installation of a BESS to the Cypriot power system is studied, in an effort to examine its impact to the enhancement of the system’s flexibility, considering IRRE as an indicator.

The appropriate circuit modeling of metal oxide gapless surge arresters is critical for insulation coordination studies. Metal oxide arresters present a dynamic behavior for fast front surges; namely, their residual voltage is dependent on the peak value, as well as the duration of the injected impulse current, and should therefore not only be represented by non-linear elements. The aim of the current work is to adjust the parameters of the most frequently used surge arresters’ circuit models by considering the magnitude of the residual voltage, as well as the dissipated energy for given pulses. In this aim, the harmony search method is implemented to adjust parameter values of the arrester equivalent circuit models. This functions by minimizing a defined objective function that compares the simulation outcomes with the manufacturer’s data and the results obtained from previous methodologies.

The adequate protection against lightning surges and the limitation of the expected annual failure rate of high-voltage substations are critical issues, in an effort to secure the safety of the equipment and the personnel. Various factors affect the lightning performance of the substations, determining the developed lightning surges and the expected outage rate, i.e., the grounding resistance, the length of the underground cable between the connected overhead transmission line and the power transformer, and the installation position of the arresters. In the current work, a heuristic method is developed to adjust different parameters of high-voltage substations that upgrade their lightning performance. The proposed methodology can be useful to the studies of substations’ designers and engineers, contributing effectively in the reduction or/and elimination of lightning failures.

This paper proposes a calculation algorithm that creates operational points and evaluates the performance of distribution lines after reinforcement. The operational points of the line are probabilistically determined using Monte Carlo simulation for several objective functions for a given line. It is assumed that minimum voltage at all nodes has to be balanced to the maximum load served under variable distributed generation production, and to the energy produced from the intermittent renewables. The calculated maximum load, which is higher than the current load, is expected to cover the expected needs for electric vehicles charging. Following the proposed operational patterns, it is possible to have always maximum line capacity. This method is able to offer several benefits. It facilitates of network planning and the estimation of network robustness. It can be used as a tool for network planners, operators and large users. It applies to any type of network including radial and meshed.