High-voltage direct current (HVDC) transmission lines are increasing in number and overall length. This means their lightning protection must be of higher importance as well. Probability-modulated attractive space (PMAS) theory is a proven geometry-based method for lightning protection calculations. However, it cannot accurately assess the number and parameters of direct lightning strikes to the phase conductor of HVDC lines, because the effect of pole voltage on lightning attachment cannot be considered. This effect can be taken into account with leader progression models, which feature lightning physics models that can quantify the effect of the electric field around the phase conductor, which can be quite complex compared to geometric models in general. In this paper, a novel method, called the attractive space matrix, is presented to examine the effect of the DC electric field around the conductor on the attractive space. The algorithm is based on the physical background of the self-consistent leader inception and propagation model. The results could lead to improved lightning protection of HVDC lines and reduce the outages caused by direct lightning strikes.

In the name of sustainability, renewable energy production plays an increasing role in the electricity generation. With the spread of photovoltaic power plants, new challenges are emerging for experts to maintain grid stability due to their dependence of sunlight intensity. The fact, that power generation of these power plants can be unpredictable, must be considered. In addition, growing in numbers also means that the lightning protection of photovoltaic power plants is more and more important to ensure their energy generation during appropriate weather conditions. According to the standardized procedure, the lightning protection of these systems can be constructed. The paper indicates, the calculations strictly based on the standard are leading to a protection system that is not cost-efficient and - in most cases - elements of the primary protection system can be neglected without significantly lowering the protection level. In order to demonstrate a more efficient way to create primary protection, a real photovoltaic power plant is featured in this article. The method to examine the geometry and plan a more efficient primary lightning protection system is based on the PMAS theory. Different zones of the examined photovoltaic power plant are selected to present the calculation.

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With the emergence of distributed and household power generation, the network usage tariffs based on the net energy consumption are becoming more and more unsuitable to express the real value of the service provided by the network operator. Assets are aging and are subjected to external overstresses even when in standby. Novel load patterns, e.g., due to electric vehicle charging, may cause accelerated aging.Accordingly, operators are seeking methods to calculate the real costs associated with asset aging and failures, which can be the basis of fair and realistic network usage tariffs. In this article, a methodology is proposed for such calculation for selected distribution network components. It considers standby aging, insulation life models and statistics of random failures and external overstresses for medium voltage buried cables, overhead line conductors and transformers.The method enables the estimation of the life consumption rate and other associated costs at any operational state, which can be the basis of tariff calculation.

Renewable energy sources, such as photovoltaic power plants, are an increasing part of the power system. Consequently, the chance of losing these power plants during a thunderstorm is growing and their loss leads to lower green energy share during appropriate circumstances, as well. This publication aims to present the design of primary lightning protection of photovoltaic systems, which has an important part in the protection of solar inverters and panels from overvoltage. The risk of lightning induced phenomena increases with greater and greater plant performance i.e., larger area, however considering plant arrangement and environmental factors a cost-efficient primary lightning protection can be realised for any installation. Incorrect solutions used to construct lightning protection system are presented. The article states that a lower lightning protection rating is sufficient, and primary lightning protection can be omitted in a lot of cases.