Hydrogen as an energy carrier holds promising potential for future power systems. An excess of electrical power from renewables can be stored as hydrogen, which can be used at a later moment by industries, households or the transportation system. The stability of the power system could also benefit from electrolysers as these have the potential to participate in frequency and voltage support. Although some electrical models of small electrolysers exist, practical models of large electrolysers have not been described in literature yet. In this publication, a generic electrolyser model is developed in RSCAD, to be used in real-time simulations on the real-time digital simulator. This model has been validated against field measurements of a 1 MW pilot electrolyser installed in the northern part of The Netherlands. To study the impact of electrolysers on power system stability, various simulations have been performed. These simulations show that electrolysers have a positive effect on frequency stability, as electrolysers are able to respond faster to frequency deviations than conventional generators.

For the future, a large-scale expansion of offshore wind energy is expected in Europe. To collect this wind energy and to enable electricity trading between countries, an offshore network will be implemented in the North Sea. Maintaining a high level of security of supply at affordable costs is one of the key objectives in the design and operation of power systems and therefore, the reliability of offshore grids is an important topic of discussion. Whereas onshore, the security of supply is assured by reliability criteria like n-1 redundancy, the same n-1 redundancy might not be an economical solution for offshore networks. For todays (small) offshore networks, n-1 redundancy is hardly economically justifiable, seen from a wind farm owner's point of view. The question then arises how the reliability of large-scale offshore networks should be evaluated and what measures can be taken to maintain a high security of supply onshore. This paper aims at discussing this topic by reviewing the results of recent research work. It is found that whereas for smaller offshore networks reliability evaluation is mainly an economic analysis seen from a wind farm owner's point of view, for large-scale offshore networks, it is necessary to consider the interaction of offshore–onshore networks in reliability analysis. It is proposed to analyze the reliability of combined offshore–onshore power systems in an integrated approach, such that various (offshore and onshore) measures can be considered to find the most economical solution. This article is categorized under: Wind Power > Systems and Infrastructure Energy Infrastructure > Systems and Infrastructure Energy Systems Economics > Systems and Infrastructure.

The increase in renewable energy sources in addition to the decrease in conventional synchronous generators is leading to significant challenges for the power system operators to maintain generation load balance and to manage the system's decreasing inertia. Proton Exchange Membrane (PEM) fuel cells are characterised by high current density and fast power injection, which makes them ideal for frequency containment. This paper presents a generic model for PEM fuel cells developed in PowerFactory for frequency stability studies and provides an evaluation of its performance in a reduced-size dynamic model of the North Netherlands high voltage transmission network. The results show that the PEM fuel cell provides improved frequency response within the containment period when compared with synchronous generators for the same amount of support reserve.

Power systems throughout the world are experiencing increasing levels of power electronics interfaced generation in their generation portfolio. As these devices have a significantly different dynamic behavior than conventional synchronous generators, it is expected that this trend will pose power system stability related challenges. This paper presents the results of a questionnaire conducted within the MIGRATE project. The aim of this questionnaire, to which more than 20 European transmission system operators (TSOs) responded, was to identify and prioritize these challenges. The TSOs identified challenges related to rotor angle stability (two), frequency stability (three), voltage stability (five), and power electronics interactions and resonances (two). In a follow-up survey, the TSOs were asked to rank the challenges based on their severity, probability of occurrence, and time of manifestation. The decrease of inertia was ranked the highest among the 11 issues. Additionally, the TSOs gave insight into current practices with regards to system monitoring and analysis. Based on the ranking, mitigation measures are currently being designed in order to facilitate an even higher amount of power electronics interfaced renewable energy sources in the power system.

In this paper, three topologies of transmission grids in the North Sea with different feasible structures for scenario 2030 are defined. Each of these topologies is optimized towards the objective of minimum total cost (i.e.The sum of investment and operational costs, including the costs of fuel, CO2 emission and load shedding, throughout the lifetime). The topologies are compared through a cost benefit analysis within the scope of six countries surrounding the North Sea. Sensitivity analysis is performed to investigate the implications of each topology against a wide range of uncertainties. As a result, the optimized North Sea Infrastructure in a hub-And-spoke structure with the North Sea Wind Power Hub located at the Dogger Bank leads to the lowest total cost among all compared topologies.

Recently, the installation of new overhead lines (OHLs) faces many challenges mainly due to social and environmental reasons. One solution with widespread public support is the installation of Extra High Voltage (EHV) AC XLPE Underground Cables (UGCs). Although it is encouraging from a social perspective, new challenges arise like concerns about the reliability impact. In this paper, an approach is developed, which examines how the installation of EHV UGCs influences the reliability of transmission networks. The approach accounts for short-term operational measures and calculates several reliability indicators. A numerical case study of the Dutch EHV transmission network is performed. Based on probabilistic sensitivity analysis, it is found that the most influencing factors on the indicators are the loading of the cable connection, the repair time and the cable configuration.

Western Europe is heavily investing in offshore wind power, but the costs of these wind farms remain high. For that reason, current transmission grids for offshore wind energy are predominately radial to reduce investment cost. To date, selection approaches of offshore grid configurations are mainly based on the level of reliability. This paper introduces an alternative selection approach to comprehensively assess the net present value (NPV) of near-shore power grids. The assessment encompasses, among others, a load flow analysis, as well as the sensitivities to parameters like failure rates, repair times and energy prices, for different grid configurations (i.e. radial/ meshed). A case study of the Dutch offshore transmission system shows that this approach helps in finding a suitable tradeoff between lowest feasible NPV, while also improving the reliability (in terms of reduced lost energy) of the offshore grid.