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Wind farm layout optimization is essential to maximize the energy production of renewable energy systems. A new layout optimization method for offshore wind farms is proposed to minimize power deficits due to the wake effect without limitation on the number of turbines, the shape, or the extension of the concession area. The main engine of the algorithm is a gradient-descent method in which throughout the optimization process, new turbines are progressively and randomly included within the concession area and quickly expand outward, looking for areas with less perturbation, in turn, pushing the previous ones. When the optimization process ends, to avoid local maxima, it enters into a process of suppression of the set of locations that cause the greatest potential (power deficit). Then, a map of potential for the entire area is created, and a greedy algorithm places new turbines to complete the layout with the final number of turbines. The overall process is completed in 25 s. To drastically speed up the search process and the creation of the potential map, a simplification has been validated and added: for turbines affected by multiple wakes, the resulting power has been calculated by using a linear aggregation of power deficits, instead of the usual linear (or quadratic) aggregation of speed deficits. Owing to this type of aggregation, an analogy is established between power deficit and repulsive non-isotropic electrostatic potential energy, which allows using the properties of conservative fields. Thanks to this, the process is 20 times faster than any other layout optimization algorithm found in the revised literature. Irregular concession areas are easily treated using Stokes' theorem to detect outer points. [ABSTRACT FROM AUTHOR]

The IEC 61850 standard has driven the development of power systems Protection, Automation, and Control Systems (PACS) over the past years. Although it is well-known for its communication protocols, several concepts and features are underused. This paper presents a new engineering and validation methodology applying the IEC61850 standards concepts to optimize the project life cycle by standardizing and enhancing engineering and testing. An electrical specification has been defined according to the IEC 61850 data modeling, reducing misinterpretations at the specification and configuration stage. The proposed top-down configuration approach establishes a user's profile and product naming to eliminate the vendor's dependability. The validations were performed using modern commercial tools. The results show that the proposed methodology makes it possible to have a reliable engineering process where the output of the previous stage provides all required information is independent of the next one. The project naming approach makes it possible to validate the system integration based on the agnostic system specification files in an early project stage. Thus, the protection devices and supervision systems can be validated independently, reducing integration issues in the later stages without affecting interoperability and making it possible to achieve interchangeability. • Novel IEC 61850 Engineering Process. • Agnostic validation for IEC 61850 compliant systems. • Human-error mitigation. • Electrical Design Enhancement. • Reduced Factory Acceptance Tests (FAT) and Site Acceptance Tests (SAT) times. [ABSTRACT FROM AUTHOR]

In 2002, the European Union set a target of 10% electricity interconnection capacity for 2020: a target that has been further extended to 15% by 2030. Cross-border interconnection of regional/national electricity systems will allow the EU to enhance its security of supply and to integrate more renewables into energy markets. Although the EU has a common renewable directive, every Member State has its own renewable support policy. For the case of Spain, consumers pay the renewable premium in their electricity bills; however, consumers would not be overburdened if premiums were counter-balanced with the energy-cost reduction due to the merit-order effect of renewables. When two markets are interconnected, the energy exchange through the interconnection yields certain expected rent transfers due to the market rules. However, this exchange is also accompanied by other unforeseen rent transfers related to the regional/national policies on renewables. To the authors' knowledge, the identification and quantification of these indirect rent transfers has not been previously addressed. This paper analyses and quantifies how the premiums on regional/national renewables are distributed between neighbouring countries through cross-border exchanges. The analysis focuses on the Iberian/Spanish system and its neighbours, although the methodology could be extended to other systems. To this end, data on the market and premiums has been considered, as well as the exchanges between France, Spain, Portugal, and Morocco, for the years 2015–2017. The main finding of this work is that the Spanish system, due to the lack of a coordinated/harmonized renewable premium policy, has been "importing" about 40 M€/year of renewable premium from France and 17 M€/year from Portugal while "exporting" about 66 M€/year towards the Moroccan systems. [ABSTRACT FROM AUTHOR]