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This study employs the PRISMA-A methodology to conduct a systematic review of transformer fault diagnostics using Dissolved Gas Analysis (DGA) data. A comprehensive analysis was performed across four major databases—IEEE, Scopus, ScienceDirect (Elsevier), and Web of Science—yielding 12,511 initial records. Following rigorous evaluation, including duplicate removal and eligibility criteria assessment, 1190 articles underwent statistical evaluation. The search strategy focused on keywords related to transformer faults and diagnostic methods, resulting in a refined dataset of 4810 DGA samples from wind park transformers. Detailed statistical analysis of gas concentrations—hydrogen, methane, carbon monoxide, carbon dioxide, ethylene, ethane, acetylene, oxygen, and nitrogen—revealed significant insights into fault indicators and distribution patterns. Furthermore, predictive modeling using various machine learning algorithms highlighted the efficacy of models such as Random Forest and CART, achieving accuracies up to 95.29 % in fault prediction tasks. Proposed revisions to IEEE gas concentration thresholds aim to enhance early fault detection capabilities, thereby improving maintenance planning and transformer reliability. The findings underscore the importance of advanced analytics and sustainable practices in transformer diagnostics, calling for continued research in predictive maintenance and eco-friendly insulation technologies to meet future energy challenges.

The aim of this work is to investigate the effect of extreme high ambient air temperature on the performance of a wind farm operating in Algeria Saharan area. The analysis is carried out using in-situ field-data and the Wind Atlas Analysis and Application Program (WAsP). The predicted annual energy production is compared to the actual performance of the wind farm. Then the influence of the air density variation on the AEP prediction is evaluated. It is shown that the error on predicted AEP is reduced when one take into account the monthly variation of the air density. [ABSTRACT FROM AUTHOR]

Offshore wind farms (OWFs) can increase the transfer and stock of organic carbon (OC) in the surrounding sediments during their operational phase, while their construction and decommissioning release carbon. To answer the question whether sediments of OWFs trap more OC than they release, we estimate the net carbon effect over the entire life cycle (construction, operational and decommissioning phases) of OWFs in the Southern North Sea. Based on existing studies we compare the increased OC flux due to the colonization of organisms at the foundations of wind turbines and the OC loss due to sediment-disturbing activities during construction and decommissioning. Our results show that the areal intensity of carbon release in the disturbed areas is about 43.5 times higher than that of carbon trapping in the entire area of the OWFs. However, since the disturbed areas only account for about 0.50 ± 0.06% of the total area of the OWFs, in absolute terms about 4.6 ± 1.4 times more carbon is trapped in the sediment of the OWFs than is released. Due to limited data availability and the resulting need for extensive assumptions, our estimates only represent orders of magnitude. We therefore provide sensitivity estimates that define the limits of our calculations in terms of disturbance depth, remineralisation ratio, scour protection measures and heterogenous OC contents. In addition, we identify shortcomings of our extrapolation. Further research, especially more advanced impact assessments of construction and decommissioning processes must follow to improve the understanding of impacts of OWFs on sedimentary OC.

This study employs the PRISMA-A methodology to conduct a systematic review of transformer fault diagnostics using Dissolved Gas Analysis (DGA) data. A comprehensive analysis was performed across four major databases-IEEE, Scopus, ScienceDirect (Elsevier), and Web of Science-yielding 12,511 initial records. Following rigorous evaluation, including duplicate removal and eligibility criteria assessment, 1190 articles underwent statistical evaluation. The search strategy focused on keywords related to transformer faults and diagnostic methods, resulting in a refined dataset of 4810 DGA samples from wind park transformers. Detailed statistical analysis of gas concentrations-hydrogen, methane, carbon monoxide, carbon dioxide, ethylene, ethane, acetylene, oxygen, and nitrogen-revealed significant insights into fault indicators and distribution patterns. Furthermore, predictive modeling using various machine learning algorithms highlighted the efficacy of models such as Random Forest and CART, achieving accuracies up to 95.29 % in fault prediction tasks. Proposed revisions to IEEE gas concentration thresholds aim to enhance early fault detection capabilities, thereby improving maintenance planning and transformer reliability. The findings underscore the importance of advanced analytics and sustainable practices in transformer diagnostics, calling for continued research in predictive maintenance and eco-friendly insulation technologies to meet future energy challenges., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Author.)

Distributed optimization methods have been vastly investigated and approved by the researchers due to their major advantages including high accuracy, secured performance and low time-consuming structure compared to the centralized frameworks. This paper aims to provide a novel method based on fuzzy primal-dual method of multipliers (PDMM) to manage the optimal energy scheduling problem in the smart grids. The proposed method illustrates some unrivaled points of interest which are more preferable than the conventional alternating direction method of multipliers (ADMM) in terms of preciseness and convergence speed. The proposed smart grid is constructed of different components such as generators, wind park and storage devices as two of the most profitable and applicable energy sources in the power grids. In order to model the uncertainty effects, a stochastic method based on fuzzy cloud theory is developed to capture the high-dimension uncertainty in a more realistic way. The units are scheduled to exchange energy in the smart grid in a fully distributed manner when meeting the active/reactive generation and demand balance. Such an energy exchanging process continues until a proper solution would be found through which all the agents in the system are satiated. The simulation results on the IEEE 24-bus test system indicate that the proposed stochastic distributed energy management framework yields an error of less than 0.018% compared to the centralized approach.

Subsynchronous Interaction (SSI) phenomenon is known to be one of the most frequent and severe stability issues of a Wind Park (WP), and can potentially lead to a significant loss of power generation. The broad impacts of this phenomenon on a power grid have made WPs interesting targets for cyber attacks. To initiate the SSI, an adversary can target either the power grid (external attacks) or the cyber system of WPs (internal attacks). This paper proposes a mitigation scheme for attacks that initiate the SSI phenomenon in series compensated doubly-fed induction generator (DFIG)-based WPs. External attacks are addressed by employing a robust static-output-feedback Subsynchronous Damping Controller (SSDC), which is designed based on the insensitive strip region and Linear Matrix Inequality (LMI) techniques. Internal attacks, however, are detected by comparing the estimated and measured converters’ currents. Once the compromised measurements are detected, the designed SSDC is restructured to mitigate the attacks. The effectiveness of the proposed method is demonstrated using detailed Electromagnetic Transient (EMT) simulations for both internal and external cyber attacks. Additionally, the performance of the proposed method is corroborated using a real-time co-simulation framework. [ABSTRACT FROM AUTHOR]

Geospatial potential for harvesting wind energy is not an easy task to perform in conditions of deficiency of accurate data in remote and large areas (macro to medium locations). There are different methodologies available to identify the most suitable location for the installation of wind power generators. One of the most suitable approaches that employ the Multi-Criteria Analysis method for wind energy potential of the Municipality of Knjaževac (East Serbia) is combining the Analytic Hierarchy Process (AHP) and Geographic Information Systems. Collection and creation of geospatial data for the research encompassed meteorological data from all available sources, digital elevation model (DEM) to analyze the orography of the terrain, and Landsat 8 satellite data to analyze six land cover (LC) classes. The identification of three best locations for the wind power generators (wind farms) using Multi-Criteria Decision Making (MCDM) analysis solved the major location problem: how to select the best locations for investment in the renewable energy sector and minimize the impact on the environment. The result indicates that only one part of the municipality, at the hub height of 100 m, has enough wind potential to produce energy.

Short-term electromagnetic interference (EMI) pertains to the total result produced by the occurrence of intermittent, inductive, and conductive couplings on a buried pipeline system. For example, this type of EMI takes place when considering the fault conditions of a single ac power line, acting in the nearby vicinity of a pipeline system. In the context of this article, the effect of the short-term EMI is unfolded through a real case study. This case study involves a 20.7-MW wind park (WP) with extended underground power cable connections, which are laid nearby a high-pressure gas pipeline system. In particular, the impact of critical fault events, associated with the WP's power cables, on the pipeline system is comprehensively assessed. The assessment is achieved by the concurrent use of two powerful software tools that are respectively eligible for the accurate short-circuit analysis of the electrical circuit of the WP and for EMI evaluation on the pipeline. To this extent, the simulation results are thoroughly discussed and an effective mitigation solution is evidently presented. [ABSTRACT FROM AUTHOR]

The paper investigates the influence of the period covering wind data on the technical and economic analysis of wind power generation. This study is applied to two sites located in the south of Algeria. Using 12 years of wind data collected by the Algerian Meteorological Office, the annual evolutions of mean wind speed and direction are examined. Then two data periods are considered for the evaluation of (i) the wind resource, (ii) the expected annual energy production and (iii) the electricity generated cost. The influence of the data period on the predicted results is highlighted. [ABSTRACT FROM AUTHOR]

In recent years, wind power in Brazil has emerged as an alternative to diversify the country′s energy mix and minimize the emission of pollutants derived from fossil fuels. The state of Rio Grande do Norte, in the Brazilian Northeast, has considerable potential for the generation of wind energy due to the occurrence of strong winds in many areas along the coast and in the interior of the state, in places with higher altitudes. However, wind energy, despite being considered clean and renewable, can cause environmental impacts in those places. Thus, the present study analyzed the perception of environmental impacts caused by the installation of wind farms in the agricultural areas of Northeast Brazil. The study was carried out in the municipality of Serra do Mel, in the western region of the state of Rio Grande do Norte, based on a survey of local farmers. The study concluded that farmers live without major problems and without apparent conflicts with wind farms but have little knowledge about the environmental impacts. In the perception of most farmers, there are few negative environmental impacts, and those that exist are barely noticed or still do not cause damage to most farmers in the region.

The foundations of offshore wind turbine parks are often constructed by means of percussion pile driving. Broadband impulsive sounds generated by pile driving may disturb and distract marine mammals such as harbor porpoises (Phocoena phocoena); their concentration may be reduced, affecting the skills they need for foraging (e.g., timing and precision) or reducing their ability to catch prey and, thus, their foraging efficiency. The resulting reduction in fitness may eventually lead to population declines. Therefore, it is important to understand the effects of these anthropogenic sounds on the ability of harbor porpoises to catch fish. Two captive harbor porpoises (porpoise F05 and porpoise M06) performed a fish-catching task (i.e., retrieving dead fish from a net feeding cage) while they were exposed to low ambient noise (quiet conditions) and impulsive pile-driving playback sounds at three (porpoise M06) or four (porpoise F05) mean received single-strike sound exposure levels (SELss) between 125 and 143 dB re 1 µPa²s. The two study animals differed in their fish-catching success rate at all noise levels, including under quiet conditions: Porpoise F05 was less likely to catch fish than porpoise M06. They also responded differently to increasing SELss: Only porpoise F05 was significantly more likely to terminate trials and less likely to catch fish as SELss increased above 134 dB, but her trial failure rate remained unaffected by increas- ing SELss. The time taken to catch a fish did not vary with SELss but was slightly longer for por- poise F05 than for porpoise M06. Results suggest that high-amplitude pile driving sounds are likely to negatively affect foraging in some harbor porpoises by decreasing their catch success rate and increasing the termination rate of their fish-catching attempts; the severity of the effects is likely to increase with increasing pile driving SELss. However, individual differences in responses to sound, termination rates, and fish-catching success (even in ambient conditions) may complicate the quantification of the impacts of pile driving sounds on harbor porpoises. [ABSTRACT FROM AUTHOR]

The use of supplementary controllers for mitigating subsynchronous control interaction (SSCI) in doubly-fed induction generator based wind parks is quite promising due to their low investment costs. These SSCI damping controllers are typically designed and tested using an aggregated wind turbine (WT) model that represents the entire wind park (WP). However, no research has been reported on their implementations in a realistic WP. This paper, first presents various implementation schemes for a linear-quadratic regulator based SSCI damping controller, and discusses the corresponding practical challenges. Then, an implementation scheme that obviates the need for high rate data transfer between the WTs and the WP secondary control layer is proposed. In the proposed implementation, the SSCI damping controller receives only the WT outage information updates from the WP controller, hence it is not vulnerable to the variable communication network latency. The SSCI damping controller parameters are also modified when there is a change in WT outage information for the ultimate performance. The effectiveness of the proposed implementation scheme is confirmed with detailed electromagnetic transient simulations, considering different wind speeds at each WT and WT outages due to sudden decrease in wind speeds. [ABSTRACT FROM AUTHOR]

Highlights • Optimization model finding market bid providing maximal profit is proposed. • Two stage optimization model maximizes profit and minimizes imbalance penalties. • Calculation of the expected profit considers all given operation scenarios. Abstract This paper presents the model for finding an optimal joint bid of hydroelectric systems and wind parks on a day-ahead electricity market. The optimization problem is presented as a two-stage model where the goal of the first stage is to maximize the profit according to the main scenario and the obtained production plan is then tested in all other scenarios that can occur in the second stage where the goal is to minimize the profit reduction caused by imbalance penalties or changes in expected day-ahead prices. The optimization procedure is presented as a mixed integer linear optimization problem. The proposed model is applied in a case study in order to present the main model features. Production assembly in the case study is based on real power plants and consists of two cascade hydropower plants and two wind parks. [ABSTRACT FROM AUTHOR]

The program "Birds" has been developed for analyzing the risks of bird collisions with turbines of wind power stations. The mathematical model of the program is based on the recommendations of the Scottish Natural Heritage Foundation. The source database contains the necessary information in relation to the operating conditions of the wind farm "Primorsk-1", which is supposed to be built on the coast of the Azov Sea in the Zaporizhia region. If necessary, the user can enter his own values and get results on the interaction of birds with wind turbine rotors on the following indicators: bird flight time through the rotor space, probability of collision of one individual with the turbine, depending on its flight characteristics and parameters of the wind electrical installation, number of bird collisions at a given time interval. The program was tested using the example of calculating the number of collisions of birds with rotors during one year of operation of the Primorsk-1 wind park. It is shown that the probability of a collision of one bird with the rotor depends little on its geometric dimensions and is in the range of 11-15%. The total number of collisions of all birds on the territory of the wind farm will be 6,4 birds, which corresponds to 0.25 individuals per turbine. Most of this amount (about 4.8) refers to two species: Merops apiaster and Larus ridibundus.

Subsynchronous control interaction (SSCI) is the interaction between the power-electronics control and the series-compensated transmission system that occurs at frequencies below the system nominal frequency. SSCI may occur between the doubly-fed induction generator (DFIG) control system and the series-compensated transmission line, to which the wind park (WP) is connected. Not only do the DFIG control system parameters, but also the WP operating conditions have a significant impact on SSCI. In this paper, the impact of WP operating conditions and DFIG control system parameters on SSCI is analyzed in detail. Guidelines are presented for modifying the DFIG control system parameters to ensure safe operation and acceptable transient responses due to faults. This paper also examines the accuracies of various analytical tools used for SSCI problem identification and proposes a new frequency scan analysis approach for accurate prediction of potential SSCI problems. [ABSTRACT FROM PUBLISHER]

The wind power generation is currently a promising renewable energy technology. A critical feature of wind park is the existence of large distributed capacitance because of the cable laying and offshore cable transmission. This phenomenon is likely to cause harmonic resonance issues, and may threat the safety operation of wind parks. Meanwhile, the operation condition of wind turbines and the topology of wind parks affect the system structure and parameters, then affect the system harmonic resonance. Therefore, a dynamic harmonic model of the most widely used doubly fed induction generator was established to study the behaviors of harmonic resonance. At the same time, other primary electrical components in wind parks are also considered, such as power cables and transformers. In this paper, the harmonic resonance of the wind park is investigated based on the measured data and the modal sensitivity analysis. With considering the impact of various parameters on the frequency and amplitude of resonance, the sensitivity indices for these parameters are also calculated. Finally, the frequency shift method is introduced to solve resonance issue. [ABSTRACT FROM PUBLISHER]

Investments in energy sector are usually long term processes both in construction and exploitation phase, and therefore require many conditions to be satisfied, mostly from legislative and technical sector. While the legislative can change in accordance with economy activities in the country, technical data (on-site measurements) which are the main base for energy facility design, need to be reliable as much as possible. Wind energy has a significant global potential which exceeds the world's electrical energy consumptions. This paper presents the estimation of wind energy potentials in Montenegro, based on all previous available studies in this field. The wind energy potential in Montenegro is based on a combination of 3-D numerical simulations of wind fields on the entire territory, and comprehensive on-site measurements. The preliminary studies show that there is a potential of areas with high and mean values of a capacity factor about 400 MW, and annual production of 900 GWh of electric energy. The share of wind parks in the total installed power in Montenegro is planned to be about 8%, while an adequate ratio of wind parks in an annual production from renewable sources (large hydro power plants are included here) is estimated to be 11.4%. The paper presents the current state of art in the field of building of wind parks in Montenegro. A particular attention was paid to the legislation framework and strategic documents in the energy area in Montenegro. [ABSTRACT FROM AUTHOR]

The foundations of offshore wind turbines are attached to the sea bed by percussion pile driving. Pile driving sounds may affect the behavior of fish. Acoustic dose-behavioral response relationships were determined for sea bass in a pool exposed for 20 min to pile driving sounds at seven mean received root-mean-square sound pressure levels [SPLrms; range: 130–166 dB re 1 μPa; single strike sound exposure level (SEL ss ) range: 122–158; 6 dB steps]. Initial responses (sudden, short-lived changes in swimming speed and direction) and sustained responses (changes in school cohesion, swimming depth, and speed) were quantified. The 50% initial response threshold occurred at an SEL ss of 131 dB re 1 μPa 2 s for 31 cm fish and 141 dB re 1 μPa 2 s for 44 cm fish; the small fish thus reacted to lower SEL ss than the large fish. Analysis showed that there is no evidence, even at the highest sound level, for any consistent sustained response to sound exposure by the study animals. If wild sea bass are exposed to pile driving sounds at the levels used in the present study, there are unlikely to be any adverse effects on their ecology, because the initial responses after the onset of the piling sound observed in this study were short-lived. [ABSTRACT FROM AUTHOR]

Hydrodynamic Ocean Circulation Models and Lagrangian particle tracking models are valuable tools e.g. in coastal ecology to identify the connectivity between offshore spawning and coastal nursery areas of commercially important fish, for risk assessment and more for defining or evaluating marine protected areas. Most studies are based on only one model and do not provide levels of uncertainty. Here this uncertainty was addressed by applying a suite of 11 North Sea models to test what variability can be expected concerning connectivity. Different notional test cases were calculated related to three important and well-studied North Sea fish species: herring ( Clupea harengus ), and the flatfishes sole ( Solea solea ) and plaice ( Pleuronectes platessa ). For sole and plaice we determined which fraction of particles released in the respective spawning areas would reach a coastal marine protected area. For herring we determined the fraction located in a wind park after a predefined time span. As temperature is more and more a focus especially in biological and global change studies, furthermore inter-model variability in temperatures experienced by the virtual particles was determined. The main focus was on the transport variability originating from the physical models and thus biological behavior was not included. Depending on the scenario, median experienced temperatures differed by 3 °C between years. The range between the different models in one year was comparable to this temperature range observed between modelled years. Connectivity between flatfish spawning areas and the coastal protected area was highly dependent on the release location and spawning time. No particles released in the English Channel in the sole scenario reached the protected area while up to 20% of the particles released in the plaice scenario did. Interannual trends in transport directions and connectivity rates were comparable between models but absolute values displayed high variations. Most models showed systematic biases during all years in comparison to the ensemble median, indicating that in general interannual variation was represented but absolute values varied. In conclusion: variability between models is generally high and management decisions or scientific analysis using absolute values from only one single model might be biased and results or conclusions drawn from such studies need to be treated with caution. We further concluded that more true validation data for particle modelling are required. [ABSTRACT FROM AUTHOR]

Observational evidence of turbulent wakes behind wind parks' piles motivated a series of numerical experiments, aiming to identify the dynamic regimes associated with wakes' generation in tidal basins. We demonstrate that the obstacles such as piles of wind parks give rise to vortices similar to the known Kármán vortices which affect substantially the turbulent kinetic energy. The latter can be considered as the agent enhancing sediment remobilization from the ocean bottom, thus making wakes well visible in satellite data. The temporal and spatial variability of studied processes is analyzed under stationary and nonstationary conditions. The dependence of a vortex generation and evolution upon the environmental conditions is also studied, which demonstrates a large variety of appearances of turbulent wakes. The comparison between simulations using a suspended sediment model and satellite images demonstrated that the model is capable to realistically simulate sediment wakes observed in remote sensing data. [ABSTRACT FROM AUTHOR]

Wind energy is among the most relevant types of renewable energy and plays a vital role in the projected European energy mix for 2020. The aim of this paper is to comprehensively present current risks and risk management solutions of renewable energy projects and to identify critical gaps in risk transfer, thereby differentiating between onshore and offshore wind parks with focus on the European market. Our study shows that apart from insurance, diversification, in particular, is one of the most important tools for risk management and it is used in various dimensions, which also results from a lack of alternative coverage. Furthermore, policy and regulatory risks appear to represent a major barrier for renewable energy investments, while at the same time, insurance coverage or alternative risk mitigation is strongly limited. This emphasizes the need for new risk transfer solutions to ensure a sustainable growth of renewable energy. [ABSTRACT FROM AUTHOR]

Development of alternative energy sources has become a necessity as fossil energy resources are declining. At the same time, energy demand is rapidly increasing, putting the world on the verge of a global energy crisis. Moreover, the extensive use of conventional energy sources is polluting the environment and causing global warming. On the other hand, wind and other renewable energy sources are viable and clean alternatives to fossil fuels. Low operating cost and extensive availability make wind one of the most advantageous and effective renewable energy sources. This paper provides an exposure to the necessity for deployment of renewable energy sources and the worldwide installed capacity of wind power as well as a review of various wind technologies in conjunction with their applications and devices of operation. Furthermore, this paper discusses the cost of electric generation in wind power plants as well as the economic and environmental policies that advocate the installation of wind energy systems. [ABSTRACT FROM AUTHOR]

A dynamic reduced order model using integral manifold theory has been derived, which can be used to simulate the DOIG wind turbine using a double-winding representation of the generator rotor. The model is suitable for use in transient stability programs that can be used to investigate large power systems. The behavior of a wind farm and the network under various system disturbances was studied using this dynamic model. Simulation results of the proposed method represents that integral manifold method results fit the detailed model results with a higher precision than other methods.