Operation Of Wind Power Plants Research Articles

The effect of variability-mitigating market rules on the operation of wind power plants

In power systems with many wind generators, market rules have been slowly changing in order to mitigate or internalize the system costs relating to wind variability. We examine several potential market policies for mitigating the effects of wind variability. For each market policy, we determine the effect that the policy would have on the operation and profitability of wind plants, using time series analysis to estimate the actions of profit-maximizing wind generators acting as price takers. We identify policy scenarios that significantly reduce short-term (30-min) wind fluctuations while having little effect on wind plant revenue. For example, in a scenario where the ramp-rate of wind is limited and ramping violations are assigned a small monetary penalty, a loose ramp rate limit (40 % per 15-min period) can reduce 30-min fluctuations by 35 % while reducing wind plant revenue by only 0.2 %. The novel market-based strategies investigated in this work may enable reductions in the overall system cost of wind integration and can be designed so that both wind generators and system operators are better off than under the status quo.

The peculiarities of the wind power generating autonomous system exploitation in the underground mountain iron-ore mining

The possibility and specifics of wind power complex functioning in operating underground iron-ore mining were analyzed. Aerodynamic features of ventilation airflows in underground iron-ore mining and their impact on the wind power plant operation were investigated. The design of wind power plant was substantiated and proposed for the practical implementation to realize its optimum possible efficiency. The structure of electromechanical part of the wind power complex and the control system for it with a predicted reliability and quality capacity of power supply to consumers of underground iron-ore mining electric power were developed. The behavior was investigated, and the control law was developed for the regulator of capacitive excitation current of induction generator of wind electromechanical complex with direct wind power conversion into electric power that provides energy-efficient operation modes of wind power plant electromechanical complex. The economic efficiency of using wind power plant in underground iron-ore mining was proved.

Recent advancement on technical requirements for grid integration of wind power

The installation of wind energy has experienced rapid development during recent years. As a result, the operation of power system can be greatly affected. Therefore, the operators of different countries have formulated the grid codes which reinforce technical requirements for wind power plants. In this paper, recent grid codes published in different countries have been carefully reviewed. The basic requirements of active power control and reactive power compensation, both of which have particular influence on wind power plants operation, are focused on. Based on this review, it is understood that with the increasing integration of wind energy, there is a worldwide trend to regulate the performance of wind power plants so that they can contribute to the stability and reliability of power system.

Doubly Fed Induction Generator in an Offshore Wind Power Plant Operated at Rated V/Hz

This paper introduces the concept of constant volt/hertz operation of offshore wind power plants (WPPs). The deployment of offshore WPPs requires power transmission from the plant to the load center inland. Because this power transmission requires submarine cables, there is a need to use high-voltage direct current (HVDC) transmission, which is economical for distances greater than 50 km. In the concept presented here, the onshore substation was operated at 60 Hz synced with the grid, and the offshore substation was operated at variable frequency and voltage, allowing the WPP to be operated at constant volt/hertz. In this paper, a variable frequency at rated volt/hertz operation was applied to a Type 3 doubly fed induction generator (DFIG) wind turbine generator. The size of the power converter at the turbine can be significantly reduced from 30 % of the rated power output in a conventional Type 3 turbine to 5 % of the rated power. The DFIG allows each turbine to vary its operating speed with respect to the other turbines. Thus, small wind diversity within the WPP can be accommodated by the DFIG, and the collector system frequency can be controlled by HVDC to follow large variations in average wind speed.

Statistical and Spectral Analysis of Wind Characteristics Relevant to Wind Energy Assessment Using Tower Measurements in Complex Terrain

The main objective of the study was to investigate spatial and temporal characteristics of the wind speed and direction in complex terrain that are relevant to wind energy assessment and development, as well as to wind energy system operation, management, and grid integration. Wind data from five tall meteorological towers located in Western Nevada, USA, operated from August 2003 to March 2008, used in the analysis. The multiannual average wind speeds did not show significant increased trend with increasing elevation, while the turbulence intensity slowly decreased with an increase were the average wind speed. The wind speed and direction were modeled using the Weibull and the von Mises distribution functions. The correlations show a strong coherence between the wind speed and direction with slowly decreasing amplitude of the multiday periodicity with increasing lag periods. The spectral analysis shows significant annual periodicity with similar characteristics at all locations. The relatively high correlations between the towers and small range of the computed turbulence intensity indicate that wind variability is dominated by the regional synoptic processes. Knowledge and information about daily, seasonal, and annual wind periodicities are very important for wind energy resource assessment, wind power plant operation, management, and grid integration.

Impact of high wind power penetration on transmission network expansion planning

Power generation from renewable sources has greatly increased in the last decade. Accordingly, the planning of power system expansions must incorporate the special features of these types of energy sources. Long-term power transmission expansion planning usually does not take these differences among energy sources into account because of the long period considered. However, modelling the special features of renewable sources may influence the optimal transmission plan. In this study, the authors propose a methodology for long-term power transmission expansion planning that incorporates the costs associated with the operation of wind power plants. In particular, the authors model the transmission expansion planning problem as a mixed-integer linear program in which the variability of the wind resource, the impact of wind power operation in the system security and the impact of wind power operation in the reserve market are incorporated. The authors illustrate the methodology using a 34-node version of the main Chilean network.

Wind Speed Prediction Model Based on Radial Basis Functional Neural Network

Wind speed forecasting is important to operation of wind power plants and power systems. To solve short term wind speed prediction problem, a radial basis functional neural network prediction model for wind speed time series based on cross iterative fuzzy clustering algorithm and regularized orthogonal least squares algorithm is proposed. First, the optimal fuzzy clustering centers of samples are computed by cross iterative fuzzy clustering algorithm. Then radial basis functional centers are optimized by regularized orthogonal least squares algorithm, and the generalized cross-validation is regarded as criteria to halt center selection. The proposed model centralizes advantages of both algorithms, and it can decrease network scale, improve generalization performance, accelerate network training speed and avoid ill-conditioning of learning problems. A case of practical wind speed time series from wind power plants verifies validity of the proposed model.

Environmental problems of wind power engineering

Results of the review and comparative analysis of the factors that impact environment and human health in the course of construction, operation, and liquidation of wind power plants (WPPs) as compared to those of traditional power engineering is presented.

A new self-scheduling strategy for integrated operation of wind and pumped-storage power plants in power markets

Competitive structure of power markets causes various challenges for wind resources to participate in these markets. Indeed, production uncertainty is the main cause of their low income. Thus, they are usually supported by system operators, which is in contrast with the competitive paradigm of power markets. In this paper, a new strategy for increasing the profits of wind resources is proposed. In the suggested strategy, a Generation Company (GenCo), who owns both wind and pumped-storage plants, self-schedules the integrated operation of them regarding the uncertainty of wind power generation. For presenting an integrated self-schedule and obtaining a real added value of the strategy, participation of the GenCo in energy and ancillary service markets is modeled. The self-scheduling strategy is based on stochastic programming techniques. Outputs of the problem include generation offers in day-ahead energy market and ancillary service markets, including spinning and regulation reserve markets. A Neural Network (NN) based technique is used for modeling the uncertainty of wind power production. The proposed strategy is tested on a real wind farm in mainland, Spain. Moreover, added value of the strategy is presented in different conditions of the market.

Wind Speed Forecasting Method: Gray Related Weighted Combination with Revised Parameter

Abstract Wind speed forecasting is very important to the operation of wind power plants and power systems. It can relieve or avoid the disadvantageous impact of wind power plants on power systems and enhance the competitive ability of wind power plants against other power plants in electricity markets. Based on Gray system, the author studied the wind speed forecasting and proposed a novel method for wind speed forecasting: Gray related weighted combination with revised parameter. The effectiveness of the proposed model is demonstrated by a test in a certain area. The result shows that the method is useful both in theory and in practice.

05/00270 Stochastic modelling in wave power-equipment optimization: maximum energy production versus maximum profit: de O. Falcõ, A. F. Ocean Engineering, 2004, 31, (11–12), 1407–1421

The construction and operation of wind-power plants may affect birds through collision mortality, reduced habitat utilization due to disturbance, barriers to movement and habitat modifications, with the nature and magnitude of those effects being site- and species-specific. Birds may however manage these effects through fleeing, activity shifts or changed habitat utilization; usually termed avoidance. Given the important role avoidance plays in estimating the impact wind-power development has on birds, there is a pressing need to formalizing the avoidance process. Crucial in this context is to identify the underlying mechanisms of behavioural responses by birds to wind-power plants and individual turbines. To provide a better basis for and improved understanding of the underlying mechanisms for avoidance a conceptual framework for wind-turbine avoidance is presented decomposing various forms of avoidance at different spatial scales. Avoidance behaviour includes displacement (macro-avoidance), anticipatory and impulsive evasion (meso-avoidance), and escape (micro-avoidance). For understanding why particular responses occur with regard to wind-turbine disturbance this concept is applied to predation risk theory. The risk-disturbance hypothesis elucidates possible trade-offs between avoiding perceived risk and fitness-enhancing activities. The four behavioural responses are related to, respectively, habitat selection, vigilance and fleeing (twice); from which specific predictions can be derived. Formalizing the different forms of avoidance facilitates design of effects studies, enhances comparisons among sites studied, and guide siting and mitigation strategies.

Greenhouse gas emissions from building and operating electric power plants in the Upper Colorado River Basin.

As demand for electricity increases, investments into new generation capacity from renewable and nonrenewable sources should include assessment of global (climate) change consequences not just of the operational phase of the power plants but construction effects as well. In this paper, the global warming effect (GWE) associated with construction and operation of comparable hydroelectric, wind, solar, coal, and natural gas power plants is estimated for four time periods after construction. The assessment includes greenhouse gas emissions from construction, burning of fuels, flooded biomass decay in the reservoir, loss of net ecosystem production, and land use. The results indicate that a wind farm and a hydroelectric plant in an arid zone (such as the Glen Canyon in the Upper Colorado River Basin) appear to have lower GWE than other power plants. For the Glen Canyon hydroelectric plant, the upgrade 20 yr after the beginning of operation increased power capacity by 39% but resulted in a mere 1% of the CO2 emissions from the initial construction and came with no additional emissions from the reservoir, which accounts for the majority of the GWE.