WIND GENERATORS SIMULATION USING SPECTRAL-CORRELATION THEORY OF RANDOM PROCESSES
Journal Title: Електромеханічні і енергозберігаючі системи - Year 2017, Vol 4, Issue 40
Abstract
Introduction. Currently, there is a significant development of the industry, which transforms the kinetic energy of the wind flow into electrical energy. Wind power plants are included in the common network, which leads to a gradual transition from a purely centralized model of power supply to consumers, the basis of which are powerful thermal power station and nuclear power station, to a combined one. Problem. Wind power plants are non-linear and abruptly alternating sources of electricity. Depending on the type of wind turbine, and considering that the power system has a power consumption peaks and dips, there are problems with power quality and electromagnetic compatibility – deviations, fluctuations, unbalance voltages, generation of higher harmonics and interharmonics. One of the reasons for the influence of wind generators and wind power stations on the power quality is the meteorological conditions: wind flow energy has a proportional cubic dependence of the wind speed therefore, the variability and inconstancy of the wind speed in time is of decisive importance for the operation of wind power. Purpose. To study the operating modes of wind generators and their influence on electrical networks, it is necessary to present a wind generator and a wind flow in the form of a model. Turbulent wind flow often described using various mathematical models with the corresponding spectral densities obtained from empirical data. To correctly simulate the operation of the wind turbine in its investigation of the effect on the power quality and electromagnetic compatibility, it is crucial to take into account the parameters of the wind flow. Methodology. As basic characteristics of the turbulent wind flow is proposed to use correlation function. Using conventional Kaimal model, the turbulent wind flow is a stationary random process with a normal distribution law and an exponential correlation function. Note that in the simulation of the wind flow can be used directly spectral density, however, such models are more complicated. For the spectral density of Kaimal, the integral can`t be expressed in terms of elementary functions; therefore, one of the methods for solving the problem is approximate the spectral density by one of the known expressions. Results. Work of wind turbines analyzed, determines the main factors influencing the power quality and electromagnetic compatibility in the distribution network. Factors influencing fluctuations in voltage and flicker, as well as the causes of the appearance of higher harmonics and interharmonic are considered. Proposed method for approximating the spectral density based on the wind flow energy equivalence and the simulated random process allows analytically obtain parameters of the correlation function from the average wind speed and turbulence intensity. A method for modeling a turbulent wind flow in studies of the parameters of power quality and electromagnetic compatibility is proposed.
Authors and Affiliations
Yuriy Sayenko, Andrii Molchan
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