Modeling and Characterization of Downwind Tower Shadow Effects Using a Wind Turbine Emulator

Abstract

This paper presents the modeling and characterization of the tower shadow effects using a wind turbine emulator in a laboratory environment. In particular, the downwind wind turbines are considered here as their tower shadow effects are more significant compared to the upwind counterpart. Simulation and experimental results have shown that the wind speed deficit due to this non-ideal effect is significant. In addition, the tower shadow effects occur typically two to three times per revolution, depending on the number of blades. The modeling of the tower shadow profiles for tubular and four-leg tower configurations are presented. Typically, these towers are used in small wind turbine applications. The tower shadow profiles are emulated experimentally using a wind turbine emulator with its characteristics being explained. The limitations of emulating the tower shadow effects using a wind turbine emulator are demonstrated through the frequency response test performed in this work. In this research, the wind turbine emulator is connected to an isolated grid which is formed by three single-phase inverters. Finally, the paper concludes with a sensitivity analysis of the power oscillations for different widths and magnitudes of the tower shadow profile.

Dynamic Modeling of Wind Turbines Based on Estimated Wind Speed under Turbulent Conditions

“…(2) Table 1 summarizes the geographical features and represents a general wind shear index [1]. As a result of height-dependent wind speeds, the turbine blades oscillate in response to the wind shear.…”

“…One solution is found in clean, sustainable, inexhaustible, environmentally friendly, and renewable sources such as solar energy, wind energy, and tidal ocean currents. Wind energy has attracted more interest for several reasons and has increasingly become the most harvested renewable energy source [1]. Increased interest in wind turbines to generate electrical power entails studying and modeling the steady state and dynamic behavior of the wind turbine in laboratory conditions to prevent possible problems during installation and later use.…”

“…Before applying a new algorithm, it must be validated in the laboratory by simulating the entire system to verify the performance, control, and disturbances. Developing and improving the characteristics of a wind turbine simulator will help reach this objective and reflect the dynamic behavior of a wind turbine in a controlled environment [1][2][3].…”

Desenvolvimento de um Emulador Eólico Eletrônico Baseado no Modelo Dinâmico do Gerador Síncrono de Ímã Permanente

“…A Figura 4 ilustra um EmE convencional empregando um MIT [14]. O motor é responsável por emular a TE, aplicando ao eixo do GSIP a potência mecânica que seria aplicada por uma turbina eólica real, submetida a determinados perfis de velocidade do vento.…”

“…Para contornar os problemas apresentados pelo uso de motores CC, tem-se usado nos EmE motores de indução trifásicos (MIT), os quais são mais eficientes, apresentam menores custos, possuem menores dimensões, além de necessitarem manutenções periódicas menos frequentes quando comparados aos motores CC [12], [14]. Contudo, mesmo com as vantagens apresentadas em relação ao uso de motores CC nos EmE, o uso do MIT, assim como também acontece com os motores CC, apresentam desvantagens adicionais, tais como a geração de ruídos audíveis e a necessidade do uso de conversores de potência para realizar o controle das máquinas, acarretando o aumento de custos.…”