Control of a DSTATCOM Coupled with a Flywheel Energy Storage System to Improve the Power Quality of a Wind Power System

Wind power generation is considered the most economic viable alternative within the portfolio of renewable energy resources. Among its main advantages are the large number of potential sites for plant installation and a rapidly evolving technology. However, the lack of controllability over the wind and the type of generation system used cause problems to the electric systems. Among such problems are those produced by wind power short-term fluctuations, e.g., in the power quality and in the dynamics of the system (Slootweg & Kling, 2003; Ackermann, 2005; Suvire & Mercado, 2008; Chen & Spooner, 2001; Mohod & Aware; 2008; Smith et al., 2007). In addition, the reduced cost of power electronic devices as well as the breakthrough of new technologies in the field of electric energy storage makes it possible to incorporate this storage with electronic control into power systems (Brad & McDowall, 2005; Carrasco, 2006; Barton & Infield, 2004; Hebner et al., 2002). These devices allow a dynamic control to be made of both voltage and flows of active and reactive power. Therefore, they offer a great potential in their use to mitigate problems introduced by wind generation. Based on the results obtained by analyzing different selection criteria, a Distribution Static Synchronous Compensator (DSTATCOM) coupled with a Flywheel Energy Storage System (FESS) has been proposed as the most appropriate system for contributing to the smoothing of wind power short-term fluctuations (Suvire & Mercado, 2007).Fil: Suvire, Gaston Orlando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan; Argentina. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Energía Eléctrica; ArgentinaFil: Mercado, Pedro Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan; Argentina. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Energía Eléctrica; Argentin

A New Control Strategy to Integrate Flow Batteries into AC Micro-Grids with High Wind Power Penetration

The penetration of wind generation into AC micro-grids (MGs) has been increasing in recent years. Wind generation is uncontrollable, variable in nature, and uncertain. If the penetration level is high, the random variations of the wind power generation could cause problems for MGs to maintain the nominal system frequency. A typical solution is to employ energy storage systems (ESS) into the MG in order to compensate the wind power fluctuations. In this chapter, the use of a vanadium redox flow battery (VRFB) coupled with a power conditioning system (PCS) is suggested to enhance the frequency stability of a MG with high wind power penetration. A new control system is developed for the PCS/VRFB. The control system performs the load leveling of the wind generation and carries out the primary and secondary frequency control of the MG. Dynamic simulations of the proposed device are performed and demonstrate that the new control system improves the transient responses of the PCS/VRFB and the MG, during minor and/or severe disturbances

Combined control of a flywheel energy storage system and a vanadium redox flow battery for wind energy applications in microgrids

The incorporation of wind generation in microgrids is growing progressively. This integration can introduce problems in the dynamics and power quality of the electrical system due to the wind fluctuations. This work proposes a controller composed by a power conditioning system (PCS), a Flywheel Energy Storage System (FESS) and a Vanadium Redox Flow Battery (VRFB) to palliate problems introducedby wind generation in microgrids. A model of the PCS/FESS-VRFB controller is presented and a method to control the power exchanged between the controller and the power system is suggested. The control method has two modes, namely: power levelling and frequency control. The performance of the PCS/FESS-VRFB controller is studied when it works with wind power generation in the microgrid through simulation tests. Results demonstrate suitable performance of the control methods and high effectiveness to level the wind power fluctuations and to provide support to the frequency control of the microgrid.La incorporación de potencia eólica en microredes está creciendo progresivamente. Esta integración puede introducir problemas en la dinámica y calidad de potencia del sistema eléctrico debido a fluctuaciones del viento. Este trabajo propone un controlador compuesto por un sistema de acondicionamiento de potencia (PCS), un almacenador flywheel (FESS) y una batería de flujo redox de vanadio (VRFB) para mitigar problemas introducidos por la generación eólica en microredes. Se presenta un modelo del PCS/FESS-VRFB y se propone un método para controlar la potencia intercambiada entre el controlador y la red eléctrica. El método tiene dos modos: nivelación de potencia y control de frecuencia. A través de simulaciones, se estudia el desempeño del PCS/FESS-VRFB cuando opera con generación eólica en microredes. Los resultados demuestran un adecuado desempeño del método propuesto y una alta efectividad para nivelar las fluctuaciones de potencia eólica y proveer soporte para el control de frecuencia de la microred

Time-varying harmonic analysis of electric power systems with wind farms, by employing the possibility theory

En este trabajo se analiza el impacto de la conexión de parques eólicos, en el flujo de cargas armónicas en un sistema de pote ncia. Algunos generadores eólicos producen arm ónicos debido a la electrónica de potencia que utilizan para su vinculación con la red. Estos armónicos son variables en el tiempo ya que se relacionan con las variaci ones en la velocidad del viento. El propósito de este trabajo e s presentar una mejora a la metodología para el c álculo de incertidumbre en el flujo de cargas armónicas, a tra vés de la teoría de la posibili dad, la cual fue previamente desarrollada por los autores. La mejora consiste en incluir la incertidumbre debida a las variaciones de la veloci dad del viento. Para probar la metodología, se re alizan simulaciones en el sist ema de prueba de 14 barras de la IEEE, conectando en una de las barras un parque eólico compuesto por diez t urbinas del tipo FPC. Los res ultados obtenidos muestran que l a incertidumbre en la velocidad del viento tiene un efecto considerable en las incertidumbres asociadas a las magnitudes de las tensiones armónicas calculadas

Time-varying harmonic analysis of electric power systems with wind farms, by employing the possibility theory

This paper focuses on the analysis of the connection of wind farms to the electric power system and their impact on the harmonic load-flow. A possibilistic harmonic load-flow methodology, previously developed by the authors, allows for uncertainties related to linear and nonlinear load variations to be modeled. Moreover, it is well known that some types of wind turbines also produce harmonics, in fact, time-varying harmonics. The purpose of this paper is to present an improvement of the former method, in order to include the uncertainties due to the wind speed variations as an input related with power generated by the turbines. Simulations to test the proposal are performed in the IEEE 14-bus standard test system for harmonic analysis, connecting to the network a wind farm composed by ten Full Power Converter (FPC) type wind turbines. Results obtained show that uncertainty in the wind speed has a considerable effect on the uncertainties associated with the computed harmonic voltage magnitudes.En este trabajo se analiza el impacto de la conexión de parques eólicos, en el flujo de cargas armónicas en un sistema de potencia. Algunos generadores eólicos producen armónicos debido a la electrónica de potencia que utilizan para su vinculación con la red. Estos armónicos son variables en el tiempo ya que se relacionan con las variaciones en la velocidad del viento. El propósito de este trabajo es presentar una mejora a la metodología para el cálculo de incertidumbre en el flujo de cargas armónicas, a través de la teoría de la posibilidad, la cual fue previamente desarrollada por los autores. La mejora consiste en incluir la incertidumbre debida a las variaciones de la velocidad del viento. Para probar la metodología, se realizan simulaciones en el sistema de prueba de 14 barras de la IEEE, conectando en una de las barras un parque eólico compuesto por diez turbinas del tipo FPC. Los resultados obtenidos muestran que la incertidumbre en la velocidad del viento tiene un efecto considerable en las incertidumbres asociadas a las magnitudes de las tensiones armónicas calculadas

Time-varying harmonic analysis in electric power systems with wind farms, through the possibility theory

This paper focuses on the analysis of the connection of wind farms to the electric power system and their impact on the harmonic load-flow. A possibilistic harmonic load-flow methodology, previously developed by the authors, allows for modeling uncertainties related to linear and nonlinear load variations. On the other hand, it is well known that some types of wind turbines also produce harmonics, in fact, time-varying harmonics. The purpose of this paper is to present an improvement of the former method, in order to include the uncertainties due to the wind speed variations as an input related with power generated by the turbines. Simulations to test the proposal are performed in the IEEE 14-bus standard test system for harmonic analysis, but replacing the generator, at bus two, by a wind farm composed by ten FPC type wind turbines