Dynamic performance improvement of wind farms equipped with three SCIG generators using STATCOM

The main causes of wind farms disconnection from the grid is the three-phase grid faults at the point common coupling (PCC) e.g. the voltage dip. The use of a Static Synchronous Compensator (STATCOM) which is from the family of Flexible AC Transmission System (FACTS) devices can be used effectively in a wind park based on FSIG to provide transient voltage and to improve wind system stability. Due to the asynchronous operation nature, system instability of wind farms based on FSIG (Fixed Speed Induction Generator) is largely caused by the reactive power absorption by FSIG because due to the large rotor slip during grid fault. STATCOM contributes to control the grid voltage at PCC and maintain wind farm connection to the grid during some severe conditions of grid faults and used for power flow control and for damping power system oscillations. The evaluation of this control strategy using (STATCOM) is investigated in terms of regulation reactive power and transient stability of the wind farm during grid disturbances

Dynamic performance improvement of wind farms equipped with three SCIG generators using STATCOM

The main causes of wind farms disconnection from the grid is the three-phase grid faults at the point common coupling (PCC) e.g. the voltage dip. The use of a Static Synchronous Compensator (STATCOM) which is from the family of Flexible AC Transmission System (FACTS) devices can be used effectively in a wind park based on FSIG to provide transient voltage and to improve wind system stability. Due to the asynchronous operation nature, system instability of wind farms based on FSIG (Fixed Speed Induction Generator) is largely caused by the reactive power absorption by FSIG because due to the large rotor slip during grid fault. STATCOM contributes to control the grid voltage at PCC and maintain wind farm connection to the grid during some severe conditions of grid faults and used for power flow control and for damping power system oscillations. The evaluation of this control strategy using (STATCOM) is investigated in terms of regulation reactive power and transient stability of the wind farm during grid disturbances

A 2MW direct drive wind turbine; vector control and direct torque control techniques comparison

This paper presents a comparative study on the most popular control strategies used to control high power, Direct Drive Wind Turbines. The studied wind turbine is equipped with a supervision scheme in order to fulfil Grid connection requirements (GCR). For the generator-side converter, performances of the Field Oriented Control (FOC) and Direct Torque Control (DTC) are compared. Concerning the grid-side converter, Voltage Oriented Control (VOC) and Direct Power Control (DPC) are examined. The comparison is based on various criteria mainly, steady-state and transient performances. In addition, performances are evaluated in terms of low voltage ride through capabilities (LVRT), power limitation and reactive power control. It has been shown that best power quality features are given by vector control techniques. On the other hand, direct control offers the better dynamic response and power cross-coupling is substantially lower. Furthermore, during fault, the wind turbine does not trip for both techniques. However, vector control is better since it gives low power oscillation

Computational Insights into the Structure of Barium Titanosilicate Glasses

International audienc

Le kyste de la vallécule symptomatique chez l’adulte: à propos de 4 cas

Le kyste de la vallécule est une lésion bénigne rare. Ces kystes sont souvent asymptomatiques chez l'adulte. Les auteurs rapportent 4 cas de kystes de la vallécule symptomatique de l'adulte. Trois patients ont consulté pour une dysphagie haute mixte associée à une dysphonie. Le quatrième patient se plaignait d'une sensation de corps étranger dans la gorge. La laryngoscopie a montré une formation kystique dans la région valléculaire gauche dans tous les cas. La tomodensitométrie a confirmé la présence d'une formation kystique de la vallécule. Le traitement a consisté en une marsupialisation du kyste dans deux cas et une résection endoscopique dans deux cas. À partir de ces 4 cas cliniques, nous nous proposons de préciser les particularités diagnostiques et thérapeutiques de cette affection

Une polyradiculonévrite inflammatoire démyélinisante chronique paranéoplasique secondaire à un lymphome natural killer nasal

Nous rapportons un cas unique d´une polyradiculonévrite inflammatoire démyélinisante chronique paranéoplasique secondaire à un lymphome non hodgkinien T de type natural killer nasal