Power System Stability Enhancement and Improvement of LVRT Capability of a DFIG Based Wind Power System by Using SMES and SFCL

This paper proposes a exhaustive study about the performance analysis of Doubly Fed Induction (DFIG) under abnormal condition. Now a days, majority of power network countenance the problem of over current and grid connectivity issues. SFCL (Superconducting Fault Current Limiter), which have the competence to limit the fault current and protect the equipments from damage. SMES (Superconducting Magnetic Energy Storage) is mainly used to compensate both real and reactive power variations, thus power quality can be enhanced. Co-ordinated operation of SFCL - SMES thus used to enhance the power system stability and improve the LVRT (Low Voltage Ride Through) capability of wind power generation systems. LVRT capability of wind turbine is refers to the ability of wind power system to conquer the voltage variations if there is any unwanted conditions. Here DFIG based wind turbine plant is used for consideration, because it will provide smoothened power output nearly double than a conventional generator. And it have more simple and rugged construction also.   Design of DFIG based wind power generation systems under fault condition with the help of SMES and SFCL is analysed   by means of MATLAB/SIMULINK block set.DOI:http://dx.doi.org/10.11591/ijece.v3i5.338

Measurement of Thermo-Elastic Deformation of an Optic using a Polarization Based Shearing Interferometer

A shearing interferometer is presented which uses polarization control to shear the wavefront and to modulate the interference pattern. The shear is generated by spatial walk-off in a birefringent crystal. By adjusting the orientation of the birefringent crystal, the components of the wavefront gradient can be independently measured to allow determination of the full wavefront vector gradient as well as reconstruction of the wavefront. Further, the monolithic nature of the crystal used for shearing allows the interferometer to be setup without need for precise alignment of any components. An algorithm incorporating homodyne detection is presented which analyzes the modulated interferograms to determine the components of the wavefront gradient, from which the wavefront is reconstructed. The thermal deformation of a mirror subject to heating from absorption of a Gaussian pump beam was accurately observed with a sensitivity better than \lambda/160. We show that this sensitivity is scale invariant, and present a method to account for the non-uniform spatial frequency response of the interferometer

A TOTAL-CONCENTRATION FIXED-GRID METHOD FOR TWO-DIMENSIONAL DIFFUSION-CONTROLLED WET CHEMICAL ETCHING

ABSTRACT This article presents a total concentration method for two-dimensional wet chemical etching. The proposed procedure is a fixed-grid approach. It is analogous to the enthalpy method used for modeling melting/solidification problems. The governing equation is formulated using the total concentration of the etchant. It includes the reacted and the unreacted concentrations of the etchant. The proposed governing equation includes the interface condition. The reacted concentration is used to capture the etchant-substrate interface implicitly. Since the grids are fixed, a diffusion problem remains a diffusion problem unlike the moving grid approach where the diffusion problem becomes the convectiondiffusion problem due to the mesh velocity. For demonstration purposes, the finite volume method is used to solve for the transient concentration distribution of etchant. In this article, two-dimensional diffusion-controlled wet chemical etching processes are modeled. The results obtained from the proposed total concentration method are compared with available "analytic" solutions and solutions from moving-grid approach

Minimally invasive inspection of technical and medical intracavities using a novel opto-digital scheme

Current endoscopes, bronchoscopes, arthroscopes, etc., report reflected or fluoresced light, but without fully exploiting the potential of coherence. By fibre optics we can light and image the body using external lasers and electronics, reducing bulk at the tip of a flexible device. Incorporating fiber optics illumination and viewing, laser speckle interferometry allows us to determine microscopic features of shape, deformation, roughness and elasticity in real time. Adjusting only the external equipment between changes of imaging mode will give cross-registered data of each type analysed, increasing the diagnostic value of each. Cancer growths found in body cavities, such as colon, are a leading cause of death all over world. Medical intra cavity inspection techniques facilitate the diagnosis of cancers and other diseases, found in the different body cavities, such as nasal cavity, esophagus, colon, bladder, rectum etc. The cancer in the colorectal region of the body, which represents the most common malignant tumor, has become the second leading cause of death around the world, requiring urgent attention for its diagnosis and follow-up treatment. Also, to optimize patient management, precise detection or exclusion of metastases as well as assessment of their number and extent is indispensable. As colon cancer is highly curable if detected at a very early stage, diagnostic procedures based on early detection of the same is having important relevance. This early stage of cancer development is indicated by the presence of polyps of very small size (≈mm) originating from the inner mucosal layer of the colon wall. The diagnostic techniques, which can identify small abnormalities such as polyp growth present at either the surface or subsurface of the mucosal layer, will be of much help in the early detection of cancer. The currently available methods for colon cancer diagnosis are still at the research and development stages within the context of early detection capability. The relevance and potential of the proposed research comes in this context.AcRF 10/0