Search for dissertations about: "high frequency permeability"

Showing result 1 - 5 of 16 swedish dissertations containing the words high frequency permeability.

2. 1. A High Frequency Transformer Winding Model for FRA Applications

   Author : Hanif Tavakoli; Göran Engdahl; Jonas Ekman; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; complex permeability; frequency response analysis; time domain reflectometry; high frequency modeling; transformer diagnosis; Electrical engineering; Elektroteknik;

   Abstract : Frequency response analysis (FRA) is a method which is used to detect mechanical faults in transformers. The FRA response of a transformer is determined by its geometry and material properties, and it can be considered as the transformer’s fingerprint. READ MORE

4. 2. Effect of Dielectric and Magnetic Material Characteristics on Frequency Response of Power Transformers

   Author : Nilanga Abeywickrama; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; frequency response analysis; dielectric insulation; Complex permeability; core magnetization; finite element method; transformer diagnosis.; high frequency modelling; magnetic viscosity; silicon steel;

   Abstract : Frequency response analysis (FRA) technique has become increasingly popular for the assessment of mechanicalintegrity in power transformers. This method is based on the fact that the shape of the frequency response at higher frequencies is uniquely determined by the geometrical construction of the transformer. READ MORE

5. 3. An FRA Transformer Model with Application on Time Domain Reflectometry

   Author : Hanif Tavakoli; Göran Engdahl; Jonas Ekman; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; complex permeability; lumped circuit model; frequency response analysis; time domain reflectometry; high frequency modeling; transformer diagnosis; reluctance network method.;

   Abstract : Frequency response analysis (FRA) is a frequency-domain method which is used to detect mechanical faults in transformers. The frequency response of a transformer is determined by its geometry and material properties, and it can be considered as the transformer’s fingerprint. READ MORE

6. 4. Novel RF MEMS Devices Enabled by Three-Dimensional Micromachining

   Author : Umer Shah; Joachim Oberhammer; Raafat Mansour; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Microelectromechanical systems; MEMS; Radio frequency microelectromechanical systems; RF MEMS; Micromachined transmission line; Micromachining; Tuneable capacitor; Switched capacitor; Coupled-line coupler; Tuneable directional coupler; Intermodulation distortion; MEMS varactor; Two-tone IIP3 measurement; Passive components and circuits; Reliability; Magnetic materials; NiFe multilayer composite; Permeability; Permittivity; Micromachined inductors;

   Abstract : This thesis presents novel radio frequency microelectromechanical (RF MEMS) circuits based on the three-dimensional (3-D) micromachined coplanar transmission lines whose geometry is re-configured by integrated microelectromechanical actuators. Two types of novel RF MEMS devices are proposed. READ MORE

7. 5. Estimation of electromagnetic material properties with application to high-voltage power cables

   Author : Yevhen Ivanenko; Sven Nordebo; Martin Norgren; Linnéuniversitetet; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Material losses; power cables; cylindrical multipole expansion; Herglotz functions; convex optimization; sum rules; Waves and Signals; Vågor och signaler;

   Abstract : Efficient design of high-voltage power cables is important to achieve an economical delivery of electric power from wind farms and power plants over the very long distances as well as the overseas electric power. The main focus of this thesis is the investigation of electromagnetic losses in components of high-voltage power cables. READ MORE