Sökning: "electrical tree"

Visar resultat 1 - 5 av 82 avhandlingar innehållade orden electrical tree.

1. 1. New Test Arrangement for Measuring Electrical Treeing in Polymers

   Författare :Ramona Huuva; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Voltage stabilisers.; Wire-plane configuration; Polyethylene LDPE; Needle electrode; XLPE ; Electrical treeing;

   Sammanfattning : Electrical treeing in high voltage cable insulation has been studied for a number of years and today the mostly used laboratory test set-up is the needle-plane electrode configuration. In this thesis a different type of electrode configuration is described. LÄS MER

3. 2. Characterization of Electrical Insulation Exposed to Arbitrary Voltage Waveforms

   Författare :Björn Sonerud; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; arbitrary voltage waveforms; partial discharge; diagnostics; dielectric response measurement; signal processing; electrical treeing; dielectric heating.;

   Sammanfattning : The extensive use of power electronics in power systems today gives rise to other voltage waveforms than the conventional 50/60 Hz sinusoidal and consequently other types of electric stress act on high voltage insulating materials. Previous studies has shown that Pulse Width Modulated (PWM) voltages and similar waveforms increase stress in Adjustable Speed Drives (ASD) as compared with sinusoidal waveforms and it has also been shown that partial discharge (PD) activity is intensified during PWM voltages and that rise time of square like pulses affect PD inception voltage. LÄS MER

4. 3. Voltage Stabilizers: From Design to Synthesis, Processing and Electrical Characterization

   Författare :Markus Jarvid; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; Polyethylene; Degradation; XLPE; Electrical treeing; Voltage stabilizer; Cable; Insulation;

   Sammanfattning : Voltage stabilizers are additives capable of inhibiting electrical treeing; a degradation mechanism for insulation materials subjected to strong divergent electric fields. The intended use is in cross-linked polyethylene (XLPE) high voltage power cable insulation where minute defects in the manufacturing process can give rise to the conditions needed for the initiation of treeing, which in the worst case scenario leads to failure of the insulation system with blackouts and expensive repairs as a consequence. LÄS MER

5. 4. Characterising Resistance to Electrical Treeing in New XLPE-Based Materials for High-Voltage Cables

   Författare :Anette Johansson; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; electrical treeing; partial discharge; cross-linked polyethylene; voltage stabiliser; degradation; power cables;

   Sammanfattning : This work looks into electrical treeing in cross-linked polyethylene-based materials (XLPE), where the ability to resist tree development is considered as an indicator of improved applicability for insulation in high voltage power cables. The thesis presents results of a twin PhD project involving joint work of two students. LÄS MER

7. 5. Polyethylene/metal oxide nanocomposites for electrical insulation in future HVDC-cables : probing properties from nano to macro

   Författare :Love Pallon; Ulf Gedde; Mikael Hedenqvist; Richard Olsson; Alun Vaughan; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Nanocomposites; polyethylene; particle dispersion; high voltage direct current cables; HVDC; HVDC insulation; MgO; intermodulation electrostatic force microscopy; ptychography; electrical tree; Nanokompositer; polyeten; HVDC; HVDC-kabel; HVDC-isolering; MgO; elektrisk isolation; partikeldispergering; elektriska träd; Fiber- och polymervetenskap; Fibre and Polymer Science;

   Sammanfattning : Nanocomposites of polyethylene and metal oxide nanoparticles have shown to be a feasible approachto the next generation of insulation in high voltage direct current cables. In order to reach an operationvoltage of 1 MV new insulation materials with reduced conductivity and increased breakdown strengthas compared to modern low-density polyethylene (LDPE) is needed. LÄS MER