Search for dissertations about: "corona discharge"

Showing result 1 - 5 of 23 swedish dissertations containing the words corona discharge.

2. 1. Numerical Simulations of Long Spark and Lightning Attachment

   Author : Liliana Arevalo; Vernon Cooray; Dan Windmar; Uppsala universitet; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; breakdown; discharge; leader channel; lightning attachment; negative discharge; positive discharge; streamer; Electrical engineering; Elektroteknik; Engineering Science with specialization in Atmospheric Discharges; Teknisk fysik med inriktning mot atmosfäriska urladdningar;

   Abstract : The research work presented here is concerned with numerical simulations of two different electrical phenomena: Long gap electrical discharges under switching impulses and the lightning attachment process associated with positive upward leaders. The development of positive upward leaders and the progression of discharges in long gaps are attributable to two intertwined physical phenomena, namely, the leader channel and the streamer zone. READ MORE

4. 2. Evaluating Resistance to Corona and Ozone in Polymeric Materials for High Voltage Outdoor Applications

   Author : Bin Ma; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; ozone; housing material; nano-composite; corona; Outdoor insulation; composite insulation;

   Abstract : Resistance to corona discharges and ozone, the well known ageing factors for polymeric materials used in outdoor insulation, has been listed as being of great importance among twelve properties identified by CIGRE WG D1.14 – Material Properties for Non-ceramic Outdoor Insulation. READ MORE

5. 3. Measurement and Analysis of Partial Discharges at Semi-Square Voltages

   Author : Elisabeth Lindell; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; space charge; Partial discharges PDs ; short rise time; partial discharge measuring techniques; square-like voltages; repetitive voltages; corona;

   Abstract : Insulation is today being exposed to voltages having considerably higher frequency components than the conventional power frequency AC 50 Hz or 60 Hz, for example in motors supplied by adjustable speed drives based on pulse width modulated converters. This has in many cases caused unexpected behaviour of the insulation systems. READ MORE

6. 4. Partial Discharges at Repetitive Rapidly Changing Voltages

   Author : Elisabeth Lindell; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; high dV dt; oil paper insulation.; repetitive voltages; short rise time; partial discharge measuring techniques; twisted pair; square-like voltages; corona; Partial discharges PDs ;

   Abstract : Electrical insulation can today be exposed to voltages having considerably higherfrequency components than the conventional power frequency AC 50 Hz or 60 Hz,for example due to the increased use of power electronics in power systems. Thishas in a number of cases caused unexpected behaviour, including failures. READ MORE

7. 5. Physics of Electrical Discharge Transitions in Air

   Author : Lipeng Liu; Marley Becerra; Ute Ebert; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; electrical discharges; transition; streamers; glow corona; leader discharges; elektriska urladdningar; övergång; streamers; glöd-korona; ledarurladdningar; Electrical Engineering; Elektro- och systemteknik;

   Abstract : Electrical discharges with a variety of different forms (streamers, glow corona, leaders, etc.) broadly exist in nature and in industrial applications. Under certain conditions, one electrical discharge can be transformed into another form. READ MORE