Sökning: "corona discharge"
Visar resultat 1 - 5 av 23 avhandlingar innehållade orden corona discharge.
1. Numerical Simulations of Long Spark and Lightning Attachment
Sammanfattning : 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. LÄS MER
2. Evaluating Resistance to Corona and Ozone in Polymeric Materials for High Voltage Outdoor Applications
Sammanfattning : 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. LÄS MER
3. Measurement and Analysis of Partial Discharges at Semi-Square Voltages
Sammanfattning : 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. LÄS MER
4. Partial Discharges at Repetitive Rapidly Changing Voltages
Sammanfattning : 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. LÄS MER
5. Physics of Electrical Discharge Transitions in Air
Sammanfattning : 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. LÄS MER