الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Polymeric housed, gapless metal oxide surge arresters are widely applied to power transmission systems in order to protect the system equipment from overvoltage. ZnO surge arresters have been improved in reliability, and reduced in size and weight. The polymer housed surge arresters are exposed to various stresses, such as temporary overvoltages (TOV), switching overvoltages and lightning overvoltages. Due to these overvoltages and high currents, surge arrester will be stressed with energy which shouldn’t exceed the arrester energy absorption capability. If the stress exceeds this limit, failure may occur and damage the arrester due to thermal heating produced inside arrester may occur. This thesis discusses the transient overvoltages generated and propagated to 220/66/11 kV Wadi-Hoff gas insulated substation. Very fast transient overvoltage (VFTO) generated inside the GIS from disconnector and circuit breaker operations were calculated and discussed. The energy stresses due to VFTO on metal oxide surge arresters (MOSA) used in substation were presented. Fast transient overvoltage (FTO), which is represented by lightning strokes, hitting one of the incoming feeders is simulated and the overvoltage transients at the GIS entrance are calculated. The energy stresses due to FTO on MOSA are calculated and compared with standard values. The effects of peak current, wave front time, wave tail time and striking point distance from GIS entrance on the energy stress were examined. Also, the effects of different connections of the substation termination on the energy stresses are presented. A temporary overvoltage, represented by single-line-to-ground fault, is calculated. The energy stresses due to temporary overvoltage were presented.Polymeric housed, gapless metal oxide surge arresters are widely applied to power transmission systems in order to protect the system equipment from overvoltage. ZnO surge arresters have been improved in reliability, and reduced in size and weight. The polymer housed surge arresters are exposed to various stresses, such as temporary overvoltages (TOV), switching overvoltages and lightning overvoltages. Due to these overvoltages and high currents, surge arrester will be stressed with energy which shouldn’t exceed the arrester energy absorption capability. If the stress exceeds this limit, failure may occur and damage the arrester due to thermal heating produced inside arrester may occur.This thesis discusses the transient overvoltages generated and propagated to 220/66/11 kV Wadi-Hoff gas insulated substation. Very fast transient overvoltage (VFTO) generated inside the GIS from disconnector and circuit breaker operations were calculated and discussed. The energy stresses due to VFTO on metal oxide surge arresters (MOSA) used in substation were presented. Fast transient overvoltage (FTO), which is represented by lightning strokes, hitting one of the incoming feeders is simulated and the overvoltage transients at the GIS entrance are calculated. The energy stresses due to FTO on MOSA are calculated and compared with standard values. The effects of peak current, wave front time, wave tail time and striking point distance from GIS entrance on the energy stress were examined. Also, the effects of different connections of the substation termination on the energy stresses are presented. A temporary overvoltage, represented by single-line-to-ground fault, is calculated. The energy stresses due to temporary overvoltage were presented.Polymeric housed, gapless metal oxide surge arresters are widely applied to power transmission systems in order to protect the system equipment from overvoltage. ZnO surge arresters have been improved in reliability, and reduced in size and weight. The polymer housed surge arresters are exposed to various stresses, such as temporary overvoltages (TOV), switching overvoltages and lightning overvoltages. Due to these overvoltages and high currents, surge arrester will be stressed with energy which shouldn’t exceed the arrester energy absorption capability. If the stress exceeds this limit, failure may occur and damage the arrester due to thermal heating produced inside arrester may occur. This thesis discusses the transient overvoltages generated and propagated to 220/66/11 kV Wadi-Hoff gas insulated substation. Very fast transient overvoltage (VFTO) generated inside the GIS from disconnector and circuit breaker operations were calculated and discussed. The energy stresses due to VFTO on metal oxide surge arresters (MOSA) used in substation were presented. Fast transient overvoltage (FTO), which is represented by lightning strokes, hitting one of the incoming feeders is simulated and the overvoltage transients at the GIS entrance are calculated. The energy stresses due to FTO on MOSA are calculated and compared with standard values. The effects of peak current, wave front time, wave tail time and striking point distance from GIS entrance on the energy stress were examined. Also, the effects of different connections of the substation termination on the energy stresses are presented. A temporary overvoltage, represented by single-line-to-ground fault, is calculated. The energy stresses due to temporary overvoltage were presented.