Results 111 to 120 of about 229 (144)
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Study on the transient characteristics of 1100kV VFTO
2017 4th International Conference on Electric Power Equipment - Switching Technology (ICEPE-ST), 2017The very fast transient overvoltage (VFTO) generated by switching disconnector (DS) in gas insulated substation (GIS) with the features of high amplitude, short rise-time and complex frequency components, may cause damage to the insulation of electrical equipment.
Wu Xixiu +4 more
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Research of VFTO in 110kV minimized GIS
2015 5th International Conference on Electric Utility Deregulation and Restructuring and Power Technologies (DRPT), 2015110kV minimized gas insulated substation (GIS) has been widely used in China, due to its great electrical properties. The closing or opening operation of disconnector switches (DS) and circuit breaker (CB), and single-phase ground fault are all probable to cause the very fast transient overvoltage (VFTO), which is a threat to the power system. Compared
He Qifei, Hao Zhiguo, Guo Jie
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The influence of the distributed trapped charge on VFTO
2010 5th International Conference on Critical Infrastructure (CRIS), 2010In this paper, the nodal admittance equation is derived for analyzing the response of the transmission line under the residual voltage due to uniformly distributed charge along the line in Laplace domain. We equivalent the trapped charge to the current sources which are located at near-end and far-end when the disconnector switching is operated.
Hongyang Yu, Binxian Lu
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Study on VFTO in UHV GIS substation
2011 4th International Conference on Electric Utility Deregulation and Restructuring and Power Technologies (DRPT), 2011In GIS substations, operations of disconnectors may cause very fast transient overvoltage (VFTO) with high amplitude and steep wave front. Considering the narrower insulation margin of UHV GIS equipments and larger absolute magnitude of VFTO in UHV GIS systems, VFTO in UHV GIS systems could cause larger damage than those in EHV and lower ones ...
Wan Yiru, Chen Guang, Zhou Hao
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Characteristic Analysis on Suppressing VFTO in GIS by Ferrite
Advanced Materials Research, 2013When disconnecting switches were operated,Very Fast Transient Overvoltage (VFTO) did great harm to power systems and their equipments in Gas Insulated Substations (GIS). Although VFTO can be suppressed by a few of known methods, there were some problems.
Xiang Gen Gan +3 more
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Measurement of VFTO Based on the Transformer Bushing Sensor
IEEE Transactions on Power Delivery, 2011Disconnector switching operations in large gas-insulated switchgear (GIS) systems may produce very fast transient overvoltages (VFTOs), causing high electric stress to other apparatuses in the substation, such as power transformers. This paper presents a VFTO measuring technique based on a transformer bushing sensor, which consists of the transformer ...
Guo-Ming Ma +3 more
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Damping of VFTO by RF resonator and nanocrystalline materials
2013 IEEE Electrical Insulation Conference (EIC), 2013Very fast transient overvoltages (VFTO) are a well known phenomena in gas insulated switchgears (GIS). The main reasons for VFTO are switching operations of disconnectors. Thereby, several pre- or restrikes between the switching contacts occur and initiate steep voltage rises propagating inside the GIS.
S. Burow +3 more
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Design of Triggering Device for VFTO Measurement System
Advanced Materials Research, 2012Very fast transient overvoltage (VFTO) can be generated during the operation of disconnect switch (DS). Especially in ultra high voltage (UHV) gas insulated substation (GIS), VFTO is a threat to the safety of the power system equipment. It is very important to measure VFTO waveforms accurately.
Gong Chang Yue +3 more
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Arcing Model of a Disconnector and its Effect on VFTO
Plasma Science and Technology, 2013In the computational process of very fast transient over-voltage (VFTO), it is essential to find an accurate model for a gas insulated substation. The arcing model of the disconnector is particularly important. The general arcing model is not able to give a good description of the arc development process. In this paper, based on the physical process of
Xin Lin, Na Wang, Jianyuan Xu
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Design Optimization of Ferrite Rings for VFTO Mitigation
IEEE Transactions on Power Delivery, 2017Very fast transient overvoltage (VFTO)-related problems are raising growing concerns in China with the development of ultra-high voltage. The practice of fitting ferrite rings on gas-insulated switchgear busbars for VFTO mitigation has long been proposed but few investigations on its' design optimization were conducted. Based on theoretical analysis of
Jiaxi He +4 more
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