A high speed, medium voltage pulse amplifier for diode reverse transient measurements

1995 ◽  
Vol 66 (11) ◽  
pp. 5352-5354 ◽  
Author(s):  
Michael J. Chudobiak
Keyword(s):  
Voltage Pulse ◽  
High Speed ◽  
Medium Voltage ◽  
Pulse Amplifier ◽  
Transient Measurements

scholarly journals High Speed Electrical Drives – Perspective of VFD Manufacturer

2020 ◽  
Vol 178 ◽  
pp. 01006
Author(s):  
Martin Bruha ◽  
Kai Pietiläinen ◽  
Axel Rauber
Keyword(s):  
High Speed ◽  
Technology Readiness ◽  
Power Electronic ◽  
Power Electronic Converters ◽  
Medium Voltage ◽  
Electrical Drives ◽  
Standard Design ◽  
Motor Design ◽  
High Level ◽  
Power Electronic Converter

This paper deals with high-speed electrical drives utilizing power electronic converters (commonly abbreviated as ASD, VFD or VSD). Existing solutions vary mainly on the motor side while the power electronic converter is very similar for all cases. Various advantages as well as technical challenges are discussed and illustrated. At certain stages comparisons between conventional and high-speed drives are made. The paper summarizes the experience of a VFD manufacturer based on state of the art technology in medium voltage and multi-megawatt power range. The authors believe that main complexity around high-speed drives is the motor design while the VFD requires only small adaptations or can sometimes be used directly without any modifications of standard design. The technology readiness is evaluated to be on a medium to high level.

Optimizing Electrical Protection for Medium Voltage Controller Lineup to Improve Liquids Pipelines Operation Reliability and Safety

2018 ◽  
Author(s):  
Ting Yu ◽  
Tushar Chaitanya
Keyword(s):  
Proximity Effect ◽  
Incident Energy ◽  
High Speed ◽  
Large Scale ◽  
Failure Modes ◽  
Partial Discharge ◽  
Light Detection ◽  
Medium Voltage ◽  
Voltage Controller ◽  
The Impact

MV (Medium Voltage) controller lineup electrical protection is crucial in protecting the equipment from large scale damage upon the occurrence of an electrical fault, reducing the time to restore power, thereby minimizing the impact to liquids pipelines operation. The paper discusses typical electrical failure modes that may occur in MV controller lineups, and demonstrates practical relaying engineering techniques that enable fast and effective fault clearing. Electrical faults in the MV controller lineup are often arcing type, commonly involve ground. Mitigating arc hazards in MV Class E2 controller lineups has traditionally been challenging without sacrificing the protection selectivity. As the paper demonstrates, a relaying scheme with the combined use of high-speed light-sensing and overcurrent detection will effectively mitigate the incident energy, while maintaining the protection selectivity for non-arcing overcurrent events. For new MV controller lineups, in addition to the “high-speed light detection and fault interruption”, zone-selective interlocking (ZSI) can also be a practical solution in improving relay protection speed, thus reduce the chance of severe arc flash occurrences. ZSI is particularly effective for fault occurrences on the line side of the phase CTs, busways or main incoming circuits. The ZSI scheme can be implemented on both Class E2 and circuit breaker (VCB) type MV controller lineups, however, with slightly different trip logic due to the limited fault clearing capability of the contactor. Although there are multiple contributing factors, the direct causes of electrical failures in MV controller lineup are commonly related to improper power cable installation and handling, potentially leading to premature insulation breakdown due mainly to the proximity effect and/or partial discharge. Inadequate cable separation and prolonged fault trip delay can increase the possibility of arcing fault occurrence. This can usually be mitigated through appropriate cable spacing, adequate conductor insulation, and optimized fault detection schemes. The paper provides overviews of the mechanisms of proximity effect and partial discharge propagation, and the modern relaying approaches for accurate fault type discrimination and facilitating fast fault interruption. Two case studies are provided in the paper as an aid in understanding the electrical fault mechanism originated from cable insulation failure, demonstrating the incident energy reduction before and after the implementation of high-speed light detection and fault interruption solutions on an existing MV controller lineup.

Substantial Reduction of Reset Current in CoO RRAM with Ta Bottom Electrode

2008 ◽  
Vol 1071 ◽  
Author(s):  
Hisashi Shima ◽  
Fumiyoshi Takano ◽  
Yukio Tamai ◽  
Hidenobu Muramatsu ◽  
Hiroyuki Akinaga ◽  
...  
Keyword(s):  
Voltage Pulse ◽  
Pulse Width ◽  
High Speed ◽  
Bottom Electrode ◽  
Substantial Reduction ◽  
Resistance Switching ◽  
Forming Process ◽  
Height Dependence ◽  
Load Resistor ◽  
Resistance Component

AbstractThe resistance switching in Pt/Co-O/Pt and Ta/Co-O/Pt has been investigated. Compared to Pt/Co-O/Pt, the reset current was more efficiently decreased in Ta/Co-O/Pt by using the load resistor in the forming process, indicating that the embedded resistance component with little parasitic capacitance effectively limits the current in the forming process. The reset process with the reset current lower than 0.15 mA was successfully demonstrated in Ta/Co-O/Pt. In addition, the high speed resistance switching by the voltage pulse with the pulse width of 20 ns was carried out, by investigating the pulse voltage height dependence of reset speed in Ta/Co-O/Pt.

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