The effects of very-high-resistance grounding on the selectivity of ground-fault relaying in high-voltage longwall power systems

2001 ◽  
Vol 37 (2) ◽  
pp. 398-406 ◽  
Author(s):  
T. Novak
1905 ◽  
Vol 74 (497-506) ◽  
pp. 319-319 ◽  
Author(s):  
Oliver Joseph Lodge

The methods hitherto employed for propelling a current through very high resistance have involved the use either of a very large static inductive machine, such as that of Wimshurst and others, or a battery of a very large number of cells, as employed by De la Rue, Trowbridge, etc. The author finds that by the use of high-tension mercury-rectifiers the same result can be attained with ordinary sources of supply, e.g ., by transforming and utilising the current from any steady or alternating main.


2018 ◽  
Vol 138 (3) ◽  
pp. 206-211
Author(s):  
Kazunori Nishimura ◽  
Yusaku Marui ◽  
Wataru Sunayama

Alloy Digest ◽  
1996 ◽  
Vol 45 (9) ◽  

Abstract Avesta Sheffield SAF 2507 is an austenitic/ferritic duplex stainless steel with very high strength. The alloy has a lower coefficient of thermal expansion and a higher thermal conductivity than austenitic stainless steels. The alloy has a high resistance to pitting, crevice, and general corrosion; it has a very high resistance to chloride stress-corrosion cracking. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, and joining. Filing Code: SS-652. Producer or source: Avesta Sheffield Inc.


Electronics ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 313
Author(s):  
Jacek Rąbkowski ◽  
Andrzej Łasica ◽  
Mariusz Zdanowski ◽  
Grzegorz Wrona ◽  
Jacek Starzyński

The paper describes major issues related to the design of a portable SiC-based DC supply developed for evaluation of a high-voltage Marx generator. This generator is developed to be a part of an electromagnetic cannon providing very high voltage and current pulses aiming at the destruction of electronics equipment in a specific area. The portable DC supply offers a very high voltage gain: input voltage is 24 V, while the generator requires supply voltages up to 50 kV. Thus, the system contains two stages designed on the basis of SiC power devices operating with frequencies up to 100 kHz. At first, the input voltage is boosted up to 400 V by a non-isolated double-boost converter, and then a resonant DC-DC converter with a special transformer elevates the voltage to the required level. In the paper, the main components of the laboratory setup are presented, and experimental results of the DC supply and whole system are also shown.


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