Elimination of transformer inrush currents by controlled switching. I. Theoretical considerations

2001 ◽  
Vol 16 (2) ◽  
pp. 276-280 ◽  
Author(s):  
J.H. Brunke ◽  
K.J. Frohlich
Keyword(s):  
Controlled Switching ◽  
Inrush Currents ◽  
Theoretical Considerations

scholarly journals Synchronous Study of Ferroresonance and Inrush Current Phenomena and their Related Reasons in Ground Power Networks

2010 ◽  
Vol 27 (1) ◽  
pp. 82-87 ◽  
Author(s):  
Amin Akrami ◽  
Mohammad Ghaderi ◽  
Saeed Ghadi
Keyword(s):  
Power Transformers ◽  
Inrush Current ◽  
Power Networks ◽  
Transient Phenomena ◽  
Controlled Switching ◽  
Inrush Currents ◽  
Very High ◽  
Inductive Reactance

Synchronous Study of Ferroresonance and Inrush Current Phenomena and their Related Reasons in Ground Power NetworksEnergizing the power transformers usually results in flowing very high inrush currents. This harmful current can be minimized using controlled switching and considering the value of residual flux. But nowadays, developing the ground power networks results in high increment of ferroresonance phenomenon occurrence due to the line' capacitance reactance and nonlinear inductive reactance of power transformer's core. In this study, these transient phenomena and their cause have studied synchronously.

Reduction of Three-Phase Transformer Inrush Currents Using Controlled Switching

2020 ◽  
Vol 56 (1) ◽  
pp. 890-897
Author(s):  
Joydeep Mitra ◽  
Xufeng Xu ◽  
Mohammed Benidris
Keyword(s):  
Controlled Switching ◽  
Three Phase ◽  
Inrush Currents

Residual flux impact in controlled switching of HVDC converter transformer

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Ajay Kumar ◽  
Inderpreet Kaur ◽  
Urmil Parikh
Keyword(s):  
Circuit Breaker ◽  
Field Tests ◽  
Electrical Circuit ◽  
View Point ◽  
Controlled Switching ◽  
Core Saturation ◽  
Three Phase ◽  
Inrush Currents ◽  
Phase Converter ◽  
Programming Package

Abstract Converter transformers are an interface point of HVDC frameworks and are basic hardware from activity and reliability view point. Converter transformers are turned off intentionally under planned support and un-deliberately during fault conditions. Random energization of HVDC Converter transformer delivers high inrush currents due to core saturation asymmetries and endanger equipment health. In this paper, charging approach has been proposed. By utilizing point on wave exchanging for moderation of charging drifters during charging of 888 MVA 400/325 kV Converter Transformer of ±800 kV HVDC Sub-station. The proposed procedure has been applied on HVAC electrical Circuit Breaker furnished with Pre-Insertion Resistor considering diverse degree of residual flux. Performance of proposed philosophy has been affirmed by field tests and reproduction in PSCAD programming package and is found very viable. Near investigation is done in this paper and shows that with the use of proposed system, the switching transient during stimulation and field tests of coupled three phase converter transformers is decreased to worthy level.

The Biological Clock and Sleep in the Elderly

2006 ◽  
Vol 19 (1) ◽  
pp. 45-51 ◽  
Author(s):  
Myriam Juda ◽  
Mirjam Münch ◽  
Anna Wirz-Justice ◽  
Martha Merrow ◽  
Till Roenneberg
Keyword(s):  
Circadian Rhythms ◽  
Biological Clock ◽  
The Elderly ◽  
Early Morning ◽  
Behavioral Changes ◽  
Older Age ◽  
Age Related ◽  
Theoretical Considerations ◽  
Sleep Difficulties ◽  
Circadian Biology

Abstract: Among many other changes, older age is characterized by advanced sleep-wake cycles, changes in the amplitude of various circadian rhythms, as well as reduced entrainment to zeitgebers. These features reveal themselves through early morning awakenings, sleep difficulties at night, and a re-emergence of daytime napping. This review summarizes the observations concerning the biological clock and sleep in the elderly and discusses the documented and theoretical considerations behind these age-related behavioral changes, especially with respect to circadian biology.

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