Results 51 to 60 of about 5,995,861 (234)

Reliability Improvement Strategy for Transformer Zero-Sequence Differential Protection Based on Zero-Sequence Current Amplitude Difference Characteristics

Zhongguo dianli
The zero-sequence differential protection of transformer may cause the reliability to decrease or even malfunction due to the fault of current transformer (CT) when dealing with complex inrush current and fault.
Junchao ZHENG, Yaming GE, Xiangping KONG, Xuchao REN, Shi CHEN, Chenqing WANG   +5 more
doaj   +1 more source

Analysis of unbalanced clustered voltage and control strategy of clustered voltage balancing for cascaded H-bridge STATCOM

Journal of Modern Power Systems and Clean Energy, 2019
To explore the clustered voltage balancing mechanism of the cascaded H-bridge static synchronous compensator (STATCOM), this paper analyzes the causes of unbalanced clustered voltage. The negative-sequence current caused by the compensation of unbalanced
Yu Jin, Jianze Wang, Yiqi Liu, Xinagyu Sai, Yanchao Ji   +4 more
doaj   +1 more source

Double-periodic quasi-periodic graphene superlattice: non-Bragg band gap and electronic transport

, 2012
Electronic band gap and transport in quasi-periodic graphene superlattice of double-periodic sequence have been investigated. It is found that such quasi-periodic structure can possess a zero-averaged wave number (zero-$\bar{k}$) gap which associated ...
Chen, Xi, Zhao, Pei-Liang, Zhu, Qi-Biao
core   +1 more source

Invariant polynomials and minimal zero sequences [PDF]

Involve, a Journal of Mathematics, 2008
A connection is developed between polynomials invariant under abelian permutation of their variables and minimal zero sequences in a finite abelian group. This connection is exploited to count the number of minimal invariant polynomials for various abelian groups.
Finklea, Bryson, Moore, Terri, Ponomarenko, Vadim, Turner, Zachary   +3 more
openaire   +2 more sources

Sequence-current control strategies for transformerless voltage-source converters in islanded grids of AC/DC distribution system under asymmetrical ground faults

International Journal of Electrical Power & Energy Systems
Islanded grids play a crucial role in AC/DC distribution systems. The adoption of transformerless voltage-source converters as the primary power source is an important development direction for AC/DC distribution systems.
Yuze Li, Peng Guo, Qianming Xu, Josep M. Guerrero, Yufei Yue   +4 more
doaj   +1 more source

A line selection method of mine leakage protectio

Gong-kuang zidonghua, 2020
Aiming at problem of low accuracy of line selection when single-phase grounding fault occurs in mine power supply system at present, according to characteristics of obvious difference of zero-sequence current waveform between fault line and non-fault ...
YU Qun, SHANG Xueli
doaj   +1 more source

Non-Directional Earth Fault Passage Indication in Isolated Neutral Distribution Networks

Energies, 2020
In this paper, two new methods for locating single-phase to ground faults in isolated neutral distribution networks are proposed. The methods are based on the analysis of symmetrical sequence currents.
Amir Farughian, Lauri Kumpulainen, Kimmo Kauhaniemi   +2 more
doaj   +1 more source

Analysis on Circulating Current and Split Capacitor Voltage Balance for Modular Multilevel Converter Based Three-phase Four-wire Split Capacitor DSTATCOM

Journal of Modern Power Systems and Clean Energy, 2021
We propose a modular multilevel converter (MMC) based three-phase four-wire (3P4W) split capacitor distribution static synchronous compensator (DSTATCOM), aiming at compensating unbalanced and reactive load currents.
Lei Lin, Jialu He, Chen Xu
doaj   +1 more source

Analysis of Mine Low-voltage Leakage Protection in Situation of Great Disparity between Long and Short Lines and Big Unbalanced Current

Gong-kuang zidonghua, 2010
The paper explained that traditional leakage protection principles such as zero-sequence direction relay principle and zero-sequence current's maximum principle are unable to implement selective leakage protection in situation of great disparity between ...
SU Po, CHEN Qing
doaj   +2 more sources

Method of damping nutation motion with minimum spin axis attitude disturbance [PDF]

, 1983
In a method of and apparatus for damping nutation of a spinning spacecraft, spin axis attitude disturbances are substantially reduced by controlling at least one nutation damping gas thruster to fire with nonuniform gas pulses.
Hoffman, H. C.
core   +1 more source