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Ground and air resonance characteristics of a soft in-plane rigid-rotor system
VTOL Research, Design, and Operations Meeting, 1969A flight research program was conducted on a soft in‐plane matched‐stiffness rotor in which it was demonstrated that a soft in‐plane rigid rotor is subject to mechanical instability in flight as well as on the ground. The research included extending existing analysis techniques to include aerodynamic forces.
R. E. Donham +2 more
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Characteristic analysis of single-phase grounding fault in resonant grounded systems based-on HHT
2016 IEEE 11th Conference on Industrial Electronics and Applications (ICIEA), 2016Transient analysis is carried out for the single-phase grounding fault in small current grounding system, the transient grounding current expression is derived, and the influence factors are analyzed. Introduces a method for non-stationary and non-linear signal analysis method-Hilbert Huang transform (HHT) to analyze the single phase grounding fault in
Yingwei Xiao +3 more
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Grounding Failure Detection Based on Wavelets Method in Resonant Grounded Power Distribution System
2010 Second WRI Global Congress on Intelligent Systems, 2010This paper analyses characteristics of single-phase ground fault and presents a fault line selecting method based on wavelet transform. Base on Sampling frequency, it selects the special frequency band, the singularity detection with wavelet is employed to obtain the polarities and magnitudes of the abrupt of current, and through comparing the ...
Yusheng Zhou +4 more
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2012 International Conference on Lightning Protection (ICLP), 2012
A joint research project between AES Sul, the Federal University of Itajuba and the University of Bologna aims at defining the required protections against lightning-originated overvoltages in a resonant grounded distribution system in order to achieve the adequate lightning performance level with minimum cost.
BORGHETTI, ALBERTO +5 more
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A joint research project between AES Sul, the Federal University of Itajuba and the University of Bologna aims at defining the required protections against lightning-originated overvoltages in a resonant grounded distribution system in order to achieve the adequate lightning performance level with minimum cost.
BORGHETTI, ALBERTO +5 more
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Systems with resonating-valence-bond ground states: Correlations and excitations
Physical Review B, 1988We consider a resonating-valence-bond state as a variational estimate for the ground state of a Heisenberg antiferromagnet. We derive an expression for the normalization of this wave function, which is a superposition of a very large number of singlet pair states, which we then use to show that the singularities, correlations, and low-lying excitations
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Proceedings of 2011 International Conference on Electronic & Mechanical Engineering and Information Technology, 2011
Establishing the mathematical model of instantaneous positive sequence network of power source, grounding petersen coil, ground point, capacitance to the ground to the 10 kV medium-voltage resonance grounding system with instantaneous symmetrical component, establishing the mathematical model of instantaneous positive sequence network to resonance ...
Xuejie Chen +5 more
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Establishing the mathematical model of instantaneous positive sequence network of power source, grounding petersen coil, ground point, capacitance to the ground to the 10 kV medium-voltage resonance grounding system with instantaneous symmetrical component, establishing the mathematical model of instantaneous positive sequence network to resonance ...
Xuejie Chen +5 more
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Resonance Analysis of Small Current Grounding System in Distribution Network
2018 China International Conference on Electricity Distribution (CICED), 2018At present, there are a large number of arc suppression coil grounding mode in the low-voltage distribution network for the equipment insulation and power supply reliability considerations. The role of arc suppression coil grounding mode is when the grid single-phase ground fault occurs, arc suppression coil will provide inductor current to compensate ...
Zhou Desheng +5 more
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Power system resonance excited by VFD ground fault
2009 IEEE International Electric Machines and Drives Conference, 2009This paper investigates the resonance phenomenon produced by a voltage source PWM variable frequency drive (VFD) on an ungrounded delta system. Many drives are installed on ungrounded delta systems without isolation transformers or other means to provide inverter ground reference.
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A novel fault line selection method of resonant grounding system
2017 IEEE Conference on Energy Internet and Energy System Integration (EI2), 2017In order to solve the problems of fault line selection in resonant grounding system, a novel fault line selection method for distribution network was proposed in this paper. First, continuously measure three-phase voltage and zero-sequence voltage, which detects single-phase ground fault.
Yongjun Yuan +5 more
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The research and realization of the low-voltage simulation for the resonant grounded system
2012 China International Conference on Electricity Distribution, 2012In order to study operational features of resonant grounded system deeply, and test all performance indexes of the control device of arc-suppression coil, this paper comes up with the research ideas and implementation of the low-voltage simulation environment, describing its technology parameters and building principles of the major parts in detail ...
null Qiu Jixing +3 more
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