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Mechanism and Measurement of Ultra-Low-Frequency Oscillations in Asynchronous Networks
2018 IEEE Power & Energy Society General Meeting (PESGM), 2018The asynchronous interconnection mode between the Yunnan Province Power Grid and China Southern Power Grid was implemented in 2016. However, during the practical experiment of raising HVDC power in the asynchronous mode, the frequency of the Yunnan Power Grid oscillated at ultra-low frequency for a long period.
Chunxiao Liu +3 more
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Emergency Control Strategy of Ultra-low Frequency Oscillations Based on WAMS
2019 IEEE Innovative Smart Grid Technologies - Asia (ISGT Asia), 2019In this paper, an emergency control strategy of ultra-low frequency oscillations (ULFO) is presented. The multi-signal Prony algorithm is used to identify frequency signals from WAMS. Then the criterion of ULFO is proposed based on the Prony analysis results.
Qin LIU +7 more
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Mode Identification and Damping Torque Analysis of Ultra-Low Frequency Oscillations
2019 IEEE Sustainable Power and Energy Conference (iSPEC), 2019After the asynchronous interconnection of Yunnan and South China Power Grid, a long period of ultra-low frequency oscillation occurred, which seriously affected the safe and stable operation of the system. This paper presents the damping analysis of hydraulic turbine governing systems under ultra-low frequency oscillations.
Junfeng Zhang +4 more
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Analysis of ultra-low frequency oscillation in yunnan asynchronous sending system
2017 IEEE Power & Energy Society General Meeting, 2017Yunnan power grid has a large-scale hydropower station whereby the power generated at the station is been transmitted via high-voltage direct current (HVDC) transmission lines under asynchronous operation mode. In the system performance test of Yunnan asynchronous operation, 0.05 Hz ultra-low frequency oscillation occurred in the grid.
Yiping Chen +6 more
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Eigen Ultra-Low-Frequency Magnetosonic Oscillations of the Near Plasma Sheet
Cosmic Research, 2008A critical analysis of existing theories of the magnetospheric resonator for fast magnetosonic waves is performed. A new variant of the theory is suggested, according to which the near-Earth part of the plasma sheet plays the role of the resonator. It is shown that the magnetosonic wave is locked inside this region over its entire boundaries. The eigen
A. S. Leonovich, V. A. Mazur
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Ultra low frequency CMOS ring oscillator design
2014 Recent Advances in Engineering and Computational Sciences (RAECS), 2014In this paper, the concept of CMOS thyristor has been used to implement low frequency ring oscillator using 2.5 volt power-supply and 1pF load capacitance using 250nm technology. By using the conventional CMOS thyristor structure the frequency of the output sinusoidal waveform is of the order of KHz, which has been further improved in proposed CMOS ...
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Ultra-Low-Frequency, Three-Phase Oscillator
Proceedings of the IRE, 1954This paper describes the design of a three-phase oscillator covering the range from 0.01 to 1,000 cycles per second. The problems peculiar to this frequency range, and their solutions, are discussed. Certain advantages inherent in three-phase operation are explained.
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Analysis of the Influence of System Characteristics on Ultra-Low Frequency Oscillation
2019The ultra-low frequency oscillation phenomenon is not only related to the characteristics of the governor of the hydropower unit, but also closely related to the system characteristics. Based on the detailed analysis of the hydroelectric governor model, a simplified analysis model of the ultra-low frequency oscillation of the power grid is proposed ...
Xuelian Wu +3 more
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Ultra Low-Frequency Oscillations of a Solar Filament Observed by the GONG Network
Solar Physics, 2016The data of ground-based telescopes of the Global Oscillation Network Group (GONG) obtained in the $\mathrm{H}\upalpha$ line provide an opportunity to study the long-period oscillations of chromospheric ...
V. I. Efremov +2 more
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An ultra-low frequency ring oscillator with programmable tracking using a phase-locked loop
2012 IEEE 55th International Midwest Symposium on Circuits and Systems (MWSCAS), 2012This paper presents a programmable ultra-low frequency ring oscillator designed in a 0.5µm CMOS technology with 3.3 V power supply. In normal operation, the oscillator produces a periodic signal without external inputs (other than power and ground).
Tsung-Hsueh Lee, Pamela Abshire
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