The dynamics of network power response play a crucial role in system stability. However, the integration of power electronic equipment leads to amplitude and angular frequency (abbreviated as “frequency”) time-varyi...
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The dynamics of network power response play a crucial role in system stability. However, the integration of power electronic equipment leads to amplitude and angular frequency (abbreviated as “frequency”) time-varying characteristics of the node voltage during dynamic processes. As a result, traditional calculation methods for and characteristics of the power response of the network based on phasor and impedance lose their validity. Therefore, this paper undertakes mathematical calculations to reveal the power response of a network under excitation by voltage with time-varying amplitude and frequency (TVAF), relying on the original mathematical relationships and superimposed step response. Then, the multi-timescale characteristics of both the active and reactive power of the network are explored physically. Additionally, this paper reveals a new phenomenon of storing and releasing the active and reactive power of the network. To meet practical engineering requirements, a simplified power expression is presented. Finally, the theoretical analysis is validated through time-domain simulations.
As the uncertainty output characteristics of wind power, the large-scale wind power integrated to the grid, has brought new challenges to power system operation. Based on the uncertainty characteristics of wind power,...
As the uncertainty output characteristics of wind power, the large-scale wind power integrated to the grid, has brought new challenges to power system operation. Based on the uncertainty characteristics of wind power, this paper establishes the wind power output model, then focuses on the positive effects of price-based demand response (PDR) and incentive-based demand response (IDR), which are allowed to participate in the power balance, on the unit commitment (UC) with high wind power penetration, and establishes the PDR and IDR models. Based on the chance constrained programming, this paper proposes a stochastic UC model with large-scale wind power integration considering demand side resources(DSR). Stochastic simulation combined with particle swarm optimization (PSO) algorithm was presented to solve this model. At last, the model is proved feasibly and effectively by testing the IEEE 10 machines system.
The key difference of laser triggered vacuum switch (LTVS) and electrical triggered vacuum switch (ETVS) is the different triggered way, because the initial plasmas were generated by laser irradiation target material ...
The key difference of laser triggered vacuum switch (LTVS) and electrical triggered vacuum switch (ETVS) is the different triggered way, because the initial plasmas were generated by laser irradiation target material of LTVS, which generates different impact on the triggered characteristics of LTVS with different target materials. There are three laser wavelength (1064nm, 532nm and 266nm) which are tested the triggered characteristics of target materials, with decreased conduction time delay under the condition of increasing laser energy.
Much effort has been devoted to the generation of fluorescent probes by synthetic approaches. In this study, we developed a facile strategy to construct far-red fluorescent probes based on through-space charge transfe...
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Much effort has been devoted to the generation of fluorescent probes by synthetic approaches. In this study, we developed a facile strategy to construct far-red fluorescent probes based on through-space charge transfer within complexes of acceptors and donors and their “twist+twist” interactions. Owing to their rare two-photon excitation property, the complexes could be used for in vivo imaging of the mouse cerebrovascular system.
The Rapid Prototyping of Application Specific Signal Processors (RASSP) program is a multi-year DARPA/Tri-Service initiative intended to dramatically improve the process by which complex digital systems, particularly ...
The Rapid Prototyping of Application Specific Signal Processors (RASSP) program is a multi-year DARPA/Tri-Service initiative intended to dramatically improve the process by which complex digital systems, particularly embedded digital signal processors, are designed, manufactured, upgraded, and supported. This paper reviews the genesis of the RASSP program, considering both the problems that defined the need for the program, and the historical conditions under which it began. The RASSP program is then presented from two viewpoints. The first is programmatic, covering the goals and constraints of the program, and describing the roles of the various program participants. The second is technical, covering the major concepts upon which the developing RASSP approach to design is based and showing how the detailed technical discussions contained in the other papers in this issue of the Journal of VLSI Signal Processing relate to one another and fit into an overall development concept. The paper closes with a review of the status of the program as of this writing (Summer 1996).
Since entering the 21st century, as wind power develops rapidly, wind power plays an increasingly important role in the safe and stable operation of power systems. Since the wind turbines under traditional control don...
Since entering the 21st century, as wind power develops rapidly, wind power plays an increasingly important role in the safe and stable operation of power systems. Since the wind turbines under traditional control don't provide frequency support, the frequency dynamics of the power grids after load disturbance will be deteriorated. Thus, wind farms are required to equip primary frequency control in many countries. Most existing researches on primary frequency control of wind turbines focus on control strategies and the impact on system frequency, but few studies pay attention to the impact of primary frequency control of wind power on ultra-low frequency oscillation. This paper first proposes an analysis framework for ultra-low frequency oscillations in power systems with wind power. On this basis, a motion equation model of wind turbines is established. Finally, an extended three-machine nine-node system is used as an example to analyze the impact mechanism of primary frequency control on ultra-low frequency oscillation. The impact mechanism provides reference for the design of primary frequency of wind turbines in some regional power grids with ultra-low frequency oscillation.
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