With the development of cities, underground tunnels are more and more widely used, and the reinforced concrete in their walls can be used as the natural grounding body of the tunnels. However, underground tunnels have...
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In N-module motors, uniform carrier phase shifting (UCPS) by 2π/N between modules can effectively suppress torque harmonics caused by high-frequency switching of power devices. In multi-module motors with fractional-...
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With the rapid growth of grid-connected wind power penetration level,it is necessary to study the impacts of wind power on powersystem *** small-signal stability of powersystems with large-scale wind power is explor...
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With the rapid growth of grid-connected wind power penetration level,it is necessary to study the impacts of wind power on powersystem *** small-signal stability of powersystems with large-scale wind power is explored using the eigenvalue analysis method.A prototype sample system,the two-synchronous-generator system with a wind farm,is proposed for theoretical ***,simplified models of wind turbines(WTs)and the corresponding equivalent models of wind farms are *** kinds of typical WT models,i.e.,squirrel cage induction generator,doubly-fed induction generator,and permanent magnet synchronous generator are ***,based on the simplified equivalent models,effects of large-scale wind farms on the electromechanical oscillation modes(EOMs)of synchronous systems are *** results indicate that wind farms of the three kinds of WTs have positive effects on ***,long transmission lines connecting wind farmto the systemmay produce negative effects on the small-signal stability of the system.
Estimating low-frequency oscillation modes and the corresponding mode shapes based on ambient data from WAMS measurements has a promising prospect in powersystem analysis and *** on the stochastic subspace method,thi...
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Estimating low-frequency oscillation modes and the corresponding mode shapes based on ambient data from WAMS measurements has a promising prospect in powersystem analysis and *** on the stochastic subspace method,this paper proposes a revised stochastic subspace method by introducing reference channels,which can estimate the modes and the mode shapes simultaneously with great computational ***,the accuracy of the estimated results is not *** discriminate the real modes from the spurious ones,the stabilization diagram is introduced.A novel algorithm is designed to deal with the stabilization diagram which can detect the real modes *** conducted on the IEEE-118 system indicate that the proposed method has good performance in terms of both computational efficiency and accuracy,and has the potential of being used on-line.
With the integration of renewable energy generations and other related changes,the smart grid,or the future electric powersystem,is confronted with new challenges and ***,it is a promising subject in electrical engin...
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With the integration of renewable energy generations and other related changes,the smart grid,or the future electric powersystem,is confronted with new challenges and ***,it is a promising subject in electrical engineering and much work has been done on *** paper reviews the recent advances on the technologies of smart grid and renewable energy integration,from the aspects of modeling,simulation,protection and control,stability,operation,and planning.
Dynamic simulation is one of the most complex and important computations for powersystems *** solutions based on normal Newton iterations almost all depend on evaluations of Jacobian matrixes,which increases the prog...
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Dynamic simulation is one of the most complex and important computations for powersystems *** solutions based on normal Newton iterations almost all depend on evaluations of Jacobian matrixes,which increases the programming complexity of and limits the parallelizability of the whole *** this paper,a new adaptive preconditioned Jacobian-free Newton-GMRES(m)method is proposed to be applied to dynamic simulations of power *** new method has totally Jacobian-free characteristics,which saves calculations and storages of Jacobian matrixes and features strong ***,several speedup strategies are introduced to enhance efficiency and parallelizability of overall *** tests are carried out on IEEE standard test systems and results show that in series computing environment,simulations based on the proposed method have comparable speed to those based on classical Newton-Raphson methods.
In this paper, the impact of stochastic time delay on wide-area damping networked controlsystems is analyzed. A disintegrate method of time-delay upon sampling period is approved. Furthermore, the expectative model o...
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ISBN:
(纸本)9781467355339
In this paper, the impact of stochastic time delay on wide-area damping networked controlsystems is analyzed. A disintegrate method of time-delay upon sampling period is approved. Furthermore, the expectative model of networked controlsystems with long and stochastic time delay, whose variance extent is larger than one sampling period, is theoretically proved and calculated. Finally, the effectiveness of this expectative model is confirmed on the simulation of a powersystem with 8 generators and 36 nodes.
Distributed integrated multi-energy systems(DIMSs)can be regarded as virtual power plants to provide additional flexibility to the power *** paper proposes a robust active dynamic aggregation model for the DIMSs to de...
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Distributed integrated multi-energy systems(DIMSs)can be regarded as virtual power plants to provide additional flexibility to the power *** paper proposes a robust active dynamic aggregation model for the DIMSs to describe the maximum feasible *** aggregation model includes the power constraints,energy constraints,and ramping constraints to aggregate different types of resources in the *** proposed generator-like and storage-like model does not depend on the ancillary service market and can be directly incorporated into the economic dispatch model of the powersystem.A novel algorithm based on the column-and-constraint generation algorithm and convex-concave procedure is proposed to solve the two-stage robust optimization problem,which is more efficient than the KKT-based ***,a case study of an actual DIMS is developed to demonstrate the effectiveness of the proposed model.
This paper presents a game-theoretic method to predict microgrid(MG) development tendency in China. As many distribution generators(DGs) are integrated in distribution systems, analysis of MG formation necessity is co...
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This paper presents a game-theoretic method to predict microgrid(MG) development tendency in China. As many distribution generators(DGs) are integrated in distribution systems, analysis of MG formation necessity is conducted from the aspect of DGs. In order to maximize the profit brought by DGs and to earn money from arbitrage, it may be necessary for customers to combine their DGs and loads and to construct an MG to obtain maximal control ability. A game model is built to emulate trading between MGs and the distribution system based on MG powercontrol, in which both trading profit and outage cost are considered for each MG. Nash equilibrium(NE) is calculated, and sensitivities of NE to some boundary conditions are studied. The results show that variable MG trading prices with appropriate net generation cost(i.e., DG generation cost minus government subsidy price) may encourage the growth of MGs. Government subsidies, generation costs, and trading prices may also affect DG use, and therefore they may impact customer motivation to build MGs.
A small electrical explosion of wire （EEW） setup for nanopowder production is constructed. It consists of a low inductance capacitor bank of 2 μF–4 μF typically charged to 8 kV–30 kV, a triggered gas switch, and...
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A small electrical explosion of wire （EEW） setup for nanopowder production is constructed. It consists of a low inductance capacitor bank of 2 μF–4 μF typically charged to 8 kV–30 kV, a triggered gas switch, and a production chamber housing the exploding wire load and ambient gas. With the EEW device, nanosize powders of titanium oxides, titanium nitrides, copper oxides, and zinc oxides are successfully synthesized. The average particle size of synthesized powders under different experimental conditions is in a range of 20nm–80nm. The pressure of ambient gas or wire vapor can strongly affect the average particle size. The lower the pressure, the smaller the particle size is. For wire material with relatively high resistivity, such as titanium, whose deposited energy Wd is often less than sublimation energy W s due to the flashover breakdown along the wire prematurely ending the Joule heating process, the synthesized particle size of titanium oxides or titanium nitrides increases with overheat coefficient k （k = W d /Ws ） increasing.
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