Although wind power ramp events(WPREs)are relatively scarce,they can inevitably deteriorate the stability of powersystem operation and bring risks to the trading of electricity *** this paper,an imprecise conditional...
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Although wind power ramp events(WPREs)are relatively scarce,they can inevitably deteriorate the stability of powersystem operation and bring risks to the trading of electricity *** this paper,an imprecise conditional probability estimation method for WPREs is proposed based on the Bayesian network(BN)*** method uses the maximum weight spanning tree(MWST)and greedy search(GS)to build a BN that has the highest fitting degree with the observed ***,an extended imprecise Dirichlet model(IDM)is developed to estimate the parameters of the BN,which quantificationally reflect the ambiguous dependencies among the random ramp event and various meteorological *** BN is then applied to predict the interval probability of each possible ramp state under the given meteorological conditions,which is expected to cover the target probability at a specified confidence *** proposed method can quantify the uncertainty of the probabilistic ramp event ***,by using the extracted dependencies and Bayesian rules,the method can simplify the conditional probability estimation and perform reliable prediction even with scarce *** results on a real wind farm with three-year operation data illustrate the effectiveness of the proposed method.
power inverter adopting virtual synchronous generator(VSG)control can provide inertia support for distributed generation ***,it cannot take into account the dynamic regulation characteristics of ***,when the system en...
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power inverter adopting virtual synchronous generator(VSG)control can provide inertia support for distributed generation ***,it cannot take into account the dynamic regulation characteristics of ***,when the system encounters a sudden change in load or disturbance,the dynamic process of frequency regulation will be greatly *** view of this issue,an improved VSG control strategy based on a coordinated self-adaptive(CSA)method is *** time domain analysis method is used to study the influences of virtual inertia and damping parameter perturbation on the system steady and dynamic ***,in order to make the control strategy suitable for large load changes and suppress frequency variations beyond the limit,the secondary frequency modulation is introduced into the control *** the coordinated adaptive control of virtual inertia,virtual damping and frequency modulation,the dynamic performance of vSG frequency regulation can be obviously *** and experiment results have verified the effectiveness of the proposed CSA control strategy.
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.
The effects of manganese dioxide (MnO 2 ) additives on the electrical characteristics of the Al-doped ZnO varistors are investigated. The leakage current densities of the samples decrease first and then increase again...
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The effects of manganese dioxide (MnO 2 ) additives on the electrical characteristics of the Al-doped ZnO varistors are investigated. The leakage current densities of the samples decrease first and then increase again with the increase of the amount of MnO 2 additives. Correspondingly, the nonlinear coefficients of the samples keep on increasing and then decrease. In addition, the donor densities increase monotonously with the amount of the doped MnO 2 increasing. The effects of MnO 2 additives on the electrical characteristics of the samples are different from the conclusion of previous literatures. The reasons of the distinct effects are supposed to be related with the donor and interface state densities of the samples.
Addressing the challenge of harnessing remote solar resources for sustainable hydrogen production, this study presents a scalable off-grid photovoltaic-to-hydrogen (OgPVtH) system. We propose a bottom-up design method...
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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.
In practical engineering,DC disturbance will lead to excitation saturation and vibration intensification on transformer core,as well as affecting the normal operation of equipment and power *** to the problem,a new id...
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In practical engineering,DC disturbance will lead to excitation saturation and vibration intensification on transformer core,as well as affecting the normal operation of equipment and power *** to the problem,a new idea is proposed in this *** on the electromagnetic characteristics of DC biased transformer,excitation saturation and core vibration are studied by using excitation-vibration harmonic response analysis *** current is identified through electromagnetic coupling to characterize the excitation saturation ***,vibration harmonic response model is established to analyze core *** characteristics of DC biased Y/△transformer are *** variation of excitation current and core vibration at different DC levels are ***-vibration characteristics of three-phase group transformer and three-phase three-limb transformer are compared and *** experimental platform built,the correctness of simulation results is verified by experimental data,and the effectiveness of the proposed method can be proved.
A new approach to determining the local boundaries of voltage stability region in power injection space (IVSR) for powersystem with wind farms is presented. It can be used for powersystem voltage stability analysis ...
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A new approach to determining the local boundaries of voltage stability region in power injection space (IVSR) for powersystem with wind farms is presented. It can be used for powersystem voltage stability analysis and on-line security assessment with considering the output uncertainty of the wind farms. Firstly, power flow tracing and double dispatching are used to determine the generators that are closely related to the wind farms, in order to balance the power fluctuations caused by the wind speed variation. Then, modal analysis is used to get the key generators to achieve an effective dimension reduction for IVSR. Finally, the forecasting output power (or wind speed) of wind farms is divided into several intervals. For each interval, the corresponding local IVSR boundaries can be calculated by the method based on small disturbance. Moreover, parallel process is used to accelerate the computing speed. The presented approach is validated by several powersystems. It can be revealed that the approach can give the local IVSR boundaries at different wind speeds and has a good engineering application prospect.
The unintentional islanding of micro-grid may cause negative impacts on distribution loads and distributed generations,so it must be detected within the acceptable *** this paper a new islanding detection algorithm is...
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The unintentional islanding of micro-grid may cause negative impacts on distribution loads and distributed generations,so it must be detected within the acceptable *** this paper a new islanding detection algorithm is *** algorithm introduces the frequency feedback method by the reactive power compensation to derive the frequency continuous shift. Accordingly,the islanding can be detected by monitoring the frequency within 0.1 *** simulation results prove that this algorithm has extremely small non-detection zone,and meanwhile it presents an excellent islanding detection speed as well.
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.
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