Navigable flow condition simulations can provide detailed information on water depth and velocity distribution, simulation speed is one of the key factors which influence real-time navigation. In this paper, a navigab...
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Navigable flow condition simulations can provide detailed information on water depth and velocity distribution, simulation speed is one of the key factors which influence real-time navigation. In this paper, a navigable flow condition simulation system is developed to provide useful information for waterway management and shipping safety. To improve the simulation speed of 2-D hydrodynamic model, an explicit finite volume method and Open MP are used to realize parallel computing. Two mesh schemes and two computing platforms are adopted to study the parallel model＇s performance in the Yangtze River, China. The results show that the parallel model achieves dramatic acceleration, with a maximum speedup ratio of 34.94？. The parallel model can determine the flow state of the navigable channel in about 4 min, efficiency is further improved by a flow simulation scheme database. The developed system can provide early warning information for shipping safety, allowing ships to choose better routes and navigation areas according to real-time navigable flow conditions.
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.
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 power system.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.
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 power system with 8 generators and 36 nodes.
Establishing a suitable closed-loop transfer function model for the grid-connected PMSG system is the key basis in performing inter-harmonic characteristics *** closed-loop transfer functions can be constructed when d...
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Establishing a suitable closed-loop transfer function model for the grid-connected PMSG system is the key basis in performing inter-harmonic characteristics *** closed-loop transfer functions can be constructed when different components of the converter controller are taken into ***,the effect of different components of the converter controller on inter-harmonic stability analysis is not *** this paper,the complete transfer function,considering different loops,is first *** on the complete closed-loop transfer function,the DC-link,PLL and voltage forward-feed are removed step by step to derive different closed-loop transfer *** inter-harmonic related poles of different closed-loop transfer functions are further calculated to analyze the effect of closedloop transfer functions on inter-harmonic characteristics ***,by performing time domain simulation,the correctness of the theoretical analysis results is *** results show that under the conditions of a weak AC system,each loop of the converter control system will reduce the stability of the interharmonic in the sub-synchronous frequency range and influence the inter-harmonic oscillation *** transfer function needs to consider the influence of each loop to accurately calculate the inter-harmonic stability of the system.
The power system now is a typical complex system, which has inherent characteristics of SOC. Studying on cascading failures are necessary and meaningful to insure the grid's safety, national security and economic ...
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ISBN:
(纸本)9781479947249
The power system now is a typical complex system, which has inherent characteristics of SOC. Studying on cascading failures are necessary and meaningful to insure the grid's safety, national security and economic development. This paper firstly establishes the indices of power system development diagnosis, which are closely relevant to the trigger of power system evolution. Then a cascading failure model is proposed, considering planning and evolution of the power system. This model is based on OPA model, including both fast dynamics and slow dynamics. The slow dynamic process simulates the evolution of power system, which represents the functions of the planning department, while the fast dynamic process simulates power flow and cascading failures, which takes the effects of dispatch, relay protection and automation into consideration. Moreover, simulations are tested on the case of Kaifeng-Shangqiu power system in Henan Province of China, and evolution results are presented.
In this paper, we propose a hybrid algorithm that combines an improved Artificial Potential Field (APF) method with the Simulated Annealing (SA) algorithm for path planning of an electric power operation robot manipul...
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ISBN:
(数字)9798331521950
ISBN:
(纸本)9798331521967
In this paper, we propose a hybrid algorithm that combines an improved Artificial Potential Field (APF) method with the Simulated Annealing (SA) algorithm for path planning of an electric power operation robot manipulator in complex distribution grid environments. To address the unreachable target issue inherent in traditional APF, we introduce a distance regulation factor to optimize the repulsive function. This modification allows the manipulator to smoothly approach the target point as it nears, while the repulsion from obstacles gradually decreases. Additionally, to overcome the limitations of the traditional SA algorithm, such as its tendency to get trapped in local minimum solutions and its inefficiency in complex environments, we propose an adaptive temperature rise strategy. This strategy increases the temperature, enhancing the probability of escaping local optimal solutions. When the APF algorithm becomes trapped in a local optimum, the improved SA algorithm is applied to escape the local minimum. Once the local optimum is avoided, the algorithm switches back to APF to continue the path planning process. simulation results demonstrate that the proposed improved APF-SA algorithm adapts effectively to various complex environments, achieving shorter planning times and higher success rates compared to traditional APF and SA algorithms. It successfully resolves the unreachable target and local minimum problems associated with APF. Finally, the feasibility of the proposed APF-SA fusion algorithm is validated through experiments conducted on an electric power operation robot experimental platform for distribution grid applications.
Due to its capability of solving decision-making problems involving multiple entities and objectives, as well as complex action sequences, game theory has been a basic mathematical tool of economists, politicians, and...
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Due to its capability of solving decision-making problems involving multiple entities and objectives, as well as complex action sequences, game theory has been a basic mathematical tool of economists, politicians, and sociologists for decades. It helps them understand how strategic interactions impact rational decisions of individual players in competitive and uncertain environment, if each player aims to get the best payoff. This situation is ubiquitous in engineering practices. This paper streamlines the foundations of engineering game theory, which uses concepts, theories and methodologies to guide the resolution of engineering design, operation, and control problems in a more canonical and systematic way. An overview of its application in smart grid technologies and powersystems related topics is presented, and intriguing research directions are also envisioned.
As an important power equipment in the power system, the electrialc motor is an important part of the transformation of electric energy and mechanical energy. Reasonable prediction of the reliability level of the runn...
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