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IEEE International Conference on Aircraft Utility systems (AUS)

作者： Chao Hu Pengfei Zhang Xiaoping Ouyang Houtao Ku Qinghe Zhou Enxiao Zhang State Key Lab. of Fluid Power Transmission and Control Zhejiang University Hangzhou China Aviation Key Laboratory of Science and Technology on Aero Electromechanical System Integration Nanjing China The High School Attached to Zhejiang University Hangzhou China

ISBN: (纸本)9781509010882

Seal is one of the most important characteristics for cylinders and suitable seal configuration will guarantee the long life cycle of the seal and the cylinder. Experiment is the only way which can demonstrate the best seal configuration in applications. In this paper, one approach is brought forward for testing the seal performance of cylinders with different seals configurations at the same load working condition for saving the test time. In the test-rig, the synchronization of cylinders is one of the key technologies. The test system is modelled in the AMESim software. The effect caused by the changes of the different physical parameters is analyzed, such as load stiffness, viscous damping coefficient of cylinder, dead volume of cylinder and internal leakage coefficient. The experiment is carried out and test results agree with the simulation results. Finally, the appropriate solution is proposed for improving the synchronization of the multi-cylinders further.

关键词： Synchronization Valves Seals Damping Load modeling Springs Servomotors

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Interval Reliability Assessment of power system under Epistemic Uncertainty Based on Belief UGF Method

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IOP Conference Series: Materials Science and Engineering 2017年第1期199卷

作者： Bolun Wang Yong Wang Ying Ding Ming Li Cong Zhang Key Laboratory of Power System Intelligent Dispatch and Control Shandong University Jinan 250061 China State Grid of China Technology College Jinan 250002 China State Grid Shan Dong Electric Power Research Institute Jinan 250002 Shandong Province China Shandong Zibo Power Supply Company Zibo 255032 Shandong Province China

At present, reliability assessment plays an important role in power systems. When the component failure probabilities are interval valued, common methods fail to achieve reasonable interval reliability assessment result of power systems. In this paper a novel approach based on the belief universal generating function (BUGF) is proposed to calculate the reliability indexes of power systems. Instead of giving a single-valued assessment result, a belief function and a plausibility function are exploited to calculate the lower and upper bounds of the loss of load probability (LOLP), the loss of load expectation (LOLE), the expected unsupplied load (EUL) and the expected unsupplied energy (EUE) in UGF, respectively. The proposed approach can track the correlation of the original data well and keep it to the end of the calculation. By using BUGF compared to other common methods to calculate the interval LOLP, LOLE, EUL, and EUE of IEEE-RTS 79, the results show the BUGF method can track the correlation of the original data well, and can get narrower and more accurate interval reliability indexes of the power generation system, which illustrates the effectiveness of the proposed approach.

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Assessment of impact of unbalancing power allocation on calculating Maximum Loading Point

Assessment of impact of unbalancing power allocation on calc...

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IEEE PES Asia-Pacific power and Energy Engineering Conference (APPEEC)

作者： Xiaoming Dong Yiming Wang Yuanyuan Ding Chengfu Wang Hua Sun Xiaoyan Qin Chao Jiang Feng He Key Laboratory of Power System Intelligent Dispatch and Control of the Ministry of Education Shandong University Jinan China Department of Electrical Automation Shandong Labour Vocational and Technology College Jinan China State Grid Shandong Electric Power Company Jinan Power Supply Company Jinan China

ISBN: (纸本)9781509054190

In traditional power Flow (PF) formulations, the unbalancing power that caused by the transmission power loss (TPL) is provided by sole slack bus, which introduces some errors. Such errors are involved in the results of Continuation power Flow (CPF) which is based on the parameterized PF formulations. Moreover, for certain class of systems, this kind of errors could be significant and few research centres on assessing the CPF with multiple slack buses (MSB). In addition, the impact of the allocations of the slack buses on PF and CPF results has not been well demonstrated. Therefore, this paper analyses the performances of the PF and CPF formulations involving MSB by applying them to calculate the Maximum Loading Point (MLP). It captures the allocation of the unbalancing power by assigning it to MSB according to a set of proportionality coefficients. Since the formulations could generate different results according to various sets of the proportionality coefficients, it is obvious that optimization techniques could be adopted to give optimal coefficients aiming at specific objectives. A particle swarm optimization (PSO) and CPF based approach is presented to help search the optimal proportionality coefficients for the MSBs with the objective of minimizing the TPL. The case studies based on the IEEE 5-bus test system and the IEEE 14-bus test system show the efficiency of the proposed approaches.

关键词： Companies Optimization

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Coupling analysis and loop pairing method via an information-theoretic approach

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ICIC Express Letters 2016年第6期10卷 1407-1413页

作者： Zhang, Jianhua Kuai, Yamin Lin, Mingming Zhang, Ting Hou, Guolian State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power University No. 2 Beinong Road Changping District Beijing102206 China School of Control and Computer Engineering North China Electric Power University No. 2 Beinong Road Changping District Beijing102206 China

It is essential to investigate coupling and loop pairing to determine control system configurations. This paper presents a new control-loop configuration criterion for multi-input multi-output (MIMO) processes based on relevant information-theoretic knowledge. Firstly, we propose a new variable pairing rule based on mutual information rate (MIR) among input and output variables. The information coupling strength is formulated in terms of mutual information rates. Then, the straightforward MIR calculation using frequency formula in MIMO linear time invariant (LTI) systems is introduced briefly under information-theoretic framework. Finally, two numerical examples are provided to demonstrate the effectiveness of the above coupling measure and the variable pairing rules. In addition, we analyze the simulation MIR results, which are consistent with RNGA method. © 2016 ISSN.

关键词： MIMO systems

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Analysis of influencing factors in hybrid state estimation

Analysis of influencing factors in hybrid state estimation

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IEEE PES Asia-Pacific power and Energy Engineering Conference (APPEEC)

作者： Xueliang Yu Hengxu Zhang Jianmei Cao Key Laboratory of Power System Intelligent Dispatch and Control of Ministry of Education Shandong University Jinan P. R. China State Grid of China Technology College Jinan P. R. China

ISBN: (纸本)9781509054190

Hybrid state estimation has become a significant tool to utilize PMU measurements in modern power dispatch center. Factors affecting estimation accuracy are discussed in this paper, including measurement number, PMU number and measurement uncertainty. And it also explores the extent of impacts with simulation results. PMU current phasors are transformed into pseudo power injections and their uncertainties are calculated by uncertainty propagation theory. PMU numbers and their optimal deployment are determined by integer quadratic programming approach. Monte Carlo simulations are carried out in IEEE 14-bus system in this paper.

关键词： Phasor measurement units Measurement uncertainty Transmission line measurements power measurement Voltage measurement Current measurement Uncertainty

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Mathematical expectation modeling of wide-area controlled power systems with stochastic time delay

Mathematical expectation modeling of wide-area controlled po...

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IEEE General Meeting power& Energy Society

作者： Chao Lu Xinran Zhang Xiaoyu Wang Yingduo Han State Key Laboratory of Control and Simulation of Power System and Generation Equipments Tsinghua University

ISBN: (纸本)9781467380416

Summary form only given: Communication network brings new challenges such as time delay and data loss to wide-area damping control of power systems. The uncertainty caused by stochastic time delay of network communication increases the difficulty of wide-area control performance analysis. This paper proposes a mathematical expectation modeling approach to model and analyze wide-area controlled power systems considering the effect of stochastic time delay. In the proposed method, mathematical expectation of stochastic time delay distribution is derived to accurately model the impact of communication network on wide-area control performance. The theoretical frame of the proposed modeling approach is presented and the effectiveness of the method is verified through the simulation of a power system with 8 generators and 36 nodes.

关键词： Mathematical model power systems Delay effects Stochastic processes control systems Data models Communication networks

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A Heterogeneous Wireless Network Selection Algorithm for Smart Distribution Grid

A Heterogeneous Wireless Network Selection Algorithm for Sma...

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International Conference on Natural Computation, Fuzzy systems and Knowledge Discovery

作者： Jiangyu Yan Xiaoyan Wang Shuxian Li Liangrui Tang School of Control and Computer Engineering North China Electric Power University Beijing China State Grid East Inner-Mongolia Electric Power Company Limited State Grid East Inner-Mongolia Electric Power Company Limited Inner-Mongolia China State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources (North China Electric Power University) North China Electric Power University Beijing China

ISBN: (纸本)9781509040940

In order to meet the smart distribution grid's demand for communicating, a heterogeneous wireless network selection model is built. This model has 3 goals, real-time services' blocking rate, non-real-time services' mean transmission time, and network load. And the model is simulated by using the quantum clonal immune multi-objective optimization algorithm. Compared to the MLB algorithm and RBF-FNN algorithm, the simulating results show that the proposed algorithm has better performance in real-time service blocking rate, mean transmission time of non-real-time services and network load balancing.

关键词： Smart distribution grid Heterogeneous wireless network selection Multi-objective optimization

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Stability analysis of wide-area damping control system with stochastic communication time delay

Stability analysis of wide-area damping control system with ...

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Innovative Smart Grid Technologies (ISGT)

作者： Xinran Zhang Chao Lu Yingduo Han State Key Laboratory of Control and Simulation of Power System and Generation Equipments Tsinghua University Beijing

ISBN: (纸本)9781479917860

Stochastic time delay is a new challenge brought out by communication network in wide-area damping control system. Uncertainty introduced by stochastic time delay increases the difficulty of modeling and stability analysis. In this paper, a new approach of stability analysis through expectation model is proposed to solve the problem of uncertainty in wide-area controlled power systems considering the effect of stochastic time delay. In the proposed method, expectation model considering detailed stochastic time delay distribution is derived to accurately model the impact of communication network on wide-area control performance. Then, through matrix transformation of expectation model, eigenvalue of wide-area damping control system considering time delay can be calculated, which can be used for analyzing the system stability. Finally, the effectiveness of this method is verified through the simulation of a power system with 8 generators and 36 nodes with different types of time delay distribution.

关键词： Delay effects power system stability Stability analysis Eigenvalues and eigenfunctions Stochastic processes Damping Analytical models

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Multiple model predictive control for organic rankine cycle (ORC) based waste heat energy conversion systems

Multiple model predictive control for organic rankine cycle ...

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UKACC International Conference on control (control)

作者： Jianhua Zhang Ting Zhang Mingming Lin Guolian Hou Kang Li State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources Beijing China School of Control and Computer Engineering North China Electric Power University Beijing China School of Electronics Electrical Engineering and Computer Science Queen's University Belfast Belfast UK

In this paper, a multiple model predictive control (MMPC) strategy is applied into an organic Rankine cycle (ORC) based waste heat energy conversion system (WHECS). The rotating speed of the pump and the shaft torque of the expander are manipulated simultaneously to provide the optimal (suboptimal) evaporating pressure and superheating temperature for nonlinear WHECSs under different operating conditions. simulation results confirm the efficacy of the proposed control scheme.

关键词： Predictive models Predictive control Waste heat Torque Cooling

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Short-term prediction model of module temperature for photovoltaic power forcasting based on support vector machine

Short-term prediction model of module temperature for photov...

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International Conference on Renewable power Generation, RPG 2015

作者： Sun, Yujing Wang, Fei Mi, Zengaiang Sun, Hongbin Liu, Chun Wang, Bo Lu, Jing Zhen, Zhao Li, Kangping State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power University Baoding Hebei Province071003 China State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Department of Electrical Engineering Tsinghua University Haidian District Beijing100084 China China Electric Power Research Institute Haidian District Beijing100192 China

ISBN: (纸本)9781785610400

To improve the prediction accuracy of photovoltaic (PV) power generation, the temperature of PV modules and its prediction is very important. A short-term step-wise temperature prediction model for PV module based on Support Vector Machine (SVM) is proposed in this paper. Firstly, the primary impact factors of PV module temperature are determined in terms of the PV module physical characteristics and the correlation coefficient between each factor and module temperature. Secondly, two kinds of prediction models, direct and step-wise models, are built to predict module temperature respectively. For direct model, the prediction model is based on SVM using the historical data. For step-wise one, the prediction models of the primary impact factors are built at the first step and then the mapping models between module temperature and the impact factors are established. In the end, the deviations of two different kinds of prediction models are analyzed and discussed based on actual operation data. The results indicate that the stepwise prediction model has better accuracy than the direct prediction model if other things are equal.

关键词： Forecasting

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