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A comparative thermodynamic analysis of Kalina and organic Rankine cycles for hot dry rock:a prospect study in the Gonghe Basin

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Frontiers in Energy 2020年第4期14卷 889-900页

作者： Xuelin ZHANG Tong ZHANG Xiaodai XUE Yang SI Xuemin ZHANG Shengwei MEI State Key Laboratory of Control and Simulation of Power System and Generation Equipments Department of Electrical EngineeringTsinghua UniversityBeijing 100084China Jingjing Energy Storage Co. Ltd.Changzhou 213200China School of QiDi(TUS)Renewable Energy Qinghai UniversityXining 810016China

Hot dry rock is a new type of geothermal resource which has a promising application prospect in *** paper conducted a comparative research on performance evaluation of two eligible bottoming cycles for a hot dry rock power plant in the Gonghe *** on the given heat production conditions,a Kalina cycle and three organic Rankine cycles were tested respectively with different ammonia-water mixtures of seven ammonia mass fractions and nine ecofriendly working *** results show that the optimal ammonia mass fraction is 82%for the proposed bottoming Kalina cycle in view of maximum net power *** analysis suggests that wet fluids should be supercritical while dry fluids should be saturated at the inlet of turbine,*** maximum net power output of the organic Rankine cycle with dry fluids expanding from saturated state is higher than that of the other organic Rankine cycle combinations,and is far higher than the maximum net power output in all tested Kalina cycle *** the given heat production conditions of hot dry rock resource in the Gonghe Basin,the saturated organic Rankine cycle with the dry fluid butane as working fluid generates the largest amount of net power.

关键词： hot dry rock Kalina cycle organic Rankine cycle thermodynamic analysis

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simulation and feature extraction of inter-shaft bearing fault in rotor-bearing-casing system 26

Simulation and feature extraction of inter-shaft bearing fau...

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26th International Congress on Sound and Vibration, ICSV 2019

作者： Yang, Yizhou Liu, Chao Jiang, Dongxiang Han, Te State Key Lab of Control and Simulation of Power Systems and Generation Equipment Department of Thermal Engineering Tsinghua University Beijing100084 China

ISBN: (纸本)9781999181000

The inter-shaft bearing could simplify the supporting structure of a dual-rotor system, so it is widely used in rotating machinery like gas turbine engine. When monitoring the vibration of an inter-shaft bearing, sensors usually could not be installed inside the engine because of the compact structure, then will be installed on the casing. The vibration of the inter-shaft bearing will be transmitted though both the two rotors to the supporting bearings then to the casing, and both the inner and outer ring rotate, making the condition monitoring much more difficult than normal bearings. In this paper, a dual-rotor system dynamic model with the rotor-bearing-casing structure is built to simulate the vibration of an inter-shaft bearing. The rotors and the casing are modelled using finite element method and the bearings are modelled using a nonlinear multi-body dynamic model. The normal state of the inter-shaft bearing is simulated, then the bearing fault states with localized defects on the inner race, the outer race and one of the rolling elements are simulated. Signal processing methods are utilized to extract bearing fault features from the casing vibration acceleration signal. Besides the fixed rotating speed condition, rotors under variable speeds are also simulated, then the vibration signal and fault feature become more complex and the signal analysis becomes a bigger challenge © Proceedings of the 26th International Congress on Sound and Vibration, ICSV 2019. All rights reserved.

关键词： Dynamic models

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Measurement-driven AA-CAES Model for Distribution Network Dispatch in Coordination with Renewable generation 4

Measurement-driven AA-CAES Model for Distribution Network Di...

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2020 4th International Conference on Sustainable Energy Engineering, ICSEE 2020

作者： Xie, Yuguang Bai, Jiayu Liu, Dangwu Zheng, Tianwen Mei, Shengwei State Grid Anhui Electric Power Research Institute Hefei230601 China State Key Lab of Control and Simulation of Power Systems and Generation Equipments Dept. of Electrical Engineering Tsinghua University Beijing100084 China State Grid Anhui Electric Power CO. LTD. Hefei230022 China Sichuan Energy Internet Research Institute Tsinghua University Chengdu610213 China

Advanced adiabatic compressed air energy storage (AA-CAES) could play an important role in power distribution system for mitigating the intermittency of distributed renewable generations and reducing the peak-valley difference of load demand, which requires to operate AA-CAES under off-design conditions. A power system dispatch oriented AA-CAES model was proposed based on the technically thermodynamic performance curves of compressor and expansion calibrated from experiments, highlighting the impact of AA-CAES part-lard features on charging/discharging efficiency and capacity. The proposed model is integrated with economic dispatch problem of power distribution systems, giving rise to a nonlinear program due to the state-dependent charging and discharging performances. The dispatch model is further linearized via piecewise linear approximation and special-ordered set of type 2, and its equivalent mixed integer linear formulation is presented. A modified IEEE 33-bus system is adopted to verify the effectiveness of proposed model for renewables accommodation. © Published under licence by IOP Publishing Ltd.

关键词： Scheduling

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Effects of temperature on creepage discharge characteristics in oil-impregnated pressboard insulation under combined AC–DC voltage

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Plasma Science and Technology 2019年第5期21卷 14-22页

作者： Fubao JIN Yuanxiang ZHOU Bin LIANG Zhongliu ZHOU Ling ZHANG Key Laboratory of Plateau Ecology and Agriculture College of Agriculture and Animal HusbandrySchool of Water Resources and Electric PowerQinghai UniversityXining 800016People's Republic of China State Key Lab of Control and Simulation of Power Systems and Generation Equipments Department of Electrical EngineeringTsinghua UniversityBeijing 100084People's Republic of China

Due to the complexity of the valve side winding voltage of the converter transformer, the insulation characteristics of the oil-impregnated pressboard(OIP) of the converter transformer are different from those of the traditional AC transformer. The study on effect of temperature on the creeping discharge characteristics of OIP under combined AC–DC voltage is seriously inadequate. Therefore, this paper investigates the characteristics of OIP creepage discharge under combined AC–DC voltage and discusses the influence of temperature on creepage discharge characteristics under different temperatures from 70 °C to 110 °C. The experimental results show that the partial discharge inception voltage and flashover voltage decrease with increasing temperature. The times of low amplitude discharge(LAD) decrease and amplitude of LAD increases. Simultaneously, the times of high amplitude discharge(HAD) gradually increase at each stage of creepage discharge with higher temperature. The analysis indicates that the charge carriers easily accumulate and quickly migrate directional movement along the electric field ahead of discharging. The residual charge carriers are more easily dissipated after *** ‘hump’ region of LAD moves to the direction of higher discharge magnitude. The interval time between two continuous discharges is shortened obviously. The concentration of HAD accelerates the development of OIP insulation creepage discharge. The temperature had an accelerating effect on the development of discharge in the OIP under applying voltage.

关键词： oil-impregnated pressboard insulation combined AC-DC voltage inception voltage creepage discharge temperature flashover voltage

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A Study of Forecast Uncertainty Handling Technologies for MGEMS Considering power Trading between MGs

A Study of Forecast Uncertainty Handling Technologies for MG...

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IEEE/IAS Industrial and Commercial power system Asia (I&CPS Asia)

作者： Yue Zhao Hong-Chao Gao Gang Luo Chao Gong Chen Zhao Xuan Zhang Power Dispatch and Control Center Guangdong Power Grid Co. Ltd Guangzhou China State Key Lab of Control and Simulation of Power Systems and Generation Equipments Tsinghua Univeristy Beijing China

ISBN: (数字)9781728143033

ISBN: (纸本)9781728143040

Attention to efficient and cost-effective utilize of energy has become a common view in the energy sector. A variety of microgrid energy management systems are developed and installed to achieve the goal. However, the performance of the microgrid energy management system depends on some factors, such as forecast uncertainty, measurement error, and so forth. Among them, a series of handling technologies for the forecast uncertainty are the focus in this paper. It includes accuracy improvement of prediction program based on time series method, operation strategy adoption, real-time control scheme for the energy storage equipment, and proposes a robust rule to against the extreme situation as well. This not only achieves effective energy management, but also helps to avoid operation cost increasing induced by the transaction bias assessment through the improvement of energy scheduling accuracy. The effectiveness and validity of these means is verified in the constructed campus microgrids at Chonnam National University.

关键词： Industrial power systems Asia Conferences

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Wavelet-based data compression for wide-area measurement data of oscillations

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Journal of Modern power systems and Clean Energy 2018年第6期6卷 1128-1140页

作者： Lin CHENG Xinchi JI Fang ZHANG He HUANG Song GAO State Key Laboratory of Control and Simulation of Power System and Generation Equipment Tsinghua University State Grid Jiangsu Electric Power Company

This paper proposes a wavelet-based data compression method to compress the recorded data of oscillations in power systems for wide-area measurement systems. Actual recorded oscillations and simulated oscillations are compressed and reconstructed by the waveletbased data compression method to select the best wavelet functions and decomposition scales according to the criterion of the minimum compression distortion composite index, for a balanced consideration of compression performance and reconstruction accuracy. Based on the selections, the relationship between the oscillation frequency and the corresponding optimal wavelet and scale is discussed, and a piecewise linear model of the base-2 logarithm of the frequency and the order of the wavelet is developed, in which different pieces represent different scales. As a result, the wavelet function and decomposition scale can be selected according to the oscillation frequency. Compared with the wavelet-based data compression method with a fixed wavelet scale for disturbance signals and the real-time data compression method based on exception compression and swing door trending for oscillations, the proposed method can provide high compression ratios and low distortion rates.

关键词： Data compression Oscillation Wavelet transform Wide-area measurement system(WAMS)

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Experimental Research on Typical Single-Phase High Resistance Grounding Fault Detection Methods in Resonant Grounding Distribution system 8

Experimental Research on Typical Single-Phase High Resistanc...

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8th IEEE International Conference on Advanced power system Automation and Protection, APAP 2019

作者： Cui, Xin Wang, Bin Dong, Xinzhou Liu, Kun Tsinghua University Key Lab of Control and Simulation of Power Systems and Generation Equipment Department of Electrical Engineering Beijing China Key Lab for Power System Protective Relaying Real Time Digital Simulation of Guangdong Power Grid Dispatching and Controlling Center of Guangdong Power Grid Guangzhou China

ISBN: (纸本)9781728117225

The problem of high resistance grounding fault detection in resonant grounding system is always the pain point and difficulty in the field of power system research. To solve the problem, based on PSCAD software, this paper firstly establishes a typical distribution system model, and analyzes the relationship between the transient component, traveling wave component and the fault initial angle, transition resistance value and arc. Secondly, this paper analyzes the effect of the main fault detection methods such as transient methods and travelling wave method, and gives the effective domain of different detection methods. Above analysis establishes a complete systematic test scheme for the high resistance grounding fault detection, and provides an effective test support for the subsequent effectual fault detection method for high resistance grounding fault. © 2019 IEEE.

关键词： Fault detection

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A Novel Method of power Swing Blocking in Impedance Relay 8

A Novel Method of Power Swing Blocking in Impedance Relay

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8th IEEE International Conference on Advanced power system Automation and Protection, APAP 2019

作者： Wang, Hao Kang, Xiaoning Dong, Xinzhou Xi'an Jiaotong University Shaanxi Key Laboratory of Smart Grid Xi'an China Tsinghua University State Key Laboratory of Control and Simulation Power System and Generation Equipment Beijing China

ISBN: (纸本)9781728117225

Distance protection is widely applied in High/Ultra- High Voltage AC transmission system. Impedance relay, the core element of distance protection, may operate incorrectly under power swing, so a power swing blocking unit is needed in distance protection. In this paper, the phase difference between the measurement voltage and compensation voltage under power swing and line fault is analyzed. Based on the analysis, a power swing blocking strategy using the change rate of phase difference between measurement voltage and compensation voltage is proposed. simulation results in PSCAD/EMTDC indicate that the proposed strategy can block the impedance relay reliably under power swing and unblock the impedance relay after detecting the fault under power swing. © 2019 IEEE.

关键词： Electric power system protection

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Study on High Impedance Grounding Fault Protection for Personal Safety Guard in Distribution Grid 8

Study on High Impedance Grounding Fault Protection for Perso...

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8th IEEE International Conference on Advanced power system Automation and Protection, APAP 2019

作者： Liu, Kun Cui, Xin Wang, Bin Dong, Xinzhou Key Lab for Power System Protective Relaying Real Time Digital Simulation of Guangdong Power Grid Dispatching and Controlling Center of Guangdong Power Grid Guangzhou China Tsinghua University Key Lab of Control and Simulation of Power Systems and Generation Equipment Department of Electrical Engineering Beijing China

ISBN: (纸本)9781728117225

In recent years, human electric shock accident caused by line fault of distribution system has happened all over the world. This kind of problem of high resistance grounding fault safety is becoming more and more the attention of the researchers. In this paper, typical arc high resistance grounding fault model is established to simulate the human electric shock accident and the line fell to the ground condition. The transient- state and steady-state fault characteristics of high resistance grounding fault are analyzed in the neutral point grounded through a small resistance grounding system and the resonant grounding system. The above analysis has laid a good foundation for the establishment of an effective fault detection method for high resistance grounding and the realization of human electric shock protection. © 2019 IEEE.

关键词： Fault detection

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Energy Management of a Residential Consumer with Uncertain Renewable generation: A Robust Dual Dynamic Programming Approach

Energy Management of a Residential Consumer with Uncertain R...

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第三十九届中国控制会议

作者： Dangwu Liu Zhongjie Guo Feng Chen Xiaodai Xue Shengwei Mei State Grid Anhui Electric Power CO. LTD. State Key Lab of Control and Simulation of Power Systems and Generation Equipments Department of Electrical EngineeringTsinghua University

This paper studies the dynamic operation of a residential electric energy system with distributed renewable *** streams among the power grid, local renewable plant, storage unit, and demand are considered;the temporal volatility of renewable generation is described by an uncertainty set, and the optimal operation problem gives rise to a multi-stage robust optimization. To deal with the non-anticipativity issue, the robust model is solved via robust dual dynamic programming（RDDP）approach. The the cost-to-go function is approximated by iteratively updating the upper and lower bounds, which can be obtained from forward-pass and backward pass procedures. Case studies validate the performance and advantage of the proposed method.

关键词： Residential energy management battery energy storage renewable generation uncertainty robust dual dynamic programming

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