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Rule Extraction in Transient Stability Study Using Linear Decision Trees

中国电机工程学报 2011年第34期31卷 I0006-I0006页

作者： SUN Hongbin WANG Kang ZHANG Boming ZHAO Feng State Key Lab of Control and Simulation of Power Systems and Generation Equipments （Dept. of Electrical Engineering Tsinghua University） Haidian District Beijing 100084 China

Traditional operation rules depend on human experience, which are relatively fixed and difficult to fulfill the new demand of the modern power grid. In order to formulate suitable and quickly refreshed operation rules, a method of linear decision tree based on support samples is proposed for rule extraction in this paper. The operation rules extracted by this method have advantages of refinement and intelligence, which helps the dispatching center meet the requirement of smart grid construction.

关键词：英文摘要内容介绍编辑工作期刊

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Short-term power Prediction Based on Improved NWP Data Considering Wind Speed Distribution Inner Wind Farm 6

Short-term Power Prediction Based on Improved NWP Data Consi...

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6th IEEE Conference on Energy Internet and Energy System Integration, EI2 2022

作者： Ma, Wei Qiao, Ying Lu, Zongxiang Liang, Zhifeng Li, Jiaming Hao, Yuchen Tsinghua University State Key Laboratory of Control and Simulation Power Systems and Generation Equipments of Electrical Engineering Beijing China State Grid Corporation of China Beijing China State Grid Jiangsu Power Grid Corporation Nanjing China

ISBN: (纸本)9798350347159

The wind farm has only one NWP data point, which cannot accurately reflect the wind resources inside the wind farm. To solve the problem of a poor match between short-term wind power prediction numerical weather forecast and wind farm measured weather. Put forward a kind of based on clustering and temporal characteristics of the modified liters of scale wind power prediction method, first of all, using EOF orthogonal decomposition method to extract the features of each fan, using hierarchical analysis method of the characteristics of the data matrix clustering, and then, each cluster sample selected representative of a fan, using the error transfer characteristic of the NWP data sequence is modified. Finally, The CNN prediction model is used for power prediction, and the weight is determined according to the cluster sample size. A wind farm in northern Hebei, China, is used to verify the effectiveness of the proposed method. © 2022 IEEE.

关键词： Weather forecasting

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generation of Atmospheric Pressure Plasma by Repetitive Nanosecond Pulses in Air Using Water Electrodes

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Plasma Science and Technology 2011年第6期13卷 735-739页

作者：邵涛于洋章程姜慧严萍周远翔 Institute of Electrical Engineering Chinese Academy of Sciences Key Laboratory of Power Electronics and Electric Drive Chinese Academy of Sciences State Key Laboratory of Control and Simulation of Power Systems and Generating Equipment Electrical Engineering DepartmentTsinghua University

Dielectric barrier discharge （DBD） excitated by pulsed power is a promising method for producing nonthermal plasma at atmospheric pressure. Discharge characteristic in a DBD with salt water as electrodes by a home-made unipolar nanosecond-pulse power source is presented in this paper. The generator is capable of providing repetitive pulses with the voltage up to 30 kV and duration of 70 ns at a 300 Ω resistive load. Applied voltage and discharge current are measured under various experimental conditions. The DBD created between two liquid electrodes shows that the discharge is homogeneous and diffuse in the whole discharge regime, Spectra diagnosis is conducted by an optical emission spectroscopy. The air plasma has strong emission from nitrogen species below 400 nm, notably the nitrogen second positive system.

关键词： non-thermal plasma dielectric barrier discharge pulsed power nanosecondpulse pulse repetition frequency atmospheric pressure air emission spectra.

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Calculation on the thermal field of the water cooling stator of three-gorge hydro-generator

Calculation on the thermal field of the water cooling stator...

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ICEMS 2005: 8th International Conference on Electrical Machines nd systems

作者： Wang, H.Y. Su, P.S. Wang, X.H. Department of Electrical Engineering State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Tsinghua University Beijing 10084 China

ISBN: (纸本)7506274078

To simplify the calculation of winding bar temperature for the condition monitoring of the water cooling stator of Three-Gorge Hydro-Generator, this paper calculates three of two-dimension thermal fields. Using the three fields simulates the different section along the axial direction of the generator. The total amount of heat taken away by water can be calculated by weighting the result of three fields on the total axial length of them. Four groups of thermal-fields with different outlet-water temperature are calculated by using ANSYS multi-physical software. The calculation results of temperature of measurement-point between up-layer and down-layer bars in stator are partly supported by the measurement data. And the relatively error between the heat taken by cooling-water and the heat generated by the stator bar is always less than 5%.

关键词： Stators

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Influences of temperature on Space Charge in Gas-to-Liquid Oil-Impregnated Paper 7

Influences of temperature on Space Charge in Gas-to-Liquid O...

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7th IEEE International Conference on High Voltage Engineering and Application, ICHVE 2020

作者： Zhou, Yuanxiang Huang, Xin Zhang, Ling Zhang, Yunxiao Zhou, Zhongliu Teng, Chenyuan China State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Tsinghua University Department of Electrical Engineering Beijing China

ISBN: (纸本)9781728155111

Gas-to-liquid (GTL) transformer oil has been on trial in converter transformers. However, its influence on the space charge characteristic is not clear. This work aims at exploring space charge characteristics of GTL oil at different temperatures as well as comparing with commercial naphthenic oil (KI50X). Space charge distribution during the polarization and the dissipation process in the GTL oil-impregnated paper at different temperature was measured by the pulse electroacoustic method (PEA), which were contrasted with those of the KI50X oil-impregnated paper. Results illustrated that high temperature accelerated the injection and migration of charge carriers in the oil-impregnated paper. And the polarity of the accumulated charge in the vicinity of anode changed from positive to negative with the increase of temperature. It was perceived that oil-paper conductivity and carrier mobility grew with the increase of temperature, resulting in the easier migration of injected charge to another electrode. Furthermore, the space charge dissipation rate in the GTL oil-impregnated paper is lower than that in the naphthenic oil-impregnated paper at the same temperature. Thus, a longer time interval of tests or switch operation in the factory test and operation process may need if GTL oil is used rather than naphthenic oil. © 2020 IEEE.

关键词： Electric space charge

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Research on the prediction-model of the surface-temperature of large oil-immersed power transformer

Research on the prediction-model of the surface-temperature ...

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ICEMS 2005: 8th International Conference on Electrical Machines nd systems

ISBN: (纸本)7506274078

In order to detect the abnormal temperature of large oil-Immersed power transformer earlier, this paper presents a new prediction-model of surface-temperature for the transformer to predict the normal surf ace-temperature. And to compare the difference between the predicted value and the measured value can judge If the condition of the transformer Is fit to operate. The model parameters are estimated from the field data by using the Partial-Least-Square method, which overcomes the instability of results estimated by using the traditional Least-Square method. Furthermore, the appropriate amount of data for the parameter estimation was decided according to the principle of Heat Transfer and the characteristics of the predicted deviation, such as mean, variance and normal distribution. The prediction model is verified from the accuracy of results predicted with one year of field data.

关键词： Electric transformers

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A novel modbus RTU-based communication system for adjustable speed drives

A novel modbus RTU-based communication system for adjustable...

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2008 IEEE Vehicle power and Propulsion Conference, VPPC 2008

作者： Sideng, Hu Zhengming, Zhao Yingchao, Zhang Shuping, Wang State Key Laboratory of Control and Simulation of Power System and Generation Equipment Tsinghua University Beijing China

ISBN: (纸本)9781424418497

The communication protocol is important for applying adjustable speed drive (ASD) systems to an industry network. This paper proposes a novel scheme of communication system for the ASD system based on Modbus protocol. The most remarkable advantage of the approach lies in the tradeoff between performance and economic cost for a power converter system. The overall system is built on master-slave structure and easy for interacting with other networks. An additional study on the cyclic redundancy check (CRC) in Modbus RTU is introduced to obtain the optimization design in the actual application and the optimization method in software design is also presented. The performance of the communication system obtained from experiment conducted on the 15kW ASD system validates the effectiveness of the proposed design method. © 2008 IEEE.

关键词： Software design

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A combined time-and-frequency-domain model for integration of wind power generation

A combined time-and-frequency-domain model for integration o...

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2016 IEEE Innovative Smart Grid Technologies - Asia, ISGT-Asia 2016

作者： Chen, Xiaoshuang Lin, Jin Wan, Can Song, Yonghua Guo, Wanfang State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing100084 China

ISBN: (纸本)9781509043033

Wind power generations (WPGs) are different from traditional generations for their considerable fluctuations. It is challenging to describe the status of a system with power fluctuation injections, especially when considering complicated network constraints. This paper proposes a combined time-and-frequency-domain (CTFD) model to evaluate whether the constraints will be violated under fluctuating wind power injection. The constraints of energy units and branch power flow are described in a generalized form, and are related to the power spectral density of power fluctuations. The distributions of the constraint variables are then discussed based on the CTFD model, and a chance criterion is conducted to describe the probability of the constraints being violated. Case studies show the effectiveness of the proposed model. © 2016 IEEE.

关键词： Probability distributions

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A Joint Prediction Method of Multi-state Variables for High-Voltage Cables Based on GRU 10th

A Joint Prediction Method of Multi-State Variables for High-...

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10th Frontier Academic Forum of Electrical Engineering, FAFEE 2022

作者： Chen, Jianning Zhou, Yuanxiang Lin, Menglong Pan, Zehua Ge, Jiamin State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing100084 China

ISBN: (纸本)9789819934034

In order to carry out risk warning for high-voltage cable transmission system and realize differentiated operation and maintenance decision-making, it is necessary to carry out time series prediction for online monitoring state quantities of high-voltage cables such as load current, partial discharge, and grounding circulating current. Therefore, a joint prediction method for multi-state variables of high-voltage cables based on Gate Recurrent Unit (GRU) is proposed. Taking the online monitoring state quantities of a certain area in central China in May as the analysis data set, a GRU network is built to predict the sequence of multi-state quantities, compared with different models. Taking the phase A load current of a node of the cable as an example to carry out state prediction, the results show that compared with the Long Short Term Memory (LSTM) neural network, back-propagation neural network (BPNN), and Auto Regressive Integrated Moving Average (ARIMA) model, the accuracy of the sequence prediction model based on GRU is Higher. When predicting for 5 min, the MAE and RMSE are 1.94 and 2.65 A, respectively, with the MAPE of 0.54%. When predicting for 30 min, the MAE and RMSE are 9.81 and 15.36 A, respectively, with the MAPE of 2.89%. When predicting for 1 h, the MAE and RMSE are 17.05 and 27.47 A, respectively, with the MAPE of 4.91%. The GRU model performs better due to the suppression on over-fitting of training data with simpler model structure. © Beijing Paike Culture Commu. Co., Ltd. 2023.

关键词： Forecasting

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Optimized design of main protection configuration scheme for internal faults of shawan generator

Optimized design of main protection configuration scheme for...

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ICEMS 2005: 8th International Conference on Electrical Machines nd systems

作者： Sun, Yuguang Wang, Xiangheng Gui, Lin Wang, Weijian Department of Electrical Engineering State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Tsinghua University Beijing 100084 China

ISBN: (纸本)7506274078

In order to provide high-quality protection for large- and medium-sized generators, a new feasible method of designing main protection configuration scheme for internal faults of generators is desirable. Based on calculation of all the possible internal faults with the multi-loop method, the optimized design method is illustrated through Shawan generator in this paper. With this method, the optimal protection configuration scheme, composed of the split-phase transverse differential protection, two sets of incomplete longitudinal differential protection as well as one set of single element transverse differential protection, is determined for the internal faults of Shawan generator, which has two branches in each phase. The rate of operation and double-protection of the optimal scheme both reach the maximum. In addition to that, on all the possible phase-to-phase faults, at least two kinds of protection of the optimal scheme are sure to operate correctly. The optimized scheme excels the conventional one in protection performance index, which verifies the validity of the optimized method of designing main protection configuration scheme for generators.

关键词： Electric generators

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