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Real-time economic dispatch model with prohibited zones considering maximum wind power injection

Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering 2015年第4期35卷 759-765页

作者： Ding, Tao Sun, Hongbin Bo, Rui Yao, Zhengyi State Key Lab of Control and Simulation of Power Systems and Generation Equipment Department of Electrical Engineering Tsinghua University Haidian District Beijing100084 China Midwest ISO Street Paul MN55108 United States Baoji Power Supply Bureau BaojiShaanxi Province721004 China

Due to the physical limitations of the generator, the vibrations in a shaft bearing may be amplified at a certain operation regimes, the prohibited zones are needed which leads to a disjoint power generation instead of continuous output. Besides, the reservation for each generator should also be considered to face with the stochastic integrated generation of large-scale wind power into power grid, which actually reduces the total reservation of the grid. Therefore, the economic dispatch with the multiple objective of minimized cost and maximized wind power integration, as well as the prohibited zones, was set up, and a standard mixed integer quadratic programming was formulated. Furthermore, the test system with six, fifteen and multiple generators were simulated respectively. The results show that the proposed method can be applied to the real-time system. ©2015 Chin. Soc. for Elec. Eng.

关键词： Real time systems

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Field Measurement and Analysis on The Characteristics of Transient Enclosure Voltage and Transient Ground Potential Rise in UHV GIS Substation

Field Measurement and Analysis on The Characteristics of Tra...

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International Conference on High Voltage Engineering and Application, ICHVE

作者： Shen Wei Wang Sen Wu Tao Yang Fan Gao Bing Liu Zhuoran Electric Power Research Institute State Grid Shaanxi Electric Power Company Xi'an China State Key Laboratory of Power Transmission Equipment & System Security and New Technology Chongqing University Chongqing China State Key Laboratory of Control and Simulation of Power System and Generation Equipments Tsinghua University Beijing China

ISBN: (数字)9781728155111

ISBN: (纸本)9781728155128

During the switching operation of GIS Substation, the Transient Enclosure Voltage (TEV)and the Transient Ground Potential Rise (TGPR) will occur, which will have a negative impact on the safety of substation. In this paper, TEV and TGPR are measured and analyzed in a 750kV substation at different locations of GIS, under three types of operation of disconnect switch and circuit breaker, include: single closing of disconnect switch, single closing of circuit breaker, three times opening and closing of circuit breaker. From the results, the maximum value of TEV and TGPR is 22.8 kV and 19.6kV, respectively, and the TGPR is higher than the TEV at many measuring points; Compared with the circuit breaker closing operation, the disconnect switch closing operation produces less electromagnetic oscillation energy, but it have longer macro-pulse duration and more breakdown times, which explained that the failure of secondary system caused by the operation of disconnect switch is more than caused by the operation of circuit breaker; Three times opening and closing operation of the circuit breaker produces stronger electromagnetic energy and more breakdown than single closing operation of the circuit breaker.

关键词： Circuit breakers Transient analysis Substations Gas insulation Switching circuits Switches Insulators

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Analysis of the toroidal HVDC grounding systems in horizontal multilayer soils

Analysis of the toroidal HVDC grounding systems in horizonta...

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作者： Zou, J. Lui, Y.Q. Yuan, J.S. He, J.L. Cao, L. Lee, J. Chang, S. State Key Lab of Control and Simulation of Power Systems and Generation Equipments Department of Electrical Engineering Tsinghua University Beijing 100084 China Electrical Environment and Transmission Group Korea Electrotechnology Research Institute Changwon 641600 Korea Republic of

A Fredholm integral equation of the first kind has been developed for analyzing the performance of the toroidal high-voltage direct current (HVDC) grounding system buried in the horizontal multilayer soil. The method of moment is used to solve the equations. The formulation of potential in the earth due to a circular current is proposed in closed form by means of conception of the complex resistivity and depth, which leads to the saving of the computational time greatly. The numerical results show the good agreements with those in other papers and the measured data. © 2006 IEEE.

关键词： Electric grounding

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High impedance fault analysis and location of single-phase-to-ground fault in feeder with multiple DGS connections

High impedance fault analysis and location of single-phase-t...

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8th Renewable power generation Conference (RPG 2019)

作者： Xuan Ren Bin Wang Xinzhou Dong Department of Electrical Engineering Tsinghua University Beijing China Key Lab of Control and Simulation of Power Systems and Generation Equipment Tsinghua University Beijing China

ISBN: (数字)9781839531248

ISBN: (纸本)9781839531255

Since the single-terminal fault location in the collection line of wind farm is seriously affected by the complex wind turbine branch, the traditional fault location methods are not applicable to the wind farm anymore. According to the traditional single-terminal impedance fault location method, the zero-fault sequence network of wind farm is studied. Generally, the box transformer is delta-connected to the wind turbine, so when a single-phase-to-ground fault occurs, there is no zero-sequence fault current flowing in the wind turbine branch. Then an improved fault location algorithm for the collection line of wind farm is proposed. In this method, with the wind turbine branch current considered, the collection line of wind farm is divided into several sections, and the fault location is searched step by step after the fault. This method can effectively reduce the influence of wind turbine branch on fault location and the fault distance and the fault resistance can be calculated accurately. Based on PSCAD simulation, the proposed fault location algorithm is validated.

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Breakdown processes of solid composite insulation system with defects under high frequency

Breakdown processes of solid composite insulation system wit...

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Conference on Electrical Insulation and Dielectric Phenomena, (CEIDP)

作者： Q. Nie Y.X. Zhou X.L. Xing Y.S. Wang State Key Lab of Control and Simulation of Power Systems and Generation Equipments Dept of Electrical Engineering Tsinghua University Beijing China

Behaviors of composite insulation system are strongly affected by the performance of interface between dielectrics, which mostly correlates to the direction of applied electrical field and the frequency of applied voltage. In this paper, experiments were carried out to study the breakdown characteristics of solid composite insulation system, consisted of a polyethylene (PE) film (with a copper needle electrode) and a glass slice. A sine wave power supply with a frequency range from 50 Hz to 100 kHz was established to fit our purposes. Voltage was smoothly raised from 0 kV to 5 kV. The processes of breakdown can be divided into four stages: (1) Electrical tree inception and propagation in polyethylene; (2) Sliding discharge along the interface between polyethylene and glass; (3) Streamer across the glass; (4) Return streamer initiation from the ground electrode and breakdown. A model was established to analyze the mechanism of sliding discharge between solid dielectrics. The influence of frequency on thermo effect is considered as the main causes of the experiment results, which can well explain the reason of insulation premature inactivation in high-frequency electrical equipment.

关键词： Electric breakdown Solids Frequency Dielectrics and electrical insulation Polyethylene Glass Voltage Electrodes Plastic films Copper

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Traveling waves based faulted feeder selector and its field application

Traveling waves based faulted feeder selector and its field ...

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2011 International Conference on Advanced power system Automation and Protection, APAP 2011

作者： Shi, Shenxing Wang, Jun Li, Aiming Du, Xinchun Cao, Xiaoxia Du, Yajun Dong, Xinzhou State Key Lab. of Control and Simulation of Power Systems and Generation Equipments Dept. of Electrical Engineering Tsinghua University Haidian District Beijing 100084 China Yulin Power Company Shaanxi 719000 China China Jiuquan Satellite Launch Center Plumbing Electrical Station Jiuquan 732750 China

ISBN: (纸本)9781424496198

The paper proposes faulted feeder selector in power distribution system with neutral non-effectively grounded. At first, the paper presents basic principle of single-phase-to-ground fault feeder selection based on traveling waves, which compares amplitude and polarity of the initial current traveling waves in all feeders. Then the implementation scheme, including hardware design and software flowchart is presented. At last field application of faulted feeder selector is introduced. The field operation results validated the correctness of faulted feeder selector based on transient traveling wave. © 2011 IEEE.

关键词： Electric grounding

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Modeling and analysis of MW-level grid-connected PV plant

Modeling and analysis of MW-level grid-connected PV plant

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Annual Conference of Industrial Electronics Society

作者： Yi Lei Zhengming Zhao Wei Xu Jianguo Zhu State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing China School of Electrical Mechanical and Mechatronic Systems University of Technology Sydney Australia

This paper focuses on the modeling and analysis of the basic composition, characteristic and the interactions with grid for megawatt (MW)-level large scale grid-connected photovoltaic (PV) plants. For a MW-level PV plant, numbers of inverters with relatively smaller capacity are employed to operated in parallel. When the irradiance on the large area of PV array is not equal, the output power verses the voltage of the PV array will have several peak values and affect the maximal power tracking. LCL filters are adopted for filtering the harmonics generated by inverters, but due to its inherent resonance character, additional damping strategy is required. The power quantity of harmonics and voltage fluctuation may occur when one MW-level PV plant is connected to grid. For these characteristics, with the modeling and simulation of a real MW-level PV plant, this paper proposed and verified a novel method toward MPPT of large area PV arrays. The parallel running of inverters and grid voltage fluctuation are also simulated. Finally, the interaction with the grid voltage fluctuation is explored in detail.

关键词： Inverters Arrays Photovoltaic systems Fluctuations Voltage fluctuations

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CCF early warning method of LCC-HVDC based on XGBoost algorithm

CCF early warning method of LCC-HVDC based on XGBoost algori...

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8th Renewable power generation Conference (RPG 2019)

作者： Zhizhong Li Bin Wang Haigang Wang Bin Yu Min Xie Shi Chen Xinzhou Dong Key Lab of Control and Simulation of Power Systems and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing 100084 China State Grid Anhui electric power company Hefei 230061 China

ISBN: (数字)9781839531248

ISBN: (纸本)9781839531255

The lack of analytical mechanism of continuous commutation failure (CCF) process hinders the development of CCF early warning algorithm and further obstructs the coordination strategy of relay protection between AC and DC size in hybrid grid. However, summarizing the protection threshold of CCF in the form of electrical quantity analytically under different fault types is a nontrivial pattern recognition problem. To overcome the difficulty of directly analysing the electromagnetic process of CCF, a statistical learning modelling approach is adapted to propose a CCF warning system, in which XGBoost algorithm was used as the backbone to regress on the relationship between AC/DC electrical quantities and the possibility of the occurrence of CCF. The design of the feature vector in XGBoost-based classifier considers not only the analytical expression of key electrical quantity during single commutation failure but also the important state variable of control system. Additionally, a special data windowing method was proposed to enrich of information encoded by the feature vector while ensuring the speed requirement posed by the protection system. Validation on multi-fault scenes simulation shows that the proposed early warning system can trigger warning signal correctly with sufficiently small measured data required, proving the practicability in engineering practice.

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Protection of microgrid

Protection of microgrid

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10th IET International Conference on Developments in power system Protection (DPSP 2010). Managing the Change

作者： Shenxing. Shi Bo. Jiang Xinzhou. Dong Zhiqian. Bo State Key Laboratory of Control and Simulation of Power System and Generation Equipments Tsinghua University China AREVA T and D Inc. Stafford UK

The paper analyses the existed protection of microgrid. And in order to meet the requirements of microgrid protection, a novel protection is presented in this paper. The protection based on local information without the need of communication, uses current traveling waves to identify faulted feeder, and the bus bar voltages to determine a event caused by fault or switch operation. In the protection scheme, current traveling waves are measured by current transducers in N line and phase lines, and wavelet multi-resolution analysis is used to decompose traveling wave signals. The initial traveling waves are compared in magnitude and polarity with each other to determine the faulted feeder. The protection is independent of microgrid operation connected with the main power grid or in island.

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Design optimization of ferrite rings for VFTO mitigation

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IEEE Transactions on power Delivery 2014年第99期PP卷 1-1页

作者： He, Jiaxi Guan, Yonggang Liu, Weidong Chen, Weijiang Li, Zhibing Department of Electrical Engineering State Key Lab of Control and Simulation of Power Systems and Generation Equipment Tsinghua University Beijing100084 China State Grid Corporation of China Beijing100031 China China Electric Power Research Institute Beijing100192 China

Very-fast transient overvoltage (VFTO)-related problems are raising growing concerns in China with the development of ultra-high voltage. The practice of fitting ferrite rings on gas-insulated switchgear busbars for VFTO mitigation has long been proposed but few investigations on its design optimization were conducted. Based on theoretical analysis of the simplified model, the optimal damping condition of ferrite rings is proposed, which is conducive to the type selection. The number of rings to be employed to ensure visible suppressing effects is given through simulations and the influence of the saturation is discussed. Impact on the power frequency is analyzed to be negligible. Finally, comparisons aremade between the theoretical conclusions and existing experiment results, which approve the optimal damping condition and agree with the number of rings to be employed. © 2014 IEEE.

关键词： Electric switchgear

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