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Positive-sequence component based three-phase unbalanced power flow solution for distribution system with PV nodes

Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering 2012年第1期32卷 115-121页

作者： Li, Hongwei Sun, Hongbin Zhang, An'an Liu, Qingyou State Key Laboratory of Oil and Gas Reservoirs Geology and Exploitation Southwest Petroleum University Chengdu 610500 Sichuan Province China State Key Lab. of Control and Simulation of Power Systems and Generation Equipments Dept. of Electrical Engineering Tsinghua University Haidian District Beijing 100084 China

The traditional power flow methods aren't appropriate to the electrical distribution systems with distributed generators (DG). Therefore, a direct unbalanced three-phase power flow algorithm was presented in this paper. The proposed approach which was developed based on the path matrix, utilized the special topological structure of distribution systems and established the incident matrix of node voltages and injection currents. Based on the assumption that the positive-sequence voltage magnitudes of PV nodes are invariable, the relation of reactive power and compensation voltage for the PV nodes had been derived by the positivesequence component and path matrix. As a result, a new approach handling PV nodes of DG had been proposed and could be integrated into the proposed power flow method. It needn't introduce any additional active power at PV nodes and kept the positive-sequence voltage magnitudes on their scheduled values, considering that reactive power limits were not violated. The results of the 6-bus and the 69-bus test systems verified the validity and universality of the proposed methods. © 2012 Chin. Soc. for Elec. Eng.

关键词： Reactive power

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Study on Travelling-wave protection Starting element

Study on Travelling-wave protection Starting element

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International Conference on Advanced power System Automation and Protection (APAP)

作者： Li Ren ShenXing Shi ShiYong Wang ShuXin Luo Dong XingZhou Status Key Lab of Control and Simulation of Power Systems and Generation Equipments Dept. of Electrical Engineering Tsinghua University Haidian District Beijing 100084 China Status Key Lab of Control and Simulation of Power Systems and Generation Equipments Dept. of Electrical Engineering Tsinghua University Beijing China

Travelling-wave starting element is an integral part of the ultra high-speed protection. Existing design method depends on engineering experience, low accuracy in travelling-wave signal recognition, easy to trip frequently or refuse to trip. To solve these problems, through mass of starting signal simulation and analysis under different fault conditions, this paper focuses on the travelling-wave starting element and figures out the travelling-wave identification method. This paper summarizes the frequency and voltage characteristics of travelling-wave head, puts forward a new method in real-time travelling-wave fault identification. In addition, the analysis course included in this paper is a useful attempt that can be used in similar fault travelling-wave analysis.

关键词： Delay Resistance Heating Resistors Nanoscale devices Hardware Capacitance

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Effect of UV Radiation Aging on Creepage Discharge Characteristics of High Temperature Vulcanized Silicon Rubber at High Altitude

Effect of UV Radiation Aging on Creepage Discharge Character...

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中国物理学会第二十二届全国静电学术年会

作者： JIN Fu-bao LIANG Bin ZHOU Yuang-xiang ZHONG Liu ZHANG Ling School Of Water Resources and Electric Power Qinghai University Xining80016China State Key Lab of Control and Simulation of Power Systems and Generation Equipments Department of Ele

Aiming at the special working environment of composite insulators at high altitude area,we investigate the creepage discharge characteristics of aged HTV(High Temperature Vulcanized,HTV)silicone rubber materials by UV(ultraviolet radiation,UV)aging method in this *** results show that the creepage discharge flashover voltage first increased,then decreased as aging time increasing,whereas the creepage discharge initial voltage was not significantly affected by aging *** aging time has little effect on creepage discharge *** aging time contributed to shorter endurance time and higher creepage discharge development *** magnitude of discharges increase rapidly in a short time after *** partial discharge detection system was used to detect the whole creepage discharge development *** to the partial discharge characteristics parameters of creepage discharge,we divided the development process of creepage discharge into initial stage,developmental stage,accelerating stage,and critical breakdown *** with characteristic parameters of unaged HTV silicone rubber,the characteristic parameters for the aged HTV silicone rubber exhibited less fluctuation and clear *** aging not only has an effect on the physicochemical and hydrophobic properties of the materials,but also accelerates the development process of creepage discharge under AC *** should be given enough attention in engineering practice,especially at high altitude area.

关键词： High temperature vulcanized silicone rubber creepage discharge UV aging creepage discharge inception voltage creepage discharge flashover voltage high altitude characteristic parameters

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Effects of Temperature on Creepage Discharge Characteristics in Oil-Impregnated Pressboard Insulation under Combined AC-DC Voltage

Effects of Temperature on Creepage Discharge Characteristics...

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中国物理学会第二十二届全国静电学术年会

The characteristics of oil-impregnated pressboard(OIP)insulation in converter transformer are different with that in traditional AC transformers due to the complication of voltage applied on valve side windings of converter *** is a serious lack of empirical research on effect of temperature on creepage discharge characteristics in OIP under combined AC-DC ***,this study investigates the characteristics spectrum of creepage discharge in OIP under combined AC-DC voltage,and explores the effect of temperature on creepage discharge characteristics under different temperature from 70 to 110℃.The experimental results show that the partial discharge inception voltage and flashover voltage decrease as temperature *** times of low amplitude discharge(LAD)decrease and amplitude of LAD *** temperature had an accelerating effect on the development of creepage discharge in the OIP under combined AC-DC voltage Meanwhile,the times of high amplitude discharge(HAD)gradually increase at each stage of creepage discharge with higher *** analysis indicates that the charge carriers easily accumulate and quickly migrate directional movement along the electric field ahead of *** residual charge carriers are more easily dissipated after ***'hump'region of LAD moves to the direction of higher discharge *** interval time between two consecutive discharges drastically *** HAD intensively appear,result in accelerating the development of creepage discharge in OIP insulation.

关键词： Oil-impregnated pressboard insulation temperature combined AC-DC voltage creepage discharge inception voltage 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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Multi-Timescale Trading Strategy for Renewable power to Ammonia Virtual power Plant in the Electricity, Hydrogen, and Ammonia Markets

IEEE Transactions on Energy Markets, Policy and Regulation

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IEEE Transactions on Energy Markets, Policy and Regulation 2023年第4期1卷 322-335页

作者： Wu, Sirui Lin, Jin Li, Jiarong Liu, Feng Song, Yonghua Xu, Yanhui Cheng, Xiang Yu, Zhipeng Tsinghua University State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Department of Electrical Engineering Beijing100087 China Tsinghua University Sichuan Energy Internet Research Institute Chengdu610213 China University of Macau Department of Electrical and Computer Engineering Macau999078 China Tsinghua University Department of Electrical Engineering Beijing100087 China State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power University Beijing102206 China

Renewablepower to ammonia (RePtA) is a prominent zero-carbon pathway for decarbonization. Due to the imbalance between renewables and production energy demand, the RePtA system relies on electricity exchange with the power grid. Participating in the electricity market as a virtual power plant (VPP) may help to reduce energy costs. However, the power profile of local photovoltaics and wind turbines is similar to those in the market, resulting in rising energy costs under the conventional strategy. Hence, we develop a multi-timescale trading strategy for the RePtA VPP in the electricity, hydrogen, and ammonia markets. By utilizing the hydrogen and ammonia buffer systems, the RePtA VPP can optimally coordinate production planning. Moreover, we find it possible to describe the trading of electricity, ammonia, and hydrogen in a unified timeframe. The two-stage robust optimization model of the electricity market is extended to multiple markets and solved by the column and constraint generation (CC&G) algorithm. The case is derived from an actual project in the Inner Mongolia Autonomous Region. Sensitivity analysis demonstrates the economic advantages of the RePtA VPP joining multiple markets over the conventional strategy and reveals the necessity of the hydrogen and ammonia buffer and reactor flexibility. © 2023 IEEE.

关键词： Ammonia

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Analysis and simulation research on cascading trips of multiple wind farms

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Dianwang Jishu/power System Technology 2014年第6期38卷 1425-1431页

作者： Xu, Fengda Guo, Qinglai Sun, Hongbin Zhang, Boming Wang, Bin Li, Zhengshuo Ding, Tao Jia, Lin Xu, Xiaofei State Key Lab of Control and Simulation of Power Systems and Generation Equipments Dept. of Electrical Engineering Tsinghua University Haidian District Beijing 100084 China North China Grid Company Limited Xuanwu District Beijing 100053 China

A simulation based analysis is proposed to find out the most relative factors during the cascading process, which is significant to support the future voltage control schemes for wind integration region. A hierarchical distributed simulation platform is built, which contains both the transmission and wind farms' distribution grid. In this way both the coupling among wind farms and the detailed characteristics of device level can be considered. By simulating shunt capacitors, wind turbine generators and static var compensators (SVCs) under different control mode, the different impact to cascading trips process are analyzed. With the simulation, it is found that centralized integrated wind farms are so closed-coupled that variations of active or reactive power in one wind farm would cause great changes of voltages in wind farms nearby. Researching results also indicate that coordination of various reactive power implements is essential to system voltage safety.

关键词： Wind farm

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Application and benefit analysis of substation state estimation

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Dianli Xitong Baohu yu Kongzhi/power System Protection and control 2012年第12期40卷 56-61页

作者： Li, Qing-Xin Wang, De-Xing Sun, Hong-Bin Wu, Wen-Chuan Wang, Jing Guo, Qing-Lai Zhang, Bo-Ming State Key Lab. of Control and Simulation of Power Systems and Generation Equipments Dept. of Electrical Engineering Tsinghua University Beijing 100084 China East China Electric Power Dispatch and Control Sub-Center East China Grid Company Limited Shanghai 200002 China

A substation three-phase nonlinear state estimation method based on zero impedance branches helps to identify topology and analogy errors at substation level and accordingly enhances the control center's state estimation reliability and accuracy. Some issues during the practical implementation process of the technology are reported, such as the hardware configuration, measurement integration, the communication between substation and control center, time setting and period selection. The benefits of the proposed technology have also been analyzed. It is shown that this technology has high reliability and low burden on communication, and improves the ability of monitoring of power grids and the reliability of the real-time power network model significantly. The proposed technology is verified effective by both simulation experiments and field-site applications in East China power Grid, and is well qualified for real-time online applications, which has broad popularization and application prospects.

关键词： state estimation

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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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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.

关键词：

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