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Weather type partition method considering sequential features in photovoltaic forecasting

The Journal of Engineering 2017年第13期2017卷 1259-1263页

作者： Hao Li Zongxiang Lu Ying Qiao Ningbo Wang Kun Ding State Key Lab of Control and Simulation of Power Systems and Generation Equipments Department of Electrical Engineering Tsinghua University Haidian District Beijing 100084 People's Republic of China Wind Power Technology Center Gansu Electric Power Corporation Lanzhou 730050 People's Republic of China

The prediction method based on the partition of weather types has been widely used in photovoltaic prediction. Here, the temporal characteristics of PV data is studied, the physical meaning of the sequential difference sequences is analysed, and a characteristic index system including sequential characteristics index is proposed. The weather types are partitioned based on self-organising map neural network algorithm. Case study shows that the partition method is helpful to improve the discrimination of weather types and to improve prediction accuracy.

关键词： load forecasting photovoltaic power systems prediction theory self-organising feature maps power engineering computing self-organising map neural network algorithm characteristic index system sequential difference sequence analysis PV data characteristics photovoltaic prediction method photovoltaic forecasting weather type partition method

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A dynamic multi-level temporal and spatial coordination method for orderly power utilization based on customer load curtailment cost characteristics

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Dianwang Jishu/power System Technology 2016年第2期40卷 425-432页

作者： Yan, Qingguo Tong, Xing Zhang, Ning Chen, Xiao Yi, Yongxian State Grid Jiangsu Electric Power Company NanjingJiangsu Province210024 China State Key Lab of Control and Simulation of Power Systems and Generation Equipments Dept. of Electrical Engineering Tsinghua University Haidian District Beijing100084 China Jiangsu Electric Power Company Research Institute NanjingJiangsu Province210019 China State Grid Key Laboratory of Electric Power Metrology NanjingJiangsu Province211103 China

When there is power supply shortage or emergency event in power system, orderly power utilization needs to be applied to cut down electricity demand to maintain power supply for important electricity consumers. Current orderly power utilization fails to consider curtailment costs for different regions and customers, and ignores temporal continuity and production regularity of customer, leading to inefficient load curtailment scheduling. This paper proposes a dynamic multi-level temporal and spatial coordinated shortage allocation method considering customer load curtailment costs for orderly power utilization. Load curtailment cost function is established from individual customer level up to provincial electrical grid level. An optimization model is proposed to strategically rearrange customer load profiles across multiple periods. Case studies show that the method efficiently coordinates power shortage in temporal and spatial scale, and significantly brings down economic cost due to curtailment allocation. This model could help promote customer satisfaction level in orderly power utilization. © 2016, power System Technology Press. All right reserved.

关键词： Electric power utilization

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

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

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IEEE Conference on Energy Internet and Energy System Integration (EI2)

作者： Wei Ma Ying Qiao ZongXiang Lu ZhiFeng Liang JiaMing Li YuChen Hao State Key Laboratory of Control and Simulation of Power Systems and Generation Equipments of Electrical Engineering Tsinghua University Beijing China State Grid Corporation of China Beijing China State Grid Jiangsu Power Grid Corporation Nanjing China

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.

关键词： Fans Wind speed System integration Wind farms Wind power generation Predictive models Feature extraction

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Analysing on characteristics of lightning shielding failure of UHVAC double circuit transmission line based on leader progression method

Analysing on characteristics of lightning shielding failure ...

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Asia-Pacific Symposium on Electromagnetic Compatibility (APEMC)

作者： Zhiyong Wang Shaoan Wang Zhanqing Yu Yinan Geng Rong Zeng Jinliang He Zhizhao Li Guangzhou Power Supply Bureau China Southern Power Grid Company Limited Guangzhou China Department of Electrical Engineering State Key Laboratory of Control and Simulation of Power Systems and Generation Equipments Tsinghua University Beijing China

ISBN: (纸本)9781424456215

Shielding failure of lightning is the key problem for safe operation of UHV transmission lines. Taking the feature of 1000KV AC double circuit transmission lines into account, the leader progression method with proper criterion was employed. The lightning shielding failure rate of top phase, middle phase and bottom phase of two different transmission line tower types were compute, in three different geography conditions. The research work is helpful for improving the lightning performance of UHV transmission lines.

关键词： Failure analysis Lightning Distributed parameter circuits Conductors power transmission lines Transmission line theory Voltage Corona Poles and towers power system simulation

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Radio interference of Ultra HVDC transmission lines in high altitude region

Radio interference of Ultra HVDC transmission lines in high ...

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Asia-Pacific Symposium on Electromagnetic Compatibility (APEMC)

作者： Zhanqing Yu Rong Zeng Min Li Ruihai Li Lei Liu Dawei Yang Zheng Zhang Bo Zhang Feng Tian State Key Laboratory of Control and Simulation of Power Systems and Generation Equipments Department of Electrical Engineering Tsinghua University Beijing China Technology Research Center China Southern Power Grid Company Limited China

ISBN: (纸本)9781424456215

Corona phenomenon of Ultra High Voltage DC in high altitude region is more serious, and corresponding electromagnetic environment is more severe as well. Radio Interference is the most important consideration during the design and operation. Characteristics of RI and its influence factors were studied based on an UHVDC test line with an altitude of 2100 m in the National Engineering laboratory for UHV Technology, located in Kunming, China. The measuring system of RI long term tests was introduced. Lateral and longitudinal distribution and spectrum of RI near the transmission line were analysed at various voltages, weather conditions.

关键词： Electromagnetic interference HVDC transmission Voltage Corona Testing power transmission lines DC generators Conductors Transmission line measurements Electromagnetic compatibility

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The influence of wind on the audible noise of ultra HVDC transmission line in high altitude area

The influence of wind on the audible noise of ultra HVDC tra...

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Asia-Pacific Symposium on Electromagnetic Compatibility (APEMC)

作者： Min Li Rong Zeng Dawei Yang Zhanqing Yu Ruihai Li Lei Liu Bo Zhang Huaying Zhang State Key Laboratory of Control and Simulation of Power Systems and Generation Equipments Department of Electrical Engineering Tsinghua University Beijing China Technology Research Center China Southern Power Grid Company Limited China

ISBN: (纸本)9781424456215

The corona performance and the electromagnetic environment of the transmission system has become a crucial issue that has been taken into consideration in the line design, and among which audible noise (AN) is one of the most important factors. The wind in the high altitude area is mostly strong, and could greatly influence the AN. This paper, based on the high altitude HDVC test line, studied the characteristics of AN generated by the transmission line, and analyzed the influence of wind velocity and wind direction on the AN lateral profile.

关键词： Acoustic noise HVDC transmission Testing Wind speed Corona power transmission lines Microphone arrays Voltage Electromagnetic compatibility power engineering and energy

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Automatic voltage control of wind farms based on model predictive control theory

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Dianli Xitong Zidonghua/Automation of Electric power systems 2015年第7期39卷 59-67页

作者： Xu, Fengda Guo, Qinglai Sun, Hongbin Lan, Haibo Liu, Haitao Liu, Xiaomin Department of Electrical Engineering Tsinghua University Beijing100084 China State Key Laboratory of Control and Simulation of Power System and Generation Equipments Tsinghua University Beijing100084 China State Grid North Hebei Grid Company Limited Beijing100053 China

Voltage fluctuations occur frequently in wind farms as a result of wind power perturbation, while reactive power control of various devices is always uncoordinated and often has a time lag when the system operates in the traditional control mode that only uses the current data for decision-making. In this case, a method for coordinated control of the reactive power of wind turbine generators (WTGs) and static var generators is proposed based on model predictive control (MPC). Unlike the traditional voltage control method, the control method proposed has the realization of optimization of the voltage control curve and the dynamic process of reactive power regulation in the future window of time as its objective. An auto regression moving average (ARMA) model is used to predict the active power of WTGs while the reactive power of WTGs and the SVG is forecasted using a first-order inertia link and a proportional integral (PI) link, respectively. Voltages in the wind farm are solved with the help of a sensitivity matrix. Thus an optimization model is developed for both the minimization of PCC voltage deviation and the maximization of SVG reactive power reservation in a future window of time. The optimizing model is solved using CPLEX tools with the dual simplex algorithm. In order to test the performance of the MPC controller, multiple cases with different wind circumstances are simulated on a DIgSILENT platform. simulation results reveal that by predicting the states of various instruments in wind farms during a period of time in the future, the proposed control method is able to rationally arrange fast/slow reactive power to respond to predictable changes of the system in advance and keep voltage stable. ©2015 state Grid Electric power Research Institute Press

关键词： Reactive power

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A convex hull based intertemporal loadability set approximation method

A convex hull based intertemporal loadability set approximat...

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2020 Tsinghua - HUST-IET Electrical Engineering Academic Forum

作者： Xinfei Yan Haiwang Zhong Zhenfei Tan Junfeng Yang Dept. Electrical Engineering Tsinghua University Beijing China State Key Laboratory of Control and Simulation of Power Systems and Generation Equipments Beijing China Power Dispatch & Control Center State Grid Corp. of China Beijing China

ISBN: (纸本)9781839533914

The uncertainty of renewable energy sources has aroused the interests in depicting the ability of power systems to accommodate the variations. Loadability set is one of the typical methods to characterize the feasible sets of power systems with uncertainties. The existing literature on loadability set do not incorporate intertemporal constraints, while for some cases like security check, intertemporal constraints are necessary and important. This paper firstly adapts loadability set to security check, enabling it to depict the capability of power systems to accommodate load variations. Singular value decomposition (SVD) and progressive vertex enumeration (PVE) are introduced to lighten the computational burden caused by multiple periods. The computational time can be traded off with the precision of approximation to the loadability set. Case studies verify that the loadability set can be approximated with proper precision.

关键词： Loadability feasible set convex hull security check loading capacity safety check convex hull power systems Approximation method

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Tests on electromagnetic environment of ultra HVDC transmission lines in high altitude region

Tests on electromagnetic environment of ultra HVDC transmiss...

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Asia-Pacific Symposium on Electromagnetic Compatibility (APEMC)

作者： Zhanqing Yu Rong Zeng Min Li Ruihai Li Lei Liu Bo Zhang Zheng Zhang Huaying Zhang State Key Laboratory of Control and Simulation of Power Systems and Generation Equipments Department of Electrical Engineering Tsinghua University Beijing China Technology Research Center China Southern Power Grid Company Limited China

ISBN: (纸本)9781424456215

The Ultra High Voltage DC power transmission technique is developed quickly in China but used barely in the world. Corona phenomenon in high altitude region is more serious, and corresponding electromagnetic environment is more severe as well. A UHVDC test lines are completed for tests in Kunming, China, with an altitude of 2100 m. An automotive electromagnetic environment testing system was installed under the line. Measurement of electromagnetic environment was carried out. Radio interference, audible noise, resultant electric field and ion current density at ground level were measured at different voltage from ±800kV to ±1000kV, and atmosphere conditions including sunny, rainy and cloudy weather. The measured result show some difference with those acquired at sea level and is significant for further studies of corona mechanism under high altitude condition. Measured results were compared with the calculated results.

关键词： HVDC transmission Atmospheric measurements Sea measurements Electromagnetic measurements Voltage Corona power transmission Automotive engineering System testing Electromagnetic interference

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A non-iterative affine arithmetic methodology for interval power flow analysis of transmission network

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Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering 2013年第19期33卷 76-83页

作者： Ding, Tao Bo, Rui Guo, Qinglai Sun, Hongbin Wu, Wenchuan Zhang, Boming State Key Lab. of Control and Simulation of Power Systems and Generation Equipment Department of Electrical Engineering Tsinghua University Haidian District Beijing 100084 China Midwest ISO St. Paul 55108 United States

power flow exhibits uncertainty when power injections randomly fluctuate. The variables of power flow problem are correlated through the constraints set forth by power flow equations. Affine arithmetic can effectively overcome the correlation and therefore is adopted in this paper. In order to improve the computational efficiency, non-iterative method was proposed, which can transform the interval power flow problem into optimization problems. Linear programming, nonlinear programming and quadratic programming optimization models were established to obtain intervals of nodal voltage magnitude, phase angle, branch active power and reactive power, respectively. simulation results of 9-bus and 57-bus test system show that the power flow interval obtained by the proposed algorithm is nearly the same as that by iterative algorithms, whereas the branch power flow results are better. The interval power flow problem can be solved quickly and efficiently with time complexity approximately O(m3). As well, parallel computing can be implemented to achieve promising improvement in computation time. © 2013 Chinese Society for Electrical Engineering.

关键词： Quadratic programming

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