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An efficient stochastic algorithm for mid-term scheduling of cascaded hydro systems

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Journal of Modern power Systems and Clean Energy 2019年第1期7卷 163-173页

作者： Xiaolin GE Shu XIA Wei-Jen LEE electric power College Shanghai University of Electric Power Shibei electricity Supply company of State Grid shanghai Municipal electric power company Energy Systems Research Center University of Texas at Arlington

Due to the stochastic and correlated attributes of natural inflows, the mid-term generation scheduling problem for cascaded hydro systems is a very challenging *** paper proposes a novel stochastic optimization algorithm using Latin hypercube sampling and Cholesky decomposition combined with scenario bundling and sensitivity analysis(LC-SB-SA) to address this *** deal with the uncertainty of natural inflows, Latin hypercube sampling is implemented to provide an adequate number of sampling scenarios efficiently, and Cholesky decomposition is introduced to describe the correlated natural inflows among cascaded *** addition, to overcome the difficulties in solving the objectives of all the scenarios, scenario bundling and sensitivity analysis algorithms are developed to improve the computational *** results from both two-station and tenstation systems indicate that the proposed method has the merits in accuracy as well as calculation speed for the midterm cascaded hydro generation *** consideration of natural inflow correlation makes the formulated problem more realistic.

关键词： Cascaded hydro systems Mid-term scheduling Stochastic optimization algorithm Correlation Sensitivity

Improved Generative Adversarial Behavioral Learning Method for Demand Response and Its Application in Hourly electricity Price Optimization

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Journal of Modern power Systems and Clean Energy 2022年第5期10卷 1358-1373页

作者： Junhao Lin Yan Zhang Shuangdie Xu shanghai Jiao Tong University ShanghaiChina Shibei electricity Supply company State Grid Shanghai Municipal Electric Power CompanyShanghaiChina

In response to the imbalance between power generation and demand, demand response(DR) projects are vigorously promoted. However, customers’ DR behaviors are still difficult to be simulated accurately and objectively. To tackle this challenge, we propose a new DR behavioral learning method based on a generative adversary network to learn customers’ DR habits. The proposed method is also extended to maximize the economic revenues of generated DR policies on the premise of obeying customers’ DR habits, which is hard to be realized simultaneously by existing model-based methods and traditional learning-based methods. To further consider customers’ timevarying DR patterns and trace the changes dynamically, we define customers’ DR participation positivity as an indicator of their DR pattern and propose a condition regulation approach improving the natural generative adversary framework to generate DR policies conforming to customers’ current DR patterns. The proposed method is applied to hourly electricity price optimization to reduce the fluctuation of system aggregate loads. An online parameter updating method is also utilized to train the proposed behavioral learning model in continuous DR simulations during electricity price optimization. Finally, numerical simulations are conducted to verify the effectiveness and superiority of the proposed method.

关键词： Demand response behavioral learning reinforcement learning generative adversarial network electricity price optimization

Subsynchronous resonance and its mitigation for power system with unified power flow controller

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Journal of Modern power Systems and Clean Energy 2018年第1期6卷 181-189页

作者： Xinyao ZHU Meng JIN Xiangping KONG Jingbo ZHAO Jiankun LIU Qian ZHOU State Grid Jiangsu electric power Research Institute State Grid Jiangsu electric power maintenance Branch company

Control strategy of unified power flow controller(UPFC)utilizing dq decoupling control is deduced in this paper,which can closely follow the control orders of the active and reactive *** subsynchronous resonance(SSR)characteristics of a series compensated system equipped with UPFC are studied,and the results reveal that SSR characteristics of the system may vary significantly with UPFC in service or ***,supplementary subsynchronous damping controller(SSDC)for UPFC is proposed and investigated,and the effectiveness of the proposed SSDC is verified by damping torque analysis and time domain simulations.

关键词： Unified power flow controller(UPFC) Series capacitor compensation Subsynchronous resonance(SSR) Supplementary subsynchronous damping controller(SSDC) Damping torque analysis

Three-phase fault direction identification method for outgoing transmission line of DFIG-based wind farms

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Journal of Modern power Systems and Clean Energy 2019年第5期7卷 1155-1164页

作者： Zhanfeng FAN Guobing SONG Xiaoning KANG Jisi TANG Xiaobo WANG Xi’an Jiaotong University Xi’anChina State Grid Beijing electric power company BeijingChina State Grid Shanxi maintenance company TaiyuanChina

Doubly-fed induction generator(DFIG)-based wind farm has the characteristic of transient fault with low voltage ride through(LVRT)capability.A new three-phase fault direction identification method for the outgoing transmission line of the wind farm is *** ability of the new directional relay to differentiate between a three-phase fault in one direction or the other is obtained by using the increment of phase angle difference between the memory voltage signal and the fault current signal within a certain time,and using the amplitude variation of the fault *** can be inferred that the fault current is supplied by the wind farm whether the phase angle differs or the current amplitude varies *** fault locations at the outgoing transmission line have been simulated by PSCAD/EMTDC to evaluate the reliability and sensitivity of the proposed *** show that the new directional relay is of faster response when a three-phase fault occurs at the outgoing transmission line of a DFIG-based wind farm.

关键词： Wind farm Doubly-fed induction generator(DFIG) Directional relay Outgoing transmission line

Line Aging Assessment in Distribution Network Based on Topology Verification and Parameter Estimation

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Journal of Modern power Systems and Clean Energy 2022年第6期10卷 1658-1668页

作者： Zhi Wu Huan Long Chang Chen School of electrical Engineering Southeast UniversityNanjing China IEEE maintenance Branch company State Grid Jiangsu Electric Power Company Ltd.Nanjing China

The aging of lines has a strong impact on the economy and safety of the distribution *** paper proposes a novel approach to conduct line aging assessment in the distribution network based on topology verification and parameter *** topology verification,the set of alternative topologies is firstly generated based on the switching *** best-matched topology is determined by comparing the difference between the actual measurement data and calculated voltage magnitude curves among the alternative ***,a novel parameter estimation approach is proposed to estimate the actual line parameters based on the measured active power,reactive power,and voltage magnitude *** includes two stages,i.e.,the fixed-step aging parameter(FSAP)iteration,and specialized Newton-Raphson(SNR)*** theoretical line parameters of the best-matched topology are taken as a warm start of FSAP,and the fitted result of FSAP is further renewed by the *** on the deviation between the renewed and theoretical line parameters,the aging severity risk level of each line is finally quantified through the risk assessment *** experiments on the modified IEEE 33-bus and 123-bus systems demonstrate that the proposed approach can effectively conduct line aging assessment in the distribution network.

关键词： Line aging topology verification parameter estimation risk assessment Newton-Raphson iteration

Rotordynamic characteristics prediction for scallop damper seals using computational fluid dynamics

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Chinese Journal of Aeronautics 2022年第8期35卷 92-106页

作者： Wanfu ZHANG Lu YIN Li YANG Haoyang TIAN Chun LI School of Energy and power Engineering University of Shanghai for Science and TechnologyShanghai 200093China electric power Research Institute of State Grid Shanghai Municipal Electric Power CompanyShanghai 200437China

Enhancing damping characteristic is one of the effective methods to solve the instability problem of the rotor *** three-dimensional numerical analysis model of scallop damper seal was established,and the effects of inlet pressures,preswirl ratios,rotational speeds,interlaced angles and seal cavity depths on the rotordynamic characteristics of scallop damper seal were studied based on dynamic mesh method and multi-frequencies elliptic whirling *** show that the direct stiffness of the scallop damper seal increases with decreasing inlet pressure and increasing rotational speed and cavity *** the seal cavity is interlaced by a certain angle,which shows positive direct *** effective damping of the scallop damper seal increases with the increasing inlet pressure,the decreasing preswirl ratio and the rotational speed and cavity *** exists an optimal interlaced angle to maximize the effective damping and the system *** leakage of the scallop damper seal is significantly reduced with decreasing inlet *** preswirl will reduce the leakage flowrate,and the rotational speed has a slight effect on the leakage *** leakage of the scallop damper seal decreases with increasing seal cavity depth.

关键词： Computational Fluid Dynamics(CFD) Effective damping Rotordynamic characteristics Scallop damper seal Stability

Galvanic Corrosion Behavior of Copper-Drawn Steel for Grounding Grids in the Acidic Red Soil Simulated Solution

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Acta Metallurgica Sinica(English Letters) 2020年第11期33卷 1571-1582页

作者： Xiao-Lei Fan Yun-Xiang Chen Jun-Xi Zhang De-Yuan Lin Xuan-Xuan Liu Xiao-Jian Xia shanghai Key Laboratory of Materials Protection and Advanced Materials in electric power Shanghai University of Electric PowerShanghai 200090China electric power Research Institute of State Grid Fujian electric power company Limited Fuzhou 350007China

The influence of pH and metallographic structure on the corrosion behavior of copper-drawn steel is studied with the simulated *** effect of pH on the corrosion behavior of copper-drawn steel has been investigated using open-circuit potential,potentiodynamic polarization,galvanic current measurement,scanning electron microscopy and scanning vibrating electrode technique *** steel is corroded as anode,while the corrosion of copper plate is protected as *** the results revealed that pH and metallographic structure had a significant influence on the corrosion behavior of copper-drawn *** the decrease in pH value from 6 to 2.4,the corrosion rate of copper-drawn steel galvanic couple(Cu-Fe GC)obviously increased in the simulated solution of acidic red *** electric field formed by the Cu-Fe GC changes the direction of ion migration between the copper and drawn steel electrodes,which impacts the composition and microstructure of corrosion products formed on the electrode surface.

关键词： Cu-Fe galvanic couple Electrochemical test Scanning vibrating electrode technique(SVET)measurement Soil corrosion

Integrated resources planning in microgrids considering interruptible loads and shiftable loads

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Journal of Modern power Systems and Clean Energy 2018年第4期6卷 802-815页

作者： Lan ZHU Xueying ZHOU Xiao-Ping ZHANG Zheng YAN Shuxin GUO Longjun TANG Department of electrical Engineering Shanghai Jiao Tong University School of electrical Engineering Shanghai University of Electric Power Pudong power Supply company State Grid Shanghai Municipal Electric Power Company School of Electronic Electrical and Systems EngineeringUniversity of Birmingham Zibo power Supply company State Grid Shandong Electric Power Grid Company East electric power Dispatch and Control Sub-Center State Grid Corporation of China

Demand response has the potential to bring significant benefits to the optimal sizing of distributed generation(DG) resources for microgrids planning. This paper presents an integrated resources planning model considering the impact of interruptible loads(ILs) and shiftable loads(SLs) in microgrids, which simultaneouslydeals with supply side and demand side resources and minimizes the overall planning cost of the microgrid. The proposed model can be applied to offer a quantitative assessment how IL and SL can contribute to microgrid planning. The pure peak clipping model with IL and SL is also provided for comparisons. Moreover, sensitivity analysis of parameters in the model is *** results confirm that the proposed model is an effective method for reducing the planning cost of microgrids. It was also found that the major contributing factors of IL and SL have great impact on the economic benefits of the proposed model in low-carbon economy environments.

关键词： Interruptible load(IL) Shiftable load(SL) Integrated resources planning(IRP) Load control Microgrid

Modeling porous structure of oil-pressboard interface and its effect on electric field distribution

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Journal of Central South University 2015年第1期22卷 338-343页

作者：司马文霞姜赤龙毛文奇唐信 State Key Laboratory of power Equipment & System Security and New Technology(Chongqing University) State Grid Hunan electric power Corporation maintenance company State Grid Hunan electric power Corporation

The oil-pressboard insulation is a typical composite insulation system widely used in the design and manufactory of large power apparatus. The implement of oil-pressboard insulation may lead to surface electrification and discharge at the interface under certain condition. It is of significant importance to take an insight into the phenomenon occurring at the interface. Through experiment, the pressboard is found as a porous material. The interface changes abruptly from bulk pressboard to the bulk oil as a result of the porous structure. A new model is proposed which divides the interface into bulk oil region, transition region, and bulk pressboard region. The width of the transition region is decided according to the microtome figure. The effective permittivity of the transition region is calculated using a new model based on fractal theory. The model is validated and compared with previous calculation model. The effect of the existence of transition region on the electric field distribution is discussed.

关键词： oil-pressboard interface transition region effective permittivity fractal electric field distribution