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作者： Xia, Yunfeng Song, Xinming Jia, Zhidong Wang, Xilin Qi, Jinfeng Xu, Zheng Production Technology Department Dongguan Power Supply Bureau Guangdong Power Grid Co. Ltd. Dongguan China Energy and Environment Department Shenzhen Graduate School Tsinghua University Shenzhen China State Key Laboratory of Power Transmission Equipment System Security and New Technology Chongqing University Chongqing China

Detection of corona discharge of the transmission line can reflect its health status and provide warning information for maintenance. Some existing detection methods are flawed and cannot be used widely. This study presents a new method by measuring the electromagnetic wave caused by corona discharge with RF antenna. Then a circularly polarised log-periodic antenna was designed by making two pairs of log-periodic antennas 90° orthogonal. Finally, this antenna was simulated and manufactured to detect electromagnetic signals, the result shows that the time domain signal of corona discharge is a high frequency oscillation wave and its fast Fourier transform main distributes between 200 and 350 MHz. © 2019 Institution of Engineering and *** right reserved.

关键词： Electric lines

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Study on dimensions of void in GRP rod of composite insulator

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Journal of Physics: Conference Series 2021年第1期2121卷

作者： Hongchuan Dong Shan Jiang Xuejun Tang Fangchao Ke Sida Zhang Yunfan Liu Economic and Technological Research Institute State Grid Hubei Electric Power Co. Wuhan Hubei Province 430000 China State Key Laboratory of Power Transmission Equipment & System Security and New Technology Chongqing University Chongqing 410044 China

As an important part of composite insulator, glass fiber reinforced polymer (GRP) rod needs to bear the main mechanical and keep certain insulation performance. The void in the material is key factor to the performance of GRP rod. The void with larger size could affect the electric field distribution significantly and lead to the "Lantern-like" heating. In this paper, the structure of void in GRP rod is studied by 3D X-ray microscope. It is found that the void dimensions in the GRP rod is generally less than 300μm, but the interconnection of linear hole makes the length of the void increase significantly. For the GRP rod with high porosity, the length of connection hole is hard to be detected directly by the existing technology, but it could be calculated based on the diameter of the hole. Based on the calculation method, the dimensions of void in GRP rod could be inspected by the observation of section using optical microscope.

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Small Signal Stability Analysis and Control Optimization of Y-connected Modular Multilevel Converter for Fractional Frequency Offshore Wind power Application

Small Signal Stability Analysis and Control Optimization of ...

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

作者： Feng Jia Yongqing Meng Jianyang Yu Shuhao Yan Rong Ye Yuchen Tang Shannxi Key Laboratory of Smart Grid Xi’an Jiaotong University Xi’an China Research Institute of Economics and Technology State Grid Fujian Electric Power Company Fuzhou China

ISBN: (数字)9781728117225

ISBN: (纸本)9781728117232

Y-connected modular multilevel converter(Y-MMC) is a new circuit topology of direct AC/AC power conversion, with competitive application prospects in fractional frequency offshore wind power system. Different from the previous converter topology, Y-MMC realizes the frequency conversion by single-phase voltage cancellation. Simultaneously, the voltages between main bridges and auxiliary bridges can be determined by the reactive power distribution coefficients. Considering the frequency leakage problem, this paper proposes the new mathematical model of Y-MMC and builds corresponding control strategy. Then, the state equation of the system and its small-signal models are established, the small distribution stability is analyzed. Furthermore, to improve the stability and dynamic performance of the closed-loop control system, the parameters of controller are optimized based on the particle swarm optimization algorithm. Finally, the effectiveness and superiority of the proposed control strategies are verified by simulation results.

关键词： power system stability Mathematical model Circuit stability Frequency conversion Stability criteria Heuristic algorithms Reactive power

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A new grounding model for complex soil environments

A new grounding model for complex soil environments

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第四届能源与环境研究进展国际学术会议（ICAEER 2019）

作者： Chong Pan Dong Zhao Xuesong Tu Shuqin Wang Tie Liu Yiqiao Li Maanshan Power Supply Company State Grid Anhui Electric Power Co. Ltd State Key Laboratory of Power Transmission Equipment & System Security and New Technology Chongqing University

The purpose of arranging the grounding electrode is to discharge large currents, such as fault current and ensure the transmission line operate safely. In the grounding system of Chinese transmission network, the common grounding electrodes are horizontal installation and vertical installation. But two installation methods usually have the disadvantages, which are long distance installation and large depth burying, and they are restricted susceptible to uncertain factors such as pipelines, roads and geology, which leads the grounding resistance increasing and affect the normal operation of transmission lines. In order to solve the problem, this paper presents a new grounding model for complex soil environments and analysis from grounding resistance, surface potential and current distribution. The results show that the helix grounding electrode has good resistance reduction performance in complex soil environment, which effectively improves the surface potential distribution and the distribution of the spill current.

关键词： A new grounding model for complex soil environments

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Substation Equipment Thermal Fault Diagnosis Model Based on ResNet and Improved Bayesian Optimization

Substation Equipment Thermal Fault Diagnosis Model Based on ...

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IEEE International Conference on power and Energy Systems (ICPES)

作者： Chao Wei Fengbo Tao Yuandi Lin Xuanhong Liang Youyuan Wang Houying Li Jian Fang State Grid Jiangsu Electric Power Research Institute Nanjing China State Key Laboratory of Power Transmission Equipment & System Security and New Technology Chongqing University Chongqing China

ISBN: (数字)9781728126586

ISBN: (纸本)9781728126593

At present, infrared detection technology is widely used to diagnose the thermal fault of substation equipment, and it is needed to use computers to intelligently handle the progressively increasing infrared images. A model based on improved Bayesian optimization to diagnose thermal fault is proposed in this paper. Firstly, in order to utilize the effective network structure of image classification, ResNet10 and ResNet14 with much smaller parameter size are created based on CNN and residual block. Secondly, Bayesian optimization based on Gauss process and expected improvement is adopted to select hyperparameter, and the constrains of validation accuracy and parameter size are set to improve the performance of the algorithm. Experiment result shows that the improved Bayesian optimization can converge faster and obtain a smaller converge value. Compared with Alexnet, VGG-16, ResNet18, the proposed model has a highest accuracy and smallest parameter size, which can diagnose the thermal fault more effectively.

关键词： substation equipment thermal fault diagnosis deep learning Bayesian optimization thermal faults Bayesian inference Machine Learning Hyperparameter diagnostic model

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Stress Simulation Study on a Novel Combination String of transmission Line Insulators

Stress Simulation Study on a Novel Combination String of Tra...

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第二届制造技术，材料和化学工程国际学术会议（MTMCE 2019）

作者： Dapeng Wang Tao Xie Zuhui Yuan Jingping Niu Wei Xia Yang Bao State Grid Chizhou Power Supply Company State Grid Anhui Electric Power Co. Ltd Anhui Huadian Engineering Consulting & Design Co. Ltd State Key Laboratory of Power Transmission Equipment & System Security and New Technology Chongqing University

The insulator string mainly plays a role of fixing wire and preventing the current from returning to the ground in the power transmission and transformation project. In order to compress the corridor width of the transmission line and make it convenient for breaking line, we proposed a novel structure in which the V-type fittings and the tensile insulator string are optimally combined. In this paper, the mathematical model of mechanical analysis for the structure is established. According to the equilibrium conditions of space force system, the factors affecting the stress of the structure are analysed. In addition, a simulation model is built in the finite element analysis software. The stress distributions of the new structure by setting two installation angles are calculated and the special parts with weak mechanical properties in the new structure are explored based on the generated stress cloud diagram. We compare the maximum value of the von Mises equivalent stress in the two arrangements. A conclusion of better than 45° at a mounting arrangement angle of 50° was obtained. The research results provide a theoretical reference for further optimization design and installation of the combined structure in the future.

关键词： Stress Simulation Study on a Novel Combination String of transmission Line Insulators

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Fault Ride-Through of Fractional Frequency Offshore Wind power System Based on Modular Multilevel Matrix Converter

Fault Ride-Through of Fractional Frequency Offshore Wind Pow...

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

作者： Jianyang Yu Yongqing Meng XiXi Pan Yichao Zou Ruanming Huang Mengyao Zhang Shaanxi Key Laboratory of Smart Grid Xi'an Jiaotong University Xi'an China Economic Technology Research Institute State Grid Shanghai Municipal Electric Power Company Shanghai China

ISBN: (数字)9781728117225

ISBN: (纸本)9781728117232

The fault ride-through (FRT) capacity has become an important grid requirement for fractional frequency offshore wind power system (FFOWPS) based on modular multilevel matrix converter (M3C). In this paper, a novel joint fault ride-through strategy is proposed, which employs a land grid voltage versus offshore grid frequency droop control on M3C. Then, the control system of wind turbines can adjust the generated active power from wind based on the offshore grid frequency. Different form the previous research, the proposed joint control method can maintain the stability of the M3C DC capacitor voltage under the premise of satisfying the reactive power support to the grid under fault condition. Simulation results validate the fault ride-through capability of the FFOWPS in MATLAB/Simulink.

关键词： Wind turbines Wind farms Wind power generation Frequency control power system stability Voltage control Frequency conversion

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Low power Design and Clock Tree optimization for UHF RFID Tags

Low Power Design and Clock Tree optimization for UHF RFID Ta...

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International Conference on Communication technology (ICCT)

作者： Xu Yi Hu Xu Feng Xi Hu Yi Tang Xiaoke State Grid Key Laboratory of Power Industrial Chip Design and Analysis Technology Beijing Smart-Chip Microelectronics Technology Co.Ltd.

One of the most important performance index of UHF RFID tags is the operating distance, which can be extended by reducing the power consumption of RFID tags. In this paper, an RFID chip based on EPC Class -1 Generation-2/ISOIS000-6C protocol is presented. An optimization method for dynamic power consumption of clock tree in digital back-end design is proposed. This method can further reduce the dynamic power consumption for the completed layout. Under the condition of return frequency 170kHz, the simulated power consumption is reduced from 1. 4S3uW to 1. 357uW for the chip which was taped out with the TSMC 0. 18um process.

关键词： power demand Clocks Capacitance Optimization Switches Timing Radiofrequency identification

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Study on the Cauer Thermal Network Model of Press Pack IGBTs

Study on the Cauer Thermal Network Model of Press Pack IGBTs

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2018 International Conference on advanced Electronic Materials, Computers and Materials Engineering, AEMCME 2018

作者： Li, Jinyuan Chen, Zhongyuan Liu, Shouwen Deng, Erping Zhao, Zhibin State Key Laboratory of Advanced Power Transmission Technology Beijing102209 China State Grid Hubei Electric Power Co. Ltd China State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources Beijing102206 China

Press Pack IGBTs (PP IGBTs) has been gradually applied in the high voltage and high current areas, for its high power density, double side cooling and high reliability. The cauer thermal network model of PP IGBTs is proposed based on the boundary effect according to heat spreading angle in this paper, and the difference between the IGBT and FRD chips is considered in this model. The thermal contact resistance among multi-layers within PP IGBTs, which is calculated and corrected by the experiment, is also included in this model. The finite element method (FEM) model is used to verify the accuracy of the cauer model, because the accurate measurement of the junction to case thermal resistance of PP IGBTs is extremely difficult. The thermal characteristic of PP IGBTs under different clamping force can be acquired through the cauer thermal model. It has significant influence on the thermal resistance optimization, as the thermal resistance percentage of the components in PP IGBTs can be obtained from the cauer thermal model. © Published under licence by IOP Publishing Ltd.

关键词： Insulated gate bipolar transistors (IGBT)

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High-Order Sliding Mode Control of Modular Multilevel Matrix Converter for Fractional Frequency Offshore Wind power System

High-Order Sliding Mode Control of Modular Multilevel Matrix...

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

作者： Xixi Pan Yongqing Meng Sijia Li Jianyang Yu Guohua Fang Ruanming Huang Mengyao Zhang Shaanxi Key Laboratory of Smart Grid Xi’an Jiaotong University Xi’an China Economic Technology Research Institute State Grid Shanghai Municipal Electric Power Company Shanghai China

ISBN: (数字)9781728117225

ISBN: (纸本)9781728117232

The Modular Multilevel Matrix Converter (M3C) is a high-power high-voltage direct AC/AC power converter topology which is suitable for low frequency power transmission and distribution systems, such as offshore wind power integration, long-distance FFTS and subsea electric system. But it has obvious non-linear characteristics, complex system structure, high model order and complex control task. Based on the analysis of vector control, this paper proposes a high-order sliding mode control (SMC) strategy combining linear sliding mode with non-singular terminal sliding mode to control a high-order nonlinear system. According to the simulation results of the output waveform quality and power characteristics, the M3C has a better performance under SMC than PI control. The control strategy proposed in this paper can quickly and simply control high-order nonlinear strongly coupled systems, which provides ideas for the stability control of power systems.

关键词： Mathematical model Wind power generation Bridge circuits Sliding mode control Frequency conversion power system stability Matrix converters

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