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4th International Conference on power Engineering, ICPE 2023

作者： Ke, Jinkun Ma, Weiwei Xu, Hangyu Yin, Yibo Huang, Xuequan State Grid Smart Grid Research Institute Co. Ltd. State Key Laboratory of Advanced Power Transmission Technology Beijing China

ISBN: (纸本)9798350340020

Isolation refers to the physical isolation of a circuit through transformers, capacitors, and optocouplers, which can prevent DC and harmful AC currents from passing between two parts of the system, but allows for signal and power transmission. By adopting a gate capacitor scheme that can be integrated into standard CMOS processes, compared to using transformers or optocouplers as integrators and traditional discrete device isolation circuits, capacitive isolation can greatly reduce the volume occupied and facilitate miniaturization of related applications. This article proposes a capacitive digital isolator scheme, which achieves good characteristics of blocking interference transmission during digital signal transmission through OOK modulation and FSK demodulation. The specific circuit design is carried out using the Huahong BCD350GE process, which mainly includes two modules: transmitter TX and receiver, and is simulated and verified through Cadence Virtuoso. The simulation results show that the isolation chip can operate normally within the power supply range of 3.3-5V, with a temperature range of -40°C-120°C, a maximum data transmission rate of 25Mbps, a delay of 20.82ns, and a pulse width distortion of 10.11ns. Under a l5pF capacitive load and 5V power supply, the maximum power consumption is l8.91mW. © 2023 IEEE.

关键词： Demodulation

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Analysis of the Suppression Effect of Series Virtual Resistors on Sub-synchronous Oscillation of New Energy 11

Analysis of the Suppression Effect of Series Virtual Resisto...

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11th International Conference on smart grid and Clean Energy Technologies, ICSGCE 2023

作者： Yu, Hongyang Liu, Zongye Zhao, Guoliang Wang, Yingpei State Grid Smart Grid Research Institute Co. Ltd. State Key Laboratory of Advanced Power Transmission Technology Beijing China

ISBN: (纸本)9798350305364

The vigorous development of new energy has promoted China's energy transformation and pointed out a new direction for China's energy strategy. However, as the capacity of new energy grid connection increases, its interaction with the system strengthens, causing fundamental changes in the local system impedance characteristics and leading to phenomena such as sub-synchronous oscillation. Currently, there has been extensive research from the perspective of optimizing the characteristics of new energy units, but there is less research on changing the local system impedance characteristics from the perspective of the power grid. This article first analyzes the differences in the effect of virtual resistance on system impedance under different access modes, proposes a virtual resistance control strategy based on chain-type converter, and finally analyzes and verifies the suppression effect of virtual resistance strategy on system sub-synchronous oscillation through semi-physical closed-loop simulation of the control system. The study shows that series access mode is more suitable for changing the equivalent impedance of the local system from the network side. By adding virtual resistance at the sub-synchronous frequency, it can effectively improve damping and suppress sub-synchronous oscillations in the system. © 2023 IEEE.

关键词： chain converter HIL simulation subsynchronous oscillation virtual resistance

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A Multi-Level Driver for Switching Trace Regulation Method of SiC MOSFET 7

A Multi-Level Driver for Switching Trace Regulation Method o...

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7th IEEE Conference on Energy Internet and Energy System Integration, EI2 2023

作者： Bai, Jiancheng Xu, Jingtao Guan, Zhaoliang Feng, Jingbo Xu, Hangyu Li, Xiao State Grid Smart Grid Research Institute Co. Ltd. State Key Laboratory of Advanced Power Transmission Technology Beijing China

ISBN: (纸本)9798350345094

SiC MOSFET has small on-resistance, low switching losses, high switching frequency, high withstand voltage values, and excellent reverse recovery characteristics. Excessively fast switching speeds of the SiC devices can lead to severe switching overshoot, oscillations, and crosstalk. These negative effects affect the application prospects of SiC devices. In this paper, a multi-level driver(MLD) for SiC MOSFET and regulation method for switching trace are proposed, which addresses the co-optimization of multiple objectives of the switching trace. It not only ensures switching speed and low switching loss, but also effectively suppresses overshoot and oscillation. The feasibility and effectiveness of the designed multi-level driver are verified using double-pulse test. © 2023 IEEE.

关键词： Silicon carbide

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Influence of Cellulose Particle Aggregation on Transformer Oil Dielectric Strength

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IEEE Transactions on Dielectrics and Electrical Insulation 2024年第3期32卷 1606-1614页

作者： Chen, Chen Yang, Lijun Feng, Shangquan Zhao, Wu Wang, Xiang Chen, Zhengyu Liao, Ruijing Chongqing University State Key Laboratory of Power Transmission Equipment Technology Chongqing400044 China State Grid Chongqing Electric Power Research Institute Chongqing400022 China

With increasing transformer voltage levels, the probability of unexplained insulation discharge failure also increases. These failures often occur despite normal insulation parameter readings prior to the event. Investigating and uncovering the mechanisms behind such failures is crucial for ensuring the safe operation of transformers. This paper focuses on the phenomenon of local aggregation and the cumulative effects of low-concentration particles in transformer oil during long-term operation, explores how these factors reduce the insulation margin of transformers, and reveals the mechanisms behind sudden unexplained failure. Using transformer oil samples containing low concentrations of cellulose particles, the aggregation of cellulose particles toward high-field regions was observed over time, and the impact of different aggregation levels on the breakdown strength of oil gaps was examined. These results indicate that the aggregation behavior of cellulose particles leads to increased impurity concentrations in high-field regions. In this experiment, after an AC voltage was applied to the electrodes for 7200 s at a field strength of 2.78 kV/mm, the breakdown voltage of the oil sample decreased by 79.57% compared with the breakdown voltage when the electrical field was directly increased until breakdown occurs. This is attributed to the aggregation effect, which causes particle clustering and increased local concentration, significantly reducing the dielectric strength of the transformer oil. The findings of this study help in understanding the relationship between impurity particle aggregation effects and the reduction in transformer safety margins, providing new theoretical support for tracing the origins of transformer discharge failures. © 2024 IEEE.

关键词： Oil filled transformers

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Study on the Mechanism of Silver-Graphene Composite Coating in Coastal High Salt and High Humidity Environment 18th

Study on the Mechanism of Silver-Graphene Composite Coating ...

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18th Annual Conference of China Electrotechnical Society, ACCES 2023

作者： Huang, Xin Pang, Zhen Zhang, Chengwei State Grid Fujian Economic Research Institute Fuzhou350000 China State Key Laboratory of Advanced Power Transmission Technology State Grid Smart Grid Research Institute Co. Ltd. Beijing102209 China

ISBN: (纸本)9789819714469

The corrosion of power grid equipment will be accelerated by the high salt and humidity environment along the coast of Fujian, and its service life will be affected, and lead to the failure of equipment and structures. This paper mainly studies the change of the metal indicator composition of silver-Graphene composite coating hanging pieces with different Graphene concentrations in the coastal high salt and high humidity environment. The mechanism of silver-Graphene composite coating on the contact resistance of metal equipment in the coastal high salt and high humidity environment is analyzed by scanning electron microscope, XPS analysis and XDR analysis. The results show that the silver coating of traditional electrical equipment will produce dark products under the action of coastal high salt and high humidity environment β-Ag2S, thus improving the contact resistance, affecting the conductivity and the reliability and stability of electrical contact. The silver-Graphene composite coating can effectively reduce the generation of Ag2S, maintain good conductivity, and achieve corrosion resistance. However, the higher the concentration of Graphene, the better the effect. © Beijing Paike Culture Commu. Co., Ltd. 2024.

关键词： Silver

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Microstructure, Mechanical and Electrical Properties of Al-Fe-Cu-RE Alloy 11th

Microstructure, Mechanical and Electrical Properties of Al-F...

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11th Frontier Academic Forum of Electrical Engineering, FAFEE 2024

作者： Chen, Rui Li, Menglin Chen, Baoan Han, Yu Zhu, Zhixiang Yang, Changlong Zheng, Wei Duo, Junlong State Key Laboratory of Advanced Power Transmission Technology State Grid Smart Grid Research Institute Co. Ltd. Beijing102209 China Yingkou Power Supply Company State Grid Liaoning Electric Power Co. LTD Liaoning Yingkou115000 China

ISBN: (纸本)9789819788316

power cable plays a very important role in power transmission and is an important part of the national economy. The demand for power cables continues to increase with the rapid development of the economy. ‘Replacing copper with aluminum’ is an effective means to save copper resources and can save costs. However, aluminum has the disadvantages of low melting point, softness and poor mechanical strength, which makes the reliability of aluminum core cable low and prone to failure. Therefore, it is necessary to improve the comprehensive performance of aluminum alloy cables to ensure their reliability and safety. In this paper, two different kinds of rare earth elements are added to Al-Fe-Cu alloy, and the results are as follows. After rolling and drawing, the dispersed phase of rare earth microalloyed Al-Fe-Cu alloy ingot still shows a streamline in the same direction as rolling and drawing under scanning electron microscope. The mixed addition of rare earth elements La and Ce can form a fine phase, and the rare earth elements in the dispersion phase will be redistributed. The rare earth element Sc will enter the Al-Fe-Cu ternary phase during *** strength of rare earth element Al-Fe-Cu alloy wire with a total mass fraction of 0.1 is about 160 MPa, and the microhardness exceeds 50 HV. The conductivity of Al-Fe-Cu-La-Ce alloy wire is 59.21% IACS, and the conductivity of Al-Fe-Cu-Sc alloy wire is 60.22% IACS. © Beijing Paike Culture Commu. Co., Ltd. 2025.

关键词： Iron alloys

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Research on the Configuration and Capacity Calculation of DC Side Dynamic Braking System 6

Research on the Configuration and Capacity Calculation of DC...

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6th International Conference on HVDC, HVDC 2024

作者： Bai, Yu Yang, Yuexi Zhou, Xiao Du, Zhenyu Hu, Yinghong Li, Yu State Grid Smart Grid Research Institute Co. Ltd. National Key Laboratory of Advanced Power Transmission Technology Beijing Key Laboratory of Dc Grid Technology and Simulation Beijing China Electric Power Research Institute State Grid JiBei Electric Power Co. Ltd. Beijing China

ISBN: (纸本)9798350387759

The Flexible DC transmission technology circumvents the limitation of transmission distance caused by the charging power of AC cables. Additionally, it boasts technical advantages such as effectively isolating the interactions between onshore AC power grids and offshore wind farms, providing stable grid-connected voltage for offshore wind farms, and enabling flexible regulation of system operations. These factors make it the preferred technology for transmitting power from remote offshore wind farms. The offshore wind power flexible grid-connected system incorporates a DC-side dynamic braking system, which functions to absorb excess power injected by the wind farm and prevent system overvoltage when the AC main grid malfunctions, leading to the inability of the onshore converter station to deliver rated power. In this paper, the technical route, configuration scheme and capacity demand of DC side dynamic braking systems are studied, and the DC side dynamic braking system configuration scheme applicable to unipolar and bipolar isolated island new energy transmission flexible system is proposed, and the capacity demand of DC side dynamic braking system is analyzed, and the capacity design scheme of DC side dynamic braking system that conforms to the national calibration and meets the demand of system power balancing and fault ride-through and other requirements under the faulty AC system is proposed. The capacity design scheme of energy consuming devices is proposed in compliance with national calibration and can meet the system power balance and fault ride-through requirements in case of AC system failure and other working conditions. © 2024 IEEE.

关键词： capacity requirements DC side dynamic braking systems flexible DC grid layout design offshore wind power

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High-performance carbon nanotube/polyaniline artificial yarn muscles working in biocompatible environments

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Nano Research 2023年第3期16卷 4143-4151页

作者： Jian Qiao Yulong Wu Chengfeng Zhu Lizhong Dong Kunjie Wu Yulian Wang Wei Yang Min Li Jiangtao Di Qingwen Li Key Laboratory of Multifunctional Nanomaterials and Smart Systems Advanced Materials DivisionSuzhou Institute of Nano-Tech and Nano-BionicsChinese Academy of SciencesSuzhou 215123China State Key Laboratory of Advanced Power Transmission Technology State Grid Smart Grid Research Institute Co.Ltd.Beijing 102209China School of Materials Science and Engineering Key Laboratory of Aerospace Materials and PerformanceMinistry of EducationBeihang UniversityBeijing 100191China

Implantable artificial muscles are of great importance for muscle function restoration and physical augmentation but are still ***,we report an artificial muscle by soaking-polymerization of polyaniline(PANI)inside a carbon nanotube(CNT)*** in aqueous biocompatible solutions,the yarn muscle generates a large contractile stroke of 17%and high isometric stress of 8 MPa at voltages lower than 2 *** excellent performance can be ascribed to the large actuation volume that is enabled by the fast electrochemical redox of PANI confined in a coiled yarn *** actuation performance outperforms that of previously reported aqueous artificial yarn ***,the yarn muscle can work well and maintain excellent actuating performance in other biocompatible solutions such as normal saline and Na2SO4 aqueous solution,which makes the CNT/PANI yarn muscles suitable for implantable bionic ***,a biomimetic arm was fabricated to demonstrate the applications of the CNT/PANI yarn artificial muscle in implantable muscle,underwater robots,and soft exoskeletons.

关键词： carbon nanotube polyaniline biocompatible implantable artificial muscle

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Thermal Field Simulation of High Voltage Shunt Capacitor Based on Electrothermal Coupling in Harmonic Environment 7

Thermal Field Simulation of High Voltage Shunt Capacitor Bas...

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7th IEEE International Electrical and Energy Conference, CIEEC 2024

作者： Xing, Zhaoliang Guo, Shaowei Sun, Qiming Zhang, Chong Zhang, Jianjun Han, Y.U. Yu, Yong Zhu, Lingyu State Key Laboratory of Advanced Power Transmission Technology Grid Smart Grid Research Institute Co.Ltd. Beijing China Xi'an Jiaotong University State Key Laboratory of Electrical Insulation and Power Equipment Xi'an China State Grid Tangshan Power Supply Company Tangshan China

ISBN: (纸本)9798350359558

The high voltage shunt capacitor is rated to work at power frequency voltage and current. Due to the existence of harmonic current in power system, the temperature rise of the high voltage shunt capacitor is different from the power frequency condition during stable operation. In order to study the heating characteristics of high voltage shunt capacitors under harmonic conditions, this paper constructs a series equivalent model of high voltage shunt capacitors considering the influence of frequency, and proposes the construction method of solving the electric and thermal field models of capacitors under harmonic conditions. According to the series model, the internal heat source distribution of capacitors is refined, and a full equivalent simulation model of the capacitor thermal field based on electrothermal coupling is built. The simulation model can calculate the capacitor temperature distribution under various current excitation conditions. The heating characteristics of capacitor under power frequency current, single harmonic current and power frequency superimposed single harmonic excitation are simulated and analyzed, and the influence of harmonic on the heating characteristics of capacitor is summarized. © 2024 IEEE.

关键词： Electric heating

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A Simulation and Test Method for Fault Current Suppression Branch in DC grid

A Simulation and Test Method for Fault Current Suppression B...

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7th International Conference on Electronics technology, ICET 2024

作者： Li, Fangyuan Gu, Huaiguang Zhou, Jiapei Gao, Yang State Grid Smart Grid Research Institute CO. LTD. State Key Laboratory of Advanced Power Transmission Technology Beijing China Beijing Key Laboratory of Dc Grid Technology & Simulation Beijing China

ISBN: (纸本)9798350363951

This paper is aimed at the research and verification requirements of fault current suppression devices applied in DC grids as actual physical test equipment. A joint test method based on digital and physical hybrid simulation is proposed, and a digital physical interface scheme is provided. It has engineering practical digital physical interface stability and accuracy, and plays a technical support role in the development of fault current suppression devices in DC grids. A fault current suppression branch is proposed for the combination of a current limiter and a high-voltage DC circuit breaker. The testing topology, main circuit interface, communication interface, and communication protocol requirements for the digital physical hybrid simulation of the fault suppression branch are proposed, and a platform for the connection of the current limiting device is developed. The experiment results show that after adding a current limiter to the current limiting branch, the maximum fault current decreases, the breaking current of the circuit breaker is reduced, and the requirements for the technical parameters of the circuit breaker are lowered. © 2024 IEEE.

关键词： Digital devices

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