Situation and Development on Soil Corrosion of Metallic Materials of HVDC Power Transmission Project

2016 ◽  
Vol 852 ◽  
pp. 218-225 ◽  
Author(s):  
An Xiang Guo ◽  
Wei Juan Hu ◽  
Ai Jun Yan ◽  
Zhi Qiang Yang ◽  
La Jun Feng
Keyword(s):  
High Power ◽  
Power Transmission ◽  
Research Direction ◽  
Research Progress ◽  
Metallic Materials ◽  
Buried Pipeline ◽  
Stray Current ◽  
Soil Corrosion ◽  
Hvdc System ◽  
Corrosion Research

UHVDC transmission could deliver high-power electricity over long distances effectively, while the DC stray current led to corrosion of grounding device and the surrounding buried metal during the operation inevitably. This paper reviewed the research progress of HVDC corrosion at home and abroad in recent years. It elaborated corrosion research direction of HVDC system from three aspects, which were pole, grounding grid and the neighboring tower grounding body buried pipeline respectively. Describing the anti-corrosion measures on grounding devices and buried pipeline, and explaining the advantages and defects of various anti-corrosion technology. At last, we proposed that it was necessary to expand the research in UHVDC field, grasp the erosion rule of DC stray current in soil comprehensively to enhance the security of UHVDC transmission system of national grid.

Research Progress and Obstacles in Development of HVDC

2014 ◽  
Vol 1030-1032 ◽  
pp. 1327-1330
Author(s):  
Yuan Feng Chen
Keyword(s):  
High Power ◽  
Power Transmission ◽  
Research Progress ◽  
Long Distance ◽  
Higher Harmonics ◽  
Application Prospects ◽  
Transmission Direction ◽  
At Home

The merits of HVDC,such as long-distance power transmission, less line lose,ability to transmit high-power and so on,were introduced. The obstacles in development of HVDC,including failure of commutation,hazards of higher harmonics,limitations of transmission direction, problems of insulation and so on,were analyzed. The research progress both at home and abroad in development of HVDC were summarized.At last,research and application prospects of HVDC were prospected briefly.

scholarly journals Advances in the role of miRNAs in the occurrence and development of osteosarcoma

Open Medicine ◽  
2020 ◽  
Vol 15 (1) ◽  
pp. 1003-1011
Author(s):  
Guanyu Zhang ◽  
Yiran Li ◽  
Jiasheng Xu ◽  
Zhenfang Xiong
Keyword(s):  
Target Gene ◽  
Early Stage ◽  
Research Direction ◽  
Research Progress ◽  
Skeletal System ◽  
Translation Process ◽  
Non Coding Rnas ◽  
New Research ◽  
Post Transcriptional Regulation

AbstractOsteosarcoma (OS) is the most common primary malignant tumor of the skeletal system in the clinic. It mainly occurs in adolescent patients and the pathogenesis of the disease is very complicated. The distant metastasis may occur in the early stage, and the prognosis is poor. MicroRNAs (miRNAs) are non-coding RNAs of about 18–25 nt in length that are involved in post-transcriptional regulation of genes. miRNAs can regulate target gene expression by promoting the degradation of target mRNAs or inhibiting the translation process, thereby the proliferation of OS cells can be inhibited and the apoptosis can be promoted; in this way, miRNAs can affect the metabolism of OS cells and can also participate in the occurrence, invasion, metastasis, and recurrence of OS. Some miRNAs have already been found to be closely related to the prognosis of patients with OS. Unlike other reviews, this review summarizes the miRNA molecules closely related to the development, diagnosis, prognosis, and treatment of OS in recent years. The expression and influence of miRNA molecule on OS were discussed in detail, and the related research progress was summarized to provide a new research direction for early diagnosis and treatment of OS.

Development of Back-to-Back Flexible HVDC Prototype Based on MMC

2013 ◽  
Vol 397-400 ◽  
pp. 1808-1813
Author(s):  
Cheng Feng ◽  
Da Li Wang ◽  
Jin Li
Keyword(s):  
Circuit Design ◽  
High Power ◽  
Working Condition ◽  
Protection Strategy ◽  
Hvdc System ◽  
Fault Protection ◽  
The World

With the development of flexible HVDC technology in the world, back-to-back HVDC system based on MMC topology have more attention. A high power back-to-back flexible HVDC prototype has been developed to assess performance and reliability of construction of converter valve segment. Valve normal working condition (rated conditions rated voltage, current, temperature), valve transient working condition (temporary overvoltage, overcurrent), valve fault protection and anti-interference ability are accessed. Performance and reliability of control and protection equipment are assessed. The design of control and protection strategy is optimized. The correctness of main circuit design is tested.

Research progress of high-power diamond laser technology (Invited)

2020 ◽  
Vol 49 (12) ◽  
pp. 20201076-20201076
Author(s):  
白振旭 Zhenxu Bai ◽  
杨学宗 Xuezong Yang ◽  
陈晖 Hui Chen ◽  
金舵 Duo Jin ◽  
丁洁 Jie Ding ◽  
...  
Keyword(s):  
High Power ◽  
Research Progress ◽  
Laser Technology

scholarly journals A comparative analysis of cascaded-multilevel hybrid filters applied in power transmission systems

2008 ◽  
Vol 19 (1) ◽  
pp. 107-113 ◽  
Author(s):  
Alexandre G. Merçon ◽  
Lucas F. Encarnação ◽  
Luís F. C. Monteiro ◽  
Emanuel L. van Emmerik ◽  
Maurício Aredes
Keyword(s):  
Comparative Analysis ◽  
High Power ◽  
Power Transmission ◽  
High Harmonic ◽  
Active Filter ◽  
Active Filters ◽  
Transmission Systems ◽  
Passive Filters ◽  
Power Transmission Systems ◽  
Hybrid Filters

Passive filters, commonly used to attenuate non-characteristic harmonics in High Voltage Direct Current (HVDC) systems, stay at risk of disconnection from the system due to overcurrent problems. A possible solution to solve the problems involving high harmonic levels would be the use of pure active filters. However, this alternative is unpractical due to the high power of the transmission systems. This paper proposes two different topologies of hybrid filters to damp harmonic resonance in power transmission systems. The first one combines a small-rated active filter in series with passive filters, limiting overcurrents, when existent, or improving its own quality factor. The second one consists of an active filter in parallel with passive filters, which compensates all eventual overcurrent in the system bus. Both topologies utilizes the state of the art in very high power semiconductors and multilevel power converters. Simulation results present a comparative analysis, highlighting the efficiency of, and the differences between, the two proposed hybrid filters.

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