Study on the external insulation performance of ±800 kV DC transmission lines at high altitudes

2012 ◽  
Author(s):  
Hong Rao ◽  
Licheng Li ◽  
Ruihai Li ◽  
Guoli Wang ◽  
Yongli Liao ◽  
...  
Keyword(s):  
Transmission Lines ◽  
High Altitudes ◽  
External Insulation ◽  
Insulation Performance

scholarly journals The Influence of Humidity on Electron Transport Parameters and Insulation Performance of Air

2022 ◽  
Vol 9 ◽  
Author(s):  
Yunzhu An ◽  
Menghan Su ◽  
Yuanchao Hu ◽  
Shangmao Hu ◽  
Tao Huang ◽  
...  
Keyword(s):  
Electron Transport ◽  
Relative Humidity ◽  
Electron Energy ◽  
Transport Parameters ◽  
Average Electron Energy ◽  
Electron Diffusion Coefficient ◽  
External Insulation ◽  
Calculation Results ◽  
Average Electron ◽  
Insulation Performance

The environmental conditions affect the external insulation performance of power equipment. In order to study the physical characteristics of air discharge, the microscopic process of electron–molecule collision in the air based on the Boltzmann equation has been studied in this paper. The influence of humidity on the air gap insulation performance was also analyzed. The calculation results show that with the temperature 300 K and the pressure 1.0 atm, the electron energy distribution function and electron transport parameters varied with the air relative humidity. As the air relative humidity is increased by each 30%, the average electron energy decreases by about 0.2 eV, the reduced electron mobility decreases by about 0.25 × 1023 [1/(V·m·s)], the reduced electron diffusion coefficient decreases by about 0.2 × 1024 [1/(m s)], and the effective ionization coefficient decreases by about 4 × 10−24 m2. As the air relative humidity increases from 0% to 60%, the critical breakdown electric field increases by 1.22 kV/cm.

scholarly journals Corona and Electric Field Distribution Analysis in 400 kV Line Insulators

2021 ◽  
Vol 6 (1) ◽  
pp. 21-30
Author(s):  
Ragaleela Dalapati Rao ◽  
Padmanabha Raju Chinda ◽  
Meduri Kiran
Keyword(s):  
Electric Field ◽  
Field Distribution ◽  
Transmission Lines ◽  
Electric Field Distribution ◽  
Design Parameters ◽  
Distribution Analysis ◽  
Simulation Studies ◽  
Two Parameters ◽  
Corona Ring ◽  
Insulation Performance

The performance of insulator strings in transmission lines can be improved by corona rings owing to their electric field grading property. The insulation performance of the string depends on the corona ring parameter settings. In this study, the design of a corona ring for a 400 kV non-ceramic overhead line insulator is presented. Two parameters were altered during the investigation, ring measurement (R) and ring tube breadth (r) while maintaining a constant ring height (h). Based on electric field distribution, the proposed composite insulators were compared with glass insulators. Simulation studies were performed for the insulator strings, including corona rings with different design parameters. The corona discharge and optimal configuration results were analyzed, and it was found that the electric field was lower with composite insulators.

scholarly journals Study on the Influencing Factors of Insulator on the Back-Flashover Lightning Withstand Performance of ±800 kV UHVDC Transmission Lines

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Wenbo Jiang ◽  
Chunlin Tang ◽  
Bo Zhou
Keyword(s):  
Transmission Lines ◽  
Surface Hydrophobicity ◽  
Stable Operation ◽  
Voltage Level ◽  
Research Results ◽  
Influencing Mechanism ◽  
Impulse Voltage ◽  
Lightning Impulse ◽  
Reliable Power Supply ◽  
Insulation Performance

The current research results indicate that the insulator’s insulation performance has a very important influence on the back-flashover lightning withstand performance of UHVDC transmission lines, especially for ±800 kV voltage level. However, it is not clear which factors will influence the insulation performance of the insulator, and the influencing mechanism is also not clear yet. To figure out this problem, the insulator’s insulation performance under different conditions has been deeply analyzed and considered to reveal the influence mechanism in this paper, such as the surface hydrophobicity, pollution degree, and the string type. Firstly, the insulator’s model is established using COMSOL software, and the lightning impulse voltage of insulator is calculated and verified with the corresponding experimental data. Then, the ±800 kV UHVDC transmission lines model is constructed using PSCAD software, and back-flashover lightning withstand level and back-flashover rate are calculated by considering the above lightning impulse voltage as the threshold of flashover. Finally, the back-flashover lightning withstand performance of ±800 kV UHVDC transmission lines is deeply analyzed based on different insulators. The simulation results demonstrate that the back-flashover lightning withstand performance of ±800 kV UHVDC transmission lines is obviously weakened with the increase of the pollution degree and slightly weakened with the decrease of the surface hydrophobicity. Considering the same pollution degree, the V-type string insulator has the least influence, while the II-type string insulator has the greatest influences on the back-flashover lightning withstand performance of ±800 kV UHVDC transmission lines. The research results are beneficial for providing theoretical basis for stable operation and reliable power supply of ±800 kV UHVDC transmission lines.

scholarly journals Development and Application of Live Replacement of Insulator Suspension Tool Components for Transmission Lines

2019 ◽  
Vol 136 ◽  
pp. 04010
Author(s):  
Ma Jun ◽  
Yu Liang ◽  
Shi Yonggang ◽  
Dong Gang ◽  
Gong Fuxing ◽  
...  
Keyword(s):  
Transmission Lines ◽  
Power Supply ◽  
Operation Mode ◽  
Operation Time ◽  
Benefit Analysis ◽  
Lightning Strikes ◽  
The Stability ◽  
Insulation Performance ◽  
Tool Assembly

Transmission line insulators will reduce the insulation level and become low-value insulators because of lightning flashover. Toughened glass insulators are used in 500kV Tongfeng 1 and 2 lines in Tonghua area. Most umbrella skirts will break and fall off after lightning flashover, which greatly reduces the insulation performance. It needs to be replaced in time, but frequent blackouts will bring great losses and reduce the reliability of power supply. Aiming at the frequent lightning hazards and lightning strikes on transmission lines in Tonghua area, a tool assembly for live replacement of insulators for transmission lines is developed. Through the application of this tool, the live operation mode is adopted to eliminate such defects. The operation time can be arranged and implemented in a very timely manner, which avoids the threat of long-term defects, effectively reduces the outage time of equipment, enhances the stability of power grid, and greatly improves the reliability of power supply of lines. Finally, taking the live line insulator suspension tool as an example, the economic benefit analysis is given, and the feasibility and correctness of the tool are verified..

scholarly journals Analysis of the Icing Accretion Performance of Conductors and Its Normalized Characterization Method of Icing Degree for Various Ice Types in Natural Environments

Energies ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2678 ◽  
Author(s):  
Caijin Fan ◽  
Xingliang Jiang
Keyword(s):  
Power Function ◽  
Transmission Lines ◽  
Field Tests ◽  
Ice Thickness ◽  
Natural Environments ◽  
Ice Accretion ◽  
Water Droplets ◽  
Collision Efficiency ◽  
External Insulation ◽  
Selection Of

Icing degree in the severe icing regions for years is an important factor considered in the anti-icing design of transmission lines. However, there is currently no normalized characterization method for the icing degree of transmission lines, which can be used to record the severity of icing at icing areas over the years and guide the design of transmission lines. This study analyzes collision efficiency of water droplets with various diameters of conductors and investigates the ice accretion law of transmission lines with various diameters under four natural ice types. Therefore, the normalized method of standard ice thickness instead of various ice morphologies is creatively used to characterize icing degree of transmission lines and a lot of field tests which have been done at six natural ice observation stations have verified the effective of the method. The results have shown that: The diameters of conductor and the droplet significantly affect collision efficiency; the relation of standard ice thickness with diameter of conductors for four typical ice types complied with the law of power function. The results can provide important references for the design and external insulation selection of transmission lines in ice region.

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