| 1 | Performance Analysis of Corroded Grounding Devices with an Accurate Corrosion Model显示文摘Grounding devices are significant to the operation of the power transmission line and power equipment.The soil and leakage current can easily cause the corrosion of carbon steel grounding devices,resulting in power accidents.Therefore,most carbon steel grounding devices in service are already corroded,and the accurate calculation of grounding parameters for corroded grounding devices is important.However,most existing methods for calculating the grounding parameters of corroded grounding devices usually have the following disadvantages:1)They only consider whether the grounding devices are broken or not,and cannot analyze the grounding parameters of grounding devices with different corrosion degrees;2)They assume that the corroded grounding device is a conductor with a smaller diameter,and ignore the impact of the corrosion product layer,resulting in calculation errors.To solve the above problems,this paper establishes an accurate corrosion model for grounding devices based on the volume expansion coefficient of corrosion products.The grounding parameters calculation method for corroded grounding devices is proposed based on the boundary element method(BEM)and Galerkin’s method.Then the grounding performance of tower grounding grids with different corrosion degrees in different soils(uniform and layered)is analyzed.Finally,some features of grounding parameters of corroded grounding devices are given.This study can accurately calculate the grounding parameters of the corroded grounding devices and has far-reaching engineering significance for the safety of power equipment. | Yihua Dan Zhanlong Zhang Pengfei Gan Huarui Ye Qiaoyi Li Jun Deng | 2023 | CSEE Journal of Power and Energy Systems2023，9，3： | 0 |
| 2 | Evidence of aircraft activity impact on local air quality: A study in the context of uncommon airport operation显示文摘Wuhan Tianhe International Airport (WUH) was suspended to contain the spread of COVID-19,while Shanghai Hongqiao International Airport (SHA) saw a tremendousflight reduction.Closure of a major international airport is extremely rare and thus represents a unique opportunity to straightforwardly observe the impact of airport emissions on local air quality.In this study,a series of statistical tools were applied to analyze the variations in air pollutant levels in the vicinity of WUH and SHA.The results of bivariate polar plots show that airport SHA and WUH are a major source of nitrogen oxides.NOx,NO_(2)and NO diminished by 55.8%,44.1%,76.9%,and 40.4%,33.3% and 59.4% during the COVID-19 lockdown compared to those in the same period of 2018 and 2019,under a reduction in aircraft activities by 58.6%and61.4%.The concentration of NO_(2),SO_(2)and PM_(2.5)decreased by 77.3%,8.2%,29.5%,right after the closure of airport WUH on 23 January 2020.The average concentrations of NO,NO_(2)and NOxscatter plots at downwind of SHA after the lockdown were 78.0%,47.9%,57.4%and 62.3%,34.8%,41.8%lower than those during the same period in 2018 and 2019.However,a significant increase in O_(3)levels by 50.0% and 25.9%at WUH and SHA was observed,respectively.These results evidently show decreased nitrogen oxides concentrations in the airport vicinity due to reduced aircraft activities,while amplified O_(3)pollution due to a lower titration by NO under strong reduction in NOxemissions. | Hao Xu Kai Xiao Jun Pan Qingyan Fu Xiaodong Wei Junrui Zhou Yamei Yu Xue Hu Huarui Ren Jinping Cheng Shitao Peng Ningning Hong Yin Ye Ning Su Zehui He Tao Hu | 2023 | Journal of Environmental Sciences2023，，3： | 0 |
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