| 1 | A novel fault section locating method based on distance matching degree in distribution network显示文摘Fault section location of a single-phase grounding fault is affected by the neutral grounding mode of the system, transition resistance, and the blind zone. A fault section locating method based on an amplitude feature and an intelligent distance algorithm is proposed to eliminate the influence of the above factors. By analyzing and comparing the amplitude characteristics of the zero-sequence current transient components at both ends of the healthy section and the faulty section, a distance algorithm with strong abnormal data immune capability is introduced in this paper. The matching degree of the amplitude characteristics at both ends of the feeder section are used as the criterion and by comparing with the set threshold, the faulty section is effectively determined. Finally, simulations using Matlab/Simulink and PSCAD/EMTDC show that the proposed section locating method can locate the faulty section accurately, and is not affected by grounding mode, grounding resistance, or the blind zone. | Zhenxing Li Jialing Wan Pengfei Wang Hanli Weng Zhenhua Li | 2021 | Protection and Control of Modern Power Systems2021,6,1: | 6 |
| 2 | Assessment of future climate change impacts on water-heat-salt migration in unsaturated frozen soil using CoupModel显示文摘The transport mechanisms of water,heat,and salt in unsaturated frozen soil,as well as its response to future climate change are in urgent need of study.In this study,western Jilin Province in north-eastern China was studied to produce a model of coupled water-heat-salt in unsaturated frozen soil using CoupModel.The water,heat,and salt dynamics of unsaturated frozen soil under three representative concentration pathway(RCP)scenarios were simulated to analyze the effects of future climate change on unsaturated frozen soil.The results show that water,heat,and salt migration are tightly coupled,and the soil salt concentration in the surface layer(10 cm)exhibits explosive growth after freezing and thawing.The future(2020–2099)meteorological factors in the study area were predicted using the Statistical Downscaling Model(SDSM).For RCP2.6,RCP4.5,and RCP8.5 scenarios,future temperatures during the freeze–thaw period increased by 2.68°C,3.18°C,and 4.28°C,respectively;precipitation increased by 30.28 mm,28.41 mm,and 32.17 mm,respectively;and evaporation increased by 93.57 mm,106.95 mm,and 130.57 mm,respectively.Climate change will shorten the freeze–thaw period,advance the soil melting time from April to March,and enhance water and salt transport.Compared to the baseline period(1961–2005),future soil salt concentrations at 10 cm increased by 1547.54 mg/L,1762.86 mg/L,and 1713.66 mg/L under RCP2.6,RCP4.5,and RCP8.5,respectively.The explosive salt accumulation is more obvious.Effective measures should be taken to prevent the salinization of unsaturated frozen soils and address climate change. | Hanli Wan Jianmin Bian Han Zhang Yihan Li | 2021 | Frontiers of Environmental Science & Engineering2021,15,1: | 2 |