With the advancement of new infrastructures,the digitalization of the substation communication network has rapidly increased,and its information security risks have become increasingly prominent.Accurate and reliable ...With the advancement of new infrastructures,the digitalization of the substation communication network has rapidly increased,and its information security risks have become increasingly prominent.Accurate and reliable substation communication network flow models and flow anomaly detection methods have become an important means to prevent network security problems and identify network anomalies.The existing substation network analyzers and flow anomaly detection algorithms are usually based on threshold determination,which cannot reflect the inherent characteristics of substation automation flow based on IEC 61850 and have low detection accuracy.To effectively detect abnormal traffic,this paper fully explores the substation network traffic rules,extracts the frequency domain features of the station level network,and designs an abnormal traffic identification model based on the ResNeSt convolutional neural network.Transfer learning is used to solve the problem of insufficient abnormal traffic labeled samples in the substation.Finally,a new method of abnormal traffic detection in smart substation station level communication networks based on deep transfer learning is proposed.The T1-1 substation communication network is constructed on OPNET for abnormal simulations,and the actual network traffic in a 110kV substation is fused with CIC DDoS2019 and KDD99 data sets for the algorithm performance test,respectively.The accuracy reached is 98.73%and 98.95%,indicating that the detection model proposed in this paper has higher detection accuracy than existing algorithms.展开更多
The leveling measurements at Daixian station appeared increasing trend since March 25, 2013, which is credible, showing normal fault activity. According to the environmental survey, it contains some interference fact...The leveling measurements at Daixian station appeared increasing trend since March 25, 2013, which is credible, showing normal fault activity. According to the environmental survey, it contains some interference factors： first, the wind is big when the leveling measures in the afternoon, which has certain influence on the measurement results, but the impact is random and should be near the base value and not appear a trend. Second, the point BM3 was maintained during Sep. to Oct. in 2012 and occurred cracks in 2013, showing that the poor stability around the point. In addition, the change of recorded program is only to change the way of data record and can not affect the observation results during the same period.展开更多
In this study,under the assumption that the two huge leveling deformation anomalies at Linfen seismic station were caused by the Luoyunshan fault( Tumen-Yuli section)movement, we computed the vertical deformation fiel...In this study,under the assumption that the two huge leveling deformation anomalies at Linfen seismic station were caused by the Luoyunshan fault( Tumen-Yuli section)movement, we computed the vertical deformation field distribution based on the rectangular fault dislocation model and measured the ground deformation field of the study area using D-InS AR technology. The results are as follows:( 1) Theoretically,the ground vertical deformation field caused by fault movement could be within the elliptical deformation area with the long axis parallel to the fault strike. The largest deformation region is located in the center of the area in the hanging wall of the fault,and the deformation gradually decreases to zero toward the periphery; the impact range induced by the two deformations is respectively as follows: The long axes are about 18 km and26km,the short axes are about 12 km and 17 km and the obvious deformation amplitude is about 1- 3mm and 4- 14 mm.( 2) The measured deformation field by D-InS AR shows that there is no continuous deformation area consistent with the fault strike,and only the presence of land subsidence possibly caused by groundwater excessive exploitation,with the deformation amplitude about 10- 12 mm and 1- 5mm.( 3) The measured deformation field is not consistent with the theoretical result on deformation area and amplitude,which indicates that the fault movement is not the main cause of Linfen huge leveling deformation,but may rather be because of local deformation of the soil layers in the hanging wall of the fault.( 4) By combining the fault dislocation model simulation with the D-InS AR technology measurement,we can determine effectively the nature of the anomalyof the huge cross-fault leveling deformation,thus provide scientific basis for verification of significant leveling anomalies.展开更多
The radioactivity level of the ambient environment of Anren Bone-coal Power Station (BCPS) was investigated systematically. The γ radiation dose rate level in the environment, the content of 238U and 226Ra in the amb...The radioactivity level of the ambient environment of Anren Bone-coal Power Station (BCPS) was investigated systematically. The γ radiation dose rate level in the environment, the content of 238U and 226Ra in the ambient soil and the farmland in the direction of downwind, the concentrations of 238U. 232Th. 226Ra 40K and 222Rn as well as α potential energy in air, and the concentrations of natural U and Th in effluent are all higher than the corresponding values of the reference site. The additional annual effective dose equivalent to the residents living in the houses made of bone-coal cinder brick is 2.7 mSv.展开更多
Based on experience of meteorological service at county-level meteorological station in recent 20 years,status quo of decision-making meteorological service,main influence factors of decision-making meteorological ser...Based on experience of meteorological service at county-level meteorological station in recent 20 years,status quo of decision-making meteorological service,main influence factors of decision-making meteorological service and writing of decision-making meteorological service materials are analyzed,and measures and suggestions of improving decision-making meteorological service level are proposed. The research aims to improve public meteorological service level at grass-roots level,provide scientific decision-making basis for government departments preventing and reducing disaster,and reduce loss of life and property of the country and people caused by meteorological disasters to the maximum extent.展开更多
This study aims to explore the role of spatial heterogeneity in ridership analysis and examine the relationship between built environment, station attributes and urban rapid transit ridership at the station level.Alth...This study aims to explore the role of spatial heterogeneity in ridership analysis and examine the relationship between built environment, station attributes and urban rapid transit ridership at the station level.Although spatial heterogeneity has been widely acknowledged in spatial data analysis, it has been rarely considered in travel behavior studies.Four models(three global models-ordinary least squares(OLS), spatial lag model(SLM), spatial error model(SEM) and one local model-geographically weighted regression(GWR) model) are estimated separately to explore the relationship between various independent variables and station ridership, and identify the influence of spatial heterogeneity.Using the data of built environment and station characteristics, the results of diagnostic identify evidence the existence of spatial heterogeneity in station ridership for the metro network in Nanjing, China.Results of comparing the various goodness-of-fit indicators show that, the GWR model yields the best fit of the data, performance followed by the SEM, SLM and OLS model.The results also demonstrate that population, number of lines, number of feeder buses, number of exits, road density and proportion residential area have a significant impact on station ridership.Moreover, the study pays special attention to the spatial variation in the coefficients of the independent variables and their statistical significance.It underlines the importance of taking spatial heterogeneity into account in the station ridership analysis and the decision-making in urban planning.展开更多
The Level-2 probabilistic safety assessment(PSA) of pressurized water reactors studies the possibility of creep rupture for major reactor coolant system components during the course of high pressure severe accident se...The Level-2 probabilistic safety assessment(PSA) of pressurized water reactors studies the possibility of creep rupture for major reactor coolant system components during the course of high pressure severe accident sequences. The present paper covers this technical issue and tries to quantify its associated phenomenological uncertainties for the development of Level-2 PSA. A framework is proposed for the formal quantification of uncertainties in the Level-2 PSA model of a PWR type nuclear power plant using an integrated deterministic and PSA approach. This is demonstrated for estimation of creep rupture failure probability in station blackout severe accident of a 2-loop PWR, which is the representative case for high pressure sequences. MELCOR 1.8.6 code is employed here as the deterministic tool for the assessment of physical phenomena in the course of accident. In addition, a MATLAB code is developed for quantification of the probabilistic part by treating the uncertainties through separation of aleatory and epistemic sources of uncertainty.The probability for steam generator tube creep rupture is estimated at 0.17.展开更多
In order to study the climate variabilities of the sea level around the Korean Peninsula, tidal data observed at local stations in Korea were compared against those obtained using TOPEX/POSEIDON (T/P) altimetric sea l...In order to study the climate variabilities of the sea level around the Korean Peninsula, tidal data observed at local stations in Korea were compared against those obtained using TOPEX/POSEIDON (T/P) altimetric sea level data. In the course of our study, the amount of sea level rise was estimated using the tidal data from 9 stations selected by an anomaly coherency analysis. The results indicated that the sea level has risen by 0.28 cm yr-1 around the Korean Peninsula over the past two decades. The extent of such a rise is about two times higher than that of the global increase (0.1-0.2 cm yr-1). However, because most global warming effects occurred mainly over mid- and high-latitudes, this level of change appears to be realistic. According to the spectral analysis (at a spectral window of k=2, k is the number of subdivisions), the decadal band of sea level variability is computed at 30% of the energy. Its spectral peak is found at 12.8 years. In the interannual band, the predominant sea level variability is in the 1.4-1.9-year band, with a sharp peak at 1.6 years. A secondary peak, although marginal, has a period of 2.2 years. Based on our estimates of sea level height from Topex/Poseidon, the quasi-biennial periodicity of 1.6 years is the representative interannual sea level variability in the seas adjacent to Korea. Trends vary greatly according to the geographical location, from a maximum of 1.0 cm yr-1 (the southern sector of the East Sea) to a minimum of 0.17 cm yr-1 (the northern sector of the East Sea). This is fairly consistent with the qualitative description already given with reference to the global map. As an analogue to the pattern seen in Korea, that of the Yellow Sea reveals practically the same trend as that of the adjacent seas (0.56 cm yr-1). However, in the case of TOPEX/POSEIDON (T/P) data, there is no clear evidence of a linkage between the interannual sea level variability around the Korean Peninsula and ENSO.展开更多
There are already several power models to estimate the power consumption of base stations at system level. However, there is so far no model that can predict power consumption of the future base station designs based ...There are already several power models to estimate the power consumption of base stations at system level. However, there is so far no model that can predict power consumption of the future base station designs based on algorithms and hardware selections with insufficient physical information. We present such an energy model for typical base stations. This model can help designers in estimating, evaluating and optimizing energy/power consumption of candidate designs in early design stages. The proposed model is verified by an LTE extreme scenario. The estimated results show that digital front-end, channel equalization and channel decoding are three major power greedy modules(consuming 39.4%, 16.3%, 13.4%) in a digital baseband subsystem. The power estimation error of the proposed power amplifier(PA) power model is 3.5%(macro cell). The major contribution of this paper is that the proposed models can rapidly estimate energy/power consumption of 4G and the future base stations(such as 5G) in early design stages with well acceptable precision, even without sufficient implementation information.展开更多
In order to specify the overvoltage and insulation level of equipments in ±1 100 kV UHVDC converter stations,the arrester configuration scheme and some basic parameters for ±1 100 kV Zhundong converter stati...In order to specify the overvoltage and insulation level of equipments in ±1 100 kV UHVDC converter stations,the arrester configuration scheme and some basic parameters for ±1 100 kV Zhundong converter station are proposed.Overvoltage of equipments in AC system,valve hall,DC busbar,and neutral busbar are also calculated in accordance with the fundamental principles of arrester configuration for UHV converter stations and the existing experiences in insulation coordination of ±800 kV UHVDC converter stations.The work is done also for specifing insulation levels for ±1 100 kV UHVDC converter stations of the ±1 100 kV UHVDC power transmission project from Zhundong to Sichuan in China.Thus,the recommended insulation margins that determine the insulation levels of converter station equipments are proposed: the insulation margins for thyristor valves are 10%/10%/15% for switching impulse/ lightning impulse/ steer front impulse; the insulation levels of lighting and swtiching impulses are recommended as 2 600 kV and 2 150 kV respectively for 1 100 kV DC buses,and as 2 250 kV and 2 100 kV respectively for equipments at the valve side of high-voltage Y/Y converter transformers.展开更多
基金supported in part by the Science and Technology Project of State Grid Corporation of China(SGHADK00PJJS2000026).
文摘With the advancement of new infrastructures,the digitalization of the substation communication network has rapidly increased,and its information security risks have become increasingly prominent.Accurate and reliable substation communication network flow models and flow anomaly detection methods have become an important means to prevent network security problems and identify network anomalies.The existing substation network analyzers and flow anomaly detection algorithms are usually based on threshold determination,which cannot reflect the inherent characteristics of substation automation flow based on IEC 61850 and have low detection accuracy.To effectively detect abnormal traffic,this paper fully explores the substation network traffic rules,extracts the frequency domain features of the station level network,and designs an abnormal traffic identification model based on the ResNeSt convolutional neural network.Transfer learning is used to solve the problem of insufficient abnormal traffic labeled samples in the substation.Finally,a new method of abnormal traffic detection in smart substation station level communication networks based on deep transfer learning is proposed.The T1-1 substation communication network is constructed on OPNET for abnormal simulations,and the actual network traffic in a 110kV substation is fused with CIC DDoS2019 and KDD99 data sets for the algorithm performance test,respectively.The accuracy reached is 98.73%and 98.95%,indicating that the detection model proposed in this paper has higher detection accuracy than existing algorithms.
基金supported by the National Natural Science Foundation of Shanxi Province(2014011035-1,2010011030-3)the Spark Program of Earthquake Technology of China Earthquake Administration(XH12007)The Key Scientific Research Projects of Earthquake Administration of Shanxi Province(SBK-1417,SBK-1525)
文摘The leveling measurements at Daixian station appeared increasing trend since March 25, 2013, which is credible, showing normal fault activity. According to the environmental survey, it contains some interference factors： first, the wind is big when the leveling measures in the afternoon, which has certain influence on the measurement results, but the impact is random and should be near the base value and not appear a trend. Second, the point BM3 was maintained during Sep. to Oct. in 2012 and occurred cracks in 2013, showing that the poor stability around the point. In addition, the change of recorded program is only to change the way of data record and can not affect the observation results during the same period.
基金supported by the Science and Technology Project of Shanxi Province(20140313023-1)the special earthquake research project of China Earthquake Administration(201208009)+1 种基金Natural Science Foundation of ShanxiChina(2011021024-1)
文摘In this study,under the assumption that the two huge leveling deformation anomalies at Linfen seismic station were caused by the Luoyunshan fault( Tumen-Yuli section)movement, we computed the vertical deformation field distribution based on the rectangular fault dislocation model and measured the ground deformation field of the study area using D-InS AR technology. The results are as follows:( 1) Theoretically,the ground vertical deformation field caused by fault movement could be within the elliptical deformation area with the long axis parallel to the fault strike. The largest deformation region is located in the center of the area in the hanging wall of the fault,and the deformation gradually decreases to zero toward the periphery; the impact range induced by the two deformations is respectively as follows: The long axes are about 18 km and26km,the short axes are about 12 km and 17 km and the obvious deformation amplitude is about 1- 3mm and 4- 14 mm.( 2) The measured deformation field by D-InS AR shows that there is no continuous deformation area consistent with the fault strike,and only the presence of land subsidence possibly caused by groundwater excessive exploitation,with the deformation amplitude about 10- 12 mm and 1- 5mm.( 3) The measured deformation field is not consistent with the theoretical result on deformation area and amplitude,which indicates that the fault movement is not the main cause of Linfen huge leveling deformation,but may rather be because of local deformation of the soil layers in the hanging wall of the fault.( 4) By combining the fault dislocation model simulation with the D-InS AR technology measurement,we can determine effectively the nature of the anomalyof the huge cross-fault leveling deformation,thus provide scientific basis for verification of significant leveling anomalies.
文摘The radioactivity level of the ambient environment of Anren Bone-coal Power Station (BCPS) was investigated systematically. The γ radiation dose rate level in the environment, the content of 238U and 226Ra in the ambient soil and the farmland in the direction of downwind, the concentrations of 238U. 232Th. 226Ra 40K and 222Rn as well as α potential energy in air, and the concentrations of natural U and Th in effluent are all higher than the corresponding values of the reference site. The additional annual effective dose equivalent to the residents living in the houses made of bone-coal cinder brick is 2.7 mSv.
文摘Based on experience of meteorological service at county-level meteorological station in recent 20 years,status quo of decision-making meteorological service,main influence factors of decision-making meteorological service and writing of decision-making meteorological service materials are analyzed,and measures and suggestions of improving decision-making meteorological service level are proposed. The research aims to improve public meteorological service level at grass-roots level,provide scientific decision-making basis for government departments preventing and reducing disaster,and reduce loss of life and property of the country and people caused by meteorological disasters to the maximum extent.
基金Under the auspices of National Natural Science Foundation of China(No.71771049)the Six Talent Peaks Project in Jiangsu Province(No.2016-JY-003)China Scholarship Council(No.201606090149)
文摘This study aims to explore the role of spatial heterogeneity in ridership analysis and examine the relationship between built environment, station attributes and urban rapid transit ridership at the station level.Although spatial heterogeneity has been widely acknowledged in spatial data analysis, it has been rarely considered in travel behavior studies.Four models(three global models-ordinary least squares(OLS), spatial lag model(SLM), spatial error model(SEM) and one local model-geographically weighted regression(GWR) model) are estimated separately to explore the relationship between various independent variables and station ridership, and identify the influence of spatial heterogeneity.Using the data of built environment and station characteristics, the results of diagnostic identify evidence the existence of spatial heterogeneity in station ridership for the metro network in Nanjing, China.Results of comparing the various goodness-of-fit indicators show that, the GWR model yields the best fit of the data, performance followed by the SEM, SLM and OLS model.The results also demonstrate that population, number of lines, number of feeder buses, number of exits, road density and proportion residential area have a significant impact on station ridership.Moreover, the study pays special attention to the spatial variation in the coefficients of the independent variables and their statistical significance.It underlines the importance of taking spatial heterogeneity into account in the station ridership analysis and the decision-making in urban planning.
文摘The Level-2 probabilistic safety assessment(PSA) of pressurized water reactors studies the possibility of creep rupture for major reactor coolant system components during the course of high pressure severe accident sequences. The present paper covers this technical issue and tries to quantify its associated phenomenological uncertainties for the development of Level-2 PSA. A framework is proposed for the formal quantification of uncertainties in the Level-2 PSA model of a PWR type nuclear power plant using an integrated deterministic and PSA approach. This is demonstrated for estimation of creep rupture failure probability in station blackout severe accident of a 2-loop PWR, which is the representative case for high pressure sequences. MELCOR 1.8.6 code is employed here as the deterministic tool for the assessment of physical phenomena in the course of accident. In addition, a MATLAB code is developed for quantification of the probabilistic part by treating the uncertainties through separation of aleatory and epistemic sources of uncertainty.The probability for steam generator tube creep rupture is estimated at 0.17.
文摘In order to study the climate variabilities of the sea level around the Korean Peninsula, tidal data observed at local stations in Korea were compared against those obtained using TOPEX/POSEIDON (T/P) altimetric sea level data. In the course of our study, the amount of sea level rise was estimated using the tidal data from 9 stations selected by an anomaly coherency analysis. The results indicated that the sea level has risen by 0.28 cm yr-1 around the Korean Peninsula over the past two decades. The extent of such a rise is about two times higher than that of the global increase (0.1-0.2 cm yr-1). However, because most global warming effects occurred mainly over mid- and high-latitudes, this level of change appears to be realistic. According to the spectral analysis (at a spectral window of k=2, k is the number of subdivisions), the decadal band of sea level variability is computed at 30% of the energy. Its spectral peak is found at 12.8 years. In the interannual band, the predominant sea level variability is in the 1.4-1.9-year band, with a sharp peak at 1.6 years. A secondary peak, although marginal, has a period of 2.2 years. Based on our estimates of sea level height from Topex/Poseidon, the quasi-biennial periodicity of 1.6 years is the representative interannual sea level variability in the seas adjacent to Korea. Trends vary greatly according to the geographical location, from a maximum of 1.0 cm yr-1 (the southern sector of the East Sea) to a minimum of 0.17 cm yr-1 (the northern sector of the East Sea). This is fairly consistent with the qualitative description already given with reference to the global map. As an analogue to the pattern seen in Korea, that of the Yellow Sea reveals practically the same trend as that of the adjacent seas (0.56 cm yr-1). However, in the case of TOPEX/POSEIDON (T/P) data, there is no clear evidence of a linkage between the interannual sea level variability around the Korean Peninsula and ENSO.
基金supporting from National High Technical Research and Development Program of China (863 program) 2014AA01A705
文摘There are already several power models to estimate the power consumption of base stations at system level. However, there is so far no model that can predict power consumption of the future base station designs based on algorithms and hardware selections with insufficient physical information. We present such an energy model for typical base stations. This model can help designers in estimating, evaluating and optimizing energy/power consumption of candidate designs in early design stages. The proposed model is verified by an LTE extreme scenario. The estimated results show that digital front-end, channel equalization and channel decoding are three major power greedy modules(consuming 39.4%, 16.3%, 13.4%) in a digital baseband subsystem. The power estimation error of the proposed power amplifier(PA) power model is 3.5%(macro cell). The major contribution of this paper is that the proposed models can rapidly estimate energy/power consumption of 4G and the future base stations(such as 5G) in early design stages with well acceptable precision, even without sufficient implementation information.
基金supported by National Basic Research Program of China(973 Program)(2011CB209405)
文摘In order to specify the overvoltage and insulation level of equipments in ±1 100 kV UHVDC converter stations,the arrester configuration scheme and some basic parameters for ±1 100 kV Zhundong converter station are proposed.Overvoltage of equipments in AC system,valve hall,DC busbar,and neutral busbar are also calculated in accordance with the fundamental principles of arrester configuration for UHV converter stations and the existing experiences in insulation coordination of ±800 kV UHVDC converter stations.The work is done also for specifing insulation levels for ±1 100 kV UHVDC converter stations of the ±1 100 kV UHVDC power transmission project from Zhundong to Sichuan in China.Thus,the recommended insulation margins that determine the insulation levels of converter station equipments are proposed: the insulation margins for thyristor valves are 10%/10%/15% for switching impulse/ lightning impulse/ steer front impulse; the insulation levels of lighting and swtiching impulses are recommended as 2 600 kV and 2 150 kV respectively for 1 100 kV DC buses,and as 2 250 kV and 2 100 kV respectively for equipments at the valve side of high-voltage Y/Y converter transformers.
