Simuliranje i upravljačka strategija 5.6 kV 17-razniskog STATCOM sustava uz SVG uvjet

To achieve high-voltage reactive power compensation, a 5.6kV 17-level STATCOM under SVG Condition is presented. In this paper, we use a cascaded H-bridge multilevel star-connection converter whose system structure and circuit schematic are described. Then by using the phase-shifted carrier modulation strategy and the active-reactive current decoupling method, the STATCOM performs quite well. Moreover modulation strategy of the 17-level STATCOM based on the active disturbance rejection control (ADRC) is presented and the analytical formulas are described. For implementation, control strategy for DC bus voltage balance in cascaded H-bridge multilevel converters, time average distribution method and extreme value offset method are applied in our design. Finally, simulation results demonstrate that the proposed 17-level STATCOM is capable of reactive power compensation, simultaneous controlling and balancing the DC side voltages during the work and verify that high-voltage reactive power can be accurately and effectively compensated.Za postizanje kompenzacije jalove snage uz visoki napon, predstavljen je STATCOM s 5.6 kV i 17-razina uz SVG uvjet. U ovom radu koristimo kaskadni višerazinski H-mosni pretvarač u zvijezda spoju uz opisane strukturu i shemu spoja. Zatim korištenjem strategije modulacije s fazno-pomaknutim signalom nosioca i metode rasprezanja radno-jalove struje, STATCOM pokazuje prilično dobro vladanje. Uz to, prikazana je strategija modulacije 17-razinskog STATCOM-a zasnovana na upravljanju s aktivnim odbacivanjem smetnji (ADRC) te su opisane analitičke formule. Za implementaciju, u naš dizajn primjenjene su upravljačka strategija balansiranja napona DC sabirnice u kaskadnom višerazinskom H-mosnom pretvaraču te metoda vremenskog uprosječavanja razdiobe i metoda ekstremne vrijednosti pomaka. Konačno, simulacijski rezultati pokazuju da je predloženi 17-razinski STATCOM sposoban za kompenzaciju jalove snage, istovremeno upravljanje i balansiranje napona DC strane u radu te potvrđuju da je jalovu snagu uz visoki napon moguće točno i djelotvorno kompenzirati

Discrepancies of video head impulse test results in patients with idiopathic sudden sensorineural hearing loss with vertigo and vestibular neuritis

ObjectiveSudden sensorineural hearing loss with vertigo (SHLV) and vestibular neuritis (VN) remain frequent causes of acute vestibular syndrome (AVS). The aim of study was to compare the results of video head impulse test (vHIT) in patients with SHLV and VN. The characteristics of high-frequency vestibule-ocular reflex (VOR) and the differences of the pathophysiological mechanisms underlying these two AVS were explored.MethodsFifty-seven SHLV patients and 31 VN patients were enrolled. vHIT was conducted at the initial presentation. The VOR gains and occurrence of corrective saccades (CSs) of anterior, horizontal, and posterior semicircular canals (SCCs) in two groups were analyzed. Pathological vHIT results refer to impaired VOR gains and presence of CSs.ResultsIn SHLV group, pathological vHIT results was most prevalent in the posterior SCC on the affected side (30/57, 52.63%), followed by horizontal (12/57, 21.05%) and anterior SCC (3/57, 5.26%). In VN group, pathological vHIT preferentially affected horizontal SCC (24/31, 77.42%), followed by anterior (10/31, 32.26%) and posterior SCC (9/31, 29.03%) on the affected side. As for anterior and horizontal SCC on the affected side, the incidences of pathological vHIT results in VN group were significantly higher than those in SHLV group (β = 2.905, p < 0.01; β = 2.183, p < 0.001). There were no significant differences in the incidence of pathological vHIT result in posterior SCC between two groups.ConclusionComparison of vHIT results in patients with SHLV and VN revealed discrepancies in the pattern of SCCs impairments, which may be explained by different pathophysiological mechanisms underlying these two vestibular disorders presenting as AVS

Research on drain and counter-clogging ability of porous asphalt mixture

Porous asphalts pavement arouses the attentions of the world by its good performance such as reduce the potential for hydroplaning, reduce splash and spray, improve visibility, decline traffic noise, and improve driving safety. But the void clogging lessens its durable function. So in this paper appropriate clogging agent was choose, and seepage coefficients were tested by using asphalt mixture pavement surface permeameter to simulation multi-cycle drainage clogging test. The influence of asphalt mixture design parameter such as the porosity, the maximum sizes of the aggregate, gradation and asphalt on the drainage and counter-clogging ability of porous asphalts was researched. The tests indicated that the porosity has an obvious influence on both porous asphalts’ permeable ability and counter-clogging ability. Comparing the specimen of 21% void to the ones of 16% void, the drain ability is improved 49.8%, the counter-clogging ability is improved 55.0%. The maximum sizes of the aggregate has an obvious influence on porous asphalts’ counter-clogging ability, but no an obvious influence on the drain ability. Comparing the specimen of 16mm to the 13mm, the counterclogging ability is proved 48%. PAC with the coarser graduation has a better performance on drain and counter-clogging ability. TPS modifier changes PAC little on drain and counter-clogging ability

Transportation in Developing Countries: Greenhouse Gas Scenarios for Shanghai, China

The transportation sector is a leading source of greenhouse gas (GHG) emissions worldwide, and one of the most difficult to control. In developing countries, where vehicle ownership rates are considerably below the OECD average, transport sector emissions are poised to soar as income levels rise. This is especially true for China, whose imminent accession to the World Trade Organization will contribute to economic growth and could make consumer credit widely available for the first time. These factors are likely to accelerate automobile purchases, and GHG emissions.Shanghai is one of China's most dynamic cities. Extremely densely populated, with very low personal vehicle ownership rates for its income level, Shanghai is also home to a nascent Chinese automotive industry. Transportation plans and policies there are designed to achieve broader urban objectives of population decentralization, with an eye to controlling increases in traffic congestion and improving environmental quality. Because Shanghai's transportation system and planning process are so sophisticated, Shanghai may be a "best case" for controlling transportation sector GHG emissions in the absence of climate change mitigation goals.This report creates two scenarios of GHG emissions from Shanghai's transportation sector in 2020. It finds:•Greenhouse gas emissions quadruple in the low-GHG scenario; they increase sevenfold in the high scenario. On a passenger-kilometer basis, the estimated increase ranges from 10 to 100 percent.•Providing an array of high-quality options to travelers can help meet the demand for transportation services while keeping traffic congestion in check and meeting other urban objectives.•Special lanes and other infrastructure to accommodate vehicles such as buses, minicars, and bicycles can save money and improve traffic circulation.•Using clean technology and fuels in motorized vehicles lowers the environmental impact of various transportation modes.•Perfecting the use of "intelligent" traffic control systems through improved coordination will yield higher returns on capital investments

Traffic Emission Pollution Sampling and Analysis on Urban Streets with High-Rising Buildings

Air pollution at many types of intersections and other roadside “hot spots” is not accurately characterized by state-of-the-practice models. In this study, data were collected on traffic flows, second-by-second CO and NO2 ambient concentrations in Shanghai, China. The sampled data were compared with CAL3QHC modeling results. We found that: (1) intersection hot spot emission concentrations were explained primarily by queuing activities of motor vehicles; (2) air quality concentrations are difficult to predict because of complex dispersion processes near high-rise buildings; and (3) screening models such as CAL3QHC are prone to large errors in dense cities with mixed traffic and high-rising buildings. Suggestions are made for improved models relevant to dense developing cities

Transportation in Developing Countries: Greenhouse Gas Scenarios for Shanghai, China

The transportation sector is a leading source of greenhouse gas (GHG) emissions worldwide, and one of the most difficult to control. In developing countries, where vehicle ownership rates are considerably below the OECD average, transport sector emissions are poised to soar as income levels rise. This is especially true for China, whose imminent accession to the World Trade Organization will contribute to economic growth and could make consumer credit widely available for the first time. These factors are likely to accelerate automobile purchases, and GHG emissions.Shanghai is one of China's most dynamic cities. Extremely densely populated, with very low personal vehicle ownership rates for its income level, Shanghai is also home to a nascent Chinese automotive industry. Transportation plans and policies there are designed to achieve broader urban objectives of population decentralization, with an eye to controlling increases in traffic congestion and improving environmental quality. Because Shanghai's transportation system and planning process are so sophisticated, Shanghai may be a "best case" for controlling transportation sector GHG emissions in the absence of climate change mitigation goals.This report creates two scenarios of GHG emissions from Shanghai's transportation sector in 2020. It finds:•Greenhouse gas emissions quadruple in the low-GHG scenario; they increase sevenfold in the high scenario. On a passenger-kilometer basis, the estimated increase ranges from 10 to 100 percent.•Providing an array of high-quality options to travelers can help meet the demand for transportation services while keeping traffic congestion in check and meeting other urban objectives.•Special lanes and other infrastructure to accommodate vehicles such as buses, minicars, and bicycles can save money and improve traffic circulation.•Using clean technology and fuels in motorized vehicles lowers the environmental impact of various transportation modes.•Perfecting the use of "intelligent" traffic control systems through improved coordination will yield higher returns on capital investments

Traffic Emission Pollution Sampling and Analysis on Urban Streets with High-Rising Buildings

Air pollution at many types of intersections and other roadside “hot spots†is not accurately characterized by state-of-the-practice models. In this study, data were collected on traffic flows, second-by-second CO and NO2 ambient concentrations in Shanghai, China. The sampled data were compared with CAL3QHC modeling results. We found that: (1) intersection hot spot emission concentrations were explained primarily by queuing activities of motor vehicles; (2) air quality concentrations are difficult to predict because of complex dispersion processes near high-rise buildings; and (3) screening models such as CAL3QHC are prone to large errors in dense cities with mixed traffic and high-rising buildings. Suggestions are made for improved models relevant to dense developing cities.traffic, emission, pollution, high-rise, buildings

Transportation in Developing Countries: Greenhouse Gas Scenarios for Shanghai, China

The transportation sector is a leading source of greenhouse gas (GHG) emissions worldwide, and one of the most difficult to control. In developing countries, where vehicle ownership rates are considerably below the OECD average, transport sector emissions are poised to soar as income levels rise. This is especially true for China, whose imminent accession to the World Trade Organization will contribute to economic growth and could make consumer credit widely available for the first time. These factors are likely to accelerate automobile purchases, and GHG emissions. Shanghai is one of China's most dynamic cities. Extremely densely populated, with very low personal vehicle ownership rates for its income level, Shanghai is also home to a nascent Chinese automotive industry. Transportation plans and policies there are designed to achieve broader urban objectives of population decentralization, with an eye to controlling increases in traffic congestion and improving environmental quality. Because Shanghai's transportation system and planning process are so sophisticated, Shanghai may be a "best case" for controlling transportation sector GHG emissions in the absence of climate change mitigation goals. This report creates two scenarios of GHG emissions from Shanghai's transportation sector in 2020. It finds: •Greenhouse gas emissions quadruple in the low-GHG scenario; they increase sevenfold in the high scenario. On a passenger-kilometer basis, the estimated increase ranges from 10 to 100 percent. •Providing an array of high-quality options to travelers can help meet the demand for transportation services while keeping traffic congestion in check and meeting other urban objectives. •Special lanes and other infrastructure to accommodate vehicles such as buses, minicars, and bicycles can save money and improve traffic circulation. •Using clean technology and fuels in motorized vehicles lowers the environmental impact of various transportation modes. •Perfecting the use of "intelligent" traffic control systems through improved coordination will yield higher returns on capital investments.greenhouse, gas, china, shanghai