Mathanker S.K.,Fujian Electric Power Company |
Hansen A.C.,University of Illinois at Urbana - Champaign
Applied Engineering in Agriculture | Year: 2014
Previous studies have shown that cutting speed and blade configurations play a critical role in crop harvesting. This study investigated the effect of cutting speed, blade oblique angle, and blade mounting in a field setting. To investigate their effect on Miscanthus harvesting power consumption, a hydraulically-driven single disk cutter head platform was developed. It has the provisions to adjust cutting parameters and was instrumented to measure the bending force on a push bar, torque, and cutting speed of the disk cutter. The cutting energy was determined at three oblique angles (0°, 30°, 40°), two blade mountings (fixed, flexible), and three hydraulic flow settings to drive the developed platform. Three hydraulic flow settings were used that resulted in average recorded cutting speeds of 31.5, 47.3, and 63.0 m s-1. The differences between the blade mountings were found to be negligible. A 40° oblique angle operating at 31.5 m s-1 had the lowest energy consumption, averaging 9.1 MJ ha-1. Similarly, a 30° oblique angle consumed 16.9 MJ ha-1 and a straight blade consumed 23.1 MJ ha-1. The results indicate that the cutting speed and blade oblique angle are directly related to the power requirements and efficiency of Miscanthus harvesting machinery. Information about the bending force of the Miscanthus was also collected and compared to the energy consumption of the machine. The data show that the energy consumption was correlated to the bending force. It is expected that the results of this study would help in modifying existing Miscanthus harvesters. © 2014 American Society of Agricultural and Biological Engineers.
Chen L.-J.,Fuzhou University |
Dai Z.-H.,Fuzhou University |
Liu Z.-W.,Fujian Electric Power Company
Yantu Lixue/Rock and Soil Mechanics | Year: 2011
A series of stress path tests on typical soft soils (silt and organic silty clay) in the influence range of foundation pit in Fuzhou city were conducted by using triaxial apparatus with stress and strain control in order to research the stress-strain behaviours of unloading and loading caused by excavation and retaining structure of foundation pit. Compared with the results of triaxial tests between normal consolidation and K0 consolidation samples in the same confining pressure, it is indicated that there are large differences in deformation and strength. Based on the results of K0consolidated triaxial tests, Duncan-Chang parameters were figured out and the methods of certification of each parameter in the model were put forward. At the same time, comparison with model parameters obtained by normal consolidation samples showed that some parameters had significant difference; and they decided the difference of stress-strain relationship. Duncan-Chang model parameters were suggested to obtained through triaxial loading and unloading test by K0 consolidation samples for the sake of satisfying numerical simulation analysis of foundation pit engineering. Duncan-Chang parameters of typical soft soils offered by the tests can be referred to numerical simulation of foundation pit engineering in Fuzhou city or other similar strata sites.
Xu L.,Fujian Electric Power Company |
Xu L.,Tsinghua University |
Su J.,Tsinghua University
Energy Policy | Year: 2016
This paper proposes a new typology that classifies innovation policy instruments into two dimensions: government-selection versus market-selection, and producer-orientation versus consumer-orientation. Such a typology articulates the importance of consumer behavior in the policy design for a transition, and the relevance for the market to select target subjects of policy during the deployment stage of clean technology innovation. We apply this typology to policy instruments of China's new energy vehicle (NEV) industry between 1991 and 2015 in order to explain the industry's rapid growth. The focus of China's policy mix has transited from government-selection to market-selection, and from producer-orientation to consumer-orientation. Other than the new typology, this paper traces the entire history of policy transition within China's NEV industry, and finds the transition to be a result of policy learning, thus contributing to future empirical studies of this industry. © 2016 Elsevier Ltd.
Zeng H.,Fuzhou Extra High Voltage Power Transmission and Substation Bureau of Fujian Electrical Power Co. |
Lin F.,Fujian Electric Power Company
Dianli Zidonghua Shebei/Electric Power Automation Equipment | Year: 2011
A fault locating algorithm based on phase characteristics is proposed for the hybrid transmission line, which defines a new fault locating function. The phase of fault locating function changes abruptly at the fault point only once when the location of reference point changes from its left side to its right side, which can be used to quickly locate the fault point. Without identifying the faulty section, the hybrid transmission line is equalized a line with the same length for fault locating. The proposed fault locating algorithm has no dead zone and is nearly immune to transition resistance, fault type, sampling frequency, fault position and load current, which are verified by PSCAD simulation.
Zeng H.,Fujian Electric Power Company |
Lin F.,Fujian Electric Power Company |
Kang X.,Fujian Electric Power Company
Dianwang Jishu/Power System Technology | Year: 2014
Utilizing distributed parameter modeling the voltage at fault point is calculated in real time by voltage and current measured at the installation position of distance protection, and according to the relation of hyperbolic tangent function between the voltage drop from installation position of the protection to the fault point and the fault distance the impedance of faulty line is solved. This protection method is suitable to the protection for single-phase earth fault protection and the distance protection for phase-to-phase fault. In the algorithm design of the proposed protection method the voltage at fault point is taken into account, thus the affects of load current and transition resistance on protection performance are eliminated in principle, so the proposed protection method possesses better protection performance than traditional protection, and the effective identification of short-circuit faults under low-, medium- or high-resistance can be implemented. The correctness and validity of the proposed method are proved by results of EMTDC simulation and the recorded field test data.
Yan Y.,South China University of Technology |
Wen F.,Zhejiang University |
Yang S.,Fujian Electric Power Company |
Macgill I.,University of New South Wales
Dianli Xitong Zidonghua/Automation of Electric Power Systems | Year: 2010
A stochastic optimization approach is proposed for the unit commitment problem with the uncertainty of wind power generation taken into account, based on mixed-integer linear programming (MILP). The problem is formulated to minimize the total operation cost of thermal units. In considering wind power generation, scenarios are generated by auto-regressive and moving average (ARMA) time series model and Latin hypercube sampling (LHS) method and the stochastic optimization problem is then transformed to a deterministic one. A large number of scenarios lead to computing complexity, scenario reduction technology is introduced to decrease scenario number in order to reduce computing cost. The proposed formulation is tested on a 10-unit system and a 100-unit system. Simulation results show that the varying wind power generally leads to the increase of total cost. In addition, the ramping rates of non-wind generators and the prediction precision of wind power are significant in making generation scheduling with volatile wind power generation. Moreover, the system operation cost decreases significantly if wind power is considered as a spinning reserve resource. ©2010 State Grid Electric Power Research Institute Press.
Liu S.,Fujian Electric Power Company |
Narentuya,China University of Geosciences |
Xia B.,Beijing University of Technology |
Chu G.,CAS Institute of Geology and Geophysics |
Tian M.,China University of Geosciences
Quaternary Geochronology | Year: 2012
Dating the desert lake sediments using 210Pb uns and 137Cs methods is challenging because of the low atmospheric fluxes and the unexpected irregular variations in the specific activity profiles. Due to the large numbers of permanent lakes in the Badain Jaran Desert, they provide abundant sites for investigating the desert 210Pb uns and 137Cs geochronology. Research was performed to determine the reliable ages using this methodology and obtain a better understanding of the principal factors that affect the dating results. The top 20-30 cm of core SH-1 from Lake Shuanghaizi and of core YD-1 from Lake Yindeertu in Badain Jaran Desert were dated. The results support multiple conclusions. (1) Both cores have low surficial 210Pb uns activities (SH-1, 24.5 Bq kg -1; YD-1, 59.7 Bq kg -1) compared with those of the cores from arid Northwest China, such as Lake Bosten (350 Bq kg -1) and Lake Wulungu (523.37 Bq kg -1) from Xinjiang. Although the 210Pb record in SH-1 has multiple irregular variations with depth, the exponential decrease in the YD-1 activity profiles appears fairly regular. (2) The 210Pb uns activities are highly correlated with the sample salt concentration (SSC). (3) Sediment dates for core SH-1 derived from the constant rate of 210Pb supply (CRS) model indicate that it spans a period of 65 years (1942 AD-2007 AD) with an average sedimentation rate of 0.21 cm a -1 (0.16 g cm -2 a -1). Sediment dates for core YD-1 derived from the corrected CRS model indicate that it spans a period of 121 years old (1889 AD-2010 AD) with an average sedimentation rate of 0.16 cm a -1 (0.12 g cm -2 a -1). In both cores, the 137Cs time markers of 1963 appeared at different depths, which may result from the differing sedimentation rates at the sites of the cores. The sedimentation rates calculated from the CRS-determined age differences between the SH-1 and YD-1 cores appear to have resulted from the topographies containing various mega-dunes and regional aeolian activity patterns. We believe that the low 210Pb flux and the unexpected fluctuations in the 210Pb profiles are the principal factors affecting our dating results. The low 210Pb uns activities were caused by infrequent rainfall and mega-dune barriers. The unexpected fluctuations in the 210Pb uns profiles resulted from the salt crystallisation that occurred via deposition or post-sedimentation. The salt crystallisation has been closely associated with abrupt regional climate changes, including rainfall, temperature and serious drought events during the 1950s-1970s. © 2012 Elsevier B.V.
Ma J.,North China Electrical Power University |
Zeng H.-M.,Fujian Electric Power Company |
Lin X.-H.,Fujian Electric Power Company
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | Year: 2012
Using distributed parameter model, a new backup protection for multi-terminal high voltage transmission lines system is proposed based on wide area information. The backup protection consists of a new principle of wide area current differential protection and an algorithm of fault branch selection. In a distributed parameter circuit under normal operation, the algebraic sum of current flow-in and flow-out of the reference point selected in the multi-terminal high voltage transmission system is zero, while in case of fault occurring, the fault current can be reflected accurately by the differential variable of the reference point. Using this character, the wide area current differential protection can detect the fault within the protective zone. Based on the root distribution features of the fault-branch-selection equation, the fault branch selection algorithm is able to select the fault branch and locate the fault position. Calculated and analyzed by the wide area backup protection server, if a fault happens in the protective zone, the master station sends control command to the tripping device of fault line via communication net. The tripping device trips off the breakers of the fault line after receiving the trip-off command, isolating the fault from the system. Simulation test verifies the correctness and effectiveness of this backup protection algorithm.
Song D.,China University of Mining and Technology |
Song D.,Fujian Electric Power Company |
Wang E.,China University of Mining and Technology |
Liu Z.,China University of Mining and Technology |
And 2 more authors.
International Journal of Rock Mechanics and Mining Sciences | Year: 2014
The applications in coal mine rock burst prevention using water jet cutting technology (WJCT) have progressed slowly. In this paper we analyzed the possibility and reasonableness of WJCT application to rock burst relief and prevention, used the ABAQUS software to simulate the distributive characteristics of stress and energy fields suffered by hard coal roadway wallrock and the internal relationships of the fields to the instability due to WJC on roadway wallrock, and conducted field WJCT tests using electromagnetic radiation (EMR) measurement technology. The results showed that WJCT can unload rock burst effectively by inducing stress release and energy dissipation in coal mass near its cut slots; its annular slots also can decrease rock burst risks through blocking or weakening stress and energy transfer in coal mass. The horizontal radial slots and annular vertical slots may cause "the beam structure" and "the small pillar skeleton", and "the layered energy reservoir structure", respectively, which lead to an increase in stress concentration and energy accumulation in coal element mass near the slots. The reasonable design and optimization of slots[U+05F3] positions and their combination not only can significantly reduce the scope of stress concentration and energy accumulation, but also can destroy coal mass structure on a larger scale to force stress to transfer deeper coal mass, eventually avoiding high intensity and large-scale rock bursts. The field tests of WJC for pressure relief using EMR verified the above conclusions. © 2014 Elsevier Ltd.
Lu L.,Zhejiang University |
Wen F.,Zhejiang University |
Xue Y.,NARI Group |
Kang J.,Fujian Electric Power Company
Dianli Xitong Zidonghua/Automation of Electric Power Systems | Year: 2013
Reasonably controlling or dispatching the charging and discharging behaviors of aggregated electric vehicles (PEVs) can provide ancillary services for a power system, and hence improve the security and economics of the system. Based on the driving pattern statistic data from the New Jersey region in USA, an economic analysis model is developed for an agent/aggregator of PEVs in providing regulation and spinning reserve services for the power system concerned, considering the optimal control of the PEVs' charging and discharging. An optimization model is developed to maximize the agent's profit while respecting relevant constraints. The revenue of the agent consists of the incomes from the regulation and spinning reserve markets, as well as the allowances for mitigating emissions, while the cost includes the battery depreciation cost and charging cost. The developed model is demonstrated with actual data from the New York Independent System Operator (NYISO) with 5 000 PEVs specified, and the economic analysis result shows that the agent of PEVs can make profits by providing regulation and spinning reserve services in the electricity environment. © 2013 State Grid Electric Power Research Institute Press.