Records Added in March 2019
Records added in March 2019
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Showing records 1 to 25 of 37. [First] Page: 1 2 Last
Finding better limit cycles of semicontinuous distillation
Pranav Bhaswanth Madabhushi, Thomas Adams II
March 22, 2019 (v1)
There are three different ways of operating the distillation process based on production requirements and operational flexibility. Semicontinuous distillation of multicomponent mixtures is a cost-effective technology in the intermediate production range when compared with traditional batch and continuous distillation processes. The process, which has both continuous and discrete dynamics, operates in a limit cycle (an isolated periodic orbit). Design of this process entails finding the system’s time-invariant parameters, for example, equipment design parameters, reflux rate etc., to operate in a limit cycle having acceptable performance. In semicontinuous distillation studies, the performance metric chosen is the separation cost, which is defined as the total annualized cost-per-production. The state-of-the-art design procedure involves determining an initial state for estimating the limit cycle through the dynamic simulation of the process and is found to be effective. However, it lac... [more]
Optimization of Reducing Sugar Production from Manihot glaziovii Starch Using Response Surface Methodology
Abdi Hanra Sebayang, Masjuki Haji Hassan, Hwai Chyuan Ong, Surya Dharma, Arridina Susan Silitonga, Fitranto Kusumo, Teuku Meurah Indra Mahlia, Aditiya Harjon Bahar
March 26, 2019 (v1)
Subject: Biosystems
Keywords: alternative fuel, bioethanol, Fermentation, hydrolysis, Manihot glaziovii (M. glaziovii), Optimization
Bioethanol is known as a viable alternative fuel to solve both energy and environmental crises. This study used response surface methodology based on the Box-Behnken experimental design to obtain the optimum conditions for and quality of bioethanol production. Enzymatic hydrolysis optimization was performed with selected hydrolysis parameters, including substrate loading, stroke speed, α-amylase concentration and amyloglucosidase concentration. From the experiment, the resulting optimum conditions are 23.88% (w/v) substrate loading, 109.43 U/g α-amylase concentration, 65.44 U/mL amyloglucosidase concentration and 74.87 rpm stroke speed, which yielded 196.23 g/L reducing sugar. The fermentation process was also carried out, with a production value of 0.45 g ethanol/g reducing sugar, which is equivalent to 88.61% of ethanol yield after fermentation by using Saccharomyces cerevisiae (S. cerevisiae). The physical and chemical properties of the produced ethanol are within the specifications... [more]
Prognosis of the Remaining Useful Life of Bearings in a Wind Turbine Gearbox
Wei Teng, Xiaolong Zhang, Yibing Liu, Andrew Kusiak, Zhiyong Ma
March 26, 2019 (v1)
Keywords: bearing in gearbox, prognostic, remaining useful life (RUL), wind turbine
Predicting the remaining useful life (RUL) of critical subassemblies can provide an advanced maintenance strategy for wind turbines installed in remote regions. This paper proposes a novel prognostic approach to predict the RUL of bearings in a wind turbine gearbox. An artificial neural network (NN) is used to train data-driven models and to predict short-term tendencies of feature series. By combining the predicted and training features, a polynomial curve reflecting the long-term degradation process of bearings is fitted. Through solving the intersection between the fitted curve and the pre-defined threshold, the RUL can be deduced. The presented approach is validated by an operating wind turbine with a faulty bearing in the gearbox.
Lobatto-Milstein Numerical Method in Application of Uncertainty Investment of Solar Power Projects
Mahmoud A. Eissa, Boping Tian
March 26, 2019 (v1)
Keywords: Egypt, numerical simulation, real option, Renewable and Sustainable Energy, stochastic differential equation
Recently, there has been a growing interest in the production of electricity from renewable energy sources (RES). The RES investment is characterized by uncertainty, which is long-term, costly and depends on feed-in tariff and support schemes. In this paper, we address the real option valuation (ROV) of a solar power plant investment. The real option framework is investigated. This framework considers the renewable certificate price and, further, the cost of delay between establishing and operating the solar power plant. The optimal time of launching the project and assessing the value of the deferred option are discussed. The new three-stage numerical methods are constructed, the Lobatto3C-Milstein (L3CM) methods. The numerical methods are integrated with the concept of Black⁻Scholes option pricing theory and applied in option valuation for solar energy investment with uncertainty. The numerical results of the L3CM, finite difference and Monte Carlo methods are compared to show the ef... [more]
Analysis on Filling Ratio and Shield Supporting Pressure for Overburden Movement Control in Coal Mining with Compacted Backfilling
Yanli Huang, Junmeng Li, Tianqi Song, Guoqiang Kong, Meng Li
March 26, 2019 (v1)
Keywords: coal mining with compacted backfilling (CMCB), elastic-thin-plate mechanical model, filling ratio, numerical simulation, overburden movement, shield supporting pressure
Since the weight of overburden is sustained by both the backfill body and the unmined solid coal in coal mining with compacted backfilling (CMCB) panels, the stress and deformation characteristics of the surrounding rocks in coal mining are radically changed. The overburden movement control mechanism by coordinating with backfill body and shield in CMCB was studied systematically in this paper. Based on the analysis of deformational and structural characteristics of surrounding rock in CMCB panels, the methods of theoretical analysis, numerical simulation and engineering test are employed. The results show that the fracture of the main roof is mainly controlled by the filling ratio φ and is non-correlated to the shield supporting pressure p. However, p has a significant control effect on the deflection of roof within the shield canopy length, and adversely affects the filling ratio. With the increase of the filling ratio of the gob, the maximum sagging of the immediate and the main roo... [more]
Experimental Study on Specific Heat of Concrete at High Temperatures and Its Influence on Thermal Energy Storage
Jianwen Pan, Renxin Zou, Feng Jin
March 26, 2019 (v1)
Subject: Materials
Keywords: concrete, high temperature, specific heat, thermal energy storage
Using concrete as a thermal energy storage (TES) material is a promising option for large-scale solar-thermal resource development and utilization. Specific heat is one of the most important characteristics for TES performance. In this paper, the half-open dynamic method based on the mixing principle is proposed and applied to measure concrete-specific heat at temperatures up to 600 °C. Measurement of the specific heat of corundum ceramic (99% Al₂O₃) is first performed, and the test results illustrate the accuracy and efficiency of the proposed test method. Furthermore, concrete-specific heat tests are carried out at high temperatures. It found that the specific heat increases as the temperature rises, especially, linearly in the range of 300⁻600 °C, in which the concrete TES module is expected to be in operation. Finally, the effect of concrete-specific heat changes with temperature on its TES capacity is investigated, demonstrating that specific heat is of great significance for conc... [more]
Power Control of Low Frequency AC Transmission Systems Using Cycloconverters with Virtual Synchronous Generator Control
Achara Pichetjamroen, Toshifumi Ise
March 26, 2019 (v1)
Keywords: cycloconverters, low frequency AC transmission system (LFAC), multi-terminal, power control, virtual synchronous generator (VSG)
This paper is focused on the application of a multi-terminal line-commutated converter-type low frequency AC transmission system (MTLF) using a cycloconverter by applying a new power control scheme for multi-terminal operation. With the virtual synchronous generator (VSG) control scheme, the transmitting power among the multi-terminal system can be accomplished without a communication link for frequency synchronization in each terminal. The details of the proposed control scheme are explained in order to understand the advantages of this method. The configuration of a two-phase low frequency AC transmission system (LFAC) is adopted to examine with the proposed control scheme. Simulation results are provided to illustrate the proposed control scheme with respect to the LFAC system’s performance.
Bioenergy from Low-Intensity Agricultural Systems: An Energy Efficiency Analysis
Oludunsin Arodudu, Katharina Helming, Hubert Wiggering, Alexey Voinov
March 26, 2019 (v1)
Subject: Biosystems
Keywords: bioenergy, biofuel, Energy Efficiency, EROEI, high-intensity industrialized agricultural production systems, low-intensity eco-agricultural production systems, NEG
In light of possible future restrictions on the use of fossil fuel, due to climate change obligations and continuous depletion of global fossil fuel reserves, the search for alternative renewable energy sources is expected to be an issue of great concern for policy stakeholders. This study assessed the feasibility of bioenergy production under relatively low-intensity conservative, eco-agricultural settings (as opposed to those produced under high-intensity, fossil fuel based industrialized agriculture). Estimates of the net energy gain (NEG) and the energy return on energy invested (EROEI) obtained from a life cycle inventory of the energy inputs and outputs involved reveal that the energy efficiency of bioenergy produced in low-intensity eco-agricultural systems could be as much as much as 448.5⁻488.3 GJ·ha−1 of NEG and an EROEI of 5.4⁻5.9 for maize ethanol production systems, and as much as 155.0⁻283.9 GJ·ha−1 of NEG and an EROEI of 14.7⁻22.4 for maize biogas production systems. Thi... [more]
Real-Time Velocity Optimization to Minimize Energy Use in Passenger Vehicles
Thomas Levermore, M. Necip Sahinkaya, Yahya Zweiri, Ben Neaves
March 26, 2019 (v1)
Keywords: dynamic programming, fuel, fuel consumption, Optimization
Energy use in internal combustion engine passenger vehicles contributes directly to CO 2 emissions and fuel consumption, as well as producing a number of air pollutants. Optimizing the vehicle velocity by utilising upcoming road information is an opportunity to minimize vehicle energy use without requiring mechanical design changes. Dynamic programming is capable of such an optimization task and is shown in simulation to produce fuel savings, on average 12%, compared to real driving data; however, in this paper it is also applied in real time on a Raspberry Pi, a low cost miniature computer, in situ in a vehicle. A test drive was undertaken with driver feedback being provided by a dynamic programming algorithm, and the results are compared to a simulated intelligent cruise control system that can follow the algorithm results precisely. An 8% reduction in fuel with no loss in time is reported compared to the test driver.
Multi-Agent System Fault Protection with Topology Identification in Microgrids
Stephanus Antonius Ananda, Jyh-Cherng Gu, Ming-Ta Yang, Jing-Min Wang, Jun-Da Chen, Yung-Ruei Chang, Yih-Der Lee, Chen-Min Chan, Chia-Hao Hsu
March 26, 2019 (v1)
Keywords: distributed energy resources, impedance matrix, microgrid, multi-agent system, topology identification bus
Data acquisition and supervisory control are usually performed using client-server architecture and centralized control in conventional power systems. However, the message transmission and fault clearing are too slow for large-scale complex power systems. Microgrid systems have various types of distributed energy resources (DERs) which are quite different in characteristics and capacities, thus, the client-server architecture and centralized control are inadequate to control and operate in microgrids. Based on MATLAB/Simulink (ver.R2012a) simulation software and Java Agent Development Framework (JADE) (JADE 4.1.1-revision 6532), this paper proposes a novel fault protection technology that used multi-agent system (MAS) to perform fault detection, fault isolation and service restoration in microgrids. A new topology identification method using the YBus Matrix Algorithm is presented to successfully recognize the network configurations. The identification technology can respond to microgri... [more]
Balanced Current Control Strategy for Current Source Rectifier Stage of Indirect Matrix Converter under Unbalanced Grid Voltage Conditions
Yeongsu Bak, June-Seok Lee, Kyo-Beum Lee
March 26, 2019 (v1)
Keywords: indirect matrix converter (IMC), negative phase-sequence component, positive phase-sequence component, unbalanced voltage
This paper proposes a balanced current control strategy for the current source rectifier (CSR) stage of an indirect matrix converter (IMC) under unbalanced grid voltage conditions. If the three-phase grid connected to the voltage source inverter (VSI) of the IMC has unbalanced voltage conditions, it affects the currents of the CSR stage and VSI stage, and the currents are distorted. Above all, the distorted currents of the CSR stage cause instability in the overall system, which can affect the life span of the system. Therefore, in this paper, a control strategy for balanced currents in the CSR stage is proposed. To achieve balanced currents in the CSR stage, the VSI stage should receive DC power without ripple components from the CSR stage. This is implemented by controlling the currents in the VSI stage. Therefore, the proposed control strategy decouples the positive and negative phase-sequence components existing in the unbalanced voltages and currents of the VSI stage. Using the pr... [more]
Experimental and Numerical Study of the Radiant Induction-Unit and the Induction Radiant Air-Conditioning System
Qiang Si, Xiaosong Zhang
March 26, 2019 (v1)
Keywords: air-conditioning system, experimental validation, induction ventilation, modeling method, radiation
In this paper we proposed the novel air-conditioning system which combined induction ventilation and radiant air-conditioning. The indoor terminal device is the radiant induction-unit (RIDU). The RIDU is the induction unit combined with the pore radiant panel on which the copper pipes with rigid aluminum diffusion fins are installed. The two-stage evaporator chiller with the non-azeotropic mixture refrigerant is utilized in the system to reduce the initial investment in equipment. With the performance test and the steady state heat transfer model based on the theory of radiative heat transfer, the relationship between the induction ratio of the RIDU and the characteristic of the air supply was studied. Based on this, it is verified that the RIDU has a lower dew-point temperature and better anti-condensation performance than a traditional plate-type radiant panel. The characteristics of the radiation and convection heat transfer of the RIDU were studied. The total heat exchange of the R... [more]
Analysis of Micronized Charcoal for Use in a Liquid Fuel Slurry
John M. Long, Michael D. Boyette
March 26, 2019 (v1)
Subject: Biosystems
Keywords: biochar, biofuel, Biomass, charcoal, Diesel, slurry
Yellow poplar (Liriodendron tulipifera) was chosen as the woody biomass for the production of charcoal for use in a liquid fuel slurry. Charcoal produced from this biomass resulted in a highly porous structure similar to the parent material. Micronized particles were produced from this charcoal using a multi-step milling process and verified using a scanning electron microscope and laser diffraction system. Charcoal particles greater than 50 µm exhibited long needle shapes much like the parent biomass while particles less than 50 µm were produced with aspect ratios closer to unity. Laser diffraction measurements indicated D10, D50, and D90 values of 4.446 µm, 15.83 µm, and 39.69 µm, respectively. Moisture content, ash content, absolute density, and energy content values were also measured for the charcoal particles produced. Calculated volumetric energy density values for the charcoal particles exceeded the No. 2 diesel fuel that would be displaced in a liquid fuel slurry.
Novel Frequency Swapping Technique for Conducted Electromagnetic Interference Suppression in Power Converter Applications
Ming-Tse Kuo, Ming-Chang Tsou
March 26, 2019 (v1)
Subject: Other
Keywords: conduction electromagnetic interference (EMI), frequency jittering, frequency swapping, quasi-resonant flyback (QRF)
Quasi-resonant flyback (QRF) converters have been widely applied as the main circuit topology in power converters because of their low cost and high efficiency. Conventional QRF converters tend to generate higher average conducted electromagnetic interference (EMI) in the low-frequency domain due to the switching noise generated by power switches, resulting in the fact they can exceed the EMI standards of the European Standard 55022 Class-B emission requirements. The presented paper develops a novel frequency swapping control method that spreads spectral energy to reduce the amplitude of sub-harmonics, thereby lowering average conducted EMI in the low-frequency domain. The proposed method is implemented in a control chip, which requires no extra circuit components and adds zero cost. The proposed control method is verified using a 24 W QRF converter. Experimental results reveals that conducted EMI has been reduced by approximately 13.24 dBμV at 498 kHz compared with a control method wi... [more]
A Transient Fault Recognition Method for an AC-DC Hybrid Transmission System Based on MMC Information Fusion
Jikai Chen, Yanhui Dou, Yang Li, Jiang Li, Guoqing Li
March 26, 2019 (v1)
Keywords: discrete wavelet packet transformation, fault recognition, feature extraction, MMC, Renyi entropy, transient faults
At present, the research is still in the primary stage in the process of fault disturbance energy transfer in the multilevel modular converter based high voltage direct current (HVDC-MMC). An urgent problem is how to extract and analyze the fault features hidden in MMC electrical information in further studies on the HVDC system. Aiming at the above, this article analyzes the influence of AC transient disturbance on electrical signals of MMC. At the same time, it is found that the energy distribution of electrical signals in MMC is different for different arms in the same frequency bands after the discrete wavelet packet transformation (DWPT). Renyi wavelet packet energy entropy (RWPEE) and Renyi wavelet packet time entropy (RWPTE) are proposed and applied to AC transient fault feature extraction from electrical signals in MMC. Using the feature extraction results of Renyi wavelet packet entropy (RWPE), a novel recognition method is put forward to recognize AC transient faults using th... [more]
A Causal and Real-Time Capable Power Management Algorithm for Off-Highway Hybrid Propulsion Systems
Johannes Schalk, Harald Aschemann
March 26, 2019 (v1)
Keywords: energy management strategy, hybrid electric diesel multiple unit train (DMU), hybrid electric vehicle, hybridization, off-highway propulsion system, power management strategy
Hybrid propulsion systems allow for a reduction of fuel consumption and pollutant emissions of future off-highway applications. A challenging aspect of a hybridization is the larger number of system components that further increases both the complexity and the diversification of such systems. Hence, beside a standardization on the hardware side for off-highway systems, a high flexibility and modularity of the control schemes is required to employ them in as many different applications as possible. In this paper, a causal optimization-based power management algorithm is introduced to control the power split between engine and electric machine in a hybrid powertrain. The algorithm optimizes the power split to achieve the maximum power supply efficiency and, thereby, considers the energy cost for maintaining the battery charge. Furthermore, the power management provides an optional function to control the battery state of charge in such a way that a target value is attained. In a simulati... [more]
Understanding Inertial Response of Variable-Speed Wind Turbines by Defined Internal Potential Vector
Lei Shang, Jiabing Hu, Xiaoming Yuan, Yongning Chi
March 26, 2019 (v1)
Keywords: Inertia control, inertial response, inner potential, variable speed wind turbines
With the rapid development of wind power generation, the inertial response of wind turbines (WTs) has become a topic of wide concern recently, due to its influence on grid frequency dynamics and stability. This paper proposes and defines the inner potential to summarize and understand the inertia control methods and inertial response of type-3 and type-4 WTs, which is analogous to typical synchronous generators (SGs), to make it more easy to understand by system operators and engineers with a traditional power system background. The dynamics of the defined inner potential of the wind turbine without any inertia control is different from SGs, thus the electromechanical inertia is completely hidden. The rapid power control loop and synchronization control loop are the major reasons that the WT’s inertial response is disenabled. On the basis of the defined inner potential’s dynamic, the existing inertia control method for WTs are reviewed and summarized as three approaches, i.e., optimizi... [more]
Development of a Numerical Weather Analysis Tool for Assessing the Precooling Potential at Any Location
Dimitris Lazos, Merlinde Kay, Alistair Sproul
March 26, 2019 (v1)
Keywords: climate effects, Energy Efficiency, precooling, weather analysis
Precooling a building overnight during the summer is a low cost practice that may provide significant help in decreasing energy demand and shaving peak loads in buildings. The effectiveness of precooling depends on the weather patterns at the location, however research in this field is predominantly focused in the building thermal response alone. This paper proposes an analytical tool for assessing the precooling potential through simulations from real data in a numerical weather prediction platform. Three dimensionless ratios are developed based on the meteorological analysis and the concept of degree hours that provide an understanding of the precooling potential, utilization and theoretical value. Simulations were carried out for five sites within the Sydney (Australia) metro area and it was found that they have different responses to precooling, depending on their proximity to the ocean, vegetation coverage, and urban density. These effects cannot be detected when typical meteorolo... [more]
A Simple Method for the Detection of Long-Chain Fatty Acids in an Anaerobic Digestate Using a Quartz Crystal Sensor
Takuro Kobayashi, Hidetoshi Kuramochi, Kouji Maeda, Kaiqin Xu
March 26, 2019 (v1)
Subject: Biosystems
Keywords: anaerobic digestion (AD), inhibition, long-chain fatty acids (LCFA), quartz crystal microbalance (QCM)
In anaerobic digestion (AD), long-chain fatty acids (LCFAs) produced by hydrolysis of lipids, exhibit toxicity against microorganisms when their concentration exceeds several millimolar. An absorption detection system using a quartz crystal microbalance (QCM) was developed to monitor the LCFA concentration during an anaerobic digester’s operation treating oily organic waste. The dissociation of the LCFAs considerably improved the sensor response and, moreover, enabled it to specifically detect LCFA from the mixture of LCFA and triglyceride. Under alkaline conditions, the frequency-shift rates of the QCM sensor linearly increased in accordance with palmitic acid concentration in the range of 0⁻100 mg/L. Frequency changes caused by anaerobic digestate samples were successfully measured after removing suspended solids and adjusting the pH to 10.7. Finally, the QCM measurements for digestate samples demonstrated that frequency-shift rates are highly correlated with LCFA concentrations, whi... [more]
Experimental Investigation on a Thermal Model for a Basin Solar Still with an External Reflector
Masoud Afrand, Rasool Kalbasi, Arash Karimipour, Somchai Wongwises
March 15, 2019 (v1)
Keywords: basin solar still, desalination, external reflector, still efficiency, thermal model
In this study, a thermal model for estimating the efficiency of a basin solar still with an external reflector was introduced using the energy balance equations of different parts of the solar still. Then, in order to verify the precision and accuracy of this model, a basin solar still with an external reflector was constructed and some experiments were performed. The hourly temperature values for different places of the still and amount of distilled water were calculated using the thermal model and compared with experimental measurements. Comparisons show that the thermal model of the still is in good agreement with the experimental results. Therefore, it can be concluded that the introduced thermal model can be used reliably to estimate the amount of distilled water and efficiency of the basin solar still with an external reflector. Results also revealed that the efficiency of the solar still is low in the early hours, while it was enhanced 44% in the afternoon. Furthermore, it was c... [more]
Analysis of the Primary Constraint Conditions of an Efficient Photovoltaic-Thermoelectric Hybrid System
Guiqiang Li, Xiao Chen, Yi Jin
March 15, 2019 (v1)
Keywords: cold side temperature, electrical efficiency, geometric size, PV-TEG
Electrical efficiency can be increased by combining photovoltaic (PV) and the thermoelectric (TE) systems. However, a simple and cursory combination is unsuitable because the negative impact of temperature on PV may be greater than its positive impact on TE. This study analyzed the primary constraint conditions based on the hybrid system model consisting of a PV and a TE generator (TEG), which includes TE material with temperature-dependent properties. The influences of the geometric size, solar irradiation and cold side temperature on the hybrid system performance is discussed based on the simulation. Furthermore, the effective range of parameters is demonstrated using the image area method, and the change trend of the area with different parameters illustrates the constraint conditions of an efficient PV-TE hybrid system. These results provide a benchmark for efficient PV-TEG design.
Operation Optimization of Steam Accumulators as Thermal Energy Storage and Buffer Units
Wenqiang Sun, Yuhao Hong, Yanhui Wang
March 15, 2019 (v1)
Keywords: minimum volume, necessary thermal energy storage capacity (NTESC), optimal operation, steam accumulator (SA), steam source (SS)
Although steam is widely used in industrial production, there is often an imbalance between steam supply and demand, which ultimately results in steam waste. To solve this problem, steam accumulators (SAs) can be used as thermal energy storage and buffer units. However, it is difficult to promote the application of SAs due to high investment costs, which directly depend on the usage volume. Thus, the operation of SAs should be optimized to reduce initial investment through volume minimization. In this work, steam sources (SSs) are classified into two types: controllable steam sources (CSSs) and uncontrollable steam sources (UCSSs). A basic oxygen furnace (BOF) was selected as an example of a UCSS to study the optimal operation of an SA with a single BOF and sets of parallel-operating BOFs. In another case, a new method whereby CSSs cooperate with SAs is reported, and the mathematical model of the minimum necessary thermal energy storage capacity (NTESC) is established. A solving progra... [more]
Thermo-Economic Comparison and Parametric Optimizations among Two Compressed Air Energy Storage System Based on Kalina Cycle and ORC
Ruixiong Li, Huanran Wang, Erren Yao, Shuyu Zhang
March 15, 2019 (v1)
Keywords: CAES, integrated energy storage system, Kalina cycle, ORC, thermo-economic
The compressed air energy storage (CAES) system, considered as one method for peaking shaving and load-levelling of the electricity system, has excellent characteristics of energy storage and utilization. However, due to the waste heat existing in compressed air during the charge stage and exhaust gas during the discharge stage, the efficient operation of the conventional CAES system has been greatly restricted. The Kalina cycle (KC) and organic Rankine cycle (ORC) have been proven to be two worthwhile technologies to fulfill the different residual heat recovery for energy systems. To capture and reuse the waste heat from the CAES system, two systems (the CAES system combined with KC and ORC, respectively) are proposed in this paper. The sensitivity analysis shows the effect of the compression ratio and the temperature of the exhaust on the system performance: the KC-CAES system can achieve more efficient operation than the ORC-CAES system under the same temperature of exhaust gas; mea... [more]
Risk Assessment Method of UHV AC/DC Power System under Serious Disasters
Rishang Long, Jianhua Zhang
March 15, 2019 (v1)
Keywords: chain failure, index system, risk assessment, ultra-high voltage (UHV)
Based on the theory of risk assessment, the risk assessment method for an ultra-high voltage (UHV) AC/DC hybrid power system under severe disaster is studied. Firstly, considering the whole process of cascading failure, a fast failure probability calculation method is proposed, and the whole process risk assessment model is established considering the loss of both fault stage and recovery stage based on Monte Carlo method and BPA software. Secondly, the comprehensive evaluation index system is proposed from the aspects of power system structure, fault state and economic loss, and the quantitative assessment of system risk is carried out by an entropy weight model. Finally, the risk assessment of two UHV planning schemes are carried out and compared, which proves the effectiveness of the research work.
An Economic and Policy Analysis of a District Heating System Using Corn Straw Densified Fuel: A Case Study in Nong’an County in Jilin Province, China
Shizhong Song, Pei Liu, Jing Xu, Linwei Ma, Chinhao Chong, Min He, Xianzheng Huang, Zheng Li, Weidou Ni
March 15, 2019 (v1)
Subject: Energy Policy
Keywords: corn straw, district heating system, economic model, policy influence, solid densified fuel
The development of district heating systems of corn straw densified fuel (CSDF-DHS) is an important option to promote the use of bioenergy on a large scale for sustainable development, especially in China. At present, China’s biomass densified solid fuel (BSDF) development lags behind previously planned target, main barriers of which are economic and policy support problems. Accurate case studies are key to analyze these problems. This manuscript takes Nong’an County in Jilin Province of China as an example to establish a techno-economic model to evaluate the economic performance of a CSDF-DHS under two policy scenarios. It calculates the economic performance under a benchmark market scenario (BMS) and the current policy scenario (CPS) and analyzes the influence of various policy instruments, including subsidies, carbon trading, and preferential taxation. The results indicate that: (1) The CSDF-DHS option is not competitive under the BMS or CPS compared to the traditional energy system... [more]
Showing records 1 to 25 of 37. [First] Page: 1 2 Last
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