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Showing records 1 to 25 of 119. [First] Page: 1 2 3 4 5 Last
Experimental Study on Electric Potential Response Characteristics of Gas-Bearing Coal During Deformation and Fracturing Process
Zhonghui Li, Yue Niu, Enyuan Wang, Lanbo Liu, Honghao Wang, Mingfu Wang, Muhammad Ali
May 16, 2019 (v1)
Subject: Other
Keywords: charge separation, damage evolution, electrical potential, gas adsorption, gas-bearing coal
Coal mass is deformed and fractured under stress to generate electrical potential (EP) signals. The mechanical properties of coal change with the adsorption of gas. To investigate the EP response characteristics of gas-bearing coal during deformation and fracture, a test system to monitor multi-parameters of gas-bearing coal under load was designed. The results showed that abundant EP signals were generated during the loading process and the EP response corresponded well with the stress change and crack expansion, and validated this with the results from acoustic emission (AE) and high-speed photography. The higher stress level and the greater the sudden stress change led to the greater EP abnormal response. With the increase of gas pressure, the confining action and erosion effect are promoted, causing the damage evolution impacted and failure characteristics changes. As a result, the EP response is similar while the characteristics were promoted. The EP response was generated due to... [more]
Experimental Study on Mixed Mode Fracture Behavior of Sandstone under Water⁻Rock Interactions
Wen Hua, Jianxiong Li, Shiming Dong, Xin Pan
May 16, 2019 (v1)
Subject: Other
Keywords: degradation mechanism, fracture criteria, mixed mode fracture resistance, T-stress, water–rock interaction
Water⁻rock interactions can significantly deteriorate the physical and mechanical properties of rocks, and it has been identified as one of the significant factors influencing the stability and safety of structures in rock⁻soil engineering. In this study, the fracture mechanical properties of sandstone under periodic water⁻rock interactions and long-term immersion have been studied with central cracked Brazilian disk specimens. The degradation mechanism of water⁻rock interactions was also studied using a scanning electron microscope (SEM). Finally, the generalized maximum tangential stress and generalized maximum tangential strain criteria were adopted to evaluate the experimental results. The results show that periodic water⁻rock interactions can remarkably affect the fracture resistance of sandstone. With the increase in the number of cycles, the pure mode I, pure mode II, and mixed mode fracture toughness decreases greatly, however, the values of KIf/KIC and KIIf/KIC decrease slight... [more]
The Effects of Backfill Mining on Strata Movement Rule and Water Inrush: A Case Study
Jian Hao, Yongkui Shi, Jiahui Lin, Xin Wang, Hongchun Xia
May 16, 2019 (v1)
Subject: Other
Keywords: backfill mining, floor failure depth, ground pressure, strata movement, water inrush prevention
Backfill mining is widely used to control strata movement and improve the stress environment in China’s coal mines. In the present study, the effects of backfill mining on strata movement and water inrush were studied based on a case study conducted in Caozhuang Coal Mine. The in-situ investigation measured abutment pressure distribution (APD), roof floor displacement (RFD), and vertical stress in the backfill area. Results are as follows: (i) The range and peak of APD, RFD, and vertical stress in the backfill area are smaller than in traditional longwall mining with the caving method. (ii) Backfill mining could change the movement form and amplitude of overburden and improve the ground pressure environment. (iii) Floor failure depth (FFD) is much smaller in backfill mining. Backfill mining can be an effective method for floor water inrush prevention.
Experimental Study on the Shear-Flow Coupled Behavior of Tension Fractures Under Constant Normal Stiffness Boundary Conditions
Changsheng Wang, Yujing Jiang, Hengjie Luan, Jiankang Liu, Satoshi Sugimoto
May 16, 2019 (v1)
Subject: Other
Keywords: constant normal stiffness conditions, hydraulic aperture, rock fracture, shear-flow coupled test, transmissivity
This study experimentally investigated the effects of fracture surface roughness, normal stiffness, and initial normal stress on the shear-flow behavior of rough-walled rock fractures. A series of shear-flow tests were performed on two rough fractures, under various constant normal stiffness (CNS) boundary conditions. The results showed that the CNS boundary conditions have a significant influence on the mechanical and hydraulic behaviors of fractures, during shearing. The peak shear stress shows an increasing trend with the increases in the initial normal stress and fracture roughness. The residual shear stress increases with increasing the surface roughness, normal stiffness, and initial normal stress. The dilation of fracture is restrained more significantly under high normal stiffness and initial normal stress conditions. The hydraulic tests show that the evolutions of transmissivity and hydraulic aperture exhibit a three-stage behavior, during the shear process—a slight decrease s... [more]
Simulating the Filtration Effects of Cement-Grout in Fractured Porous Media with the 3D Unified Pipe-Network Method
Zizheng Sun, Xiao Yan, Weiqi Han, Guowei Ma, Yiming Zhang
April 15, 2019 (v1)
Subject: Other
Keywords: filtration effects, fractured porous medium, grout penetration, two-phase flow, unified pipe-network method
In grouting process, filtration is the retention and adsorption of cement-grout particles in a porous/fractured medium. Filtration partly/even completely blocks the transportation channels in the medium, greatly decreasing its permeability. Taking into account filtration effects is essential for accurately estimating the grout penetration region. In this paper, the 3D unified pipe-network method (UPM) is adopted for simulating 3D grout penetration process in a fractured porous medium, considering filtration effects. The grout is assumed to exhibit two-phase flow, and the filtration effects depend on not only the concentration and rheology of the grout but also the porosity and permeability of the fractured porous medium. By comparing the model with the experimental results, we firstly verify the proposed numerical model. Then sensitivity analysis is conducted, showing the influences of grout injection pressures, the water⁻cement ratios of grout (W/C) and the grout injection rates on fi... [more]
Acknowledgement to Reviewers of Processes in 2018
Processes Editorial Office
April 15, 2019 (v1)
Subject: Other
Rigorous peer-review is the corner-stone of high-quality academic publishing [...]
Ambient Pressure-Dried Graphene⁻Composite Carbon Aerogel for Capacitive Deionization
Chen Zhang, Xiaodong Wang, Hongqiang Wang, Xueling Wu, Jun Shen
April 15, 2019 (v1)
Subject: Other
Keywords: capacitive deionization, desalination, electrosorption, graphene–composite carbon aerogel (GCCA)
Capacitive deionization (CDI) technology possessing excellent desalination performance and energy efficiency is currently being widely studied in seawater desalination. In this work, the graphene⁻composite carbon aerogels (GCCAs) easily prepared by an ambient pressure drying method served as electrodes to remove salt ions in aqueous solution by CDI. The microstructure of the obtained GCCAs was found to depend on the component content in the precursor solution, and could be controlled through varying the mass ratio of resorcinol and formaldehyde to graphene oxide (RF/GO). The surface characteristics and microstructure of GCCAs were characterized by Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). In addition, the electrochemical tests and CDI experiments of GCCA electrodes were conducted in NaCl solution. Thanks to the reasonable pore structure and highly conductive network, GCCA-150 achieved the best salt adsorption capacity of 26.9 mg/... [more]
Numerical Investigation of Hydraulic Fracture Propagation Based on Cohesive Zone Model in Naturally Fractured Formations
Jianxiong Li, Shiming Dong, Wen Hua, Xiaolong Li, Xin Pan
April 15, 2019 (v1)
Subject: Other
Keywords: hydraulic fractures, multitude parameters, naturally fracture, PPCZ, propagation pattern, stress interference
Complex propagation patterns of hydraulic fractures often play important roles in naturally fractured formations due to complex mechanisms. Therefore, understanding propagation patterns and the geometry of fractures is essential for hydraulic fracturing design. In this work, a seepage⁻stress⁻damage coupled model based on the finite pore pressure cohesive zone (PPCZ) method was developed to investigate hydraulic fracture propagation behavior in a naturally fractured reservoir. Compared with the traditional finite element method, the coupled model with global insertion cohesive elements realizes arbitrary propagation of fluid-driven fractures. Numerical simulations of multiple-cluster hydraulic fracturing were carried out to investigate the sensitivities of a multitude of parameters. The results reveal that stress interference from multiple-clusters is responsible for serious suppression and diversion of the fracture network. A lower stress difference benefits the fracture network and he... [more]
Chemical Recycling of Used Printed Circuit Board Scraps: Recovery and Utilization of Organic Products
Se-Ra Shin, Van Dung Mai, Dai-Soo Lee
April 15, 2019 (v1)
Subject: Other
Keywords: chemical recycling, glycolysis, recycled polyol, rigid polyurethane foam, used printed circuit board
The disposal of end-of-life printed circuit boards (PCBs) comprising cross-linked brominated epoxy resins, glass fiber, and metals has attracted considerable attention from the environmental aspect. In this study, valuable resources, especially organic material, were recovered by the effective chemical recycling of PCBs. Pulverized PCB was depolymerized by glycolysis using polyethylene glycol (PEG 200) with a molecular weight of 200 g/mol under basic conditions. The cross-linked epoxy resins were effectively decomposed into a low-molecular species by glycolysis with PEG 200, followed by the effective separation of the metals and glass fibers from organic materials. The organic material was modified into recycled polyol with an appropriate viscosity and a hydroxyl value for rigid polyurethane foams (RPUFs) by the Mannich reaction and the addition polymerization of propylene oxide. RPUFs prepared using the recycled polyol exhibited superior thermal and mechanical properties as well as th... [more]
Special Issue on Feature Papers for Celebrating the Fifth Anniversary of the Founding of Processes
Michael A. Henson
April 9, 2019 (v1)
Subject: Other
The Special Issue “Feature Papers for Celebrating the Fifth Anniversary of the Founding of Processes„ represents a landmark for this open access journal covering chemical, biological, materials, pharmaceutical, and environmental systems as well as general computational methods for process and systems engineering. [...]
Formation Mechanism of Trailing Oil in Product Oil Pipeline
Enbin Liu, Wensheng Li, Hongjun Cai, Shanbi Peng
April 9, 2019 (v1)
Subject: Other
Keywords: Computational Fluid Dynamics, contamination, dead-leg, pipeline, trailing oil, transportation
Trailing oil is the tail section of contamination in oil pipelines. It is generated in batch transportation, for which one fluid, such as diesel oil follows another fluid, such as gasoline, and it has an effect on the quality of oil. This paper describes our analysis of the formation mechanism of trailing oil in pipelines and our study of the influence of dead-legs on the formation of trailing oil. We found that the oil replacement rate in a dead-leg is exponentially related to the flow speed, and the length of the dead-leg is exponentially related to the replacement time of the oil. To reduce the amount of mixed oil, the main flow speed should be kept at about 1.6 m/s, and the length of the dead-leg should be less than five times the diameter of the main pipe. In our work, the Reynolds time-averaged method is used to simulate turbulence. To obtain contamination-related experimental data, computational fluid dynamics (CFD) software is used to simulate different flow rates and bypass le... [more]
Investigation of Deep Mine Shaft Stability in Alternating Hard and Soft Rock Strata Using Three-Dimensional Numerical Modeling
Xiaoming Sun, Gan Li, Chengwei Zhao, Yangyang Liu, Chengyu Miao
April 9, 2019 (v1)
Subject: Other
Keywords: alternate strata, mine shaft, relief excavation, shaft lining, surrounding rock
The problem of shaft instability has always been a major difficulty in deep mining practices. The shaft fracture has a high probability of being located near the aquifers and the soft⁻hard rock contact zone. This paper describes the deformation and stress characteristics of surrounding rock and the shaft lining under the interactive geological conditions under soft and hard rock strata in Anju coal mine, Shandong Province, China. Using the Method of Geological Strength Index (GSI ) and considering the rock-softening characteristics of water, the parameters of rock mass are calibrated. By means of the 3DEC-trigon method, the variation characteristics of surrounding rock and the shaft lining are simulated. After shaft excavation, under the condition of no support, shear failure and tensile failure occur in shallow surrounding rock shafts, and a pressure relief zone is formed. Shear failure is the main destruction mode in deep surrounding rock. Because of the different strengths of the su... [more]
Recent Advance on Draw Solutes Development in Forward Osmosis
Qingwu Long, Yongmei Jia, Jinping Li, Jiawei Yang, Fangmei Liu, Jian Zheng, Biao Yu
April 8, 2019 (v1)
Subject: Other
Keywords: draw solutes, Energy, forward osmosis, membrane separation, regeneration
In recent years, membrane technologies have been developed to address water shortage and energy crisis. Forward osmosis (FO), as an emerging membrane-based water treatment technology, employs an extremely concentrated draw solution (DS) to draw water pass through the semi-permeable membrane from a feed solution. DS as a critical material in FO process plays a key role in determining separation performance and energy cost. Most of existing DSs after FO still require a regeneration step making its return to initial state. Therefore, selecting suitable DS with low reverse solute, high flux, and easy regeneration is critical for improving FO energy efficiency. Numerous novel DSs with improved performance and lower regeneration cost have been developed. However, none reviews reported the categories of DS based on the energy used for recovery up to now, leading to the lack of enough awareness of energy consumption in DS regeneration. This review will give a comprehensive overview on the exis... [more]
The Seepage Control of the Tunnel Excavated in High-Pressure Water Condition Using Multiple Times Grouting Method
Bin Gong, Yujing Jiang, Keisuke Okatsu, Xuezhen Wu, Jin Teduka, Koichi Aoki
April 8, 2019 (v1)
Subject: Other
Keywords: FLAC3D, high groundwater table, leakage control, multiple grouting, tunnel, ultramicro cement
Groundwater can cause many hazardous problems when a tunnel is excavating. Seepage force acting on the support structure and the tunnel surface cannot be negligible. Under high groundwater table condition, the seepage situation becomes more complex and it is more difficult to control the leakage of groundwater to flow into a tunnel. In the paper, a multiple times grouting method is proposed, and the mechanical deformation behavior of surrounding rock is analyzed using the FLAC3D (Fast Lagrangian Analysis of Continua in 3 Dimensions) software according to the high groundwater table condition of the Hokusatsu tunnel. The results present that multiple times grouting can control leakage and the rock deformation well, compared with one-time grouting condition in rock breaking and high water pressure area. The seepage force decrease around the tunnel and the displacement is controlled effectively. The pore pressure reduces inside the grouting zone using a new kind of grouting material, which... [more]
Temporal Mixing Behavior of Conservative Solute Transport through 2D Self-Affine Fractures
Zhi Dou, Brent Sleep, Pulin Mondal, Qiaona Guo, Jingou Wang, Zhifang Zhou
April 8, 2019 (v1)
Subject: Other
Keywords: conservative solute, fractal, fracture, Mixing, roughness
In this work, the influence of the Hurst exponent and Peclet number (Pe) on the temporal mixing behavior of a conservative solute in the self-affine fractures with variable-aperture fracture and constant-aperture distributions were investigated. The mixing was quantified by the scalar dissipation rate (SDR) in fractures. The investigation shows that the variable-aperture distribution leads to local fluctuation of the temporal evolution of the SDR, whereas the temporal evolution of the SDR in the constant-aperture fractures is smoothly decreasing as a power-law function of time. The Peclet number plays a dominant role in the temporal evolution of mixing in both variable-aperture and constant-aperture fractures. In the constant-aperture fracture, the influence of Hurst exponent on the temporal evolution of the SDR becomes negligible when the Peclet number is relatively small. The longitudinal SDR can be related to the global SDR in the constant-aperture fracture when the Peclet number is... [more]
Shear-Flow Coupled Behavior of Artificial Joints with Sawtooth Asperities
Cheng Zhao, Rui Zhang, Qingzhao Zhang, Zhenming Shi, Songbo Yu
April 8, 2019 (v1)
Subject: Other
Keywords: artificial joint rock, hydraulic aperture, roughness, seepage pressure, shear-flow coupled test
The coupling between hydraulic and mechanical processes in rock joints has significantly influenced the properties and applications of rock mass in many engineering fields. In this study, a series of regular shear tests and shear-flow coupled tests were conducted on artificial joints with sawtooth asperities. Shear deformation, strength, and seepage properties were comprehensively analyzed to reveal the influence of joint roughness, normal stress, and seepage pressure on shear-flow coupled behavior. The results indicate that the shear failure mode, which can be divided into sliding and cutting, is dominated by joint roughness and affected by the other two factors under certain conditions. The seepage process makes a negative impact on shear strength as a result of the mutual reinforcing of offsetting and softening effects. The evolution of hydraulic aperture during the shear-flow coupled tests embodies a consistent pattern of four stages: shear contraction, shear dilation, re-contracti... [more]
Analysis of Overlying Strata Movement and Disaster-Causing Effects of Coal Mining Face under the Action of Hard Thick Magmatic Rock
Quanlin Wu, Quansen Wu, Yanchao Xue, Peng Kong, Bin Gong
April 8, 2019 (v1)
Subject: Other
Keywords: bed separation, disaster-causing mechanism, fracture, hard and thick magmatic rocks, orthogonal ratio test, similar simulation
When the hard and thick key strata are located above the working face, the bed separation structure is easy to be formed after mining because of the high strength and integrity of the hard and thick key strata and the initial breaking step is large. After the hard, thick strata are broken, the overburden will be largely collapsed and unstable in a large area and the dynamic disaster is easily induced. In this study, considering the fundamental deformation and failure effect of coal seam, the development law of the bed separation and the fractures under hard and thick magmatic rocks and the mechanism of breaking induced disaster of hard and thick magmatic rocks are studied by similar simulation tests. The results of the study are as follows: (1) The similar material ratio of coal seam is obtained by low-strength orthogonal ratio test of similar materials of coal seam, that is, cement:sand:water:activated carbon:coal = 6:6:7:1.1:79.9. (2) The magmatic rocks play a role in shielding the d... [more]
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 Feedback Passivation Design for DC Microgrid and Its DC/DC Converters
Feifan Ji, Ji Xiang, Wuhua Li, Quanming Yue
March 15, 2019 (v1)
Subject: Other
Keywords: DC microgrid, distributed control, feedback passivation
There are difficulties in analyzing the stability of microgrids since they are located on various network structures. However, considering that the network often consists of passive elements, the passivity theory is applied in this paper to solve the above-mentioned problem. It has been formerly shown that when the network is weakly strictly positive real (WSPR), the DC microgrid is stable if all interfaces between the microgrid and converters are made to be passive, which is called interface passivity. Then, the feedback passivation method is proposed for the controller design of various DC⁻DC converters to achieve the interface passivity. The interface passivity is different from the passivity of closed-loop systems on which the passivity based control (PBC) concentrates. The feedback passivation design is detailed for typical buck converters and boost converters in terms of conditions that the controller parameters should satisfy. The theoretical results are verified by a hardware-i... [more]
A New Dynamic Injection System of Urea-Water Solution for a Vehicular Select Catalyst Reduction System
Long Li, Wei Lin, Youtong Zhang
March 15, 2019 (v1)
Subject: Other
Keywords: dynamic correction, NH3 slip, select catalyst reduction (SCR), urea water solution (UWS)
Since the Euro-ІІІ standard was adopted, the main methods to inhibit NOx production in diesel engines are exhaust gas recirculation (EGR) and select catalyst reduction (SCR). On these methods SCR offers great fuel economy, so it has received wide attention. However, there also exists a trade-off law between NOx conversion efficiency and NH₃ slip under dynamic conditions. To inhibit NH₃ slip with high NOx conversion efficiency, a dynamic control method for a urea water solution (UWS) injection was investigated. The variation phenomena of SCR conversion efficiency with respect to the cross-sensitivity characteristics of the NOx sensor to NH₃ have been thoroughly analyzed. The methodology of “uncertain conversion efficiency curve tangent analysis” has been applied to estimate the concentration of the slipped NH₃. The correction factor “φ” of UWS injection is obtained by a comparative calculation of the NOx conversion ability and subsequent NH₃ slip. It also includes methods of flow compen... [more]
Performance Study on a Single-Screw Expander for a Small-Scale Pressure Recovery System
Guoqiang Li, Yuting Wu, Yeqiang Zhang, Ruiping Zhi, Jingfu Wang, Chongfang Ma
March 15, 2019 (v1)
Subject: Other
Keywords: Natural Gas, pressure energy recovery, single-screw expander
A single-screw expander with 195 mm diameter is developed to recover pressure energy in letdown stations. An experiment system is established using compressed air as a working fluid instead of natural gas. Experiments are conducted via measurements for important parameters, such as inlet and outlet temperature and pressure, volume flow rate and power output. The influence of inlet pressure and rotational speed on the performance are also analyzed. Results indicate that the single-screw expander achieved good output characteristics, in which 2800 rpm is considered the best working speed. The maximum volumetric efficiency, isentropic efficiency, overall efficiency, and the lowest air-consumption are 51.1 kW, 83.5%, 66.4%, 62.2%, and 44.1 kg/(kW·h), respectively. If a single-screw expander is adopted in a pressure energy recovery system applied in a certain domestic natural gas letdown station, the isentropic efficiency of the single-screw expander and overall efficiency of the system are... [more]
Torque Distribution Characteristics of a Novel Double-Stator Permanent Magnet Generator Integrated with a Magnetic Gear
Shehu Salihu Mustafa, Norhisam Misron, Norman Mariun, Mohammad Lutfi Othman, Tsuyoshi Hanamoto
March 15, 2019 (v1)
Subject: Other
Keywords: cogging torque, double-stator magnetic geared machine (DS-MGM), field magnet, finite element method, flux density, harmonic analysis, magnetic gear (MG), permanent-magnet (PM), prime magnet, torque distribution, transmission torque
This paper presents a novel double-stator permanent-magnet machine integrated with a triple rotor magnetic gear structure, which is proposed to address problems of mechanical geared generators for low-speed applications. Torque transmission is based on three rotors consisting of prime permanent-magnet (PM) poles in the middle rotor and field PM poles in the inner and outer rotors. The proposed machine combines the functions of magnetic gearing and electrical power generation. The operating principles of the magnetic gear and generator are discussed and the torque distribution characteristics of the integrated machine are analysed using the 2D finite-element method (2D FEM). Also the power, torque, and speed characteristics are reported. A prototype is fabricated and tested experimentally. The predicted and measured results validate the proposed machine design.
The Effect of Distributed Parameters on Conducted EMI from DC-Fed Motor Drive Systems in Electric Vehicles
Li Zhai, Liwen Lin, Xinyu Zhang, Chao Song
March 15, 2019 (v1)
Subject: Other
Keywords: conducted electromagnetic interference (EMI), DC-fed, distributed parameter, electric vehicle, motor drive system
The large dv/dt and di/dt outputs of power devices in DC-fed motor drive systems in electric vehicles (EVs) always introduce conducted electromagnetic interference (EMI) emissions and may lead to motor drive system energy transmission losses. The effect of distributed parameters on conducted EMI from the DC-fed high voltage motor drive systems in EVs is studied. A complete test for conducted EMI from the direct current fed(DC-fed) alternating current (AC) motor drive system in an electric vehicle (EV) under load conditions is set up to measure the conducted EMI of high voltage DC cables and the EMI noise peaks due to resonances in a frequency range of 150 kHz⁻108 MHz. The distributed parameters of the motor can induce bearing currents under low frequency sine wave operation. However the impedance of the distributed parameters of the motor is very high at resonance frequencies of 500 kHz and 30 MHz, and the effect of the bearing current can be ignored, so the research mainly focuses on... [more]
HVDC-System-Interaction Assessment through Line-Flow Change-Distribution Factor and Transient-Stability Analysis at Planning Stage
Sungchul Hwang, Jaegul Lee, Gilsoo Jang
February 27, 2019 (v1)
Subject: Other
Keywords: high-voltage direct current (HVDC), interaction, Planning, transient stability
Many of the recent projects for new transmission line have considered the high-voltage direct current (HVDC) system, owing to the many advantages of the direct current (DC) system. The most noteworthy advantage is that a cable can serve as a substitute for the overhead transmission line in residential areas; therefore, the HVDC system application is increasing, and as the number of DC systems in the power system increases, the interaction assessment regarding the HVDC system gains importance. An index named multi-infeed interaction factor (MIIF) is commonly used to estimate the interaction between power converters; however, the HVDC system is composed of two converters and a transmission line. The MIIF represents the interaction between the rectifiers and inverters, but not for the whole system. In this work, a method to assess the interaction of the whole system was therefore studied. To decide on the location of the new HVDC transmission system at the planning stage, in consideration... [more]
Development of Seismic Demand for Chang-Bin Offshore Wind Farm in Taiwan Strait
Yu-Kai Wang, Juin-Fu Chai, Yu-Wen Chang, Ti-Ying Huang, Yu-Shu Kuo
February 27, 2019 (v1)
Subject: Other
Keywords: design earthquake, offshore wind, response spectrum, seismic hazard analysis, supporting structures
Taiwan is located on the Pacific seismic belt, and the soil conditions of Taiwan’s offshore wind farms are softer than those in Europe. To ensure safety and stability of the offshore wind turbine supporting structures, it is important to assess the offshore wind farms seismic forces reasonably. In this paper, the relevant seismic and geological data are obtained for Chang-Bin offshore wind farm in Taiwan Strait, the probabilistic seismic hazard analysis (PSHA) is carried out, and the first uniform hazard response spectrum for Chang-Bin offshore wind farm is achieved. Compared with existing design response spectrum in the local regulation, this site-specific seismic hazard analysis has influence on the seismic force considered in the design of supporting structures and therefore affects the cost of the supporting structures. The results show that a site-specific seismic hazard analysis is required for high seismic area. The paper highlights the importance of seismic hazard analysis to a... [more]
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