Volume 39,Issue 6,2016 Table of Contents

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  • 1  Calculation of radio interference and audible noise of high voltage AC/DC hybrid lines mounted on the same tower
    ZOU Jun WANG Siying LI Benliang
    2016, 39(6):1-10. DOI: 10.11835/j.issn.1000-582X.2016.06.001
    [Abstract](1072) [HTML](575) [PDF 2.90 M](1332)
    Abstract:
    It aims to search for a proper calculation method of radio interference and audible noise to AC/DC hybrid lines arranged on the same tower. First, the characteristics of surface field strength were analyzed theoretically; second, the synthesized field strength was calculated with linear superposition theorem; then the principle, which contains radio interference and audible noise of hybrid lines should be computed in the same weather, was proposed in this paper combined with influence of humidity to corona. The results of three calculation methods were compared and calculated in a sunny and a rainy day. And it indicates the BPA correction formula is an effective method to calculate radio interference and audible noise of AC/DC hybrid lines at present.
    2  Control strategy and protection switch optimization of hybrid energy storage system for PV-storage microgrid system
    BI Xiaohui SUN Tao MAO Rui FANG Yong HOU Shiying
    2016, 39(6):11-18. DOI: 10.11835/j.issn.1000-582X.2016.06.002
    [Abstract](894) [HTML](898) [PDF 3.75 M](1258)
    Abstract:
    In the conventional control strategy of the PV-storage micro-grid hybrid energy storage system (HESS), battery is regarded as an ideal element which has infinite capacity. However, the battery capacity is limited and the conventional control strategy is no longer suitable when the threshold of battery state-of-charge (SOC) is reached and can not work properly. Thus, we proposed a new control strategy for the PV-storage micro-grid HESS based on the second-order low-pass filtering method. This strategy takes the SOC of super-capacitor and battery into account, adjusts the reference value of output current of energy storage element and maintains the SOC of storage element. But in extreme weather conditions, the strategy still needs to cooperate with the protection switch of energy storage element. Furthermore, the HESS using conventional protection switch of energy storage element needs separate charging and discharging circuits, which leads to some problems such as high cost, discontinuous of charge and discharge, etc. So the protection switch of energy storage elements was improved in this paper, which has four working states based on the shunt of switch and diode. The modified protection switch can make SOC back to normal when it reaches threshold, which can reduce cost and improve the quality of grid-connected power output. The overall control scheme of hybrid energy storage system that combines new control strategy with improved protection switch was proposed and simulated in MATLAB Simulink, and the results validate the correctness and the feasibility of the proposed method.
    3  Impedance analysis and decoupling capacitance optimization of power delivery network
    WANG Quandi WANG Yingcong GAO Feng
    2016, 39(6):19-26. DOI: 10.11835/j.issn.1000-582X.2016.06.003
    [Abstract](1085) [HTML](486) [PDF 10.99 M](1146)
    Abstract:
    Power ports of power delivery networks(PDN) in high digital circuit are designed to satisfy the requirements of large transient current and low target impedance. In order to solve the impedance matrix of arbitrary shaped power plane, a new time-efficient complementation method, combining analytical expression with finite difference method, was proposed. Then PSO (particle swarm optimization) technique was processed to find the optimum values and positions of decoupling capacitors. Matlab simulation shows the result of the proposed method is basically consistent with that of the full-wave finite element method, but its calculation time is greatly reduced. The calculation and the measurement results both indicate that impedance of all power ports after optimization can meet the demands of their target impedance.
    4  Solution algorithm of apparent resistivity based on independent variable input mode of neural network
    CAO Min QIN Shanqiang HU Xuquan FU Zhihong WANG Haowen
    2016, 39(6):27-33. DOI: 10.11835/j.issn.1000-582X.2016.06.004
    [Abstract](821) [HTML](339) [PDF 3.37 M](1161)
    Abstract:
    According to the relationship between the response and the independent variables in transient electromagnetic field theory, a BP neural network with nonlinear equation model was proposed to solve the resistivity. By constructing a single-input-single-output network structure, a neural network with current normalized induced voltage at different time points as input and the apparent resistivity as the output was set up to simulate the secondary eddy current curve of the transient electromagnetic field. The accuracy of the trained network was verified by the data calculated by numerical computation, and the training accuracies and the convergence speeds of different algorithms were compared. The effectiveness of the proposed algorithm was verified by the experiments in an air-raid shelter in Chongqing University. The presented solution algorithm avoids calculation of complex electromagnetic field or numerical inverse problem, and realizes fast calculation of resistivity.
    5  Analysis of low voltage ride through capability of double fedinduction generator with STATCOM
    LI Hongnan JIN Tao
    2016, 39(6):34-40. DOI: 10.11835/j.issn.1000-582X.2016.06.005
    [Abstract](864) [HTML](743) [PDF 5.27 M](799)
    Abstract:
    To improve the low voltage ride through(LVRT) capability on double fed induction generator(DFIG), we developed a double closed-loop feedback control strategy combining voltage outer loop with current inner ring on the basis of STATCOM, and verified its effectiveness through simulation. In the simulations, STATCOMs were respectively installed at the terminal of wind generator, the high voltage side and the low voltage side of common coupling point. And then different depths of voltage drop were added to the grid, and different compensation effects were compared and discussed. Experimental results suggest that the compensation effect is the best when STATCOM is installed at the wind generator terminal. When the voltage drops, STATCOMs can provide power grid with reactive power quickly, raise the voltage of the wind turbine generator, and improve the LVRT capability of wind farms. In the aspects of STATCOM output reactive power and rising percentages of wind farm terminal voltage, the compensation effect of STATCOM is significant for different depths of voltage drop.
    6  Automatic impedance matching based on improved particle swarmoptimization algorithm
    YANG Xiaobo LI Yang XIAO Zhaoxia YANG Qingxin DONG Weihao WANG Yinhuan
    2016, 39(6):41-48. DOI: 10.11835/j.issn.1000-582X.2016.06.006
    [Abstract](970) [HTML](356) [PDF 2.82 M](1176)
    Abstract:
    As the wireless power transmission distance changes, resonance coil offsets, load changes and other aspects of the system's input impedance change, the input impedance will not match with the RF(radio frequency) source impedance, and the transmission efficiency will drop significantly. Adding an impedance matching network between the RF source and the transmit coil can improve the transmission efficiency of the wireless power. In order to improve the accuracy and the speed of impedance matching, an improved particle swarm optimization algorithm was proposed in this paper. By comparing the improved algorithm with the traditional algorithm, it proved the superiority of the improved algorithm in matching precision and speed. Finally, the algorithm was embedded into the automatic impedance matching system and the transmission efficiency of the wireless power transfer system was improved. Meanwhile, the effectiveness of the proposed algorithm was also demonstrated.
    7  Modeling and analysis of disturbance voltage induced on the intelligentelectronic device ports based on the transmission-line network inultra high voltage gas insulated substations
    LIU Xiaofan JIAO Chongqing CUI Xiang JI Jianfei
    2016, 39(6):49-57. DOI: 10.11835/j.issn.1000-582X.2016.06.007
    [Abstract](941) [HTML](624) [PDF 4.68 M](1076)
    Abstract:
    With the development of intelligent GIS equipment, a lot of electronic equipments are integrated on the GIS. The very fast transient electromagnetic disturbance (VFTED) resulted from the GIS switching operation has potential impact on the electronic equipment by the electromagnetic coupling between the VFTED and the circuit of "sensor-cable-intelligent electronic device(IED)". In this paper, a theoretical model based on the transmission-line network was established first to calculated the coupling of the ground potential rise produced by switching operations to the circuit of "sensor-cable-IED". Then the validation of this model was verified when it was used to a simple configuration. Finally, based on this model, the disturbance voltages on the sensor/IED ports and those between the IED ports were calculated and the suppression effectiveness of the grounding of the cable shield layer on the disturbance voltages was investigated. The results show that the grounding modes have great influence on disturbance voltage. By choosing the appropriate grounding mode, electromagnetic disturbance caused by switching operations can be effectively suppressed.
    8  Small-signal stability analysis of a micro-grid with a synchronous generator and an inverter-interfaced micro source
    XIAO Zhaoxia ZHAO Yuzhu ZHAO Qianyu JIA Shuang
    2016, 39(6):58-70. DOI: 10.11835/j.issn.1000-582X.2016.06.008
    [Abstract](888) [HTML](353) [PDF 4.81 M](944)
    Abstract:
    An independent microgrid control strategy including voltage source inverter (VSI) and synchronous generator(SG) was proposed, and its small signal stability was analyzed. Both VSI interfaces and SG interfaces used droop control strategy, sharing the load power without real-time communication. A small-signal micro-grid model was developed, including a small-signal model of the synchronous generator and its controller, a small-signal model of the inverter-interfaced micro source and its controller, and a small-signal model of the power network and its load. The eigenvalues were calculated when the droop gains change. The root locus of the principal eigenvalues were obtained when the main parameters change. And the participation factor of different state variables to the eigenvalues was investigated by PSCAD time domain simulations. The results show that the frequency stability is improved greatly by the synchronous generator when all micro sources use droop control. PSCAD time domain simulation verified the correctness of the eigenvalue calculation.
    9  Finite element analysis and optimal design of Lamb wave EMATs for aluminum plate
    LIU Suzhen ZHANG Yanwei HUO Dan ZHANG Chuang CAI Zhichao YANG Qingxin
    2016, 39(6):71-77. DOI: 10.11835/j.issn.1000-582X.2016.06.009
    [Abstract](835) [HTML](577) [PDF 3.63 M](997)
    Abstract:
    The electromagnetic acoustic transducers (EMATs) possess the capability of generating Lamb waves. The waves manifest the characteristics of multi-mode, dispersion and weak singal, which limit the development and application of EMATs. To enhance the signal of Lamb wave EMATs, we proposed an optimal design method. By adding super-microcrystals between the permanent magnets and the coils, the eddy current in the surface of the permanent magnet was reduced and the eddy current in the specimen was increased. Meanwhile, the distribution of the static magnetic field was improved, and the signal intensity in the aluminum plate was enhanced. In this paper, the effect of ultra crystallite on electromagnetic ultrasonic signal was mainly studied. The finite element software was used to simulate and analyze the experiment. The experimental results show that the method can effectively enhance the intensity of Lamb wave signal.
    10  Scale model test on shallow tunnel anchorage under soft rock geological conditions
    LIANG Ninghui ZHANG Rui LIU Xinrong ZHONG Zuliang
    2016, 39(6):78-86. DOI: 10.11835/j.issn.1000-582X.2016.06.010
    [Abstract](871) [HTML](351) [PDF 3.44 M](920)
    Abstract:
    In order to study the deformation and bearing capacity of the tunnel anchorage, a field model test on the scale of 1:30 was carried out on the north shore of the Chongqing Jijiang Yangtze River bridge. The follow conclusions are drawn:From the design load (240 kN) to 1 680 kN, the average maximum displacement of the front anchor face of the anchorage along the drawing direction ranges from 0.020 mm to 0.808 mm, and the average maximum displacement of the upper rock mass above the front and the rear ends of the anchorage along the vertical direction ranges from 0.028 mm to 749 mm and 0.014 mm to 0.645 mm, respectively; The failure type of the rock-anchor system is tension-shear failure; About 2-3 m range rock mass above the lateral direction of the two anchorages participates in bearing deformation, and the damage area of the rock mass along the axis of the anchorage is similar to a plug body; The reliable bearing capacity of the anchorage model under tension is 1 344 kN through the model test; The rheological behavior of anchorage model under tension of 840 kN is stable, and its long-term stability coefficient is 3.5. The results of the model test show that the tunnel anchorage has high bearing capacity under tension, thus, the design scheme is proved to be feasible.
    11  Parameter design and soft-switching frequency characteristics of capacitive power transfer systems with a LCL resonant circuit
    DIAO Qinqing ZHU Lingyun
    2016, 39(6):87-94. DOI: 10.11835/j.issn.1000-582X.2016.06.011
    [Abstract](888) [HTML](399) [PDF 2.69 M](1003)
    Abstract:
    To simplify the complex parameter design process and reduce the switching loss of CPT (capacitive power transfer) system with a LCL resonant circuit, we proposed a simple parameter design method based on impedance transformation principle and presented a calculation method for the soft-switching frequency. With the stroboscopic method and the fixed-point theory, the precise ZCS (zero current switching) soft-switching frequencies can be calculated. The effect of the coupling capacitance and the load resistance on the soft-switching frequency was analyzed, and then the capacitance and the load range allowing the soft-switching were given. A simulation model and an experimental prototype were built to verify the accuracy of the parameter design and the soft-switching frequency. It shows the whole efficiency of the system is about 87%.
    12  Preparation of Ni-Co sulfide and the influence of reaction temperature on the morphology and the properties of supercapacitor
    LIAO Mingjia QIAO Lei CHEN Haian JIE Fangfang
    2016, 39(6):95-100. DOI: 10.11835/j.issn.1000-582X.2016.06.012
    [Abstract](1083) [HTML](426) [PDF 2.43 M](1768)
    Abstract:
    Nickel cobalt sulfidenanospheres was synthesized by facile solvothermal synthesis method. The properties of the as-prepared Ni-Co sulfide powders were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Cyclic voltammetry (CV), galvanostatic charge-discharge measurement were also employed to test the electrochemical performances of nickel cobalt sulfide as electrode material of supercapacitor. The mass specific capacitance and the area specific capacitance of the electrode prepared under 160℃ was 1 298 F/g and 1.13 F/cm2 respectively at charge and discharge current density of 2 mA/cm2. After a 10 000 cycle test at current density of 10 mA/cm2, the specific capacitance retains 70.8% of its initial capacitance. In addition, the influence of reaction temperature on the performance of the supercapacitor was studied by controlling the reaction temperature. The results show that the reaction temperature have little influence on its morphologies, but a certain impact on electrochemical performance.
    13  Resonance frequency prediction of reradiation interference from power lines in medium wave band based on the generalized resonance
    TANG Bo CAO Hongying WANG Shuang PENG Youxian LI Yu
    2016, 39(6):101-110. DOI: 10.11835/j.issn.1000-582X.2016.06.013
    [Abstract](813) [HTML](330) [PDF 2.30 M](1136)
    Abstract:
    The existing IEEE (Institute of Electrical and Electronics Engineers) standards, which are developed based on antenna theory, can only explain the reradiation interference mechanism of transmission lines within a limited frequency band of 0.5~1.7 MHz. To study the reradiation interference at higher frequencies, the generalized resonance theory was introduced in this paper, and a method for predicting resonant frequency based on the energy balance of electromagnetic fields was proposed. By taking the power transmission lines, tower arrays and antennas in a large-scale space as a generalized closed system, we were able to derive the expression of the generalized resonance factor of a open electromagnetic system based on the complex Poynting theorem, and hence to obtain the resonant frequencies of reradiation interference, which were the zero points of the generalized resonance factors. Unlike the conventional methods, which take towers as half-wave antennas, this method is able to predict the resonant frequencies of reradiation interference in mid-wave frequency band. The method was used to calculate the examples in IEEE standards. The results show that at frequencies below 1.7 MHz, the error between the prediction results and the resonant frequencies measured using scaled models is no more than ±0.169 MHz.
    14  Inverse Petri net and its application to spindle fault diagnosis
    GU Dongwei ZHANG Xuewen WANG Zhiqiong SHEN Guixiang ZHANG Yingzhi
    2016, 39(6):111-117. DOI: 10.11835/j.issn.1000-582X.2016.06.014
    [Abstract](895) [HTML](340) [PDF 3.12 M](848)
    Abstract:
    In order to quickly find the cause of the spindle failure, inverse Petri net was adopted to diagnose the fault of CNC(computerized numerical control) machine tool spindle. An inverse Petri net model of related failure for CNC machine tool spindle was established to obtain the inverse Petri net reachability graph of the spindle. And the failure of subsystems, failure modes and failure causes can be thorough analyzed. In addition, the relevance of fault modes and fault causes can be analyzed by the reachability graph. By analyzing state transferring reachable set, we can grasp the transmission process of spindle related failure and get the root cause of failure. By taking the loud noise of spindle as an example, its fault diagnosis process with inverse Petri net was described. Studying inverse Petri net of spindle related failure can help to diagnosis and repair the spindle quickly, shorten the repair time and improve the availability of the spindle.
    15  Load-sharing characteristics of two-stage five-branching star gear by considering deformation coordination
    DONG Hao FANG Zongde WANG Baobin
    2016, 39(6):118-126. DOI: 10.11835/j.issn.1000-582X.2016.06.015
    [Abstract](851) [HTML](315) [PDF 3.75 M](861)
    Abstract:
    In order to analyze the load sharing of two-stage five-branching star gear, the coordination conditions of torsion angle deformation were derived according to the power flow closed-loop characteristics of the system. Based on the theory of moment equilibrium condition and equivalent meshing error, the load sharing model under static condition was established, and the load sharing coefficient was obtained. The influence of manufacturing error, installation error, component floating on load sharing characteristics was analyzed. Results show that when sun gear, ring gear and star gear error independently act on load sharing characteristics, the the ring gear error influence is the biggest. Each component manufacturing error periodically affect the load sharing coefficient. The sun gear floats based on spline clearance and radially in the ring gear, which helps to improve the load sharing characteristics. The correctness of the theoretical analysis is verified by experiments.
    16  Synthesis of graphene oxide nanosheets with ultrasonication-centrifugation process
    ZHANG Xing LUO Zhijia ZHANG Songting LU Zhanguo DU Baotan CHEN Kai MA Sujun ZHANG Jinqiu WANG Jing WANG Jie GENG Hongzhang
    2016, 39(6):127-134. DOI: 10.11835/j.issn.1000-582X.2016.06.016
    [Abstract](1005) [HTML](623) [PDF 4.88 M](2118)
    Abstract:
    Graphene oxide(GO) was prepared by modified Hummers method utilizing natural graphite powders. The obtained GO was dispersed in water and broken into small pieces with different sizes by ultrasonication. Then, the GO dispersion was separated by centrifugation. At last, more uniform graphene oxide nanosheets were obtained. Through statistical analysis of the size of GO, based on vast of field emission scanning electron microscope (FE-SEM) images, it is can be found that the size of GO could be effectively controlled by adjusting ultrasonication power, ultrasonication time, centrifugation speed and centrifugation time. With the optimized parameters of ultrasonication-centrifugation (UC) process, GO nanosheets with an average size of about 100 nm were synthesized, and the content of GO nanosheets smaller than 100 nm was more than 60%.
    17  The establishment and testing of a model called virtual articulated arm coordinate measuring machine
    FENG Xugang XU Chi ZHANG Jiayan XU Qiang FEI Yetai
    2016, 39(6):135-140. DOI: 10.11835/j.issn.1000-582X.2016.06.017
    [Abstract](951) [HTML](396) [PDF 3.27 M](981)
    Abstract:
    The measurement error of articulated arm coordinate measuring machine is affected by various factors, and the error caused by the physical component cannot be eliminated. This paper aims to construct a virtual articulated arm coordinate measuring machine. First, the measuring machine's kinematics model was built by using D-H (Denavit-Hartenberg) matrix. Then the measuring machine's data was analyzed by utilizing PC-DMIS measurement software and the accuracy of the model was tested. Finally, the simulation was carried out with Monte Carlo method. By comparing the models constructed with the actual parameters and the manufacturer parameters, it is showed that the measuring accuracy of the established measuring machine's model can satisfy requirements. The result of simulation indicates that the virtual model and the testing method we proposed are of great engineering value to the application of the coordinate measurement.
    18  A new car-following model with consideration of anticipation drivingbehavior and its stability analysis
    ZHOU Tong ZHENG Linjiang LIU Weining
    2016, 39(6):141-147. DOI: 10.11835/j.issn.1000-582X.2016.06.018
    [Abstract](757) [HTML](375) [PDF 5.46 M](936)
    Abstract:
    Based on the OV model, a new microscopic anticipation driving car-following model was proposed to study the relationship between anticipation driving behavior and traffic congestion. The stability criterion was derived by using stability theory. The simulation results show that the new model can simulate practical traffic phenomena, such as stop-and-go, system critical phrase transition, etc., and its simulation results are more close to practical value than that of the OV model under the open boundary conditions. At the same time, the anticipation driving effect can enhance the stability performance of traffic flow, improve the threshold of density which the state of traffic flow will turn into congestion state and reduce the effect scope of congestion, finally the optimal value range of anticipation parameter in the new model is obtained under the open boundary conditions when viewing the minimum smoothness and minimum fluctuation amplitude of speed as the evaluation index.
    19  Potential output and output gap model based on GRNN algorithm
    ZHANG Qiangjin CHEN Zhonghua
    2016, 39(6):148-154. DOI: 10.11835/j.issn.1000-582X.2016.06.019
    [Abstract](940) [HTML](399) [PDF 2.25 M](1626)
    Abstract:
    Based on the advantages of learning and non-parametric estimating of neural networks, we built a general regression neural network (GRNN) model to estimate the output gap and the potential output growth of China according to the data from 1978 to 2015, and predict the data from 2016 to 2020. Meanwhile, the relationship between the mentioned data and the economic growth was empirically analyzed. The model can overcome the problems of the function form determined by the presupposition in the production function method and different results coming from different functions, and the estimated output growth has a high degree of fit with the economic growth. Based on the model analysis, it is concluded that if China's economic growth rate is maintained at the level of potential output growth rate, the inflation rate will be maintained at a reasonable level, and the balance between supply and demand will be well achieved.

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