The paper considers application of the method of conversion functions for modeling converters and devices with distributed RC - parameters, including those consisting of non-linear elements, for a given frequency band...
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ISBN:
(纸本)9781509013227
The paper considers application of the method of conversion functions for modeling converters and devices with distributed RC - parameters, including those consisting of non-linear elements, for a given frequency band that satisfy the requirements of attenuation and the input(output) immittance. It proposes analytical expressions and the method of calculating the minimum required number of links in the model. The expressions and formulas allow simulation of devices with distributed RC - parameters with the required accuracy in the given frequency range.
A novel method for fault location is proposed in this paper, which is based on fault voltages and currents sampled synchronously on both ends of the fault line. This algorithm is based on precise integration. Using th...
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ISBN:
(纸本)9781509037100
A novel method for fault location is proposed in this paper, which is based on fault voltages and currents sampled synchronously on both ends of the fault line. This algorithm is based on precise integration. Using the synchronous measurement data at the ends of the fault line, it computes the voltage along transmission line. Then comparing two groups of voltage, it can find out the location of trouble spot. This method has the advantages of quick calculating speed and accurate calculating results. Both theoretical analysis and simulation results justify the feasibility of the algorithms above.
Relay protection is one of problems troubling the development of half-wavelength AC transmission technology. This paper modeled the half-wavelength line with the distributedparameter, researched the fault characteris...
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ISBN:
(纸本)9781467390682
Relay protection is one of problems troubling the development of half-wavelength AC transmission technology. This paper modeled the half-wavelength line with the distributedparameter, researched the fault characteristics and the adaptability of phase-splitting steady current differential protection theoretically and through plenty of simulation work, and analyzed its influencing factors from three respects. The result indicates that conventional steady differential protection algorithm is not very suitable for half-wavelength transmission, the sensitivity of middle range is the biggest problem. Then adaptability of zero sequence current differential protection and differential protection based on deviation of power frequency component are researched, the simulation results indicate they have better sensitivity. The research result shows the differential protection can be set as backup protection, and need to coordinate with the quick protection which protect the range close to two ends.
The flexible manipulator is a spatially distributed mechanical system. An accurate model of the flexible manipulator is essential for the positioning control of the end effector. In this study, a grey box distributed ...
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The flexible manipulator is a spatially distributed mechanical system. An accurate model of the flexible manipulator is essential for the positioning control of the end effector. In this study, a grey box distributed parameter modeling approach is proposed for the flexible manipulator with unknown nonlinear dynamics. First, a nominal Euler-Bernoulli beam model is derived to describe the linear dynamics. To compensate unknown nonlinear dynamics, a nonlinear term is added in the nominal model. The Galerkin method is used to reduce the infinite-dimensional partial differential equation (PDE) model into a finite-dimensional ordinary differential equation (ODE) model. A neural network is designed to estimate the unknown nonlinearities from the input-output data. The effectiveness of the proposed grey box distributed parameter modeling approach is verified by the simulations on a flexible manipulator. (C) 2015, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved.
Design and modeling of a micro channel Fischer-Tropsch reactor was considered in this study. A crosscurrent heat-exchange reactor was modeled using a new method, in which all the process and cooling channels are decom...
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Design and modeling of a micro channel Fischer-Tropsch reactor was considered in this study. A crosscurrent heat-exchange reactor was modeled using a new method, in which all the process and cooling channels are decomposed into a number of unit cells. Each neighboring process and cooling channel unit cells are coupled to set up material and energy balance equations, including heat-transfer equations for the entire reactor domain, which are then solved simultaneously. The model results were compared with the experimental data for a pilot-scale reactor described in the literature, and were found to be in good agreement. Several case studies were performed to see the effect of variables such as catalyst loading ratio, coolant flow rate, and channel layout on design of a reactor with state-of-the-art Fischer-Tropsch catalyst. The developed model could handle more than 5800 process channels, 7500 cooling channels, and 130 layers, with implementation of six complex reaction kinetics. (C) 2015 Published by Elsevier Ltd.
In this study, China＇s current macro-environ- mental policies as well as their implementation and management tools are analyzed. By using the basic economic methodology, detailed studies are conducted focusing on the...
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In this study, China＇s current macro-environ- mental policies as well as their implementation and management tools are analyzed. By using the basic economic methodology, detailed studies are conducted focusing on the implementation effect of contemporary China＇s typical environmental policy of the total pollutant discharge quantity control type, and also the two types of environmental management tools are compared from the perspective of implementation costs and policy uncertainty. By introduction of distributed management tools into the implementation of environmental policies, marketoriented means and the methods of economic analysis are introduced into environmental policy decision-making mechanisms, which could afford a new method for changing the current relatively low efficiency of environ- mental policy, solving the problem of＂government failure＂ in environmental policy implementation, and providing a new way to make environmental policy system more flexible and more efficient. It is of great practical significance to solve China＇s current structural, complex and accumulative environmental problems.
With the rapid development of high-speed railway technology, more and more countries enjoy the convenience which travels with high speed *** of the high speed train running on the railway use distributed power technol...
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With the rapid development of high-speed railway technology, more and more countries enjoy the convenience which travels with high speed *** of the high speed train running on the railway use distributed power technology, the converter on the train get power from traction network to supply the traction motorsIn the actual line,4-quadrant converter's(4QC) switching actions will inject harmonic into the traction network,while it may lead to the problem of the coupling resonance of the network when the harmonics match with the network's ***,in analysis of practical problems,it plays an important role if the model of the netwoek is accurateThis paper will analyze and have a comparation with the difference and accuracy of three different traction network modeling methods.
This paper presents the development of a nonlinear state observer to estimate the different gas species concentration profiles in a Proton Exchange Membrane Fuel Cell energy system. The selection of the estimated stat...
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This paper presents the development of a nonlinear state observer to estimate the different gas species concentration profiles in a Proton Exchange Membrane Fuel Cell energy system. The selection of the estimated states follows functionality and fuel cell performance criteria. The implementation is based on the finite element discretisation of a fuel cell distributed parameter model. Forward and backwards discretisation of the partial derivative equations is performed to take advantage of the boundary conditions of the problem and also to apply lumped systems theory in the synthesis procedure of the observer. A second-order sliding-mode super-twisting corrective input action is implemented to reduce the estimation error to zero in a finite amount of time. The sliding-mode control approach grants a suitable corrective action without incrementing the model-dependency of the observer. Simulation results are presented to show the performance of the proposed observer of the fuel cell internal states and to extract conclusions for future research work. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.
In this paper, a distributed parameter model for the evaporation system of a supercritical spiral water wall boiler is developed based on a 3-D temperature field. The mathematical method is formulated for predicting t...
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In this paper, a distributed parameter model for the evaporation system of a supercritical spiral water wall boiler is developed based on a 3-D temperature field. The mathematical method is formulated for predicting the heat flux and the metal-surface temperature. The results show that the influence of the heat flux distribution is more obvious than that of the heat transfer coefficient distribution in the spiral water wall tube, and the peak of the heat transfer coefficient decreases with an increment of supercritical pressure. This distributed parameter model can be used for a 600 MW supercritical-pressure power plant.
This brief presents an analytical method to study the effects of wind farm location on the interarea oscillation spectrum of large radial power systems along with a means to shape this spectrum. We consider a continuu...
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This brief presents an analytical method to study the effects of wind farm location on the interarea oscillation spectrum of large radial power systems along with a means to shape this spectrum. We consider a continuum representation of the electromechanical swing equations for the power system with the wind power injection modeled as a spatial point source forcing applied at a certain electrical distance from one end of the transfer path. The resulting forced hyperbolic wave equation for the rotor phase angle is used to derive an analytical expression for the spectrum of the power flow as a function of the wind power injection location. A simulation study shows that judicious siting of the wind farm can provide effective damping to a particular set of modes. Finally, we show how the analysis framework can be extended to provide a means of shaping the interarea oscillation spectrum for a grid with a wind farm at an arbitrary location using a simple optimal control design for the wind power output.
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