In this paper, we first study the voltage and electric field distribution characteristics under the basic lightning impulse level (BIL) of 2400 kV by finite element method (FEM) calculation which are affected by the i...
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In this paper, we first study the voltage and electric field distribution characteristics under the basic lightning impulse level (BIL) of 2400 kV by finite element method (FEM) calculation which are affected by the internal shielding structure of the gas-insulated bushing for the 1100-kV gas-insulated substation (GIS). On this basis, four parameters of the shielding structure are determined to be the decision variables in the optimization process. Four electric field objective functions and four potential objective functions are also proposed. Using a multiobjective optimization method, we then construct an evaluation function with the eight objective functions mentioned above, which are used to evaluate the electric field and potential distribution synthetically. Furthermore, a combination of FEM and the evolution strategy is used to construct the stochastic optimization objective function with the multiobjective evaluation function. The electric field and potential distribution of the gas-insulated bushing are greatly improved after optimization, and the electric field strength at key spots is effectively reduced. The insulation system of gas-insulated bushing for 1100-kV GIS designed by this method has passed type tests and worked well nearly 3 years. So, this optimization provides a constructive method and useful basis for the design of gas-insulated bushings for 1100-kV GIS and other electrical equipment. (c) 2013 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
An interactive multi-objective optimisation method has been introduced in this study for tuning multi-loop PID controllers. Several design specifications may be simultaneously considered in this optimisation problem. ...
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An interactive multi-objective optimisation method has been introduced in this study for tuning multi-loop PID controllers. Several design specifications may be simultaneously considered in this optimisation problem. The multi-objective PID tuning problem was then reformulated into the goal attainment framework. Minimisation of the attainment factor was used as a design index for checking the system whether it met the goals. A trade-off procedure should be performed to achieve the acceptable control effects if the goals were unsatisfied. The one-parameter tuning PID controller was introduced in this work so that the number of the tuning parameters of the multi-loop controllers was reduced. The interactive optimisation search was accordingly lightened. Two examples, a two-loop and a three-loop process, were given to illustrate the design concept.
Distributed generations (DGs) have significant benefits in the electric power industry, such as a reduction in CO2 and NOX emissions in electricity generation, improvement of voltage profile in distribution feeders, a...
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Distributed generations (DGs) have significant benefits in the electric power industry, such as a reduction in CO2 and NOX emissions in electricity generation, improvement of voltage profile in distribution feeders, amending voltage stability in heavy load levels, enhancement of reliability and power quality, as well as securing the power market. Despite the numerous advantages of DG technologies, weak capability in dispatching and management of DGs is a major challenge for distribution system operators. Hence, during recent years, several studies about various aspects of control, operation, placement, and sizing of DGs have been conducted. This paper presents a novel application of multiobjective particle swarm optimization with the aim of determining the optimal DGs places, sizes, and their generated power contract price. In the proposed multiobjectiveoptimization, not only are the operational aspects, such as improving voltage profile and stability, power-loss reduction, and reliability enhancement taken into account, but also an economic analysis is performed based on the distribution company's and DG owner's viewpoints. The simulation study is performed on the IEEE 33-bus distribution test system and the consequent discussions prove the effectiveness of the proposed approach.
In terms of the characteristics of multi-objective and interactions among optimization objectives of the tubular permanent magnet linear generator with 120 degrees phase belt toroidal winding (120 degrees-TPMLG), a mu...
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In terms of the characteristics of multi-objective and interactions among optimization objectives of the tubular permanent magnet linear generator with 120 degrees phase belt toroidal winding (120 degrees-TPMLG), a multi-objective optimizationmethod is proposed to improve the generators performances, which is based on the combination of response surface method and the genetic algorithm. First, the sensitivity analysis of different structural parameters on the performances of the 120 degrees-TPMLG is conducted to pick out the sensitive structural parameters. Then develop those sensitive parameters as optimization variables to establish the response surface equation of the generator performances including output power (P), detent force (F), and the efficiency (eta). Subsequently, based on the surface equation, the genetic algorithm (GA) fitness function is proposed to conducted the global optimization and the optimization results are finally obtained. To verify the effectiveness of the proposed optimizationmethod, the performances of the optimal 120 degrees-TPMLG are analysed and compared with the initial one. The results show that the performances including the detent force and power density of the 120 degrees-TPMLG are greatly improved, which prove that the proposed multi-objective optimizationmethod is effective for the 120 degrees-TPMLG.
For many microwave circuit designs, there are multiple performance characteristics to be optimized simultaneously. It becomes more and more difficult to design these microwave circuits with the number of structural pa...
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ISBN:
(纸本)9781728121680
For many microwave circuit designs, there are multiple performance characteristics to be optimized simultaneously. It becomes more and more difficult to design these microwave circuits with the number of structural parameters and performance characteristics increasing. In this paper, a new multiobjectiveoptimization technique, MOEA/D (multiobjective evolutionary algorithm based on decomposition) combined with FDTD (Finite Difference Time Domain) method, is proposed. As an example, a microstrip low-pass filter with 160 structural parameters and 4 performance characteristics is designed for obtaining low insertion loss, sharp out-of-band rejection, high stop-band attenuation, and good linearity. Comparisons on computational cost and searching speed are made to verify the high-efficiency of the proposed multiobjective optimization method.
Firstly,different combinations of four geometrical parameters of a wedged-ring joint structure were determined by using the response design method and structural stresses and eigenfrequencies for each of the combinati...
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Firstly,different combinations of four geometrical parameters of a wedged-ring joint structure were determined by using the response design method and structural stresses and eigenfrequencies for each of the combinations were numerically calculated by use of the software ***,a structural optimization with three objectives that were to decrease maximum stress,lighten mass and lower the first order eigenfrequency was performed and an optimal geometric parameters combination was *** last,a FEM analysis was carried out for the optimized structure and the results indicate that the maximum stress,the mass and the first order eigenfrequency decrease by 10.3%,8.2%and 0.4%,respectively.
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