Yundong Cao

Numerical simulation of electric field with open boundary using intelligent optimum charge simulation method

For improving the calculation precision of the electric field, a novel combination of genetic algorithms (GA) and charge simulation method (CSM) is proposed. In which, the allocations and quantities of the optimized charges can be obtained using GA, and higher calculation precision can be achieved. The combined CSM and the hybrid conventional and optimized CSM were applied for computing the electric field of the demonstration examples. The comparison of the relative error between the conventional and optimized CSM has been obtained. The feasibility, practicability and validity of the proposed optimized CSM have been verified

Optimization of SF/sub 6/ circuit breaker based on chaotic neural network

The chaotic mechanism has been introduced to optimize the electric apparatus in this paper. By combining the chaotic mechanism and artificial neural network (ANN), the chaotic Hopfield neural network (CHNN) has been established, and applied to solve the optimum problem of the demonstrated examples. From the simulation results, it can be found that the proposed CHNN can be employed to solve the optimization problems with multivariables and complex energy function. Furthermore, a novel optimum algorithm for optimizing the electric apparatus has been provided

Electric field optimization design of a vacuum interrupter based on the Tabu search algorithm

During interruption in the vacuum interrupter, the re-ignition between the contact and the shield is influenced by the shape of the contact and size of the shield. The design of the contact and the shield is an intricate optimization problem. In this paper, the Tabu search algorithm is applied to optimize the contacts of a 35 kV vacuum interrupter. The optimization design is based on electric field computation using the finite element method. By solving the inverse problem, the optimization of the contacts is achieved, and a reasonable distribution of the electric field is obtained. Based on the combinatorial optimization Tabu search algorithm, an improved universal algorithm for continuous variables global optimization is proposed.

Design and Analyses on Permanent Magnet Actuator for Mining Vacuum Circuit Breaker

A novel permanent magnet actuator (PMA) for mining vacuum circuit breaker (VCB) is presented in this paper. Which is monostable, has two coils and able to break the VCB when the fault of low-voltage happened. And can detect the voltage variation in main circuit at each instant. When the fault of low-voltage happened, it can automatically break without additional detection and control of apparatus. Moreover, the different states and parameters of breaking and closing courses have been numerical computed and analyzed by adopting ANSOFT software. Based on the simulation results, the prototype is manufactured and assembled in the mining VCB. The feasibility and validity of the proposed PMA have been proved by testing results

Study on Chaotics of Turbulent Gas Flow for a EHV SF6 Circuit Breaker

Based on the numerical computation of 2D compressible, viscous and turbulent gas flow physical-mathematical model for a extra high voltage SF 6 circuit breaker (EHV SF 6 CB), the aerodynamic behavior and pressure characteristics under no load interrupting have been obtained using the improved combination method of FVM and TVD scheme. And the pressure time series of different points, the phase space reconstruction of pressure time series have been achieved. Moreover, the embedding dimension and delay time are obtained using C-C method. And the largest Lyapunov exponent (LE) of the pressure time series using small data sets method has been calculated, which illustrates that the system exists chaotic behavior. Furthermore, the principal component analysis (PCA) shows that, during no load interruption, the turbulent gas flow pressure time series is a chaotic series.

Flow rate measurement system using thermal air flow sensor

An intelligent digital flow rate measurement system is presented to replace the conventional hot-wire flow rate measurement system, which uses original analog feedback circuit. In this paper, the conventional Wheatstone bridge measurement circuit is replaced by a new Pulse Width Modulation (PWM) circuit for the purpose of energy conservation. The system employs a PIC18F452 chip to interface a thermal flow measurement system to measure the flow rate. And a signal prediction algorithm is introduced to speed up the measurement. It has been proved that the performance of the intelligent digital flow rate measurement system has been increased compared with conventional flow rate measurement system based on the thermal air flow sensor.

Optimization of Extra-High-Voltage SF

Electrode contour optimization of arc quenching chamber of extra-high-voltage SF6 circuit breaker using the proposed variable interval genetic algorithm (VIGA) has been carried out to obtain not only a uniform field but also a dynamic distribution of electric field strength along different contact surface. In order to investigate the validity of VIGA quantitatively, optimization of two testing functions has been computed in detail. From comparison of the optimized solution to the analytical solution for the testing functions, the feasibility and practicability of the proposed VIGA has been verified. Moreover, in optimization, for enhancing the convergence efficiency of the optimization, the real-coded mode and improved blend-crossover strategy is proposed and applied.

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In this paper, the axial magnetic field of vacuum interrupter (VI) has been computed. Moreover, the static, transient magnetic field and 3D electric field have been analyzed using finite element method (FEM). The dynamic distributions of the axial magnetic field along the contact surface varying with interrupting instant and space have been simulated. Accordingly, the influence of the contact structure on the interrupting and insulation performance has been analyzed. The theoretical basis for optimizing the structure and investigating the interrupting capacity of the vacuum circuit breaker (VCB) has been provided

Circuit Breaker Based on Improved Genetic Algorithm

Combined electric field and flow field are numerically simulated based on the computation of the N-S equation and turbulent model, taking the influence of temperature, pressure, and the effect of gas flow on the dynamic arc into consideration. In computing, self-adaptive adjustment of the current has been considered for reflecting the variation of the dynamic arc during the whole interrupting course. Moreover, the gas flow field of high voltage SF6 circuit breakers (HVCBs) with complex flow path, supersonic nozzle, source, viscous, compressible and variable boundaries has been solved. Consequently, the interaction of dynamic arc and gas flow has been simulated. The feature of dynamic arc-gas flow interaction has been numerically analyzed, and the arc choke varying with the pressure of gas flow, velocity, and the flow flux has been simulated. The theoretical foundation for further studying the utilization of arc energy and improving interrupting performance has been established

Numerical Simulation of 3D Electromagnetic Field for Vacuum Interrupter

In this paper, a combined method of traditional and optimized charge simulation method (CSM) based on the genetic algorithms (GA) is presented for calculating electric field. Based on the well studied and analyzed traditional CSM, the optimized charges locations and quantities have been realized using GA as the optimization method. The feasibility and practicability of the combined method are verified by calculating the electric field of a 35 kV vacuum interrupter (VI).