Intelligent computer simulation tools for HV circuit breakers and issues related to simulation
Intelligent simulation tools are developed within the Integrated Simulation and Evaluation Environment using Visual Studio C++ and object oriented programming. Such an environment should result in huge savings in time and cost for switchgear manufacturers. Conventional k-epsilon turbulence model has been modified to take into account of steep radial temperature gradient at the arc edge with much improved results. Investigations of computational convergence and the effects of initial conditions show that solutions independent of initial arc conditions with sufficient accuracy can be achieved with the Liverpool arc model.
Stability of a DC SF/sub 6/ arc in an axially accelerating flow
The stability of a DC arc burning in an axially accelerating flow of SF/sub 6/ is investigated. The method of normal modes is applied to the equations governing an axisymmetric, infinitesimal perturbation of a self-similar arc, and solutions are obtained numerically. Results are presented for a range of discharge conditions. The physical mechanisms causing instability are deduced from equations for the time-averaged, squared enthalpy, and velocity of a perturbation. The steep radial gradient of the density at the edge of the arc is shown to cause instability. The effect of density fluctuations in comparison with velocity fluctuations is not negligible, and the possible implication of this result for turbulent arc modeling is discussed.
Kinemamtic analysis of flying-saw vehicle
The paper analyzes the kinematic motion of the flying-saw vehicle.After the analysis,it is concluded that the ac- celerating periods and decelerating periods in both forward and backward directions will follow sin~2αcurve and,in order to increase the sawing dimensional accuracy,flying-saw vehicle must come back as soon as possible while acceleration remains constant.Based on this premise,the paper gives out the equations of kinematic motion of the flying-saw vehicle in every sta- ges and one example result in a common situation.By now this method has been used in the real situation.