The Mayr-Pentegov Model of Electric Arc with Selected Static Current-Voltage Characteristics

The basic properties of the Mayr-Pentegov mathematical model of the electric arc were described. A set of generalized functions has been selected to approximate static voltage-current characteristics. On their basis, derivatives of the conductance function relative to the squared current, which are used to calculate the non-linear damping function, were determined. Families of static characteristics dependent on parameters of approximating functions are presented. As a result of the simulations of processes in the circuit with the electric arc model, the family obtained dynamic voltage-current characteristics. By using wide ranges of parameter changes, the usability of the developed model using various approximations of static characteristics was demonstrated.

Optimisation of electric arc model parameters based on simplex annealing and genetic algorithms

This paper presents the method for obtaining the coefficients of the dynamic Cassie-Mayr electric arc model by means of annealing and genetic optimisation algorithms. The extraction of the coefficients can be obtained by means of the iterative fitting process based on e.g. multiple measurements results. However, this requires a significant effort and can generate significant costs. The approach presented in this paper relies solely on simulations. The methodology used herein consists in finding the match to the maximum produced TRV generated during high-voltage shunt reactor current breaking, for ideal switch and conductance based Cassie-Mayr circuit breaker models. This is done for a given chopping current value assigned to the ideal switch which is used as a target. The arc model coefficients are obtained by means of the optimisation process for various values of the desired chopping current level to be reflected by the Cassie-Mayr conductance-based electric arc model. As a result, an advanced conductance based model can be used for assessment of switching overvoltage. Genetic and simplex annealing algorithms have been selected for optimisation. The models as well as the optimisation process were conducted in EMTP-ATP software using its built-in functionalities. The article presents the error assessment and sample traces.

Estimation of the Intensively Blasted Electric Arc Model Sensitivity to Selected Variables

<p>Results of measurements carried out on the fabricated experimental modular-type arc heater serve as input data for the designed simplified model of the intensively blasted electric arc burning in argon inside the cylindrical arc heater's anode channel. The axial dependence of the arc temperature and radius is expressed using the exponent, the current density on the cathode tip and the arc temperature at the end of the near-cathode boundary layer. These quantities form the vector of state variables that is sought to minimize the value of the objective function expressing the deviations between measured and computed values. On a typical example, the paper demonstrates the sensitivity of the modelling to individual state variables.</p>