Dynamic arc models and computer simulations of circuit breakers

The purpose of this thesis is to investigate the dynamic models of the electric arcs andsimulation of medium and high voltages circuit breakers.In power systems, it is very important to switch the load and source without anyproblem and to provide a reliable protection in the case of short circuit faults. Most of theshort circuit faults are in the form of electrical arcs. Also, electrical arcs occur between thecontacts of the circuit breakers. Determination of current flowing in the system and changes inthe voltage under these conditions is important for the protection process and for the design ofthe circuit breakers. Although an electrical arc can be modeled as a constant resistor, moreaccurate models are needed for a detailed analysis. To achieve this, dynamic arc modelswhose characteristics varying with time are used instead of constant resistance models.However, there are some difficulties in simulation of these models. With a recently developedstate-space technique, it has been shown that non-linear and time-variant circuit elements canbe modeled easily.In this thesis, the structure and the types of the circuit breakers are investigated, anduseful knowledge about the occurrence and the types of the electrical arcs is given. Variousarc models are simulated using a benchmark power system in MATLAB and the state-spacetechnique is also used for transient simulation of fault arcs. Arc current and voltage areobtained.