الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
Switching operations in power networks associated with circuit
breakers are a common cause of transient disturbances, so recent attention
has focused on the transient voltage interaction of a switching device. With
the widespread application of vacuum breakers for transformer switching,
recently, this phenomenon has been attributed to a significant number of
transformer failures.
Vacuum circuit breaker switching of electric arc furnace transformers
raises concern because of their inductive currents. High-frequency transients
and overvoltages result when the vacuum breaker exhibits virtual current
chop and multiple re-ignitions.
This thesis will present a detailed case study of vacuum breaker
switching of arc furnaces transformer involving current chopping and
restrike simulations using the electromagnetic transients program (ATP).
Overvoltage transients were calculated and discussed at the different points
in the arc furnace circuit, especially at the arc furnace transformer terminals.
Several techniques and equipment that have proven to successfully mitigate
the breaker switching transients were presented including surge arresters,
surge capacitors, and RC snubbers.