Uneventful energizing of two, three phase 138,000 / 24,900 step-down power transformers using a SF6 circuit switcher.
The arms you see being lowered are just for the purpose of a visible open for maintenance. The actual current switching is made in the long horizontal porcelain insulator to the right of the arms. It contains SF6 insulating gas and contacts. The loud boom you hear before the hum of the transformer is those contacts coming closed.
