A new heavy-duty 3-phase oil circuit recloser

THE ECONOMIC DESIGN of automatic circuit reclosers has been made possible through the use of a series solenoid which opens the recloser when current exceeds a minimum trip value and stores energy for automatic reclosing. As the power output of the series solenoid at minimum trip current is small, this design has limited 3-phase reclosers to single-pole operation. Single-pole operation has the disadvantage that feedback through transformer banks can prevent the interruption of transient phase to ground faults and cause unnecessary lockout of the recloser.