Inductive Load Switching

The inductive load switching cases to be considered are the switching of shunt reactors and unloaded transformers. Shunt reactors with isolated neutrals are applied at system voltages up to 170 kV. Those applied at so‐called medium voltages of 52 kV or less are typically on the tertiaries of system transformers. Above 52 kV, the shunt reactors are connected directly to busbars. Each case is treated separately using actual application examples. Shunt reactors with neutral reactor earthed neutrals are most common on EHV systems, i.e. at system voltages of 300 kV or greater, in order to enable single‐pole fault‐clearing. The purpose of the neutral is to ensure that the secondary arc is extinguished before reclosing on the faulted phase. For circuit breakers applied, particularly at 72.5 kV and above, experience has shown that reignitions are to be avoided.