Choke-coils versus extra insulation on the end-windings of transformers

Surges along a transmission line are stopped and thrown back by choke-coils in a manner analogous to the reflection of water waves by a breakwater at the entrance to a harbor. The quiet of a harbor is obtained by setting up a strong wall capable of withstanding the shock of the waves that strike against it; so is the analogous quiet of a transformer obtained by placing a choke-coil in the path of a disturbance.