Line Discharge by Potential Transformers

The isolation of a section of a high-voltage transmission line or cable may leave the section charged to a voltage in the order of operating values. Upon automatic reclosing, dangerous transient overvoltages which may exceed tolerable overvoltage factors could be produced unless the isolated section is discharged to a small fraction of operating voltage. Of all the means presently available that act to discharge the section, including shunt devices and circuit- breaker resistors, the electromagnetic potential transformers (under conditions described in this paper) could be the most effective. A theoretical analysis of the discharge phenomena which permits determination of instantaneous voltage as a function of time is included.