General presentation
Instrument transformers - General information. Theory. How it works

High-voltage (HV) substations are the site of exceptional electrical and electromagnetic disturbances, due in particular to equipment switching. The lines are exposed to atmospheric discharges, and transmit rapid surges corresponding to the equipment coupled to them.

As a result, very high amplitudes of interference (several kiloamperes, several hundred kilovolts) are superimposed on the nominal current...