The primary risk of not short-circuiting a current transformer secondary is the development of what?

The primary risk of not short-circuiting a current transformer secondary is the development of dangerous high voltages. Current transformers are designed to operate with their secondary short-circuited; this allows them to provide a low voltage proportional to the primary current. When the secondary is open-circuited while current is flowing through the primary winding, the current transformer continues to induce a voltage in the secondary circuit. Since there is no place for the induced current to go, this can lead to extremely high voltages that may exceed the insulation rating of the transformer, posing safety hazards.

This high voltage condition can result in electrical arcing, equipment damage, and significant safety risks for personnel working around the equipment. Maintaining the integrity of the current transformer through proper short-circuiting of the secondary is essential to prevent these dangerous high voltages from occurring, ensuring both equipment longevity and safety in the substation environment.