The pair were disturbed at the transformer unit near Old Inverlochy Castle by SSE engineers responding to loss of power in the Caol and Inverlochy areas.
Police Scotland said the incident happened at around 3am.
A spokesman said: “On further inspection it was clear that there was an attempt to remove copper from a transformer unit at the sub-station, which caused a short power cut.
“Police Scotland wishes to highlight the extreme dangers to anyone interfering with any electrical infrastructure.
“In addition to the risk to life to those committing this type of crime, considerable disruption is caused to communities affected when the power is cut.
“It is anticipated that there may be some further disruption to power in the Inverlochy area today as engineers carry out repairs.”
Police Scotland are appealing for anyone with information in relation to this crime to make contact on 101.
SCOTSMAN TABLET AND MOBILE APPS