The utility discovered damage Monday at substations near Valley Center and in Wichita.
Westar Manager Doug VenJohn says thieves have hit 31 substations in April. There were only 15 similar thefts all of last year.
Westar crews were at six different substations Monday to make repairs related to copper thefts.
Westar is replacing the copper stolen with something with no scrap value. But VenJohn says the material is more expensive, takes special crews to install and is more time-consuming. He says that increases costs, which will eventually be passed on to customers.