Here is a list of Power BI conferences for the remainder of 2018. I attended the Chicago World Tour last year and learned a great deal about many topics in Power BI. It was so great I am planning on attending another World Tour this year.

Business Applications Summit: ($895, I think)
Jul 22-24 Seattle WA

World Tour:  Cost $399 early bird, $499 full
Aug 21-22 Melbourne Aus
Aug 28-29 Sydney Aus
Aug 28-29 Charlotte NC
Sep 11-12 Copenhagen Den
Oct 29-30 Seattle WA
Nov 13-14 Dubai UAE
Nov 14-15 Montreal Can
Nov 28-29 Dallas TX

Power Summit: ($1099 early bird through $1499)
Oct 15-18 Phoenix AZ