2007 Tahoe loeses all power than halfhour later comes back this has happen 3 times. jumping it does not help. new battery no help

First ,check positive/negative battery cable terminals at the battery for corrosion, make sure cable connection is tight and clean. Check positive connection at starter for loose or corrsion. Negative bolts to front of engine on right side, make sure its tight, no damage, no corrsion. Electrical senter located on left fender. Use a circuit test light clipped to neagtive and probe for 12v on the buss-bar located center of fuse panel ( large red wire on back feeds this connection. I suspect your loosing circuit at starter, but thats just my first thought if you've already have eleminated the battery posts.