With the Content-Aware Spot Healing tool you can easily remove power lines from images.
Simply follow these steps: Using the Pen tool, create a path that follows the powerline you want to remove.
Then select the Spot Healing Brush tool and click on the Content-Aware option in the Options Bar.
Change the brush size to about twice the width of the wire and in the Paths panel (Window > Paths), go to the flyout menu (four line icon on the top right) and choose “Stroke Path” and select the Spot Healing Brush from the drop down.
This will stroke the path and remove the power lines!
Watch the video tutorial here: