"Transmission lines" running over the rear of the property could be a problem if the property lies within an easement for the same. "Distribution lines" wouldn't be a problem unless they pass over improvements. Not sure about getting a response from HUD, better to let 4000.1 be your guide. Here is the specific guidance from page 582-583 revised 01/18/2023…
Overhead Electric Power Transmission and Local Distribution Lines
(a) Definitions
Overhead Electric Power Transmission Lines refer to electric lines that supply power from power generation stations to Local Distribution Lines.
Local Distribution Lines refer to electric lines that commonly supply power to residential housing developments, similar facilities and individual Properties.
The Appraiser must notify the Mortgagee of the deficiency of MPR or MPS if the Overhead Electric Power Transmission Lines or the Local Distribution Lines pass directly over any dwelling, Structure or related property improvement, including pools, spas, or water features.
The Appraiser must notify the Mortgagee of the deficiency of MPR or MPS if the dwelling or related property improvements are located within an Easement or if they appear to be located within an unsafe distance of any power line or tower.