Distribution or transmission Line - Overhead line.
or

Waveguide - Circular, recognition symbol.
Derivative from this file.
(in English) (1993)  315-1975 - IEEE Standard American National Standard Canadian Standard Graphic Symbols for Electrical and Electronics Diagrams (Including Reference Designation Letters), IEEE  DOI:  10.1109/IEEESTD.1993.93397. ISBN:  0738109479. 
Page 46 for the first symbol, and page 48 for the second.
Michel Bakni