Examining overhead power lines is one of the classic applications of IR cameras.
Here the transformer mounted halfway up the poles is clearly warm, as it generates heat when stepping the supply voltage down for delivery to a nearby building. Of greater interest to the line checker is the temperature of the glass or ceramic insulators at the top of the installation: if one cracks or starts to fail, that insulator will appear significantly warmer than the others, and can be replaced before it shorts out completely.
Below the lines, the rough grazing is relatively warm too, in comparison with the cold sky. The lowest section of the poles appears very warm, but this is most probably an artefact resulting from the relative thinness of the poles compared to the resolution of the camera. The fine wires and sharp horizon are the result of the superimposed visible light image, with MSX processing.