The main problem of working in the field of utility is that the personnel need to work at heights mostly and this is particularly dangerously regardless of the safety precautions taken. Moreover, working in the field of utilities can expose humans to live high voltage circuits which can totally fry a human body within microseconds. All such dangers are overcome by using drones in place of inspectors who would have to physically go close to these utility lines.
When you deploy the humans to carry out the job of inspecting the lines for fault, there is a lot of time taken with safety precautions and physical limits being two major reasons. But with the drones those concerns are futile and they can normally reduce the time of inspection greatly.