Which of the following is NOT a component part of a distribution system?

The correct answer is solar panels, as they are not a component of the distribution system. A distribution system primarily involves the infrastructure used to deliver electricity from substations to end users, which includes various components like distribution substations, feeder circuits, and distribution transformers.

Distribution substations play a crucial role by stepping down voltage from transmission levels to levels suitable for distribution. Feeder circuits are responsible for carrying electrical power from substations to different distribution points, and distribution transformers further reduce voltage levels to what is needed for residential and commercial use.

In contrast, solar panels generate electricity and can be part of a generation system or a customer's energy supply source but do not fit into the framework of a distribution system. They usually connect to the grid at different points and serve to supplement or replace traditional energy sources, rather than being integral components of the infrastructure designed to move electricity from substations to consumers.