If you are looking for a distribution substation you should know that the word substation comes from the days before the distribution became a grid. This is important because a switchgear is directly related to the reliability of the electricity supply. Relating to electrical switchboards, a sub station may include transformers to change voltage levels between high transmission voltages and lower distribution voltages. This could also happen at the interconnection of two different transmission voltages.
A non segregated phase bus is a metal enclosed, non segregated phase bus designed specifically for 600 V, 5 kV or 15 kV applications. Siemens bus plugs are available in 240V and many other sizes. By using company provided diagrams, getting your bus plugs and phase bus installed will not be difficult. By getting professional help all your non segregated phase bus needs will be filled.
A medium voltage switchgear line up would be a metal enclosed structure with electrically operated switching elements using oil circuit breakers, by the early 20th century. When you are considering electrical switchboards you should remember that substations generally have switching, protection and control equipment and transformers.