The HVDC back-to-back system connects two AC systems directly without a transmission line, resembling two events occurring consecutively, hence the term "back to back." This configuration features two converters located at the same site, facilitating the transfer of power between the two AC systems. The analogy of "two games back to back" highlights the immediate connection between the systems. The discussion seeks clarification on the similarities between the diagram and the described configuration. Understanding this concept is crucial for grasping the operational mechanics of HVDC systems.