Transmission System Operators (TSOs) are organizations responsible for the reliable transportation of electricity from power plants to distribution networks. They manage the high-voltage transmission lines and ensure that electricity flows smoothly across regions, balancing supply and demand in real-time. TSOs play a crucial role in maintaining grid stability and preventing outages. In many countries, TSOs operate independently from electricity producers and distributors to ensure fair access to the transmission network. They also coordinate with other TSOs to facilitate cross-border electricity trading, enhancing energy security and efficiency. Examples of TSOs include National Grid in the UK and PJM Interconnection in the United States.