The International Thermonuclear Experimental Reactor (ITER) is a cutting-edge project that aims to develop a sustainable energy source by harnessing the power of nuclear fusion. One of the key challenges in the development of the ITER is the complex electrical grid that is required to support its operations. To address this challenge, a digital twin (DT) of the Central Solenoid (CS) Converter Power Supply grid has to be developed, and real-time simulation strategies have been proposed to monitor and study the performance of the ITER grid. Real-time simulation strategies allow for continuous feedback on the performance of the grid, enabling the quick identification and resolution of issues. However, it is not always possible to perform real-time simulation easily in a real-time simulator; therefore, specific strategies have to be implemented in the DT. This paper focuses on decoupling lines and explicit partitioning as solutions to allow the real-time simulation of the CS Converter Power Supply grid with two converter units (CUs), as required by the ITER Organization (IO). As will be shown later in this article, the proposed approach is progressive and applicable to a more complex grid with multiple CUs. The results concerning the proposed strategies will be analyzed and discussed in terms of real-time performance.