In this chapter, an integral approach for Grid-Forming and Black-Start capability of a large-scale interconnected Power System model is developed. This chapter introduces a model for Electro-Magnetic Transients (EMT) simulations, where a three-area power system is presented, containing different devices interfaced to the transmission network via voltage-source converters (VSC); seventeen wind power plants (WPP), seven battery-energy storage systems (BESS), and two HVDC transmission links. Of the total energy produced in this model, 90% is generated by the WPP and the other 10% by conventional generation units (CGU). The control systems that regulate the WPP and the HVDC stations were upgraded with Grid-Forming capability. Therefore, the power system model is suitable for simulations during both steady-state and transient operational scenarios. If the latter case may derive in a Blackout, it allows simulating Black-Start and Restoration strategies. The proposed grid-forming and black-start capabilities were tested with various EMT simulations reproducing severe short-circuit faults, deriving in a full blackout in one of the areas of the power system. The model also was upgraded with five protection relays with a restoration algorithm that determines the best re-energisation path for the fastest possible restoration strategy. The simulation results demonstrate that a power system with high penetration of converter-based generation and transmission is completely capable of managing a grid during all circumstances if its control systems are designed to do so, without encountering the problems arising from current injection control.