This paper analyzes Power System Transient Stability Improvement through a Voltage Source Converter High Voltage Direct Current (VSC-HVDC) system with Large Wind power injection. The modern large wind farms and other renewable energy sources (RES) have no system inertia and are prone to system disturbances under fault. Though wind farms have little inertia, in the event of sudden loss of generation or a sudden loss of large load, the system frequency will start to decrease and may result into voltage collapse because the little inertia in the wind farm is not adequate to counter such large system disturbances. It is therefore crucial to analyze the existing conventional power networks before integrating large wind power into the grid. Global trend indicate that, countries are generating more and more wind power because it is a cheap source of energy and has less negative impact on environmental. In this study, one of the three synchronous generators of an IEEE 9 bus system is replaced by a wind farm of an equivalent generated power. Three scenarios investigated in this study includes a conventional generation alone, the convention generation injected with wind power and a conventional grid injected with wind power through a VSC-HVDC system. A short circuit fault to ground is initiated at 2s along the transmission line and cleared at 2.45s. Simulation results show that the inclusion of VSC-HVDC system improves system transient stability and allows large wind power injection into a conventional grid.