This paper presents the development of Electromagnetic Transient (EMT) and EMT-(transient stability)TS co-simulation models of power grid with photovoltaic (PV) plants. The EMT models are used to study the impact of fault disturbance events on PV plants in a bulk grid. The step-by-step approach for developing the EMT-model from the TS-model of a grid is discussed, followed by an exhaustive comparison among different grid and PV plant models to understand the effectiveness of those for replicating the event accurately. The TS-model of the Western Electricity Coordinating Council (WECC) grid, and information about the Angeles forest fault event have been utilized in this case study. The objective is to simulate the event near the fault location as well as in one of the affected large plants where partial generation loss occurred. First, a region of the grid is developed in the EMT domain to replicate the events sequentially near the fault location, and match the voltage near affected PV plant. Next, various models of the PV plant are compared in the EMT-model to demonstrate the necessity for a high-fidelity model of the PV plant that accurately replicates the partial generation loss observed during the fault event.