This paper investigates the impact of: i) the Low Voltage Ride-Through (LVRT) and Dynamic Voltage Support (DVS) capability; ii) the active current recovery rate; iii) the local voltage control; and iv) the plant-level voltage control of large-scale PhotoVoltaic (PV) systems on Short-Term (ST) voltage stability and Fault-Induced Delayed Voltage Recovery (FIDVR). Moreover, the influence on transient and frequency stability is studied briefly. To evaluate FIDVR, a novel metric, the socalled Voltage Recovery Index (VRI), is defined. The studies are performed with the WECC generic PV system model on an IEEE voltage stability test system, namely the Nordic test system. The results show that without LVRT capability the system is ST voltage and transient unstable. Only the LVRT and DVS capability help to avoid ST voltage and transient instability.Considering voltage and frequency dynamics, an active current recovery rate of 100 %/s shows the best performance. To further enhance voltage dynamics, plant-level voltage control together with local coordinated reactive power/voltage control should be applied. Moreover, the VRI provides useful information about the FIDVR and helps to compare different ST voltage controls.Index Terms-Fault-induced delayed voltage recovery, dynamic reactive power support, dynamic grid support, fault ridethrough, induction motors, large-scale photovoltaic plants. I. INTRODUCTIONA. Motivation T HE electrical power system has undergone fundamental changes due to the increasing penetration of inverter based generation, i.e., wind and PhotoVoltaic (PV) generation. The dynamic characteristics of these technologies are different from conventional synchronous generators, which may impact the performance of the power system.

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Dynamic simulations have played an important role in assessing the power system dynamic studies. The appropriate numerical model is the key to obtain correct dynamic simulation results. In addition, the appropriate model including the selection of the individual model component (such as protections, controls and capabilities) is different depending on the type of phenomena to be observed or examined. However, the proper selection of the model is not an easy task especially for Inverter Based Generators (IBGs). Considerable industry experience concerning power system dynamic studies and the dynamics of the IBGs is required for the proper selection of the IBG model. The established CIGRE C4/C6.35/CIRED Joint Working Group (JWG) has gathered a wide variety of experts which fully cover the required industry experience. The JWG provides the guidance on the model selection for analyzing the phenomena such as frequency deviation, large voltage deviation, and long-term voltage deviation, individually. This helps to reduce the computational burden as well as it clarifies the required characteristics/functions that should be represented for the power system dynamic studies with the IBGs.