Faults and Fault Ride Through strategies for grid-connected photovoltaic system: A comprehensive review

With the exponential penetration of Photovoltaic (PV) plants into the power grid, protection has gained exceptional importance in recent years for ensuring stability, reliability, security, and power quality of the power systems. Thus, to address these issues many countries have established new requirements in the form of grid codes for grid connection of PV plants. One of the main requirements of grid codes is Fault Ride Through (FRT) capability. FRT describes the power generator performance during and in post-fault circumstances. In this paper, an in-depth review is carried out on various scientific aspects of faults and FRT strategies available in the literature. First, various faults occurring in the grid-connected PV system are classified and compared along with a critical and analytical assessment of grid codes especially FRT requirements i.e., Low Voltage Ride Through (LVRT) and High Voltage Ride Through (HVRT) for various countries. Then, FRT approaches and strategies are classified and compared based on improved controller-based methods and external devices methods in detail. The existing FRT strategies are compared based on various aspects i.e., complexity, economically, and technically. After that, a case study that explains the complete design and implementation of conventional Crowbar, Bridge Type Fault Current Limiter (BFCL), and Switch Type Fault Current Limiter (STFCL) as an FRT strategies for 100 kW three-phase grid-connected PV system in MATLAB/Simulink is presented. A comparative assessment is also carried out among these strategies that validate the robust performance of BFCL and STFCL. Lastly, the conclusion is presented along with a brief proposal for future work.