19. Voltage Fault Ride-Through Operation of Solar PV Generation

Solar PV (SPV) resource-based distributed generation units with installations ranging from few kW to hundreds of MW are an immediate solution to meet the ever-increasing energy needs. Voltage fault ride-through (FRT) operation is an emerging requirement for SPV units that ensures reliable operation of the utility grid. This chapter discusses different aspects pertaining to the voltage FRT operation of the SPV generating units. The present grid code pertaining to the voltage FRT operation of SPV units for different countries is presented followed by the description of the IEEE 1547-2018 standard. The recent addition in this standard like provision for multiple FRT operation, abnormal performance categorization of generating units, and multiple performance regions within the ride-through characteristics is emphasized. The structure and control of a conventional double-stage SPV unit are elucidated with an analysis of response of the SPV unit for both high and low voltages at the network interface during symmetrical faults. The possible solutions for both control and structural changes required to facilitate the voltage FRT operation of SPV units are explained. A detailed methodology for retrofitting the existing PV units with crowbar circuit option or energy storage option is presented along with the design examples considering practical scenarios. Finally, a control strategy is presented in synchronous reference frame for facilitating the voltage FRT operation of the SPV unit along with the simulation case studies for both high- and low-voltage ride-through operations of the retrofitted SPV unit.