Frequency and Voltage Disturbances Ride-Through Control Strategy for PV Power Plants

Large-scale photovoltaic power plants (PVPP) are being rapidly integrated to power systems worldwide. However, large penetration of PVPP will affect the frequency and voltage stabilities, especially for a weak power grid during individual and simultaneous disturbances. This paper introduces an adaptive control strategy for PVPP to accurately comply with grid code requirements and achieve fast frequency support (FFS) and enhanced low voltage ride-through (LVRT) performance during simultaneous disturbances events (SDE). The proposed control strategy relies on the support priority scheme for the grid frequency and voltage based on real-time measurements. An adaptive active power ramp rate (AAPRR) function imposed on the active power control loop of the PVPP is used to realize the simultaneous frequency and voltage support. Moreover, the voltage support is enhanced using a voltage regulation scheme that supports the voltage recovery post-fault without exceeding the PVPP inverter power headroom. The proposed control strategy demonstrates superior performance in enhancing the transient voltage and frequency responses when the power grid is subjected to consecutive and simultaneous disturbance events. The effectiveness of the proposed strategy is verified using the OPAL-RT real-time simulator test bench.