Digital Twin of Photovoltaic Power Plants Considering Spatio-Temporal Characteristics

Due to the rapid increase in photovoltaic power plant penetration in electricity grids, it has become increasingly important to model the impact of plant site-specific characteristics on system behavior when developing systems to meet grid regulations. In a large-scale PV system, not all panels can operate under the same conditions, so meteorological data from a single point in the field cannot accurately map the electrical characteristics of the plant. Differences at this point cause a cumulative gap in energy calculation in the long term. While it may be possible to solve this issue by using sensors with higher resolution in spatial manner, it is not economically or technically feasible to take measurements using too many sensors under field conditions. In addition, due to the difficulties in proper maintenance, the reliability of the sensors used in the field is reduced due to factors such as dust, dirt, lack of calibration and malfunction. As an alternative, this study develops an equivalent lumped model instead of a distributed model to approximate the electrical characteristics of the PV plant. This model is based on the concept of relational matrices depicting spatial and temporal characteristics of the field. These matrices are dynamic in nature and allow the electrical behavior of the entire site to be mapped over time. The results obtained with the static and dynamic Matlab/Simulink models are compared with field measurements to demonstrate the effectiveness of the proposed method. The developed models are used for LVRT compatibility tests and broadcast and individual inverter control approaches are compared from a grid code perspective.