Optimal damping controller design for large-scale PV farms to damp the low-frequency oscillation

Abstract

With increasing the number of large-scale photovoltaic (PV) farms (LPFs) connected to the power grids in the world, some characteristics of power systems are affected. Studies show that the LPFs could have the negative effect on lowfrequency oscillation (LFO) relative to their location and size. Considering that the LPFs cannot be located in ideal points and their installation location depends on geographical conditions, it is important to consider an auxiliary controller as a damping controller for them. On the other hand, the new generation of LPFs has a centralized plant controller (CPC) for voltage and power regulation at the point of common coupling (PCC); therefore, it is required to add the damping controller to the CPC. In this paper, the LFO damping by an optimal damping controller (ODC) that implemented in the CPC of LPFs is proposed. The ODC structure is a single input 2nd-order lead-lag controller. A benchmark test system for LFO studies is used to show the performance of the proposed ODC. The robustness of ODC is assessed in the different operating conditions. The simulation results demonstrate the proper function of the proposed ODC for the wide range of operating conditions.