Analysis of the Integrated Effect of Temporary Overvoltages, PV Transformer Connection and Overcurrent Protection in Hybrid PV-Wind Energy System

Abstract

The integration of solar and wind energy in hybrid PV/Wind energy systems (HPWES) have allowed it to be more reliable renewable energy source. However, the overvoltage protection for HPWES is scarcely covered in literature. To fill this gap, an investigative analysis of the effect of temporary overvoltages (TOVs) in HPWES is presented in this paper. Sources of TOV considered were ground faults and load rejection events. The HPWES was simulated and tested for TOVs under different fault conditions. The results showed that the TOV response was dependent on three more elements; overcurrent protection relays (OCRs), surge protective devices (SPDs) and the type of the PV transformer connection. The analysis showed that an interactive effect between these three elements after the occurrence of TOVs. This interactive effect has affected the tripping time of the OCRs which in turn affected the TOV duration and the energy absorbed by SPDs. It was concluded that the impact of the type of transformer connection and OCR tripping settings upon SPD could be critical that in some cases could lead to SPD failure. Conclusions are presented to the designers of HPWES to consider them during the design phase to overcome possible failures of SPDs.