In cooperation with the Iranian Nuclear Society

Document Type : Research Paper

Authors

1 Mechanical Engineering Department, Shiraz University

2 Safety Research Center of Shiraz University

3 Mechanical Faculty of Shiraz University

Abstract

The reliability of the transmission grid affects the occurrence frequency of Loss of Offsite Power (LOOP) to the non-passive nuclear power plants (NPPs), as the most dominant core damage-inducing initiating event. Meanwhile, the recent tendency toward the connection of wind farms to the transmission grids, regarding the existing economic and environmental merits, influences the stability of the grid. Therefore, the need to investigate the effects of the former on the frequency of occurrence of Grid-Related LOOP is indubitable. In this regard, this study surveys the effect of change in the grid conditions in terms of wind penetration on the occurrence frequency of GR-LOOP. For this, the proposed methodology is applied to the grids in various operational conditions, regarding the percentage of wind farm penetration, loading conditions, and power flow method. Afterward, the frequency of occurrence of GR-LOOP scenarios upon 3-phase short circuit faults on the transmission lines is evaluated for the pre-fault grids with 0%, 10% and, 20% of wind penetration, as 3.23E-05, 4.49E-05 and, 4.86E-05/ (reactor-year) for the riskiest power plant location. The results for the safest location are 8.58E-06, 1.55E-05, and 1.52E-05/ (reactor-year), respectively. The results highlight the non-negligible impact of the percentage of penetration of wind farms in the mixed grids on the GR-LOOP frequency. Furthermore, the non-linearity and non-proportionality of the changes of the corresponding frequencies with the percentage of wind penetrations in the grid signifies the importance of considering the latter in safety studies of nuclear power plants.

Keywords