Negative Effects of Cyber Network (Control, Monitoring, and Protection) on Reliability of Smart Grids Based on DG Penetration

Smart grid is a cyber-physical system containing two heterogeneous networks including power and cyber network (control, monitoring, and protection systems). Without the cyber network, the power grid cannot work effectively and reliably. The reliability indices of smart grid can obtain accurate results if the cyber-power interdependencies (CPIs) are taken into account. In this paper, a novel analytical method is proposed to evaluate the reliability indices. The eventual cyber impacts on reliability of smart grid are analyzed based on the distributed generation (DG) penetration. Because of the important factors such as CPIs effects in presence of DGs and investigating in probabilistic condition, they are included in the proposed method. Reliability assessment of smart grid using renewable DGs besides conventional ones is one of the novelties of this paper. The method is applied to a realistic distribution network of Hormozgan Regional Electrical Company (HREC). The test results indicate that reliability evaluation without considering the CPIs is along with significant inaccuracies. Moreover, results demonstrate the reliability variation, as a function of the DG penetration level, presenting a rather monastically increasing characteristic which saturates after a certain DG penetration level. Furthermore, to improve reliability indices, it is vital to consider cyber effects in presence of DGs in different scenarios especially with existence of renewable DGs having probabilistic nature.