Protection system plays an important function in maintaining the stability and reliability of the electric power grid. However, most of the major blackouts happened throughout the world has identified that hidden failure of a protection system is one of the major causes of system cascading failure. This paper proposes a computationally systematic approach to assess the impact of protection system hidden failures to the probability of system cascading collapse. Additional analysis is performed by analyzing the results of the probability of a system cascading collapse which will then be applied tin order to obtain the severe loading condition contributing to greater risk of critical system cascading outages. According to the findings that have been achieved in this analysis, it is essential to choose the accurate value of the hidden failure probability as it will have an impact on the probability of system cascading outages. This information is important to the system utility as it could assist the operator to determine the highest point of increased system loading condition prior to the event of critical system cascading collapse.
