The invention utilizes modified form of Event Tree Analysis (ETA) technique for developing a semi-quantitative approach for modeling and estimating cyber-risks due to timing intrusions in the power system towards development and experimentation of timing intrusion detection systems in the planning stage. The method is able to capture the vulnerability of the components of the power system to cyber-attacks, and the impact of such attacks on data which is being used as input for various power system applications and controls within utilities.