Power reliability studies can minimize high costs associated with power outages. Installations must consider service reliability requirements of loads supplied and the service reliability provided by the electrical supply system. PSS power system reliability assessment and evaluation methods use probability theory to assess system reliability quantitatively.

PSS provides an electrical engineer who collects sufficient data to conduct a reliability analysis. Reliability indexes for any power system are computed from knowledge of the constituent components of the system. Alternative system designs are then studied to evaluate their impact on service reliability and the cost of changes in component reliability, system configuration protection and switching scheme, or system operating policy, including maintenance practice. The study will be completed by PSS electrical engineers, or by A/E contractors.