The most applied method for reliability study is: Markov analysis method (state -space analysis) because it is an efficient and realistic method as it takes into account the repair transition aspects whereas other methods, like Cut -set, Tie -set, Path tracing, and Fault tree analysis, neglect it.This book studies the reliability of Iraqi national super grid using Markov method in contribution with reduced tie set method and comparing the results obtained with predetermined reliability indices using Fault tree method. The book introduces a Markov reliability model for Iraqi whole region by studying the operational data in 2009. The most important reliability indices are found namely failure rate, and repair rate. The availability and reliability are evaluated taking into account dividing Iraqi national (400 KV system) super grid from operation and control point of view to three operational subsystems: North region, Middle region, and South region. which are connected in parallel.It is evident that parallel connection between the three regions is raising the total reliability of Iraqi super grid.