The purpose of the study is to redesign, evaluate the performance and impact analysis of the 825 KVAR automatic power factor corrections, which is installed in Amhara Plastic Pipe Factory with the total transformer capacity of 4.45 MVA. The necessary reactive power for the capacitor bank calculated according to practical readings for equipment's information that printed on the nameplates, by using two calculation methods namely table of coefficient, Mathematical analysis and verified by Matlab /Simulink software. The researcher selected the power factor of the site from 0.84 to 0.98 because to see the effects up to the AC drive motor loads i.e. 0.97. The investigation shows that the factory total power factor correction capacity is 825KVAR. But this study ensures that the factory total need of power compensator is 1650 KVAR. The Mathematical analysis of the results prove that automatic power factor correction (APFC) significantly reduces the cost of electric power by the annual saving 2.15 million birr per year, it's payback period of the cost procurement by 1.23 years, the capacity increment by 16%, loss reduction by 14.29% & voltage raise increased by 1.8%. The main recommendation of the thesis is the factory has been to solve this problem will be adding additional 825 KVAR reactive powers for the new expansion of factory machines.