This study proposes the outage cost assessment in electronic industries which is affected from the power interruption. The concept of fuzzy logic is used to develop the outage cost model for applying in various sizes of electronic industries. In
case study, the results of outage cost assessment are applied to the investment analysis of 115/22 kV substation construction. Two types of substation comprising AIS and GIS are presented in this investment analysis. The study results show that the ROI and IRR of the AIS substation are better than the GIS when considering and without considering the outage cost. In addition, the 115/22 kV substation can reduce the frequency of power interruption by 39.28% when compare with the 22kV which directly supplied from distribution system of PEA. Moreover, the electrical cost of electronic industries with 115/22 kV substation can be decreased with the average 5.56% per month. Although the 115/22 kV substation have benefits of electrical cost and reliability, the costs of construction 115/22 kV substation is still high. Therefore, the industry should be attended in the outage cost assessment and used to judge for determining the optimal investment cost of 115/22 kV substation construction.