The construction cost is divided into 3 main parts; consist of civil structure, electrical equipment and commissioning. The annual preventive maintenance cost comprises the cost of functional test, equipment test, healthy check following periodical schedule. Both of costs refer to the PEA consultant service as shown in Table I and Table II. Furthermore, the power losses of power transformer during peak demand of 4-9 MW as shown in Table III [4] are the significant parameter for economic analysis.