Today, electrical energy has an indispensable place. The transmission and distribution lines deliver electrical energy from power plants to usage areas. However, as the reactive power balance in the long transmission lines cannot be achieved, the transmitted energy is both has poor quality and increases the transportation losses. Shunt reactors developed as an integral part of the transmission lines should be used to avoid these adverse events. Shunt reactors have an important place in the design phase in order to perform this function in the best way. Important parameters such as the reactor size, the total length of the air gap, the number of air gaps, directly affect the reactor's inductance value. The inductance value of the reactor is a factor that directly affects the result of the compensation process to ensure the reactive power balance in the transmission lines. In this study; three-legged and five-legged core shunt reactor designs are done with different air gap numbers and equally distributed air gapped. Simulation studies of the designs are done by using Finite Element Method with high accuracy and stability. A comparative evaluation of the results of simulation studies and economic analyzes are done.