A study on the Specification Decision Method of AF-SMES System considering Internal Fault Condition

Recently, utility network is becoming more and more complicated and huge due to IT and OA devices. In addition to, demands of power conversion devices which have non-linear switching devices are getting more increased. Consequently, because of the non-linear power semiconductor devices, harmonics current is unavoidable. Sometimes those harmonics current flows back to utility network and become one of the main reasons which can make the voltage distortion. Voltage sag from sudden increasing loads is also one of the serious problems inside of utility network. In order to compensate the harmonics current and voltage sag problem, we analyzed an active filter system. SMES is a very good promising source according to its high response time of charge and discharge. Therefore, the combined AF and SMES system can be a proper device to compensate both harmonics current and voltage sag. However, SMES needs a superconducting magnetic coil. Because of using this superconducting magnetic coil, quench problem caused by unexpected reasons has always been unavoidable. Therefore, this paper presents a decisive method using shunt and series active filter system combined with SMES (AF-SMES). Especially, authors analyzed the change of original energy capacity of SMES regarding to the size of resistance caused by quench of superconducting magnetic coil. Finally, based on the result of simulation, we manufactured AF system controlled by DSP