Vulnerability Case Analysis of the High Power Electromagnetic Pulse on Digital Control System

The risk of high power electromagnetic(HPEM) pulse exposure to the devices used in digital control system such as PLC(programmable logic controller) and communication cable is increasing. In this paper, two different frequency ranges HPEMs were exposed to those control systems to assess the each vulnerability. The vulnerability of the EUTs exposed from HPEM were analyzed and compared with a variation of distances and source power. As the EUTs were exposed to higher level of HPEM, the voltage and communication waveform of the control system had shown a distorted response. And the unshielded twisted pair(UTP) cable connected to the EUTs showed operation failures with induced voltage. However, the foiled twisted pair(FTP) cable shielded the connected device efficiently from the HPEM exposure. Therefore, the necessity of the protection measures against the vulnerability of HPEM exposure for the digital control system used in power facilities and industrial site were verified.