Development of a PCM Current Differential Relaying System Using Fiber-Optic Data Transmission

Asdemandforelectric powerhasincreased, EHV cable systems havebeenintroduced intocityareas;inthissituation, problems ofsystemprotection thatmay arise whenpilot-wire protection is usedinclude electromagnetic induction, limitation ofline length, etc. Lastyear,we solved thoseproblems bydeveloping aPCM current differential relaying system using fiber-optic datatransmission. This systemhasbeeninstalled andoperation hasstarted onthe275KV cable line (MINAMIOSAKAs/s --SENBOKUs/s).