This thesis presents enhanced ultra high speed (UHS) protectivescheme that is based on the travelling wave rrw: technique. It includestwo main fault detection units; the first is analogue for primary protectionand the second is digital for secondary (backup) protection. The two unitsare combined in an integrated protective scheme with the appropriate logic.The algorithm is proposed based on simulation studies that are achieved byusing standard power system simulation software namely electromagnetictransients including DC (EMTDC). The information contained in thetravelling waves has been used to discriminate between internal andexternal faults.The analogue unit will respond directly after fault inception,however the digital unit requires analogue-to-digital (AID) conversion inaddition to algorithm processing time and may be delayed by a suitablebackup time. Therefore, the operation of the analogue unit will be faster. Ithas a fault detection operating time of 2-3 ms, The final trip decision is totransmit the trip signal to the output interface if the fault incidence ISconfirmed by the analogue unit or confirmed by the digital unit.The prototype hardware of the analogue unit was implemented andtested by a laboratory tests and its performance is found to be accepted.The algorithm of the digital unit was presented. The performance ofproposed integrated protective scheme for protecting extra high voltage(EHV) transmission lines has been tested using the simulation data andconfirmed to be satisfactory