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The theoretical aspects, design and testing of a new accelerated trip scheme for second-zone distance protection of HV/EHV transmission lines is described. The scheme is simple and provides relatively high-speed (60-70 ms) operation of the second-zone distance protection without requiring a communication channel. The scheme has been extensively tested using EMTDC simulations under various power system operating conditions. Simulation results show that the selectivity and speed of the proposed scheme are satisfactory for practical use in HV/EHV transmission line distance relays.