This paper investigates the impact on operating time delay and relay maloperation i.e. selectivity, when high sampling rate is used in numerical distance protection (NDP). Simulation is carried out in an on-line way, for different source to line reach impedance ratio (SIR), fault type, fault locations and for different loading conditions. The voltage and current signals from capacitive voltage transformers and current transformers respectively are fed to the numerical distance relay (NDR). Sampling rate of 12, 16, 24, 32 and 64 times the fundamental frequency (50 Hz) are chosen for this investigation, since these are typically used in conventional distance relays. © 2012 IEEE.