High frequency protection scheme for multi-terminal HVDC overhead lines

This paper proposes a novel protective relaying technique for multi-terminal HVDC system based on the high frequency components in the current signals received at each end of the DC transmission line. A simple model of a mono-pole, ground return, MTDC system is built in ATP draw using a distributed parameter, frequency dependent overhead line model. For this system, the high frequency content in the current signal directly following a fault (at approximately 0.2 kHz) is shown to vary significantly with fault location but not fault resistance. The protection algorithm is then validated in real time using an RTDS system, where both the ATP primary system model and the MATLAB developed algorithm are demonstrated in a real time context.