Fault and load change differentiation in High Voltage Direct Current (HVDC) system

High Voltage Direct Current (HVDC) system has come a long way to shift the direction of power transmission in future. With respect to that, the protection is still one of the hot topics that need to be addressed, particularly the DC fault detection method. This paper presents the fault simulation study of a two-terminal HVDC system. DC fault and load change are of interest here. With the help of wavelet transform, these two cases can be differentiated by determining the wavelet coefficient of DC line current. Details regarding synchronous reference frame dq current controller at source terminal, RMS method controller at load terminal are also discussed and the corresponding obtained simulation results for steady state, load change and fault conditions using Matlab/Simulink are presented.