A MATHEMATICAL FRAMEWORK FOR ANALYZING THE STEP RESPONSE OF RECTIFIER AND INVERTER CONTROLLERS IN A CURRENT SOURCE CONVERTER BASED HIGH VOLTAGE DC TRANSMISSION SYSTEMS

Transmission of wattage through High Voltage electricity (HVDC) has attracted the eye of several researchers in recent years. In this paper, to investigate the step response of rectifier and inverter controllers in a twelve-pulse current source converter-based HVDC transmission system, a well-developed linear continuous model is presented. In which, the converter AC system is represented by damped LLR equivalents at the first harmonic and at the third harmonic. Also, they're equipped with a double-tuned harmonic filter and second-order high pass filter to suppress the AC harmonics and a capacitor for reactive power compensation. The DC system is secured with rectifier current control, inverter current control, inverter voltage control, and inverter angle of extinction control. The HVDC transmission system model is implemented in the MATLAB/Simulink environment and the step response of the rectifier and inverter controllers has been investigated by observing the rectifier and inverter side DC quantities.