Control block diagram representation of an HVDC system for sub-synchronous frequency interaction studies

A linearized model of an HVDC system is presented in a control block diagram form. The converter models (rectifier and inverter), DC transmission system, phase lock oscillators (PLOs) and the HVDC controllers are included. The control block diagram model of HVDC system simplifies, in understanding and modelling, the complex operation of the HVDC system. The model can be used in small signal stability assessment to analyze subsynchronous frequency HVDC interactions such as generator-turbine torsional interactions. Furthermore, the model can be easily implemented in a software environment such as Simulink for response analysis, control tuning and other educational purposes.