Analysis of Subsynchronous Torsional of Wind–Thermal Bundled System Transmitted via HVDC Based on Signal Injection Method

With the development of large-scale new energy, wind–thermal bundled system transmitted via high-voltage direct current (HVDC) has become main method to solve problem wind power consumption. At same time, subsynchronous oscillation among generators, (HVDC), and synchronous generators (SGs) increasingly prominent. According dynamic interaction doubly fed induction (DFIGs), HVDC, SGs, a linearization model DFIGs SGs HVDC is established, influence electromagnetic transient turbines on electromechanical processes studied. Using additional excitation signal injection, factors DFIG damping characteristics each torsional mode SG analyzed, including control parameters operation conditions when capacity fixed. The mechanism negative identified. A time-domain simulation built in Electromagnetic Transients DC/Power Systems Computer Aided Design (EMTDC/PSCAD) verify correctness effectiveness theoretical analysis.