Research on subsynchronous oscillation suppression measures for photovoltaic grid-connected system

With the wide application of large-scale photovoltaic power generation system, subsynchronous oscillation below the synchronous frequency has become an important problem affecting the stability of the power system and the safety of equipment. In order to reduce the risk of subsynchronous oscillation in photovoltaic grid-connected systems, this paper proposes a method to suppress subsynchronous oscillation in photovoltaic grid-connected systems by additional damping control of photovoltaic inverters. The additional damping control is introduced into the control link of the PV inverter with the DC voltage as the feedback input signal, so as to enhance the sub-synchronous mode damping of the PV grid-connected system. In addition, the suppression effect of different access positions of the damping controller is analyzed and compared, and the access position with the best suppression effect is proposed.