The invention belongs to the power
system field and particularly relates to a method for improving the sub-synchronous oscillation (SSO) damping of a thermal power
plant in a wind-thermal power series-compensation combined
transmission system by utilizing a supplementary controller to modulate the reactive
power output of a wind generation set. The method is based on the rotor current active and reactive decoupling
control principle of a double-fed wind generation set, and introduces shafting rotational speed difference of a combined-transmission thermal power
plant as the characteristic
signal for designing a damping controller, and the output of the damping controller is modulation component under the control of rotor reactive power; and through the regulation on the reactive power of the wind generation set, the effect of enhancing the SSO damping of the combined-transmission thermal power
plant is achieved. The invention is applicable to large-capacity wind-thermal power combined series
capacitance compensation transmission occasions, so the SSO property of the thermal power plant can be improved, the
electric power of a
new energy resource is ensured to be transmitted safely, continuously and reliably, and the power
system is also ensured to operate safely and stably.