Wind-thermal bundled power transmission system with series compensation (WTBPTSSC) is widely used in the power system. Power system stabilizer (PSS) and traditional supplementary damping controller (TSDC) are often installed to mitigate low-frequency oscillation (LFO) and subsynchronous oscillation (SSO) in the power system. In this paper, the damping characteristics and interaction of the controllers are analyzed to guide the coordinated control of different controllers. In light of this issue, a small-signal state-space model of WTBPTSSC was built first. Then, the path-damping torque coefficient method combined with the small-signal state-space model is proposed. The damping characteristics of PSS and TSDC were analyzed, at the same time, PSS and TSDC providing damping in different frequency bands were pointed out. Finally, through theoretical analysis and simulation verification, the conclusion is that there are few interactions between PSS and TSDC, but due to their damping characteristics, PSS should be configured in priority when the controller parameters are configured, which can make both low-frequency oscillations and subsynchronous oscillations well suppressed.