There are problems of a low-frequency oscillation phenomenon that may occur because of insufficient damping in the wind-thermal-bundled (WTB) system during interference, as well as high operating costs due to high network losses. These hinder the achievement of the "dual carbon" goal. Thus a coordinated optimization strategy for the parameters of the power system stabilizer (PSS) and unified power flow controller (UPFC) with additional power oscillation damping controller (POD) and the installation position of UPFC is proposed. First, a WTB transmission system and a controller model are constructed based on Matlab. Then, the multi-objective salp swarm algorithm (MSSA) is used to transform the coordination optimization problem into a multi-objective optimization problem. The adjustment characteristics of the UPFC device are taken into account in the objective function design. Finally, the IEEE 4-machine 2-area system and 16-machine 5-area system are used for simulation in various operating conditions. The results show that the coordinated and optimized controller can increase system damping, maintain the stability of generator speed, suppress the fluctuations for system active power, voltage etc. caused by low-frequency oscillation, and reduce active power network losses of the system, thus improving system stability and operational economy. The application of MSSA in engineering problems is thus extended.