This paper initial on the dynamic support characteristics of inertia flywheel synchronous phase-modulated motor (FSPM). Connecting the condenser to the flywheel is an effective way to enhance the rotational inertia of the condenser itself, and a high inertia condenser can be constructed. The FSPM can cope with the challenge of high requirements of short-circuit capacity and inertia support in distributed energy field stations. In order to verify the dynamic support characteristics of FSPM, this paper introduces the construction of FSPM, and verifies its superiority over the normal synchronous condenser through three working conditions, namely, load disturbances, three-phase ground faults, and PV farm output fluctuations.