Hami area in Xinjiang is a complex power system with wind or PV power bundled with thermal power and DC transmission. The sub-synchronous harmonic due to a large number of application of electric and electronic devices causes the sub-synchronous oscillation problem more and more serious. Therefore

the specific sub-synchronous oscillation control strategy is proposed throughout the analysis of identification of the sub-synchronous oscillation with combination of existing upgrade scheme research of stability control device for subsynchronous oscillation control

including such two modes as combination and non-combination of modal frequency characteristics. Such design procedures as threshold setting and confirmation is started up through criterion analysis of subsynchronous oscillation frequency and a new SSO safety control device is developed. It is verified by nearly one hundred times of synchronization oscillation accident at site that operation of the device is all correct

which suppresses effectively the subsynchronous oscillation in Hami power grid and assures the safe and stable operation of the power grid.