Currently

some units in Yunnan Power Grid have the problem that the high frequency gain of PSS2B（dualinput Power System Stabilizer） restricts the gain of the middle and low frequency band. A New-PSS2B（New structure of PSS2B） is proposed to increase the gain of middle and low frequency band and reduce the restriction of high frequency band on the gain of medium and low frequency band. New-PSS2B user-defined model is built in PSASP UDM（User-Defined Model）. It can be found that the New-PSS2B can effectively improve the medium and low frequency gain by analyzing the gain of PSS2B and New-PSS2B model. Finally

the New-PSS2B model is implemented to single-machine infinite system on PSASP. Simulative results verify that the New-PSS2B is superior to the existing PSS2B in terms of suppressing low-frequency oscillation at each frequency point in both medium and low frequency band. These results indicate that the New-PSS2B provides sufficient damping in the whole frequency band and satisfies the requirements of low frequency oscillation suppression in power grid.