In order to solve the problem that the phase parameters of Siemens power system stabilizer PSS3B are not easy to be set

a PSS3B phase parameter setting method is proposed. Firstly

the Siemens PSS3B structure is transformed into the conventional lead-lag series structure through mathematical derivation

and then the nonlinear least square method is used to adjust the lead-lag phase compensation parameters which is based on the phase compensation principle. The step response test is carried out on the Heffron-Philips model of the one machine infinite bus system. The step response results show that PSS3B has a good effect on the low frequency active power oscillation which verifies the effectiveness of the setting method.