As an additional control function of the generator excitation system, power system stabilizer (PSS) plays an important role in suppressing the low frequency oscillations of the power system. In this paper, the focus of research lies in PSS field test. For the risk of oscillations that may be triggered in the PSS critical gain test, a simple safety control method is proposed. The critical gain test is performed by temporarily reducing the PSS output limit value to obtain a PSS operating gain more safely. Taking the PSS field test of a grid-conne...