High voltage and high load in the power grid can cause a decrease in system damping and low-frequency oscillation.The power system stabilizer(PSS)can increase the damping of the system.Firstly

it analyzes the causes of the low-frequency oscillation of the 660 MW unit and confirms that it is due to insufficient system damping.Under conditions that do not meet the test regulations

it confirms the PSS test conditions based on the actual situation on site.Secondly

it compares and analyzes the calculated values and experimental values of the non-compensation characteristics of the excitation system.It adjusts the phase compensation link of the PSS.It pre-calculates the critical gain of the PSS by using the root locus method

and confirms the critical gain by the time domain method at the same time.Finally

by increasing the PSS amplification factor

it analyzes the impact on the stable operation of the unit to achieve full-load stable operation of the unit.