To study on power system low frequency oscillation, can
not study power system in isolation and ignore thermal
system which coupling with power system. The custom
modeling method is adopted in simulation, including unit
nonlinear model, coordinated control system and turbine
digital electro-hydraulic control system model etc. Then the
relationships between turbo-pressure pulsation and power
system forced oscillations are studied, the reasons that
caused pressure pulsation are explored in particular. The
simulation results indicate that power system low frequency
oscillations of resonance mechanism might be caused by the
pulsation of turbine’s main steam pressure, when its
pulsating frequency is consistent with or close to power
system natural oscillations frequency. In thermal system, the
introduction of a large number of control strategies is one of
the reasons that caused the turbine pressure pulsation.