The article discusses the use of a synchronous motor as an electric starter of a gas turbine plant. A gas turbine plant is used to drive an electric generator in a power plant. It is shown that the same starter can be used in the electric motor mode to stabilize the rotational speed of the gas turbine plant. This is especially important and relevant for fast and large changes in the load of a gas turbine plant. Changing the electrical load of the power plant directly affects the load of the gas turbine plant. Since the gas turbine plant has a large time constant, it is necessary to quickly supply additional power to stabilize the rotational speed of its shaft. It is proposed to use an electric starter for this. The control of the starter by a perturbing signal is studied by means of simulation. Then the scheme of the control system is modified to determine the disturbing effect by calculation. Graphs of simulation results are presented and the results obtained are discussed.