Power oscillation impact on generator/turbine interaction for an isolated power system

Abstract

This paper demonstrates the impact power oscillations have on the turbines/generators on an isolated power system from large synchronous motor-driven compressors. The paper describes the isolated system and the methods used to model the electrical and mechanical system. The system models the mechanical compressors with torque pulses which are translated into the electrical system as current pulsations and then through the generators and onto the generator/turbine mechanical system as power oscillations. These oscillations can impact the shaft torsional modes of the turbines/generators and this impact is detailed in this paper. The key to this evaluation was the integration of the electrical synchronous machine models with the mechanical system models. The validity of the turbine torsional model was critical and was checked against the manufacturer's model used for the turbine design. The paper reviews various options to mitigate the impact of the power oscillations and compares the effectiveness of each option. Several operating modes are evaluated for the oscillation frequency and magnitude of torque and power impact on each generator/turbine. The results of each mitigating option and various operating modes are detailed in the paper.