The Improved SSR Electromagnetic Simulation Model and Its Comparison with Field Measurements

Abstract

Electromagnetic simulation (EMS) plays an important role in the evaluation of subsynchronous resonance (SSR). To meet the requirement of practical engineering, this paper discusses how to improve the modeling method of SSR-EMS in three important aspects, i.e., the shaft system of turbine generator, the series compensation and the supplementary excitation damping controller (SEDC). Thus a systematically improved EMS model was put forward, which includes a lumped mass-spring model with adjustable and non-linear mechanical damping, a series compensation model incorporating MOV with the gap protection logic and an engineering model of SEDC to reflect the dynamics of the power-electronic exciter. The developed model overcomes the shortage of the traditional one and is applicable to the accurate analysis on SSR stability, transient torque and fatigue expenditure when the system experiences large disturbances. The proposed method is then used for the simulation of a real SSR event caused by a short-circuit fault in the Shangdu series-compensated power system. The simulation results are compared with the field measurements and a good consistence is found. Consequently, the improved EMS model is proved to be applicable, accurate and effective for SSR analysis in practical engineering.