Developing Piecewise Damping Terms of Fifth-order Generator Model under Large Disturbances

It is essential to adopt an appropriate synchronous generator model for power system stability analysis. The fifth-order generator model, which neglects the stator transients, is popular in the power industry. But one key problem with the fifth-order generator model is that it may lead to overestimation or conservativeness in stability analysis, making it inadequate at times in terms of accuracy. In this paper, a piecewise damping term is proposed and developed into the fifth-order generator model, which can greatly improve the stability analysis accuracy when the fifth-order generator model is employed. An iterative method for calculating the damping coefficient of the piecewise damping term is proposed and validated via numerical studies on two test systems. A suggestion is presented for industrial applications.