Comprehensive dimensioning of series braking resistor for transient stability improvement

This paper addresses comprehensive dimensioning of series braking resistors designed to improve transient stability of the power system. Since dynamic braking is one of the most cost-effective ways to improve transient stability, the applications of shunt and series braking resistors have recently expanded in the power industry. To find an effective algorithm for controlling series braking resistors appropriate resistor dimensioning should be performed first. This paper addresses the problem of dimensioning of series braking resistors. To solve that problem a mathematical model is employed for different operating states of the system equipped with a series braking resistor. This paper describes and discusses in detail the impact of series braking resistors on: power angle characteristics, intensity of dynamic braking in terms of transient stability improvement, voltage dynamic response during and after a fault, and turbo-generator shaft fatigue. Based on the analysis performed, criteria for the dimensioning of series braking resistors are formulated. Theoretical considerations are supported by simulation tests for nonlinear models of single-machine as well as multi-machine test systems.