Research and Countermeasure of Subsynchronous Resonance Transient Torque Amplification

This paper analyzes the principle and harm of Transient Torque Amplification (TA), and puts forward the factors that affect the severity of TA in power plants. TA problem is most serious under the condition that the removal time of transient fault is odd times of half wavelength of the dominant torsional natural frequency of the shaft system. The better the electrical resonance frequency of the system is in accordance with the torsional natural frequencies of the unit, the higher the series compensation degree is, the more serious the TA problem is. Taking two plants in Ximeng area as examples, the electromagnetic transient simulation and complex torque coefficient method are used for calculation and analysis to verify the correctness of the above conclusions. In terms of the measures to solve the TA problem, Blocking Filter(BF) and Generator Terminal Sub-synchronous Damping Controller (GTSDC) are compared. The results show that compared with GTSDC, BF has a better effect on TA inhibition.