Torsional Vibrations Control of Double‐Ended Driving and Dual‐Excited Turbo‐Generator Shafts Based on Multi‐Index Nonlinear Control

Abstract

Non-member Yejie Tian, Non-member The problem of shafting torsional vibrations has been increasingly emerging due to the increasing capacity of turbo-generator and the complexity of power grid. Therefore, how to reduce the torsional vibration of the turbo-generator shaft and improve the stability of the power system has become the focus of our research. First, in order to solve the problem and alleviate the torsional vibrations of turbo-generator shafts, this paper proposed a new shafting structure model of Double-ended Driving and Dual-Excited Turbo-Generator set (DDDETG). A static excitation mode is used for the excitation of the DDDETG and the mechanical power is supplied symmetrically and synchronously from both ends of the generator rotor. Then, in order to improve the output characteristic of the generator and further suppress the torsional vibrations of the turbo-generator shafts, combined with the nonlinear control design method of partial feedback linearization, a Multi-Index Nonlinear Coordinated Control (MINCC) strategy for the double-ended driving and dual-excited turbo-generator is proposed to ensure good dynamic and static state performances of each state in the system. Finally, the simulation results on a single-machine infinite bus system demonstrate the effectiveness of the proposed control strategy. In addition, this paper compares the performance of DDDETG and the traditional Single-ended Drive and Single-Excited Turbo Generator (SDSETG), the simulation results show that the restraint effect of the DDDETG structure on shafting torsional vibrations is more obvious under the proposed control strategy.

Study on torsional vibration suppression effect of double‐ended driving turbo‐generator shafting structure

“…Compared with SDTG, the shafting structure of DDTG also has some advantages described in Ref. [8] with the same unit capacity. In Fig.…”

“…In particular, Li et al . [8] considered limiting the shafting torsional vibration by changing the shaft structure of condensation type turbo‐generator set, but it simplified the combined HP‐IP casing and the LP cylinder as a concentrated rigid mass, and without considered the torsional vibration of the shaft between HP cylinder and LP cylinder.…”

“…It can be seen from the above that most of them are based on the modulation of the effective and reactive powers to bring supplementary damping into the system, little consideration is given to solving the shafting stability problem from the structure of the turbo-generator itself. In particular, Li et al [8] considered limiting the shafting torsional vibration by changing the shaft structure of condensation type turbo-generator set, but it simplified the combined HP-IP casing and the LP cylinder as a concentrated rigid mass, and without considered the torsional vibration of the shaft between HP cylinder and LP cylinder. In addition, many scholars have studied the suppression of torsional vibration with modern control theory.…”