چكيده به لاتين
One of the essential requirements for the design and construction of synchronous turbo generators is the calculation and evaluation of torque under various fault conditions. For this purpose, three types of faults are typically analyzed: three-phase short-circuit, phase-to-phase short-circuit, and synchronizing out-of-phase (SOP) faults. The out-of-phase synchronization fault can introduce significant electromagnetic torque—exceeding that generated under a three-phase short-circuit fault—which makes it a crucial factor in generator and shaft design. SOP fault occurs when there is a phase angle difference between the two ends of the circuit breaker connecting the generator to the power grid. This fault may arise when the generator is connected to the grid due to a system malfunction, operator error, or improper shutdown key operation. Moreover, worst-case scenarios regarding the phase difference between the machine and power network terminal voltages, voltage magnitude, and frequency should be considered in studies. Due to the unique and distinct nature of torque variations under out-of-phase synchronization fault conditions, this fault generally imposes the most critical conditions for rotor dynamics analysis. Therefore, investigating, analyzing, and predicting the behavior of the synchronous generator set and its connected components is of utmost importance. The existing analytical models for calculating the torque induced by out-of-phase synchronization fault, as presented in some references, are relatively simplistic and approximate. These models only estimate the peak torque of the response curve and lack damping terms, which are essential for a more precise and comprehensive analysis. This fault is also described in the references under titles such as Synchronizing Out of Phase (SOP) and Out of Phase Synchronization (OPS). In this thesis, the term SOP will be used for consistency.
In this thesis, the causes and background of out-of-phase synchronization faults are examined, along with an investigation of the effects of different synchronization angles and voltage and frequency mismatches on the parameters of synchronous generators, particularly torque. The results indicate that contrary to many previous studies, the impact of voltage and frequency variations on peak torque is significant and cannot be neglected. The simulations in this study were conducted using MATLAB software. Additionally, a comparison between the simulation results and analytical calculations is presented.
