The study of principle and applicability of complex torque coefficient approach

The paper analyzes the basic characteristics of the stable response of electromagnetic torque of synchronous generator, deduces the main calculation procedure of complex torque coefficient (CTC), and validates them by simulation. The study shows, the apply condition of CTC approach is the linearity and stability of the system. Under a stable system, the CTC can be calculated by the transfer function, and there is not a rigid CTC under an unstable system. The CTC based quasi-stable state model is an approximation in low frequency rang of the CTC discussed former, so they are different coefficients. The model of linear component does not influence the application of CTC approach, but will lead to error.