Convergence RLC circuit model-based method for analyzing subsynchronous resonance in power system

Abstract

The present invention discloses an convergence RLC circuit model-based method for analyzing subsynchronous resonance in a power system. The method comprises the following steps of: establishing a power plant model and a series compensated transmission line system model so as to acquire a non-linear differential equation model of each subsystem; generating a state equation model according to a parameter under a particular working condition and the non-linear differential equation model; generating an algebraic equation model according to the Laplace transform and the state equation model; acquiring a final equivalent resistance model so as to acquire a series resonance point; aggregating the final equivalent resistance model into an equivalent second order RLC electric circuit model according to the series resonance point; and quantifying SSR analysis. According to the analysis method provided by an embodiment of the present invention, the final equivalent resistance model is aggregated into the equivalent second order RLC electric circuit model, so that the SSR analysis is quantified, thus implementing the accurate quantification evaluation of SSR, reducing analysis errors and improving analysis accuracy.

Description

technical field [0001] The invention relates to the technical field of electric power systems, in particular to a power system subsynchronous resonance analysis method based on an aggregated RLC circuit model. Background technique [0002] Fixed series capacitor compensation can effectively improve the transmission capacity of the line and the transient stability of the power system, and it is more and more widely used in modern power systems. However, the interaction between the fixed series compensation and the surrounding turbogenerators or wind turbines is likely to cause a special power system stability problem, that is, SSR (Subsynchronous Resonance, Subsynchronous Resonance). SSR has adverse effects on the stability of the machine network and equipment safety. For example, SSR causes fatigue damage to the mechanical system of the large shaft of the steam turbine unit, reduces the life of the unit and even causes the main shaft to break, causing serious equipment damag...

AI Technical Summary

Problems solved by technology

[0004] However, in the previous impedance modeling process, for the convenience of derivation, the quasi-steady-state model of the motor was mostly used without considering its dynamic characteristics

Moreover, the control strategy of the controller in the system is also simplified accordingly, ignoring the dynamic characteristics of some controllers

Although these simplified operations are beneficial to the establishment of the system impedance model, they have brought analysis errors that cannot be ignored. The original impedance model can only use the Nyquist stability criterion to judge the stability of the system, and is not suitable for accurate assessment and quantitative analysis of SSR risks.

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