Fault transient current analysis method considering nonlinear characteristics of inverter power supply control system

Abstract

The invention discloses a fault transient current analysis method considering the nonlinear characteristics of an inverter power supply control system, and the method comprises the steps: firstly, carrying out the calculation according to the phase-locked loop control response of a new energy power supply control system, and obtaining a transient current under the dynamic response of a phase-locked loop during a fault transient period; according to the working state of the dq axis controller of the current loop during the fault transient period, performing segmentation processing on the fault transient process; and according to the divided response of the dq-axis controller of the current loop in each fault transient stage, realizing fault full transient current analysis under the non-linear characteristic of the inverter power supply control system based on segmented equivalence. According to the method, a phase-locked loop coordinate transformation nonlinear link and a controller saturation nonlinear link objectively existing in an inverter power supply control system are fully considered, and a large amount of complex operation is avoided.

Description

technical field [0001] The invention relates to the technical field of power system analysis, in particular to a fault transient current analysis method taking into account the nonlinear characteristics of an inverter power control system. Background technique [0002] At present, the access of new energy has led to fundamental changes in the fault characteristics of the power system. There is a necessary demand for protection configuration on the AC sending side of the new energy. In view of the weak characteristics and short duration of the fault of the inverter power supply, based on the transient waveform of the new energy The new principle of protection of time-frequency information has received great attention. The transient characteristics of inverter faults mainly depend on the transient response of the control system. However, the existing fault analysis methods for inverters do not consider the objectively existing nonlinear links in the control system from a quant...

AI Technical Summary

Problems solved by technology

The transient characteristics of inverter faults mainly depend on the transient response of the control system. However, the existing fault analysis methods for inverters do not consider the objectively existing nonlinear links in the control system from a quantitative level, resulting in inaccurate description of fault characteristics. It is difficult to meet the protection requirements of the new energy AC sending side

The key crux is that during the fault transient state, the output current of the inverter power supply is in the control response time scale, and each control link jointly determines the time-domain current characteristics. , will cause the transient output of the converter to present significant nonlinear characteristics

[0003] Each control response unit in the control system is an important link to adjust the closed-loop error, and its response during the fault transient period will play a decisive role in the output current of the inverter. However, the conventional short-circuit current analysis method based on linear analysis often Neglecting the influence of phase-locked loop coordinate transformation and controller output saturation on the transient current at the quantitative level will lead to increased analysis errors, and lack of general analytical results considering the existence of nonlinear links in the control system, making it difficult to obtain accurate Therefore, the analysis of the fault transient current characteristics of the inverter power supply is insufficient, and it is impossible to provide a correct theoretical research basis and an effective verification method for the new protection principle of the new energy AC transmission system.

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