Real-time fault detection method applied to voltage source converter

Abstract

The invention relates to a real-time fault detection method applied to voltage source converter. Continuous discrete separation is carried out on a power electronic model, linear and non-linear models are extracted, and a multi-speed coordinative simulation system is utilized to carry out real-time simulation test analysis on a high-frequency switch device. Transient disturbance and stable disturbance are distinguished by high frequency wavelet decomposition coefficients obtained after frequency domain segmentation by a Mallat decomposition method. Fault beginning and ending time is determined by transient signals according to a model maximum value point, and the model maximum value in the fault time is used as a threshold for judging whether a fault occurs. Wavelet entropy transient characteristic extraction is carried out the high frequency decomposition coefficients, and when the frequency domain calculation result is inaccurate, the wavelet decomposition coefficient entropy is calculated to determine the phase having the fault.

Description

technical field [0001] The invention relates to the field of electronic technology, in particular to a real-time fault detection method applied to a voltage source converter. Background technique [0002] In recent years, renewable energy such as wind energy and solar energy has developed vigorously. The power system composed of converters has become the mainstream structure of future grid interconnection because of its flexible operation and good controllability. The power electronic device used in the fields of AC and DC grid interconnection, distributed energy grid connection, reactive power dynamic compensation and other fields of power system is a complex nonlinear time-varying element. Its high-frequency converter also has many problems (such as faults, harmonics, control and protection, etc.), which have attracted widespread attention from scholars. In order to improve its reliability and ensure safe operation, a large number of simulation tests must be carried out o...

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Problems solved by technology

[4] A fault-tolerant method for IGBT open-circuit fault detection in three-phase modular multi-level converters and its sub-modules (application number: 201310198506.3), which discloses the problem that the existing MMC cannot work due to open-circuit faults

The above simulation based on the power electronic system makes a detailed discussion on the problems of transient simulation, digital modeling and faults, but does not discuss in detail the problems of power electronic model segmentation and real-time fault detection.

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