Decoupling Method of Deterioration Mechanism of Metallized Film Capacitors Under AC-DC Composite Voltage

Abstract

The invention discloses a method for decoupling the degradation mechanism of a metallized film capacitor under an AC-DC composite voltage, and belongs to the technical field of power equipment testing. The present invention compares the metallized film capacitor and the wire capacitance with the same parameters as the metallized film capacitor in the aging test, and decouples the deterioration of the metallized film capacitor caused by electrochemical corrosion, thermal effect, and self-healing phenomenon, and the decoupling method Simple and easy to implement, it is helpful to accurately analyze the failure reasons of metallized film capacitors, guide the design and application methods of capacitors, as well as the reliability and life prediction of capacitors in engineering applications, thereby ensuring the long-term stable operation of the converter. The invention can be widely applied to DC supporting capacitors in equipment such as DC transmission converter valves and wind power converters, and has strong practicability.

Description

technical field [0001] The invention belongs to the technical field of power equipment testing, and more particularly, relates to a decoupling method for the deterioration mechanism of a metallized film capacitor under AC and DC composite voltages. Background technique [0002] Due to its self-healing properties, metallized film capacitors have the advantages of high working field strength and high reliability. They are often used as the core components of DC transmission converter valves, wind power converters and other equipment - DC support capacitors to stabilize the DC side. It plays an important role in providing energy regulation when the load changes, compensating reactive power, reducing voltage overshoot and transient overvoltage. Because it is connected in parallel with the switching device, the DC support capacitor needs to withstand the AC and DC composite voltage when working, and the AC voltage component mainly includes the first harmonic, the second harmonic,...

AI Technical Summary

Problems solved by technology

The combined effect of the three effects makes the deterioration mechanism of the metallized film capacitor under the AC-DC compound voltage unclear, and the influence weight of the three effects cannot be clarified

At present, there is no decoupling analysis method for this multi-factor degradation. In this case, it is easy to analyze the cause of failure of the wrong metallized film capacitor, resulting in wrong design and application of the capacitor, which will affect the The reliability and life prediction of capacitors in engineering applications may lead to frequent failures of DC support capacitors in engineering and affect the long-term stable operation of converters

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