Method for selecting capacitance value and voltage mean value at DC side of static reactive power compensator

Abstract

The invention discloses a method for selecting capacitance values and voltage mean values at the DC side of a static reactive power compensator. The method comprises the following steps: equalizing each phase of an H-bridge cascade type static reactive power compensator to a module; determining the value of filter reactance and the maximum allowable value of the DC side voltage when the equivalent module stably works; determining the minimum equivalent capacitive reactance of a DC side capacitor of the equivalent module based on a minimum equivalent capacitance value curve, wherein the equivalent capacitive reactance of the DC side capacitor of the equivalent module is designed to 0.85-0.98 times of the minimum equivalent capacitive reactance; determining the maximum value of the DC side voltage which corresponds to the equivalent capacitive reactance according to the minimum equivalent capacitance value curve; determining the range of the voltage mean value at the DC side of the equivalent module; determining the number of cascaded modules at each phase, and determining the range of voltage mean value and the capacitive reactance at the DC side of each module. According to the method disclosed by the invention, a quantitative design method is provided for the design of the capacitance value and the voltage mean value, the foundation for the research of power electronic technologies can be laid, and the value of promotion and use can be brought.

Description

technical field [0001] The invention relates to the technical field of power electronics engineering, in particular to a method for selecting the DC side capacitance and voltage average value of an H-bridge cascaded static var compensator applied to a three-phase symmetrical system. Background technique [0002] The star-connected H-bridge cascaded static var compensator is gradually applied to the 6kV, 10kV and 35kV transmission and distribution networks in my country. It has the advantages of fast dynamic response and low harmonic content of the output current. Advanced technology for compensation. [0003] The H-bridge cascaded static var compensator adopts a single-phase cascaded structure, which is easy to adapt to different grid voltages. However, due to the double-frequency instantaneous reactive power in the single-phase circuit, the capacitor voltage on the DC side has fluctuations, which requires The large-capacity capacitor buffers the instantaneous reactive power...

AI Technical Summary

Problems solved by technology

In the article "Control Method for Reducing the Capacitance Value of Modular Multilevel Converter Sub-modules" in "Power System Automation", Volume 39, Issue 16, 2015, they provided a method that can be used in modular multilevel converters The control method of reducing the capacitance value of the module uses the fluctuation voltage of the capacitor in the modulation link, and then reduces the control value of the average value of the DC side voltage, but this article has not yet involved the quantitative selection of the capacitance value of the capacitor and the average value of the DC side voltage

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