DC transmission system constant voltage control method

Abstract

The invention relates to a DC transmission system constant voltage control method. The method comprises steps: according to a DC voltage set value, an AC voltage effective value at an inverter station converter transformer valve side, system DC current and equivalent phase change resistance, an extinction angle of the inverter is determined; a firing angle of the inverter is determined by the extinction angle of the inverter, the output DC voltage of the inverter is thus determined, a method in which a rectifier tracks current changes of the system to properly adjust the firing angle is used for realizing voltage adjustment of the rectifier. The extinction angle of the inverter is determined, and precise control on the DC voltage is ensured; a novel extinction angle-firing angle conversion method is designed, the output voltage and the current of the inverter are ensured to change according to a positive slope relationship, and control disorder due to appearance of multiple stable operation points can be avoided; and the method in which the rectifier tracks current changes of the system to properly adjust the firing angle is used for realizing voltage adjustment of the rectifier, and the DC current can be ensured to be stabilized at the set value.

Description

technical field [0001] The invention relates to a voltage control method, in particular to a constant voltage control method of a direct current transmission system. Background technique [0002] High-voltage direct current transmission has been widely used in the field of electric energy transmission and plays a huge role due to its advantages of large transmission capacity, long transmission distance, and flexible control. The converter that changes from AC to DC is called a rectifier, and the converter that changes the form of electric energy from DC to AC is called an inverter. By adjusting the firing angle of the converter, the DC voltage output by the converter can be adjusted. The rectifier Cooperating with the adjustment of the inverter can realize the flexible control of the DC transmission system. Usually, in a DC power transmission system, the DC voltage is controlled by the inverter, and the DC current is controlled by the rectifier; at present, the DC power tra...

AI Technical Summary

Problems solved by technology

Usually, in a DC power transmission system, the DC voltage is controlled by the inverter, and the DC current is controlled by the rectifier; at present, the DC power transmission projects that have been put into operation mostly use the inverter to control the DC voltage with a fixed arc-extinguishing angle control method. Since the arc-extinguishing angle is a constant value, the adjustment of the DC voltage can only be realized by adjusting the tap of the converter transformer. Since the adjustment of the tap of the converter transformer can only be realized by a mechanical mechanism, the response speed of the DC voltage adjustment is very fast. Slow, weakening the advantage of flexible control of DC transmission system

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