A method and device for controlling reactive power of multi-infeed flexible DC transmission

A flexible direct current transmission and flexible direct current technology, applied in reactive power adjustment/elimination/compensation, reactive power compensation and other directions, which can solve the problem of inability to coordinate and distribute the reactive power output of converters

CN104333012BActive Publication Date: 2016-08-10STATE GRID CORP OF CHINA +2
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Publication Date
2016-08-10

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Abstract

The invention discloses multi-feed flexible DC transmission reactive power control method and device. The method comprises the following steps: calculating a margin parameter Kq1 of a reactive power coordinating controller of each converter based on the absolute value of the reactive power output by each converter and the maximum reactive power value of each converter when that the voltage value of an AC bus is beyond the first preset value is detected; regulating the reactive power output of each inverter through the margin parameter Kq1. According to the method and device, each converter is able to coordinate the output reactive power according to relative margin (difference between the maximum reactive power output by the converter and the absolute value of measured reactive power of the converter under a rated working condition) when the reactive power load of the AC bus is increased, so as to enable the sum of the reactive power output by all the converters to be maintained within the allowable range of the voltage of the AC bus; meanwhile, the converter with high margin can output more reactive power, and the converter with small margin can output less reactive power.
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Description

technical field

[0001] The present application relates to the technical field of power systems, and more specifically, to a method and device for controlling reactive power of multi-infeed flexible DC transmission. Background technique

[0002] Flexible DC transmission has the advantages of low harmonic level, no commutation failure, power supply for passive networks, and convenient power flow reversal. It is becoming a hot spot in the DC field.

[0003] Multi-infeed flexible DC transmission system refers to a DC system in which double-circuit lines or multi-circuit flexible DC lines transmit power to the AC system. If each converter of the multi-infeed flexible DC system adopts constant AC voltage control, then the multi-infeed flexible DC transmission system can only determine the The reactive power output of the converter; when the multi-infeed flexible DC transmission system adopts constant reactive power control, when the reactive power load of the AC bus increases, th...

Examples

Embodiment Construction

[0052] The following will clearly and completely describe the technical solutions in the embodiments of the application with reference to the drawings in the embodiments of the application. Apparently, the described embodiments are only some of the embodiments of the application, not all of them. Based on the embodiments in this application, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the scope of protection of this application.

[0053] see figure 1 , figure 1 It is a schematic structural diagram of a multi-infeed flexible DC power transmission system disclosed in the embodiment of this application.

[0054] Such as figure 1 As shown, several converters VSC convert DC to AC, and then confluence to the AC bus through the transformer to obtain the AC bus voltage U s .

[0055]In order to better coordinate the reactive power output of each converter when the reactive power load of the AC bus increases, the ...