Converter and control method of multi-end soft direct current power transmission system

A DC transmission system, multi-terminal flexible technology, applied in the direction of DC network circuit devices, electrical components, circuit devices, etc., can solve the problem that the coordination and control of DC voltage and power flow cannot be carried out at the same time, so as to prevent the expansion of accidents, the control structure is simple, and can be Scalable effects

Active Publication Date: 2013-10-23
XJ ELECTRIC
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Problems solved by technology

[0007] The object of the present invention is to provide a converter control method for a multi-terminal flexible direct current transmission system, a converter using the control method and a flexible dire

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  • Converter and control method of multi-end soft direct current power transmission system
  • Converter and control method of multi-end soft direct current power transmission system
  • Converter and control method of multi-end soft direct current power transmission system

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Embodiment Construction

[0028] The present invention will be described in further detail below in conjunction with the accompanying drawings.

[0029] The structure diagram of the multi-terminal flexible DC transmission system is as follows: figure 1 Shown: The positive direction of power flowing from the AC side to the DC side, S1, S3, and S4 are power supplies, and Load2, Load5 are power loads. Figure 2a is the equivalent circuit of the flexible DC transmission system converter, where P s , Q s is the active and reactive power on the AC side, I a1 , I b1 , I c1 , U sa , U sb , U sc are the current and voltage of the three phases on the AC side, U ca , U cb , U cc is the AC voltage consumed by the converter impedance, P c , I dc Input the power and current of the DC grid to the converter, with the flow from the AC side to the DC side as the positive direction, U dc is the DC side terminal voltage of the converter, and the specific working method will not be repeated here. Figure 2bIt...

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Abstract

The invention relates to a converter control method of a multi-end soft direct current power transmission system, and a converter adopting the control method and a soft direct current power transmission system, when the direct current bus voltage is positioned between a preset voltage upper limit value udc_ref_high and a preset voltage lower limit value udc_ref_low, the converter is operated in a constant power control mode; when the direct current bus voltage is not positioned between the preset voltage upper limit value udc_ref_high and the preset voltage lower limit value udc_ref_low, the converter is operated in a direct current bus voltage control mode; when the bus voltage is higher than the set upper limit value, the converter adjusts the direct current bus voltage to be steady at the upper limit value; and when the bus voltage is lower than the lower limit value, the converter adjusts the direct current bus voltage to be steady at the lower limit value. By adopting the method, the coordinating control on the direct current voltage and the tide can be performed at the same time, and the method is suitable for the large-scale distributed multi-end soft direct current system engineering with multiple drop points.

Description

technical field [0001] The invention relates to a converter control method of a multi-terminal flexible direct current transmission system, a converter using the control method and a flexible direct current transmission system using the converter. Background technique [0002] Flexible DC transmission technology is based on power electronic devices that can be shut down and voltage source converters (VSCs). Most of them are BtB topological structures and use underground cables and submarine cables as transmission media to realize power transmission. Among them, the voltage source converter (VSC) is the basic unit of the transmission system. At present, the topological structures used in practical engineering include two-level, three-level and modular multi-level topological structures. [0003] A multi-terminal DC transmission (MTDC) system refers to a DC transmission system that includes multiple rectifier stations or multiple inverter stations. Its notable feature is tha...

Claims

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Application Information

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IPC IPC(8): H02J1/00H02J3/36
CPCY02E60/60
Inventor 姚为正吴金龙梁燕韩坤左广杰刘普
Owner XJ ELECTRIC
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