Determination method of network side harmonic current of high-voltage direct current power transmission system

A technology of DC transmission system, harmonic current, applied in AC network to reduce harmonics/ripple, harmonic reduction device, power transmission AC network, etc., can solve problems such as difficult application and time-consuming

Inactive Publication Date: 2010-10-13
ZHEJIANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

This method is currently a common method for simulation calculations, but this method is time-consuming and difficult to apply to complex systems, and is usually only used as a standard for testing and checking other algorithms

Method used

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  • Determination method of network side harmonic current of high-voltage direct current power transmission system
  • Determination method of network side harmonic current of high-voltage direct current power transmission system
  • Determination method of network side harmonic current of high-voltage direct current power transmission system

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Embodiment 1

[0073] (1) According to the characteristics of the DC transmission system, it is assumed that the harmonic voltage at the entrance of the DC transmission line is zero, and the harmonic current calculations on the rectifier side and the inverter side are decoupled from each other, and the following is obtained: Figure 8 The rectification side unipolar single valve group (twelve-pulse) metal circuit wiring method shown in the figure, the DCF in the figure is the DC filter, the transmission power is 1250MW, the load level is 100%, and the DC current is the rated value of 3.125kA. This circuit is equivalent to image 3 In the twelve-pulse unit bridge circuit shown, the upper six-pulse unit is the YY bridge, and the lower six-pulse unit is the YD bridge. The trigger sequence of the valves in the YY bridge is V 1 , V 2 , V 3 , V 4 , V 5 , V 6 , the electrical angle corresponding to the trigger pulse moment is α 1 、α 2 、α 3 、α 4 、α 5 、α 6 , and the corresponding commutat...

Embodiment 2

[0176] In order to further verify the accuracy of the algorithm of the present invention at low load levels, the load level tested in this embodiment is about 10% of the rated power, the DC current is 0.3125kA, and the firing angle is 26°. Other conditions are the same as those described in Example 1. Consistent, then according to the steps of embodiment 1, the following results can be obtained:

[0177] Table 13 Comparison of AC side characteristic harmonic results

[0178]

[0179] Table 14 Comparison of non-characteristic harmonic results on the AC side

[0180]

[0181] As can be seen from the above analysis, the algorithm of the present invention adopts a unified expression form, which is very easy to program and realize, and all adopts analytical methods to solve. In the solution process, various non-ideal factors are fully considered. Compared with the accurate simulation results of PSCAD / EMTDC, it has great advantages High precision. However, although the PSCAD...

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Abstract

The invention discloses a determination method of network side harmonic current of a high-voltage direct current power transmission system. The determination method comprises the following steps: if the harmonic current voltage at a direct current power transmission line inlet is zero, decoupling and equalizing a rectifying side and an inverting side into a plurality of independent six-pulse moving bridge units; dividing a work period of the six-pulse moving bridge units into six phase converting sections and six non-phase converting sections; calculating a phase converting overlapping angle of each phase converting section; equalizing a current converter into a harmonic current voltage source containing internal resistance; calculating the direct current side harmonic current according to the concrete forms of a smoothing reactor and a direct current filter; obtaining valve side harmonic current according to an equivalent circuit of the current converter; and converting the valve side harmonic current to a network side according to a connecting structure of a transformer to obtain the network side harmonic current. The invention considers background harmonic current and other nonideal factors, and can quickly and accurately obtain the harmonic current at the network side of a converter transformer, accelerate the period for designing an alternating current filter in the high-voltage direct current power transmission engineering and improve the design quality and the design efficiency.

Description

technical field [0001] The invention relates to the technical field of high-voltage direct current transmission, in particular to a method for determining harmonic currents at the grid side of a high-voltage direct current transmission system. Background technique [0002] With the development of west-to-east power transmission and the national power grid, my country has formed a grid pattern of long-distance and large-capacity power transmission. High-voltage direct current transmission (HVDC) has been widely used due to its unique advantages such as large transmission capacity, long transmission distance, and less investment. Applications. However, due to the nonlinear characteristics of the converter, the HVDC converter will generate a large amount of harmonic current and voltage on the AC and DC sides during operation, which will cause serious harm and interference to the power equipment and communication lines in the system. In order to eliminate Due to the influence of...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02J3/36H02J3/01
CPCY02E60/60Y02E40/40
Inventor 徐政薛英林王峰屠卿瑞翁华
Owner ZHEJIANG UNIV
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