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Calculation method for harmonic current of direct-current side of hybrid bipolar direct-current transmission system

A technology of DC transmission system and harmonic current, applied in the direction of power transmission and AC network, etc., can solve the problems of consuming a lot of computing time and computing resources, and time domain simulation technology is not suitable for the calculation of harmonic current on the DC side.

Inactive Publication Date: 2013-12-04
ZHEJIANG UNIV
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Problems solved by technology

[0009] Although time-domain simulation technology can be used to calculate the DC side harmonic current, time-domain simulation requires a lot of computing time and computing resources
Considering that there are various wiring methods and power levels in actual engineering, time domain simulation technology is not very suitable for the calculation of DC side harmonic current

Method used

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  • Calculation method for harmonic current of direct-current side of hybrid bipolar direct-current transmission system
  • Calculation method for harmonic current of direct-current side of hybrid bipolar direct-current transmission system
  • Calculation method for harmonic current of direct-current side of hybrid bipolar direct-current transmission system

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Embodiment Construction

[0049] In order to describe the present invention more specifically, the technical solutions of the present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0050] In this embodiment, the hybrid bipolar direct current transmission system is as follows: figure 1 As shown, its system parameters are shown in Table 1:

[0051] Table 1

[0052]

[0053]

[0054] The DC filter DCF configuration used in the system is as follows: Figure 5 As shown, its parameters are shown in Table 2:

[0055] Table 2

[0056]

[0057] Such as Image 6 As shown, the harmonic current of the DC side of the bipolar DC transmission system is calculated according to the following method:

[0058] (1) According to the operating conditions of the system and the parameters of the main circuit, the equivalent transformation of the LCC in the system is carried out to obtain the equivalent three-pulse voltage source corresponding...

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Abstract

The invention discloses a calculation method for harmonic current of a direct-current side of a hybrid bipolar direct-current transmission system. The calculation method includes the steps: (1) performing equivalent transformation to obtain an equivalent three-pulse voltage source corresponding to an LCC (line-commutated converter) and an equivalent passive circuit corresponding to an MMC (modular multilevel converter); (2) sectioning a direct-current transmission line and a ground wire thereof, and calculating an admittance matrix of each subsection to obtain an admittance matrix of the whole direct-current transmission line by a recurrence method; (3) building a systemic direct-current network according to the equivalent three-pulse voltage source, the equivalent passive circuit and the direct-current transmission line to obtain node voltage of the front end and the tail end of the direct-current transmission line according to the admittance matrixes; (4) acquiring node voltage of each subsection node of the direct-current transmission line by an inverse method according to the node voltage to obtain the harmonic current of the direct-current side. Calculation efficiency of a direct-current loop is remarkably improved on the premise of ensuring effectiveness.

Description

technical field [0001] The invention belongs to the technical field of electric power system transmission, and in particular relates to a method for calculating harmonic currents at the DC side of a hybrid bipolar direct current transmission system. Background technique [0002] One of the main problems in the application of flexible DC transmission to long-distance large-capacity overhead line transmission is the self-clearing problem of DC side faults. Since there is no real commercial application of high-voltage large-capacity DC circuit breakers, the flexible DC transmission system will The method of jumping the AC side switch is used to clear the DC side fault. According to ABB’s experience in the Caprivi Link project, this method takes 2-2.5s from the beginning of the fault to clearing the fault and returning to the power level before the fault, which is still a gap of about 0.5s compared with the traditional DC transmission processing similar fault time . For this r...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02J3/36
CPCY02E60/60
Inventor 徐政张哲任薛英林唐庚刘昇
Owner ZHEJIANG UNIV
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