A grounding device for a flexible direct current transmission system

A technology of power transmission system and grounding device, applied in emergency protection circuit devices, electrical components, power transmission AC network, etc., can solve the problems of DC bias voltage, overvoltage, etc.

Active Publication Date: 2021-10-29
GLOBAL ENERGY INTERCONNECTION RES INST CO LTD +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, when a fault occurs inside the converter station, since the zero-sequence current needs to pass through the large resistance connected to the neutral point on the valve side of the transformer, it may cause significant DC bias voltage and overvoltage

Method used

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  • A grounding device for a flexible direct current transmission system
  • A grounding device for a flexible direct current transmission system
  • A grounding device for a flexible direct current transmission system

Examples

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Embodiment 1

[0051] In this embodiment, the energy absorbing branch includes a nonlinear resistance, such as figure 2 with 3 As shown, the energy absorption branch 204 and 304 may include a non-linear resistance, the voltage at both ends of the nonlinear resistor, and the current flowing through the nonlinear resistance in a monotonous incremental relationship, i.e., a monotonic increasing voltage-current relationship. The nonlinear resistance of the energy absorbing branch in this embodiment employs zinc oxide resistance.

[0052] In this embodiment, in order to ensure the operation of the grounding device, the non-linear resistance is not generated, and the non-linear resistance is not generated, and the maximum DC voltage and the power frequency voltage set may occur according to the above possible. A reference voltage for nonlinear resistance.

Embodiment 2

[0054] In this embodiment, the energy absorbing branch includes a metal oxide arrester, such as figure 2 with 3 As shown, energy absorption branches 204 and 304 can include a metal oxide arrester. In this embodiment, the energy absorption capacity of the metal oxide arrester can be set according to the maximum DC voltage and the power frequency voltage that may occur. For example, when the reference current of the metal oxide arrester is 1 mA, it can set its energy absorption capacity of not less than 10 mJ, and the reference current of the metal oxide arrester is 5 mA, and the energy absorption capacity can be set to not less than 12 mJ.

[0055] Further, the control module in this embodiment may include the following configuration, specifically:

[0056] In this embodiment, the control module 101 includes a voltage measuring unit, a first trigger unit, and a second trigger unit.

[0057] Among them: the voltage measuring unit, for measuring the zero sequence voltage of the groun...

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Abstract

The present invention provides a grounding device for a flexible direct current transmission system. The grounding device includes a high-impedance branch, a low-impedance branch, and an energy absorption branch connected in parallel; the high-impedance branch includes a first power electronic switch and a first Impedance unit; the low impedance branch includes a second power electronic switch and a second impedance unit; the grounding device also includes a control module, which is used to trigger the conduction of the first power electronic switch or the second power electronic switch to turn on the first impedance unit Or the second impedance unit is connected to the flexible direct current transmission system. Compared with the prior art, the grounding device of the flexible direct current transmission system provided by the present invention can be connected to different impedance branches according to the actual working conditions of the flexible direct current transmission system. At the same time, the high impedance branch and the low impedance branch All circuits include power electronic switches, which can flexibly control the switching of high-impedance branches and low-impedance branches.

Description

Technical field [0001] The present invention relates to the field of power electronics, and more particularly to a grounding apparatus for a flexible DC transmission system. Background technique [0002] The flexible DC transmission system uses a power-off power electronics and the rapid independent control of active power and reactive power by controlling the output voltage of the power electronic device, and increases the grid while increasing the stability of the grid. The flexibility of running, in the field of new energy power grid, sea wind power grid, large urban power supply, grid Internet, long-distance high-voltage large capacity DC transmission and other fields have significant application advantages. [0003] The traditional flexible DC transmission system mainly adopts the high-discipline-resistant manner in the alternating transformer valve side neutral point, and can suppress the effect of AC power network fault on the flexible DC transmission system. However, when...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02J3/36H02H7/26
CPCH02H7/26H02J3/36Y02E60/60
Inventor 李泓志周杨阳岳希别晓玉杜镇宇孙宝宝高凯韩子娇
Owner GLOBAL ENERGY INTERCONNECTION RES INST CO LTD
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