Overvoltage protection method and device, and modular multilevel converter valve

A modular multi-level, overvoltage protection technology, applied in the power grid field, can solve problems such as affecting the operation of the converter valve, prone to overvoltage, affecting the stable operation of the flexible DC converter station, etc.

Active Publication Date: 2020-01-03
国网冀北电力有限公司超高压分公司 +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The sub-module of the converter valve is prone to overpressure under some abnormal working conditions. Once such an expensive sub-module is damaged due to over-pressure, it will not only cause heavy economic losses, but also affect the operation of the entire converter valve, and even It affects the stable operation of the entire flexible DC converter station, so it is necessary to protect the sub-modules from overvoltage

Method used

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  • Overvoltage protection method and device, and modular multilevel converter valve
  • Overvoltage protection method and device, and modular multilevel converter valve
  • Overvoltage protection method and device, and modular multilevel converter valve

Examples

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Embodiment 1

[0039] figure 1 A flow chart of an overvoltage protection method according to an embodiment of the present application.

[0040] The overvoltage protection method of this embodiment is applied to a modular multilevel converter valve. The modular multilevel converter valve is composed of multiple sub-modules connected in series and parallel, specifically as figure 2 As shown, it includes a plurality of bridge arms, and each bridge arm includes a plurality of submodules. Among them, the structure of each submodule is as follows image 3 shown.

[0041] Such as figure 1 As shown, the overvoltage protection method provided in this embodiment specifically includes the following steps:

[0042] S1. Obtain the capacitor voltage of each sub-module.

[0043] Specifically, the capacitor voltages of all the sub-modules constituting the converter valve detected by corresponding voltage detection devices are received. After obtaining the capacitor voltages of all sub-modules, calcu...

Embodiment 2

[0068] Figure 4 A block diagram of an overvoltage protection device according to an embodiment of the present application.

[0069] The overvoltage protection device of this embodiment is applied to a modular multilevel converter valve. The modular multilevel converter valve is composed of multiple sub-modules connected in series and parallel, specifically as figure 2 As shown, it includes 6 bridge arms, and each bridge arm includes multiple sub-modules. Among them, the structure of each submodule is as follows image 3 shown.

[0070] Such as Figure 4 As shown, the overvoltage protection device provided in this embodiment specifically includes a voltage acquisition module 10, a first judging module 20, a second judging module 30, a third judging module 40, a first execution module 50, a second execution module 60, and a second execution module 60. Four judgment modules 70 , a third execution module 80 and a fourth execution module 90 .

[0071] The voltage obtaining ...

Embodiment 3

[0094] This embodiment provides a modular multilevel converter valve, which is provided with the overvoltage protection device provided in the previous embodiment. The overvoltage protection device includes a voltage acquisition module, a first judgment module, a second judgment module, a third judgment module, a first execution module, a second execution module, a fourth judgment module, a third execution module and a fourth execution module.

[0095] It is specifically used to obtain the capacitor voltage of each sub-module, and calculate the average capacitor voltage of all sub-modules on each bridge arm according to all capacitor voltages; judge whether the converter valve is in a locked state as a whole; if the converter valve is in an unlocked state, according to the capacitor voltage Whether the voltage exceeds the first preset protection setting value judges whether there is an overvoltage in the sub-module, the first preset protection setting value is between the rated...

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PUM

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Abstract

The invention discloses an overvoltage protection method and device, and a modular multilevel converter valve. The method specifically comprises the steps of: obtaining a capacitor voltage of each sub-module, and calculating the average capacitor voltage of all sub-modules on each bridge arm according to all capacitor voltages; if a converter valve is in an unlocked state, determining whether overvoltage occurs in the sub-module or not according to whether the capacitor voltage exceeds a first preset protection constant value or not; if the sum of the number of the sub-modules with the overvoltage and the number of the bypassed sub-modules is greater than the number of the redundant modules, locking the converter valve and performing tripping; and if the sum is smaller than or equal to thenumber of the redundant modules, locking and bypassing the sub-modules with the overvoltage; if the converter valve is in a locked state, and if the average capacitor voltage of the sub-module of anybridge arm is greater than a preset value, bypassing the sub-module of which the capacitor voltage is greater than a second preset protection constant value; and if the average capacitor voltage of the sub-module of any bridge arm is less than a preset value, bypassing the sub-module of which the capacitor voltage is greater than a third preset protection constant value. Through the above operation, overvoltage protection of the sub-modules is achieved.

Description

technical field [0001] The present application relates to the technical field of power grids, and more specifically relates to an overvoltage protection method, device and modular multilevel converter valve. Background technique [0002] The flexible DC transmission technology based on modular multi-level converter valves can independently and quickly control the active power and reactive power of the system, and improve the stability of the system. It is widely used in new energy grid-connected fields such as large-scale wind power generation. Among them, the converter valve is the most core equipment of the flexible DC transmission project. It is composed of a series of parallel sub-modules composed of a large number of power electronic devices. For some sub-modules of large-capacity converter valves, the single price is more than 200,000 yuan. [0003] The sub-module of the converter valve is prone to overpressure under some abnormal working conditions. Once such an expen...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02M1/32H02H7/122H02H7/125
CPCH02H7/122H02H7/125H02M1/32H02M1/325
Inventor 安海清李振动刘亚新贺俊杰张恩伟王珣田凯哲李金卜张晓飞金海望岳娜柳杨翟永尚滕孟锋董海飞余黎明高宏达刘宪辉刘海勇李涛赵凯曼赵佳鑫刘洁范彩杰
Owner 国网冀北电力有限公司超高压分公司
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