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A method for determining the minimum startup mode based on AC-DC cascading faults

A start-up mode and cascading failure technology, which is applied in the direction of power transmission AC network, AC network voltage adjustment, emergency treatment AC circuit layout, etc., can solve the problems of AC and DC cascading failure characteristics, so as to prevent the occurrence of AC and DC cascading failures and avoid large-scale Power outage accidents and the effect of avoiding grid instability

Active Publication Date: 2019-05-28
ELECTRIC POWER RES INST OF STATE GRID ZHEJIANG ELECTRIC POWER COMAPNY +1
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  • Abstract
  • Description
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Problems solved by technology

[0004] The technical problem to be solved by the present invention is to provide a calculation method for the minimum start-up mode of the DC converter station in the vicinity of the DC converter station before the grid has not solved the DC continuous commutation failure through control means, so that when the actual grid is running At least meet the requirements of the minimum start-up mode to avoid DC blocking caused by AC system fault cascading

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  • A method for determining the minimum startup mode based on AC-DC cascading faults
  • A method for determining the minimum startup mode based on AC-DC cascading faults
  • A method for determining the minimum startup mode based on AC-DC cascading faults

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Embodiment Construction

[0017] The commutation failure is caused by the instantaneous drop of the AC bus voltage of the converter station. In engineering, the critical voltage U critical Approximately describe the conditions under which commutation failure occurs. According to the quasi-steady-state mathematical model of DC transmission system, U critical The analytical formula:

[0018]

[0019] In the formula: I d0 and I d0 ' are the initial operating value and the value after the fault of DC current respectively; γ min and gamma 0 are the critical turn-off angle and the initial operating value of the inverter, respectively; U 0 is the initial operating voltage of the AC bus; u k is the short-circuit impedance of the converter transformer.

[0020] When the AC system fails, if the start-up level in the vicinity of the DC landing point is low and the dynamic reactive power is insufficient, it will make it difficult for the bus voltage of the converter station to recover quickly in a short ...

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Abstract

The invention discloses a method for determining a minimum start-up mode based on AC (Alternating Current) / DC (Direct Current) cascading failures. At present, in order to improve an ability to resist ultra-high voltage direct current commutation fault, generally, reactive power compensation devices such as a phase modifier and a static reactive power generator are required to be additionally mounted. However, additionally mounting equipment to an actual power grid requires perform complicated processes such as approval, construction and testing, so that time is consumed. In the method provided by the invention, based on a typical operation mode data of a target grid, at first, a key failure that causes the ultra-high voltage direct current commutation fault is determined by scanning failures of an AC system; generator units are sequenced according to sizes of short circuit current contribution values to determine a key generator unit which provides a high supporting capacity to voltage of an ultra-high voltage direct current convertor station bus; and on the above basis, key failure domain simulation of the AC system of the target grid is performed, and a start-up mode of the key generator unit is adjusted to determine the minimum start-up mode. The method provided by the invention may be used to arrange an actual power grid operation mode, so as to improve a safety and stability level of an AC / DC hybrid power grid.

Description

technical field [0001] The invention relates to the field of voltage safety and stability of power grids, in particular to a method for determining the minimum start-up mode based on AC-DC cascading faults, which is suitable for AC-DC hybrid power grids. Background technique [0002] As the scale of UHV DC feed-in increases, the replacement effect of DC power on conventional power sources will intensify, the power grid will appear in a small-start operation mode, and the dynamic reactive power support capacity in some areas will decline. Especially when there is no large power supply support in the vicinity of the DC converter station, if a serious fault occurs in the AC system, the DC commutation will fail. In recent years, there have been several cases of multiple DC simultaneous commutation failures or continuous commutation failures caused by AC system failures in my country's power grid. Subsequent commutation failures still occur after the AC fault is cleared, which n...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02J3/16H02J3/36
CPCH02J3/001H02J3/16H02J3/36Y02E40/30Y02E60/60
Inventor 邓晖黄晓明楼伯良孙维真叶琳华文黄弘扬赵一琰卢岑岑王龙飞杨滢张静周正阳
Owner ELECTRIC POWER RES INST OF STATE GRID ZHEJIANG ELECTRIC POWER COMAPNY
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