Method for judging commutation failure caused by coupling of multi-circuit direct-current transmission lines erected on same tower in parallel
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A technology of commutation failure and DC line, which is applied in the direction of measuring devices, instruments, and measuring circuits, and can solve problems such as commutation failure, no criterion for commutation failure, and current changes in non-fault poles.
Active Publication Date: 2014-02-05
EXAMING & EXPERIMENTAL CENT OF ULTRAHIGH VOLTAGE POWER TRANSMISSION COMPANY CHINA SOUTHEN POWER GRID +1
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However, for the multi-circuit HVDC transmission system paralleled on the same tower, due to the coupling between lines, the current mutation caused by the fault of one pole line will cause the current of the non-faulted pole to change, which may cause commutation failure. The criterion of commutation failure in DC system caused by AC fault is no longer suita
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Embodiment 1
[0088] Such as figure 1 As shown, this embodiment uses the proposed method to judge whether the commutation failure occurs in the non-faulty pole when the dual-circuit DC of Xiluodu is in rated operation and the metallic fault at the end of the DC positive line of the I-circuit occurs, including the following steps:
[0089] 1) According to the structure and parameters of the double-circuit DC transmission line on the same tower, calculate the current coupling coefficient K between the lines;
[0090] 2) According to the parameters of the converter transformer and the operating parameters of the AC-DC system, calculate the maximum commutation time area B that the AC grid can provide max ;
[0091] 3) According to the system parameters, calculate the maximum sudden change current ΔI on the inverter side of the faulty pole when the pole line is faulty f.max ;
[0092] 4) According to the maximum mutation current ΔI fmax , the current coupling coefficient K and the rated DC ...
Embodiment 2
[0152] Such as figure 1 As shown, in this embodiment, judging whether commutation failure occurs in the non-faulty pole when the positive metal loop of Xiluodu double-circuit DC I DC positive circuit is running, and the end of the positive DC positive line of I circuit fails, includes the following steps:
[0153] 1) According to the structure and parameters of the double-circuit DC transmission line on the same tower, calculate the current coupling coefficient K between the lines;
[0154] 2) According to the parameters of the converter transformer and the operating parameters of the AC-DC system, calculate the maximum commutation time area B that the AC grid can provide max ;
[0155] 3) According to the system parameters, calculate the maximum sudden change current ΔI on the inverter side of the faulty pole when the pole line is faulty f.max ;
[0156] 4) According to the maximum mutation current ΔI fmax , the current coupling coefficient K and the rated DC current I o...
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Abstract
The invention discloses a method for judging a commutation failure caused by coupling of multi-circuit direct-current transmission lines erected on the same tower in parallel. The current coupling coefficient K between the lines is calculated; the maximum commutation time area Bmas which an alternate-current power grid can supply is calculated; the maximum break variable current deltaIf.max of a fault pole inversion side generated when a polar line breaks down is calculated; the commutation area A needed by successful commutation of a non-fault pole is calculated; the A and the Bmax are compared, and if A>Bmax, the commutation failure of the non-fault pole is possibly caused by the coupling of the multi-circuit direct-current transmission lines erected on the same tower in parallel. According to the method, the relation of the change of direct currents and the commutation failure in the commutation transient process is analyzed based on a commutation voltage time area theory, the maximum commutation time area criterion for judging whether the commutation failure caused by the coupling of the multi-circuit direct-current transmission lines erected on the same tower in parallel or not is built by combining the derived current coupling coefficient between the multi-circuit direct-current transmission system lines erected on the same tower in parallel, and the method is simple and can fast and effectively carry out judgment.
Description
technical field [0001] The invention relates to the field of fault analysis of power systems, in particular to a method for judging commutation failure caused by the coupling effect of multiple DC lines paralleled on the same tower. Background technique [0002] The parallel multi-circuit power transmission technology on the same tower can reduce the power construction cost while increasing the power transmission capacity and land utilization rate of the line unit corridor. At present, the parallel multi-circuit AC power transmission technology on the same tower has been widely used, and the double-circuit DC power transmission project on the same tower has also begun to appear in recent years. The Linfeng DC and Genan DC projects of the State Grid Corporation of China and the Xiluodu DC project of the China Southern Power Grid Corporation are all double-circuit DC projects erected on the same tower. With the development of DC transmission technology and the implementation ...
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IPC IPC(8): G01R31/00
Inventor 周全钱海周尚礼王钢李海锋刘俊磊
Owner EXAMING & EXPERIMENTAL CENT OF ULTRAHIGH VOLTAGE POWER TRANSMISSION COMPANY CHINA SOUTHEN POWER GRID
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