Differential protection setting method for alternating current filter group in direct current power transmission engineering
An AC filter, differential protection technology, applied in the direction of automatic disconnection of emergency protection devices, emergency protection circuit devices, electrical components, etc., can solve problems such as malfunctions, and achieve the effect of avoiding malfunctions
Active Publication Date: 2017-01-04
EXAMING & EXPERIMENTAL CENT OF ULTRAHIGH VOLTAGE POWER TRANSMISSION COMPANY CHINA SOUTHEN POWER GRID
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Problems solved by technology
[0004] During the process of opening the AC filter group from the connection to the three-phase sequentially, the differential protection of the AC filter group malfunctioned without a ground fault.
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[0028] The technical solutions implemented by the present invention will be clearly and completely described below in conjunction with the embodiments. Apparently, the described embodiments are only some of the embodiments of the present invention, not all of them.
[0029] This embodiment is aimed at the AC filter group protection of a certain DC transmission project in actual operation. The AC filter group differential protection high and low voltage terminal current transformer adopts a three-phase complete star connection mode, and its secondary circuit passes through the neutral wire to ground. In order to avoid the differential protection malfunction of the AC filter group in the case of a disconnection of the neutral line of the secondary circuit of the current transformer during the three-phase sequential opening process of the AC filter group of the DC transmission project, according to the method of the present invention, the The differential current threshold and ac...
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The invention discloses a differential protection setting method for an alternating current filter group in direct current power transmission engineering. The differential protection setting method comprises the steps of obtaining a maximum difference current Icd detected by a three-phase high-voltage end current transformer and a three-phase low-voltage end current transformer, and obtaining a differential protection difference current threshold value Idz of the alternating current filter group through coefficient conversion; obtaining a differential protection time-delay threshold value T2 of the alternating current filter group according to the operating frequency of an alternating current electric power system; step 3, taking the difference current threshold value Idz and the time-delay threshold value T2 as a difference current threshold value and a time-delay threshold value of a time-delay tripping section of difference protection for the alternating current filter group in the direct current power transmission engineering; and enabling the determined time-delay tripping section to be matched with difference protection of an existing alternating current filter group in the aspects of the difference current threshold value and the time-delay threshold value to form new and complete difference protection for the alternating current filter group in the direct current power transmission engineering. By adoption of the differential protection setting method, a false operation of the difference protection for the alternating current filter group in three-phase successive tripping periods of the alternating current filter group in the direct current power transmission engineering caused by disconnection of a neutral line in a secondary circuit of the current transformer can be avoided.
Description
technical field [0001] The invention relates to the technical field of direct current transmission control and protection, in particular to a differential protection setting method for an AC filter group in a direct current transmission project that takes into account the influence of the disconnection of the neutral line of a secondary circuit of a current transformer. Background technique [0002] A large amount of harmonic voltage and harmonic current are generated on both the AC side and the DC side of the DC power transmission project converter. The AC filter plays an important role in filtering out the harmonics on the AC side, and at the same time compensates for the reactive power consumed by the converter. Three-tuned AC filters, double-tuned AC filters and shunt capacitors are often used in DC transmission projects, such as figure 1 shown. [0003] The differential protection of the AC filter group is the main protection of the AC filter group, and is used to ref...
Claims
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Login to View More IPC IPC(8): H02H7/26H02H3/32
CPCH02H3/32H02H7/26H02H7/268
Inventor 郑伟彭光强张楠顾保全洪思远梁宁
Owner EXAMING & EXPERIMENTAL CENT OF ULTRAHIGH VOLTAGE POWER TRANSMISSION COMPANY CHINA SOUTHEN POWER GRID