An Online Monitoring Method of CVT Capacitance Based on Zero Sequence Voltage Monitoring

A technology of zero-sequence voltage and capacitance, which is applied in the field of online monitoring of CVT capacitance based on zero-sequence voltage monitoring, can solve problems such as the inability to find capacitive voltage transformers, large test instruments, and unqualified CVT ratio errors, etc. Monitor the effect of a small number of capacitor breakdown, good anti-interference performance, and avoid electromagnetic interference

CN105589052BActive Publication Date: 2018-06-26CHINA SOUTHERN POWER GRID EHV POWER TRANSMISSION COMPANY WUZHOU BUREAU
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Publication Date
2018-06-26

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Abstract

The invention discloses a CVT capacitance on-line monitoring method based on zero sequence voltage monitoring. The method comprises the steps of: S10, parallelly reading the zero sequence voltage of at least one CVT by a plant station monitoring system, wherein the zero sequence voltage is normal if only deviating from normal values; S20, querying each CVT for detecting whether each zero sequence voltage exceeds a first voltage threshold, and for one CVT, if the zero sequence voltage thereof is larger than or equal to the first voltage threshold, entering a step S30; and S30, counting the abnormity duration time of zero sequence voltage of the CVT, judging whether the zero sequence voltage of the CVT exceeds a second voltage threshold, if the zero sequence voltage is smaller than the second voltage threshold and the duration time is larger than a first set time, then determining that the capacitance of the CVT is broken down. The operation condition of the CVT capacitance is accurately judged by the utilization of the zero sequence voltage of the CVT, deep processing is carried out by the utilization data of the plant station monitoring system, no equipment needs to be added, and the reliability is improved.
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Description

technical field

[0001] The invention relates to the technical field of electric power online detection, in particular to an online monitoring method of CVT capacitance based on zero-sequence voltage monitoring. Background technique

[0002] If you want to find out whether the capacitance of the CVT breaks down, you generally need to rely on the ratio error test. However, it is more difficult to carry out CVT ratio error testing at this stage: 1. Corresponding qualifications are required. The state controls the ratio error testing more strictly. Generally, only one unit in a province is qualified to carry out this test, and its work schedule is relatively full. , it is difficult to arrange the construction period; 2. The test equipment is relatively large, and the test is time-consuming and laborious, resulting in a higher price.

[0003] The existing pre-test inspection cannot find the capacitive breakdown defect of the capacitive voltage transformer (CVT in English abbrevi...

Examples

Embodiment Construction

[0026] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings and embodiments. Apparently, the described embodiments are only some of the embodiments of the present invention, not all of them.

[0027] see figure 1 , is the structural principle diagram of the CVT. The CVT is mainly composed of the capacitive voltage divider 1 and the electromagnetic part 2 in structure, and the capacitive voltage divider C1 and C2 are two parts. For example, a CVT is composed of three porcelain bushings in appearance, C11 and C12 are in the upper and middle porcelain bushings respectively, and C13 and C2 are in the lower porcelain bushing and are connected together by the flange and the electromagnetic part. In this embodiment, the CVT takes the following parameters as an example: There are 154 elements in the capacitor of the ceramic sleeve, among which C13 has 130 elements, and C2 has 24 elements. No...