Method for online detection and total loss determination of neutral current of distribution transformer

A technology for determining distribution transformers and methods, which is applied in the direction of measuring electrical variables, measuring resistance/reactance/impedance, instruments, etc., can solve the problems of no online monitoring device for distribution transformer neutral current, and achieve the effect of improving anti-interference ability

CN102279311AInactive Publication Date: 2011-12-14STATE GRID CHONGQING ELECTRIC POWER +1
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2011-12-14
Estimated Expiration
Not applicable · inactive patent

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Abstract

The invention discloses a method for the online detection and total loss determination of the neutral current of a distribution transformer. Four precise split core type current transformers are used for respectively detecting the three-phase current and the neutral current, each harmonic component is obtained by using fast Fourier transform, a fundamental current is calculated, and then the iron loss, the copper loss, the neutral line loss and the earth current loss of the transformer are calculated according to each current, thus obtaining the total loss of the transformer. The method can effectively monitor and acquire the electric signal of the transformer, a DSP high speed central processor performs digital filtering on the electric signal, the anti-interference capability is improved, and the neutral current of the transformer and loss caused thereby are measured on line, realtimely, rapidly and accurately, providing necessary basis for the safe and stable operation of the transformer.
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Description

technical field

[0001] The invention belongs to the field of power systems, and in particular relates to a method for on-line detection of neutral line current of distribution transformers and determination of total loss. Background technique

[0002] During the operation of the power system, the existence of neutral current will cause more energy loss to the transformer. Excessive neutral line current causes a huge waste of electric energy; at the same time, heat is emitted, causing the transformer to heat up, causing chemical reactions such as the decomposition of insulating oil, and reducing the service life of the transformer; continuous excessive neutral line current may also cause the neutral line to fuse. As a result, electrical appliances are burned, and even a fire accident is caused in severe cases. At present, there are mainly electromagnetic current transformer measurement, electronic current transformer measurement and photoelectric current transformer measurem...

Examples

Embodiment Construction

[0040] The present invention will be further described below with reference to a non-limiting embodiment given in the accompanying drawings.

[0041] A distribution transformer neutral line current online detection and total loss determination method specifically includes the following steps:

[0042] (1) Signal acquisition: use the first precision clamp current transformer 21, the second precision clamp current transformer 22, the third precision clamp current transformer 23 and the fourth precision clamp current transformer 24 to collect phase A respectively Line current signal I A , B-phase line current signal I B , C-phase line current signal I C and neutral current signal I N .

[0043] (2) Signal processing: the three-phase current signal I A , I B , I C and neutral current signal I N They are respectively converted into (0-3V) DC voltage signals that can be converted by the DSP central processor, and then converted into digital signals by A / D after amplification...