CN201282021Y - Current transformer - Google Patents

Abstract

The embodiment of the utility model relates to the field of power electrons, and provides a current transformer. A conductive tube is sleeved in the middle of a primary loop conductive tube and separated from another conductive tube through an insulator; another conductive tube is inserted in the middle of the conductive tube again and separated from the conductive tube through an insulator; a conducting rod is inserted in the middle of the conductive tube and separated from the conductive tube through an insulator; and each conductive tube and the conducting rod are connected through a connection terminal conducting bus-bar to form a primary winding. Therefore, the turns of the primary winding are increased, and the measurement is more precise.

Description

Current transformer

Technical field

The utility model relates to field of power electronics, and a kind of SF6 (sulphur hexafluoride) is provided current transformer.

Background technology

The SF6 of prior art (sulphur hexafluoride) current transformer structure is inverted; comprise winding, secondary winding; insulators etc., a windings in series are in measured power circuit, and secondary circuit is serially connected with secondary devices such as measuring instrument, relaying protection automatics.Therefore according to the law of magnetic circuit, error is directly proportional with load, no-load voltage ratio is inversely proportional to, and an existing winding mostly is 2 circles most, will guarantee the precision measured under the low big load of no-load voltage ratio, and the current transformer of prior art is that the comparison difficulty realizes.

The utility model content

The utility model embodiment provides a kind of current transformer, to improve the precision of measuring.

Current transformer embodiment provided by the utility model is achieved through the following technical solutions:

A kind of current transformer, described current transformer comprises the primary circuit, secondary winding and insulator, be with second contact tube in the middle of first contact tube of described primary circuit, described first contact tube and second contact tube are isolated with insulator, be installed with the 3rd contact tube in the middle of described second contact tube again, isolate with insulator between described the 3rd contact tube and described second contact tube, be installed with conducting rod in the middle of described the 3rd contact tube again, isolate with insulator between described the 3rd contact tube and the conducting rod, each contact tube, by winding of the continuous formation of binding post busbar, a described winding passes in the middle of secondary winding between the conducting rod.

The current transformer that the utility model embodiment provides has been owing to improved the number of turn of a winding, makes the measurement can be more accurate.

Description of drawings

The current transformer structure chart that Fig. 1 provides for the utility model;

The enlarged drawing of the primary circuit that Fig. 2 provides for the utility model.

Embodiment

In a winding, flow through electric current I ₁The time, because electromagnetic induction induces electromotive force in secondary winding, under the situation of secondary winding external circuit connection, secondary current I is just arranged ₂Circulation, I ₁With a umber of turn N ₁Product be called magnetomotive force one time.I ₁N ₁Be also referred to as ampere-turn one time, secondary current I ₂With secondary number of turn N ₂Product, be secondary magnetomotive force I ₂N ₂

I ₁N ₁+I ₂N ₂＝I ₀N ₁

According to the law of magnetic circuit, its error $f_i(\%)=-\frac{I_2{Z}_{2\mathrm{<figure-callout\; id="2"\; label="S\; L\; C"\; filenames="Y200820099485E00061.png"\; state="\{\{state\}\}">S</figure-callout>}}{L}_C{}_{}}{2\mathrm{pfmAc}{N}_2{I}_1{\mathrm{<figure-callout\; id="1"\; label="N"\; filenames="Y200820099485E00061.png"\; state="\{\{state\}\}">N</figure-callout>}}_1}\sin (\mathrm{\&alpha;}+\mathrm{\&theta;})\&times;100$

Z _{2 ∑s}Be the secondary circuit total impedance; A _cThe iron core net sectional area, unit is: mm ²L _cThe average length of magnetic path of iron core, unit is mm; F frequency 50Hz; μ iron core magnetic capacity, from above formula as can be seen, error is directly proportional with load, no-load voltage ratio is inversely proportional to, and therefore will guarantee its precision under the big load of low no-load voltage ratio, is the comparison difficulty, also improves ampere-turn I as can be seen one time from formula ₁N ₁, can improve precision.

The current transformer that the utility model embodiment provides can be realized 4 circle punchings, and than 2 circles that many of prior art, certainty of measurement can improve greatly under the equal volume thereby make.Describe the technical scheme that the utility model provides in detail below in conjunction with accompanying drawing.

With reference to Fig. 1, shown in Figure 2, a kind of current transformer mainly is made up of the body 1, insulator 2 and base 3 three parts.The body 1 is positioned at the top of current transformer, and secondary winding is contained in the housing of the body 2, uses the SF6 gas-insulated between them.The housing of the body 1 and primary circuit 10 are by insulator 2 and base 3 insulation.Secondary winding relies on insulating part to be fixed in the housing of the body 1, and its lead-in wire links to each other with each terminal of secondary connection plate in the base 3 by the metallic shield pipe in the insulator 2, connects for the user and measures or protect and use load.Base 3 is provided with the secondary connection plate.Shown in Figure 2, be with second contact tube 12 in the middle of first contact tube 11 of described primary circuit 10, described first contact tube 11 and second contact tube, 12 usefulness insulators are isolated, be installed with the 3rd contact tube 13 again in the middle of described second contact tube 12, isolate with insulator between described the 3rd contact tube 13 and described second contact tube 12, be installed with conducting rod 14 again in the middle of described the 3rd contact tube 13, isolate with insulator between described the 3rd contact tube 13 and the conducting rod, each contact tube, by winding of the continuous formation of binding post busbar, a described winding passes in the middle of secondary winding between the conducting rod 14.

The current transformer that the utility model provides has improved the number of turn of a winding, makes the measurement can be more accurate.

More than a kind of current transformer that the utility model embodiment is provided be described in detail, for one of ordinary skill in the art, thought according to the utility model embodiment, part in specific embodiments and applications all can change, in sum, this description should not be construed as restriction of the present utility model.

Claims (1)

1, a kind of current transformer, described current transformer comprises the primary circuit, secondary winding and insulator, it is characterized in that, be with second contact tube in the middle of first contact tube of described primary circuit, described first contact tube and second contact tube are isolated with insulator, be installed with the 3rd contact tube in the middle of described second contact tube again, isolate with insulator between described the 3rd contact tube and described second contact tube, be installed with conducting rod in the middle of described the 3rd contact tube again, isolate with insulator between described the 3rd contact tube and the conducting rod, each contact tube, by winding of the continuous formation of binding post busbar, a described winding passes in the middle of secondary winding between the conducting rod.

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