CN103606449A

CN103606449A - High-precision current transformer

Info

Publication number: CN103606449A
Application number: CN201310573044.9A
Authority: CN
Inventors: 吴兴燕; 杜桂芬; 印丽琴; 陈莹
Original assignee: JIANGSU JINGJIANG INSTRUMENT TRANSFORMER FACTORY CO Ltd
Current assignee: JIANGSU JINGJIANG INSTRUMENT TRANSFORMER FACTORY CO Ltd
Priority date: 2013-11-13
Filing date: 2013-11-13
Publication date: 2014-02-26

Abstract

The invention discloses a high-precision current transformer. The secondary ends S1 and S2 of multiple coils are parallelly connected to form secondary windings 3. Each secondary winding is wound on an iron core 5. Circular nuts are welded to the connected outlet wire heads in an embedded manner to serve as the secondary wire outlet end 1 of the transformer. An outer insulator 2 wraps outside each secondary winding 3. A sufficient insulating layer 4 wraps outside each iron core 5. Corresponding turns of electromagnetic wires are wound on each insulating layer 4. The high-precision current transformer has the advantages that the error problem of a small-current transformer whose primary mandrel is single-turn and measuring accuracy is 0.2S level is solved; the error of the transformer can meet the national standard 0.2S level error requirements under the condition that the primary current is below 100A and the minimum primary current is at 20A; mounting convenience is brought to power supply departments, and accuracy of electric bill settlement of users is increased at the same time.

Description

High precision current transformer

Technical field

The invention belongs to instrument transformer field, particularly a kind of high precision current transformer, especially a kind of primary current is below 100A, and precision will be in 0.2S level, and punching number of turn high precision current transformer that is a circle.

Background technology

Current transformer is the visual plant of electric power system and electricity consumption department, and its main application is the safe operation of the visual plant in protection circuit and carries out exactly energy calculate.Its whether accurate quality and the safe operation that directly has influence on power system power supply, also has influence on for the charge calculation accuracy rate between electricity consumption department.Along with the development of market economy and the raising that the quality of power supply is required, requirement to instrument transformer is also more and more higher, the measuring accuracy of the current transformer using is at present mostly 0.2 grade, national grid and south electric network are had higher requirement to the precision of instrument transformer, require the precision of instrument transformer to bring up to 0.2S level, that is to say the error regulation that requires instrument transformer all will meet national Specification between the 1%-120% of rated current, and to require current ratio be a circle at 100/5A and a following punching number of turn.

Traditional manufacture method, by requirement recited above, the precision of instrument transformer is at 3 grades to 10 grades, and this brings very large error to the electric energy metrical of power supply department.

Summary of the invention

The problem existing for solving above-mentioned prior art, the invention provides a kind of high precision current transformer, and its primary current is at 100A and following, and minimum primary current can be 20A, and measuring accuracy is 0.2S level, and a wire is the shape small size current mutual inductor of a circle.

For achieving the above object, technical scheme of the present invention is:

A kind of high precision current transformer, by the secondary terminals S1 of a plurality of coils and the S2 difference secondary winding 3 that forms in parallel, secondary winding 3 is wound on iron core 5, terminal welding setting-in round nut after connection, secondary outgoing line end 1 as instrument transformer, described secondary winding 3 outsourcing external insulations 2, are surrounded by enough insulating barriers 4 in the outside of iron core 5, more in the above around the electromagnetic wire of the corresponding number of turn.

The iron core 5 of described instrument transformer adopts without shell microcrystalline iron core.

Described external insulation 2 adopts insulation crust sealing resins fixed-type or directly adopt epoxy resin or unsaturated-resin moulding by casting.

Described iron core 5 and the electromagnetic wire number of turn are corresponding with primary current amperage.

Described iron core 5, the electromagnetic wire number of turn and the concrete corresponding relation of primary current amperage are: 100A adopts three iron cores, and every iron core uses electromagnetic wire around 60 circles; Four iron cores for 75A, every iron core with electromagnetic wire around 60 circles around circle; 50A adopts five iron cores, and every iron core uses electromagnetic wire around 50 circles; 40A adopts five iron cores, and every iron core uses electromagnetic wire around 40 circles; 30A adopts six iron cores, and every iron core uses electromagnetic wire around 36 circles; 20A adopts eight iron cores, and every iron core uses electromagnetic wire around 32 circles.

With respect to prior art, beneficial effect of the present invention is: it is that single turn, measuring accuracy are the error problem of the small current mutual inductor of 0.2S level that the present invention has solved a punching effectively.Can guarantee that primary current is at 100A and following, the error of minimum primary current instrument transformer when 20A can meet the error requirements of national Specification 0.2S level.For the installation of power supply department has brought convenience, also improved the accuracy that user settles accounts the electricity charge simultaneously.

Accompanying drawing explanation

Fig. 1 is structural representation of the present invention;

1-secondary outgoing line end, 2. external insulation, 3. secondary winding, 4. insulating barrier, 5. iron core;

Embodiment

Below in conjunction with drawings and the specific embodiments, the present invention is described in detail.

As shown in Figure 1, a kind of high precision current transformer, by the secondary terminals S1 of a plurality of coils and the S2 difference secondary winding 3 that forms in parallel, secondary winding 3 is wound on iron core 5, terminal welding setting-in round nut after connection, as the secondary outgoing line end 1 of instrument transformer, described secondary winding 3 outsourcing external insulations 2, in the outside of iron core 5, be surrounded by enough insulating barriers 4, more in the above around the electromagnetic wire of the corresponding number of turn.

Use principle of the present invention is that current transformer provided by the invention is (according to the size of current ratio by a plurality of coils, for 3-8) by mode in parallel, by the secondary terminals S1 of each coil and the S2 difference secondary winding 3 that forms in parallel, terminal welding setting-in round nut after connection, secondary outgoing line end 1 as instrument transformer, secondary winding 3 use epoxy resin or unsaturated-resin moulding by casting, external insulation 2 as instrument transformer, the external insulation 2 of instrument transformer also can directly be used the insulation crust of moulding, then fixes with sealing resin.

The iron core 5 of instrument transformer adopts without shell microcrystalline iron core, in the outside without shell microcrystalline iron core, is surrounded by enough insulating barriers 4, more in the above around the electromagnetic wire of the corresponding number of turn.For example: 100A adopts three without shell microcrystalline iron core, every iron core uses electromagnetic wire around 60 circles (the secondary number of turn); Four iron cores for 75A, every iron core with electromagnetic wire around 60 circles around circle; 50A adopts five iron cores, and every iron core uses electromagnetic wire around 50 circles; 40A adopts five iron cores, and every iron core uses electromagnetic wire around 40 circles; 30A adopts six iron cores only, and every iron core uses electromagnetic wire around 36 circles; 20A adopts eight iron cores, and every iron core uses electromagnetic wire around 32 circles.Electromagnetic wire adopts many high strength enamelled wires, can compensate according to error condition.It is that single turn, measuring accuracy are the error problem of the small current mutual inductor of 0.2S level that the present invention has solved a punching effectively.Can guarantee that primary current is at 100A and following, the error of minimum primary current instrument transformer when 20A can meet the error requirements of national Specification 0.2S level.For the installation of power supply department has brought convenience, also improved the accuracy that user settles accounts the electricity charge simultaneously.

Result of the test

The error information of table 1 routine

The error information of table 2 the present invention program gained

The error limit of table 3GB 1208-2006 < < current transformer > > regulation

Should be understood that, for those of ordinary skills, can be improved according to the above description or convert, and all these improvement and conversion all should belong to the protection range of claims of the present invention.

Claims

1. a high precision current transformer, it is characterized in that, by the secondary terminals S1 of a plurality of coils and the S2 difference secondary winding (3) that forms in parallel, secondary winding (3) is wound on iron core (5), terminal welding setting-in round nut after connection, as the secondary outgoing line end (1) of instrument transformer, described secondary winding (3) outsourcing external insulation (2), in the outside of iron core (5), be surrounded by enough insulating barriers (4), more in the above around the electromagnetic wire of the corresponding number of turn.

2. current transformer as claimed in claim 1, is characterized in that, the iron core of described instrument transformer (5) adopts without shell microcrystalline iron core.

3. current transformer as claimed in claim 1, is characterized in that, described external insulation (2) adopts insulation crust sealing resin fixed-type or directly adopt epoxy resin or unsaturated-resin moulding by casting.

4. current transformer as claimed in claim 1, is characterized in that, described iron core (5) and the electromagnetic wire number of turn are corresponding with primary current amperage.

5. current transformer as claimed in claim 4, is characterized in that, described iron core (5), the electromagnetic wire number of turn and the concrete corresponding relation of primary current amperage are: 100A adopts three iron cores, and every iron core uses electromagnetic wire around 60 circles; Four iron cores for 75A, every iron core with electromagnetic wire around 60 circles around circle; 50A adopts five iron cores, and every iron core uses electromagnetic wire around 50 circles; 40A adopts five iron cores, and every iron core uses electromagnetic wire around 40 circles; 30A adopts six iron cores, and every iron core uses electromagnetic wire around 36 circles; 20A adopts eight iron cores, and every iron core uses electromagnetic wire around 32 circles.