CN206516474U - Current transformer - Google Patents

Abstract

The utility model provides a current transformer, which comprises a primary coil winding (10) and at least one secondary coil winding (20), and the primary coil winding (10) passes through the secondary coil winding (20); each of the secondary coil windings (20) The secondary coil winding (20) includes at least two iron cores, which are respectively the first iron core (21) of the secondary coil winding and the second iron core (23) of the secondary coil winding; the first iron core (21) of the secondary coil winding The first iron core coil (22) of the secondary coil winding is wound on it; the second iron core coil (24) of the secondary coil winding is wound on the second iron core (23) of the secondary coil winding; The first core coil (22) is connected in parallel with the second core coil (24) of the secondary coil winding. The number of coil turns on each core of the secondary coil winding is the same.

Description

Current Transformer

technical field

The utility model relates to the field of electrical technology, in particular to the technical field related to the winding error and output capacity of a secondary coil of a current transformer, in particular to the secondary coil winding technology of a current transformer with a low ampere-turns number.

Background technique

In the power system, the current transformer is a device that connects the primary system and the secondary system, and provides accurate and standard information for the measurement and relay protection of the power system. If the error of the current transformer does not meet the requirements, it will affect the accuracy of measurement and the reliability of relay protection, and endanger the safe operation of the power system.

Usually a current transformer consists of a primary coil winding and one or more secondary coil windings. Each secondary coil winding is wound with a single iron core. The following is a simple illustration of the existing products.

Fig. 1A-1B is the structural representation of existing current transformer; Wherein, the current transformer shown in Fig. 1A comprises a secondary coil winding, primary coil winding 10 passes through secondary coil winding 12, secondary coil winding 12 It includes an iron core 121 and a secondary coil winding wire 122 wound on the iron core 121 . The current transformer shown in FIG. 1B includes two secondary coil windings, namely a first secondary coil winding 13 and a second secondary coil winding 14 . The primary coil winding 10 passes through the first secondary coil winding 13 and the second secondary coil winding 14; the first secondary coil winding 13 includes an iron core 131 and a secondary coil wound on the iron core 131 Winding wire 132 ; the second secondary coil winding 14 includes an iron core 141 and a secondary coil winding wire 142 wound on the iron core 1241 .

Taking the current transformer shown in FIG. 1A as an example, the number of turns N2 wrapped by the secondary coil winding wire 122 and the number of turns N1 wrapped around the primary coil winding 10, the rated primary current I1n and the rated secondary current I2n satisfy the relationship Formula: I1n*N1=I2n*N2, its physical unit is: ampere*turns, abbreviation: ampere-turns.

In the conventional current transformer shown in FIGS. 1A-1B , no matter how many secondary coil windings are included, each single secondary coil winding is wound with a single iron core.

For current transformers with low ampere-turns, due to the small ampere-turns of the secondary coil winding, there are the following main problems:

1) It cannot meet the error requirements of high precision and accuracy level;

2) It cannot meet the large-capacity output requirements, and cannot meet the needs of secondary circuit relay protection equipment.

In order to meet the above two requirements as much as possible, the cross-sectional area of the iron core must be increased, thereby increasing the size of the iron core, resulting in an increase in the size of the secondary coil winding and even the entire current transformer, which cannot be installed in the switch cabinet.

Utility model content

Aiming at the main problems of the above-mentioned existing current transformers, the utility model provides a current transformer, which includes a primary coil winding and at least one secondary coil winding, and the primary coil winding passes through the secondary coil winding; each secondary coil The winding includes at least two iron cores, which are respectively the first iron core of the secondary coil winding and the second iron core of the secondary coil winding; the first iron core of the secondary coil winding is wound with a coil of the first iron core of the secondary coil winding; The second core coil of the secondary coil winding is wound on the second core of the secondary coil winding; the first core coil of the secondary coil winding and the second core coil of the secondary coil winding are connected in parallel.

According to a preferred embodiment of the present invention, when the rated current is less than 200 amperes, the primary coil winding is a single-turn coil.

According to a preferred embodiment of the present utility model, the number of coil turns on each iron core of the secondary coil winding is the same.

The current transformer of the utility model is compact in structure, small in size and light in weight, and can meet the requirements for installation in a switch cabinet with a small size; the utility model has reliable performance and low cost.

Description of drawings

1A-1B are structural schematic diagrams of existing current transformers; wherein, the current transformer shown in FIG. 1A includes a secondary coil winding, and the current transformer shown in FIG. 1B includes two secondary coil windings;

Fig. 2 and Fig. 3 are the overall structure schematic diagrams of the current transformer of the present utility model; Wherein, the current transformer shown in Fig. 2 comprises a secondary coil winding;

The current transformer shown in Figure 3 includes three secondary coil windings.

detailed description

The structure and function of the current transformer of the present invention will be described in detail below in conjunction with the accompanying drawings.

Aiming at the main problems of existing current transformers in the above-mentioned background technology, the utility model provides a current transformer, and Fig. 2 and 3 are schematic diagrams of the overall structure of the current transformer of the present utility model; wherein, the current shown in Fig. 2 The transformer includes one secondary coil winding, and in the current transformer shown in FIG. 3, three secondary coil windings. As shown in Fig. 2 and Fig. 3, the current transformer of the present invention includes a primary coil winding 10 and at least one secondary coil winding 20, and each of the secondary coil windings 20 includes at least two iron cores, respectively two The secondary coil winds the first core 21 and the secondary coil winds the second core 23 . The primary coil winding 10 passes through a secondary coil winding 20 .

In the current transformer shown in Figure 3, in order to further compare the existing description current transformer to illustrate the characteristics and advantages of the current transformer of the present utility model, it is convenient to illustrate. Among the three secondary coil windings, one of the two The secondary coil windings include one iron core; one of the secondary coil windings 20 includes two iron cores; and the other secondary coil winding 30 includes three iron cores. In practical applications, the secondary coil winding can have one or more secondary coil windings according to the parameters and requirements of the transformer, and each winding can have at least 2 iron cores, and wires are wound on each iron core. After connecting the wires wound on these iron cores in parallel, a secondary coil winding is formed.

As shown in FIG. 3 , the secondary coil winding 30 includes three cores, the secondary coil winding first core 31 , the secondary coil winding second core 32 and the secondary coil winding third core 33 .

As shown in Figure 2 and Figure 3, the first iron core 21 of the secondary coil winding is wound with the first iron core coil 22 of the secondary coil winding; the second iron core 23 of the secondary coil winding is wound with the second coil of the secondary coil winding The core coil 24 ; the first core coil 22 of the secondary coil winding and the second core coil 24 of the secondary coil winding are connected in parallel at the output terminal side. As shown in FIG. 3 , the secondary coil winding 30 including three iron cores is also connected in parallel on the output terminal side.

According to a preferred embodiment of the present utility model, the primary coil winding 10 is a single-turn coil. In existing current transformers, the primary coil winding is a single-turn coil only in high-current current transformers, especially when the rated current is greater than 400 amperes. In this embodiment, for a current transformer with a small current, such as less than 200 amperes, the primary coil winding adopts a single-turn coil.

According to a preferred embodiment of the present invention, the number of turns of the first core coil 22 of the secondary coil winding and the second core coil 24 of the secondary coil winding are the same. The number of turns is the same, which is conducive to the calculation of the number of turns. Since the first iron core coil 22 of the secondary coil winding and the second iron core coil 24 of the secondary coil winding are connected in parallel, compared with the secondary coil winding of the existing single iron core, Under the same parameters, the number of turns of the first iron core coil 22 of the secondary coil winding and the second iron core coil 24 of the secondary coil winding can be doubled. Similarly, in the current transformer shown in FIG. 3 , the secondary coil winding 30 with three iron cores is included, and the number of turns of the wires that can be wound on the three iron cores is the same, and the number of turns of each iron core is three. times.

According to the number of secondary coil windings connected in parallel, the number of turns of the secondary coil winding is increased, thereby increasing the number of ampere-turns of the secondary coil winding to meet the requirements of the error and the output capacity of the secondary coil winding.

Further, due to the increase in the number of turns of the secondary coil winding, the size of each secondary coil winding will be greatly reduced. After parallel connection, the total size of the secondary coil winding will be smaller than that of the existing current transformer, saving the size space .

The current transformer of the utility model, because the size of the new solution is small, uses less materials, thereby also reducing the cost of materials.

The current transformer of the utility model is not limited to a certain type of current transformer, but can be applied to all current transformers. The advantages of the current transformer of the present invention will be described below in combination with examples of specific parameters.

For example, current transformer parameters: rated current ratio: 50/1A, accuracy class: 0.5, rated output: 5VA;

The existing current transformer adopts a secondary coil winding, the secondary coil winding is a single iron core, the size of the iron core is φ100/φ140×110 (inner diameter/outer diameter×height, mm), and the number of winding turns is 50 turns , the secondary ampere-turns is 50 ampere-turns;

Adopt the current transformer of the present utility model, adopt a secondary coil winding, this secondary coil winding adopts two identical iron core windings, each iron core size is φ100/φ140×30 (inner diameter/outer diameter × height, mm ), the wires are connected in parallel at the output. The number of winding turns of each iron core is 100 turns, and the number of ampere-turns of the secondary coil winding is increased to 100 ampere-turns.

Through the comparison of the above examples, it can be seen that according to the current transformer of the present invention, iron cores with the same inner and outer diameters are used. As in the above example, the original iron core height is 110mm. The iron core is 30mm, the height of the two iron cores is 60mm, and the height of the winding space of the two iron cores is about 20mm. The iron core height of the current transformer of the present utility model is reduced to about 80mm from the original about 120mm (additional 10mm winding height), which is more than 30%. According to the error measurement results, there is still a margin of 20% in the error score, but the error score of the existing current transformer is close to the limit, and there is no margin.

Compared with the existing current transformer, the current transformer of the present utility model has at least the following advantages:

1) The low ampere-turns current transformer can meet the requirements of high accuracy and large capacity output;

2) The current transformer of the present utility model is compact in structure, small in size and light in weight, and can meet the requirements for installation in smaller size switch cabinets;

3) Reliable performance and low cost.

In summary, the current transformer of the present invention can solve the problem of high-precision error and large-capacity output of low-ampere-turns current transformers, and can reduce the size of the transformer, making it suitable for small-sized switch cabinets .

Although the preferred embodiment of the utility model and accompanying drawings are disclosed for the purpose of illustration, those skilled in the art can make various replacements, Variations and retouching. Therefore, the utility model should not be limited to the content disclosed in the preferred embodiments and drawings, and the scope of protection of the utility model should be defined by the appended claims.

Claims (3)

1. A current transformer, comprising a primary coil winding (10) and at least one secondary coil winding (20), the primary coil winding (10) passes through the secondary coil winding (20), characterized in that: each of the The secondary coil winding (20) comprises at least two iron cores, respectively the first iron core (21) of the secondary coil winding and the second iron core (23) of the secondary coil winding; The first iron core (21) of the secondary coil winding is wound with the first iron core coil (22) of the secondary coil winding; the second iron core (23) of the secondary coil winding is wound with the second iron core coil of the secondary coil winding (twenty four); The first iron core coil (22) of the secondary coil winding and the second iron core coil (24) of the secondary coil winding are connected in parallel. 2. The current transformer according to claim 1, characterized in that: when the rated current is less than 200 amperes, the primary coil winding (10) is a single-turn coil. 3. The current transformer according to claim 1 or 2, characterized in that: the coil turns of each iron core on the secondary coil winding are the same.