Non-circular current transformer intended for use in high voltage switchgear systems

Abstract

The invention relates to a non-circular current transformer (1), which is used especially in a high voltage switching cell and allows more than one cable to pass through it.

Description

[0001] NON-CIRCULAR CURRENT TRANSFORMER INTENDED FOR USE IN HIGH VOLTAGE SWITCHGEAR SYSTEMS

[0002] Technical Field

[0003] The invention relates to a non-circular current transformer. The structure of said current transformer is preferably formed in the form of an ellipse and thus an advantage is provided in terms of cost.

[0004] State of the Art

[0005] Current transformers are metering transformers used to measure the current flowing through the circuit. High currents are sometimes very dangerous and difficult to measure directly by measuring instruments, as well as being costly. Therefore, the current flowing through the circuit must be reduced to a certain value in order to be measured. The current transformer, which is connected to the circuit in series, reduces the magnetic field created by the current flowing through the primary circuit and transfers it to the second circuit called the secondary circuit. Thanks to the cyclic current in the secondary circuit, the amount of current passing through the primary circuit can be measured with the meter connected in parallel to the secondary winding.

[0006] Current transformers mainly consist of a magnetic core, a primary winding wound on this core, and a secondary winding wound in the opposite direction to this primary winding. The current passing through the primary winding creates a magnetic flux on the magnetic core. This magnetic flux formed in the core causes a voltage to be induced on the secondary winding. The meter connected in parallel to the secondary winding creates a magnetic flux in the opposite direction in the magnetic core due to the opposite direction of the current winding passing through the secondary circuit. This magnetic flux balances the magnetic flux formed by the current passing through the primary winding. For this reason, the secondary ends of the current transformers must be short-circuited with a measuring device or a load. Otherwise, a magnetic flux will not occur in the opposite direction and since the flux is not balanced, it may malfunction by heating the magnetic core. In addition, since this will increase the tension at the secondary ends, it poses a danger to users.

[0007] Circular current transformers are used to measure the current in high-voltage switchgear cells. These current transformers are circular in structure and are passed to the power cables, and the magnetic field and the windings in the current transformer core are converted to 1 A or 5A current.

[0008] However, in order to create a circular current transformer, the core must be wrapped with windings in the circular structure. When the core is formed in a circular structure, the winding must be applied in a way that surrounds the entire circle in order to create a current on the winding.

[0009] In order to create this functional unity, it will be necessary to provide the windings in a magnetic structure that can provide a core and current in both the core and the winding in a way that completely surrounds the circumferentially circular form of the windings.

[0010] This type of winding and core requirement may cause an increase in the total cost of the current transformer.

[0011] Again, the necessity of creating the current transformer in a full circular form causes the total dimensions of the current transformer to grow. This creates a handicap, especially for gas-insulated switchgear cells. Due to the demands of such cells to be produced in limited sizes, the dimensions of the current transformers in their current circular form and their geometric structure that is not suitable for placement can create a handicap.

[0012] Current transformers used in high-voltage switchgear cells may require the passage of more than one current-conducting cable through them. In this type of case, it will be necessary to enlarge the internal cavity of the ring-shaped structure for each additional cable to be passed through the current transformer designed in a circular structure. Considering the thickness of the cables used in such systems, the required in-ring cavity increases.

[0013] In fact, this problem can be partially solved with the use of thicker cables. For example, a single cable with a cross-section of 300 mm2can be used for the 1250 A current requirement. However, the use of a single cable of this thickness may cause serious problems in terms of installation. It will be very difficult for the worker to bend and twist a cable of this thickness while installing the system.

[0014] On the other hand, since there are no cables larger than 240 mm2in the inventory of some countries such as Turkiye, it may not be possible to use a single cable in such countries. For this reason, two cables for 1250 A and four cables for 2500 A have to be used in such countries.

[0015] In fact, extending the length of the cavity created for the cables to pass through in a single axis will ensure that this need is met. However, the circular form of the current transformer can cause the total ring form to be enlarged if the cavity in the internal structure is enlarged.

[0016] Again, when the structure grows, the total cost of the current transformer will increase as the amount of raw materials used will grow.

[0017] In the structure of patent application TR 2022 / 009364, it is understood that at least the current transformer refers to the metal-housed medium and high voltage switching cell used in medium and high voltage switching systems, which comprises at least one primary door associated with the breaker section and at least one secondary door associated with the cable section, so that said current transformer can be positioned in the metal-housed medium and high voltage switching cell.

[0018] Within the relevant patent, a medium and high voltage switching cell containing a circular form current transformer is described.

[0019] Further, patent application numbered WO9215104 discloses a circular current transformer intended for use in gas-insulated switchgear cells. Problems to be Solved by the Invention

[0020] The object of the invention is to create a non-circular current transformer, preferably in the form of an ellipse or an oval, especially used in a high voltage switching cell.

[0021] In this way, it will be sufficient to produce all the core of the current transformer from magnetic materials and to form a winding only on at least one part of the lateral walls. In this way, the total cost of the current transformer could be significantly reduced.

[0022] Considering that the main cost-forming parts of a current transformer are these parts, a significant cost advantage can be provided. In this case, the user does not have to wrap the upper and lower walls of the core. Cost can be reduced in this way.

[0023] More generally, said core is designed in a geometric structure whose lateral walls are longer than the floor and ceiling walls. In this way, the length required for the positioning of more than one cable in the structure can be provided by extending a single axis.

[0024] Although this one-axis elongated embodiment increases the number of cables to be positioned in it, the dimensions of the high voltage switching cell can be reduced.

[0025] It will be possible to place more than one current transformer in the cell with only one axis extended current transformer structure.

[0026] Figure 1 . A side perspective view of the current transformer,

[0027] Figure 2. A side view of the current transformer,

[0028] Figure 3. A B-B cross-sectional view of the current transformer,

[0029] Figure 4. A perspective view of the current transformer from the other side, Description of References in Figures

[0030] 1 . Current transformer

[0031] 2. Lateral wall

[0032] 3. Upper-lower wall

[0033] 4. Core

[0034] 5. Primary isolator socket

[0035] 6. Secondary isolator socket

[0036] 7. Upper body

[0037] 8. Lower body

[0038] 9. Inner body ascription of the Invention

[0039] The invention relates to a non-circular current transformer (1 ), which is used especially in a high voltage switching cell and allows more than one cable to pass through it.

[0040] The inner cavity of said current transformer (1 ) is designed in a geometric structure whose lateral walls (2) are longer than the upper-lower walls (3) in its most basic form.

[0041] In this way, the length required for the positioning of more than one cable in the structure can be provided by extending a single axis.

[0042] In order to create this structure of the current transformer, the core (4) is formed in a geometric structure whose lateral walls (2) are longer than the upper-lower walls (3).

[0043] In this embodiment, it may be sufficient to wrap only at least one part of the lateral walls (2) of the core (4). In this case, it will be possible to produce the upper-lower walls (3) of the core (4) from compatible materials that may be much cheaper.

[0044] This embodiment may allow the creation of a low-cost current transformer (1 ). According to the preferred embodiment of the invention, the entire core is made of magnetic materials and has windings on all of the lateral walls (2).

[0045] According to the preferred embodiment of the invention, the inner cavity of the current transformer (1 ) can be produced in oval or elliptical form.

[0046] According to Figure 1 , the current transformer (1 ) is formed from two lateral walls (2) in the same structure, planar opposite, and two upper-lower walls (3) in the same structure, in the form of an arc.

[0047] Within the embodiment described in Figure 1 , the current transformer is inclined to take a 90° different angle from the ground plane. This design will also provide an advantage in terms of placement in the cell.

[0048] According to Figure 2, the current transformer (1 ) is equipped with an upper body (7) and a lower body (8) with a flat surface in its upper part. In this embodiment, the inner body (9) of the current transformer (1 ) and containing the core (4) is designed to be inclined to form an angle of 30-60° to the upper body (7) and the lower body (8) and therefore to the ground plane.

[0049] The embodiment of Figure 3 describes the application of the current transformer containing more than one core (4). More specifically, there are four cores (4) within this application.

[0050] Within this application, two different structure cores (4) can be used.

[0051] According to Figure 4, the lower body (8) of the current transformer (1 ) is provided with the primary isolator socket (5) and the secondary isolator socket (6). Within this application, the primary isolator socket (5) and the secondary isolator socket (6) are located on the floor of the lower body (8).

Claims

CLAIMS1. A non-circular current transformer (1 ) especially used in a high-voltage switching cell, which allows more than one cable to pass through it, characterized in that the inner cavity of the current transformer (1 ) is designed in a geometric structure in which the lateral walls (2) are longer than the upper-lower walls (3).

2. The non-circular current transformer (1 ) according to claim 1 , characterized in that it comprises a core (4) formed in a geometric structure whose lateral walls (2) are longer than the upper-lower walls (3).

3. The non-circular current transformer (1 ) according to claim 2, characterized in that only at least one part of the lateral walls (2) is wound.

4. The non-circular current transformer (1 ) according to claim 3, characterized in that all of the mutual lateral walls (2) of the core (4) are wound.

5. The non-circular current transformer (1 ) according to claim 1 , characterized in that the inner cavity is in oval or elliptical form.

6. The non-circular current transformer (1 ) according to claim 1 , characterized in that the internal cavity is formed by two planar opposing lateral walls (2) and two identical opposing upper-lower walls (3) in the form of an arc.

7. The non-circular current transformer (1 ) according to claim 1 , characterized in that the current transformer (1 ) is inclined to take an angle different from 90° relative to the ground plane.

8. The non-circular current transformer (1 ) according to claim 7, characterized in that the current transformer (1 ) is inclined to an angle of 30-60° relative to the ground plane.

9. The non-circular current transformer (1 ) according to claim 8, characterized in that the inner body (9) of the current transformer (1 ) and containing the core (4)is designed inclined to form an angle of 30-60° to the upper body (7) and the lower body (8) and therefore to the ground plane.

10. The non-circular current transformer (1 ) according to claim 1 , characterized in that it comprises more than one core (4).

11. The non-circular current transformer (1 ) according to claim 10, characterized in that it comprises four cores (4) in two different structures.

12. The non-circular current transformer (1 ) according to any one of the preceding claims, characterized in that it comprises the lower body (8) equipped with a primary isolator socket (5) and a secondary isolator socket (6).

13. The non-circular current transformer (1 ) according to claim 12, characterized in that it comprises a primary isolator socket (5) and a secondary isolator socket (6) located on the base of the lower body (8).

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