Secondary winding of current transformer and current transformer
By installing a protective case outside the core and electromagnetic wire of the secondary winding of the current transformer, the waste problem caused by increasing the core size in the prior art is solved, and the effect of avoiding stress concentration and material waste is achieved.
Patent Information
- Application Number
- CN202411892780.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-20
- Publication Date
- 2025-04-25
AI Technical Summary
The existing secondary windings of current transformers uniform the appearance size by increasing the core size, resulting in the waste of iron core and electromagnetic wires.
The outer diameter of the iron core and the electromagnetic wire is installed to compensate the outer diameter of the iron core to reach the set size. The upper end surface of the housing is higher or flush with the electromagnetic wire, thereby sharing the pressure from the upper winding.
The core stress concentration is avoided, the fixed mechanical strength and product excitation characteristics of the secondary winding are ensured, the core size is not increased, and the core material is avoided.
Smart Images
Figure CN119889897A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of mutual inductors, and in particular to a secondary winding of a current mutual inductor and a current mutual inductor. Background Art
[0002] Current transformer is an important equipment for power system and power consumption department. Its main purpose is to protect the safe operation of important equipment in the line and accurately calculate the electric energy. The structure of current transformer for GIS is as follows: Figure 1 As shown, it is mainly composed of an outer cylinder 8, an inner cylinder 7, a primary winding and a plurality of current transformer secondary windings. The primary winding is contained in the inner cylinder 7, and all the current transformer secondary windings are contained in the annular space between the inner cylinder 7 and the outer cylinder 8. Once the current transformer product model structure is determined, the external dimensions of the current transformer secondary winding are fixed. Figure 2 As shown, the secondary winding of the current transformer consists of an iron core 1 and an electromagnetic wire 2. The iron core 1 is in a circular shape, and the electromagnetic wire 2 is wound on the iron core 1. The amount of the iron core 1 and the electromagnetic wire 2 depends on the transformer parameters. Figure 1 As shown in , the secondary winding of the current transformer can be divided into a metering winding 5, a protection winding 6 and a transient winding 4, etc. All the secondary windings are coaxially stacked in sequence. Generally, the iron core cross-sectional area of the transient winding 4 is larger, and the iron core cross-sectional areas of the metering winding 5 and the protection winding 6 are smaller. The transient winding 4 is arranged above the metering winding 5 and the protection winding 6. The weight of the transient winding 4 is large, and the weight acts on the metering winding 5 and the protection winding 6. If the iron core size of the metering winding 5 and the protection winding 6 is not increased, stress concentration will occur in the iron core of the metering winding 5 and the protection winding 6, affecting the mechanical strength of the winding fixation and the excitation characteristics of the product. Therefore, in the prior art, in order to ensure the uniform appearance of the three specifications of windings, the iron core size of the metering winding and the protection winding is usually increased, but this will cause waste of iron core and electromagnetic wire. Summary of the invention
[0003] The object of the present invention is to provide a secondary winding of a current transformer to solve the problem that the secondary winding of the existing current transformer increases the size of the core to make the product reach the set external dimensions, resulting in waste of the core and electromagnetic wire; the object of the present invention is also to provide a current transformer to solve the problem that the core size of individual secondary windings is increased in order to make the external dimensions of the secondary winding uniform, resulting in waste of the core and electromagnetic wire.
[0004] In order to achieve the above object, the secondary winding of the current transformer of the present invention adopts the following technical solution: The secondary winding of the current transformer includes an iron core and an electromagnetic wire wound on the iron core, and also includes a protective shell. The protective shell is sleeved outside the iron core and the electromagnetic wire to compensate the outer diameter of the iron core to make it reach a set size. The upper end surface of the protective shell is higher than or flush with the electromagnetic wire.
[0005] Furthermore, the upper end surface of the protective shell is 1-2 mm higher than the electromagnetic wire.
[0006] Furthermore, the protective shell, the iron core and the electromagnetic wire are wrapped into a whole through a film structure.
[0007] Furthermore, the protective shell is a non-magnetic protective shell.
[0008] Furthermore, the protective shell is an insulating protective shell or a stainless steel protective shell.
[0009] Beneficial effects: The present invention is an improved invention. Based on the existing secondary winding structure of the current transformer, a protective shell is added to the outside of the iron core and the electromagnetic wire to compensate for the outer diameter of the iron core to reach a set size. The upper end surface of the protective shell is higher than or flush with the electromagnetic wire, so that the protective shell can share the pressure from the upper winding, avoid stress concentration caused by the smaller cross-sectional area of the secondary winding below, ensure that the fixed mechanical strength of the secondary winding below and the product excitation characteristics are not affected, and the size of the iron core itself is not increased, thereby avoiding the waste of iron core and electromagnetic wire materials.
[0010] The current transformer of the present invention adopts the following technical solution: A current transformer comprises an outer cylinder, wherein two or more secondary windings are stacked inside the outer cylinder, each secondary winding comprises an iron core and an electromagnetic wire wound on the iron core, the outer diameters of the iron cores of at least two secondary windings are different and the outer diameter of the iron core on the lower side is smaller than the outer diameter of the iron core on the upper side, a protective shell is sheathed outside the iron core and the electromagnetic wire on the lower side to compensate for the outer diameter of the iron core so that the secondary winding on the lower side has the same outer dimensions as the secondary winding on the upper side, and the upper end surface of the protective shell is higher than or flush with the electromagnetic wire.
[0011] Furthermore, the upper end surface of the protective shell is 1-2 mm higher than the electromagnetic wire.
[0012] Furthermore, the protective shell, the iron core and the electromagnetic wire are wrapped into a whole through a film structure.
[0013] Furthermore, the protective shell is a non-magnetic protective shell.
[0014] Furthermore, the protective shell is an insulating protective shell or a stainless steel protective shell.
[0015] Beneficial effects: The present invention is an improved invention. By adding a protective shell to the outer part of the iron core and the electromagnetic wire with a small outer diameter on the lower side to compensate for the outer diameter of the iron core, the secondary winding on the lower side has the same outer dimensions as the secondary winding on the upper side, and the upper end surface of the protective shell is higher than or flush with the electromagnetic wire, so that the protective shell can share the pressure from the upper winding, avoid stress concentration caused by the smaller cross-sectional area of the secondary winding on the lower side, ensure that the fixed mechanical strength of the secondary winding on the lower side and the excitation characteristics of the product are not affected, and the size of the iron core itself is not increased, thereby avoiding the waste of iron core and electromagnetic wire materials. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1 This is a schematic diagram of the internal structure of the current transformer used in existing GIS; Figure 2 It is a structural schematic diagram of the secondary winding of an existing current transformer; Figure 3 Schematic diagram of the internal structure of the current transformer of the present invention; Figure 4 for Figure 3 A schematic diagram of the structure of the secondary winding with a smaller cross-sectional area of the iron core at the lower side; In the figure: 1. Iron core; 2. Electromagnetic wire; 3. Protective shell; 4. Transient winding; 5. Metering winding; 6. Protection winding; 7. Inner cylinder; 8. Outer cylinder. DETAILED DESCRIPTION
[0017] In order to avoid stress concentration in the secondary winding on the lower side due to the smaller outer diameter of the iron core, which affects the mechanical strength, the existing current transformer is usually designed to increase the size of the iron core of the secondary winding on the lower side, thereby causing waste of the iron core and electromagnetic wire. The present invention achieves the effect of compensating the outer diameter of the iron core by installing a protective shell on the outside of the iron core and the electromagnetic wire. The overall outer diameter of the secondary winding after the protective shell is installed is the same as the outer diameter of the secondary winding with a larger core section on the upper side, thereby avoiding stress concentration in the iron core of the secondary winding on the lower side. At the same time, the size of the iron core itself is not increased, thereby avoiding waste of iron core and electromagnetic wire materials.
[0018] The embodiments of the current transformer of the present invention are described in detail below.
[0019] like Figure 3As shown, the current transformer includes an outer cylinder 8 and an inner cylinder 7. The outer cylinder 8 is covered on the outside of the inner cylinder 7. The inside of the inner cylinder 7 is used to install the primary winding. A plurality of secondary windings are stacked in sequence along the axial direction in the annular space between the outer cylinder 8 and the inner cylinder 7. In this embodiment, the secondary winding includes a transient winding 4, a metering winding 5 and a protection winding 6 stacked in sequence from top to bottom. The outer diameter of the iron core of the transient winding 4 is larger than the outer diameters of the iron cores of the metering winding 5 and the protection winding 6. The structure of the transient winding 4 is unchanged, and the structure of the existing secondary winding of the current transformer can be adopted. The structures of the improved metering winding 5 and the protection winding 6 can be referred to. Figure 4 The metering winding 5 and the protection winding 6 both include an iron core 1 and an electromagnetic wire 2 wound on the iron core 1. The iron core 1 and the electromagnetic wire 2 are covered with a protective shell 3 to compensate the outer diameter of the iron core 1 to reach a set size, so that the metering winding 5 and the protection winding 6 have the same outer dimensions as the transient winding 4 on the upper side. Figure 3 The upper end surface of the protective shell 3 is higher than or flush with the electromagnetic wire 2, and the protective shell 3 is used to share the pressure from the upper winding, thereby avoiding stress concentration in the iron core of the secondary winding below.
[0020] In this embodiment, if Figure 4 As shown in , the upper end surface of the protective shell 3 is 1-2 mm higher than the electromagnetic wire 2. The advantage of such a setting is that the weight of the upper secondary winding acts on the protective shell 3, and even if the protective shell 3 is slightly squeezed and deformed, it will not affect the electromagnetic wire 2, thereby protecting the electromagnetic wire 2. Of course, in other embodiments, the upper end surface of the protective shell 3 can also be flush with the electromagnetic wire 2, and the protective shell 3 and the iron core 1 share the weight from the upper secondary winding.
[0021] The protective shell 3 is mounted on the outside of the iron core 1 and the electromagnetic wire 2 and is wrapped as a whole by a film structure. When installed, the protective shell 3 is directly installed in the outer cylinder 8. The protective shell 3, the iron core 1 and the electromagnetic wire 2 can be wrapped as a whole by a polyester film. The iron core 1 and the electromagnetic wire 2 are prevented from being exposed, and the iron core 1 and the electromagnetic wire 2 are protected.
[0022] The protective shell 3 is a non-magnetic protective shell to avoid induction heating and the influence on the iron core 1 and the electromagnetic wire 2. The protective shell 3 can be an insulating protective shell, a stainless steel protective shell, an aluminum shell, etc. Considering strength and cost, a suitable non-magnetic material can be selected to make the protective shell.
[0023] The current transformer of the present invention makes the secondary winding on the lower side have the same outer dimensions as the secondary winding on the upper side by adding a protective shell to the outside of the iron core and electromagnetic wire with a smaller outer diameter on the lower side to compensate for the outer diameter of the iron core. The protective shell is used to share the pressure from the upper winding to avoid the pressure of the upper winding acting completely on the iron core of the lower winding and causing stress concentration on the iron core of the lower winding, thereby ensuring that the fixed mechanical strength of the secondary winding at the lower side and the excitation characteristics of the product are not affected. Since the size of the iron core itself is not increased, the waste of iron core and electromagnetic wire materials is avoided.
[0024] The present invention further provides an embodiment of a secondary winding of a current transformer, the specific structure of which is the same as the structure of the improved secondary winding in the above-mentioned current transformer embodiment, and will not be described in detail here.
[0025] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. The patent protection scope of the present invention shall be based on the claims. All equivalent structural changes made using the contents of the description and drawings of the present invention should also be included in the protection scope of the present invention.
Claims
1. A secondary winding of a current transformer, comprising an iron core and an electromagnetic wire wound on the iron core, characterized in that: It also includes a protective shell, which is sleeved on the outside of the iron core and the electromagnetic wire to compensate the outer diameter of the iron core to make it reach a set size, and the upper end surface of the protective shell is higher than or flush with the electromagnetic wire.
2. The current transformer secondary winding according to claim 1, characterized in that: The upper end surface of the protective shell is 1-2 mm higher than the electromagnetic wire.
3. The current transformer secondary winding according to claim 1, characterized in that: The protective shell, the iron core and the electromagnetic wire are wrapped into a whole through a film structure.
4. The current transformer secondary winding according to any one of claims 1 to 3, characterized in that: The protective shell is a non-magnetic conductive protective shell.
5. The current transformer secondary winding according to claim 4, characterized in that: The protective shell is an insulating protective shell or a stainless steel protective shell.
6. A current transformer, comprising an outer cylinder, wherein two or more secondary windings are stacked in the outer cylinder, each secondary winding comprises an iron core and an electromagnetic wire wound on the iron core, the outer diameters of the iron cores of at least two secondary windings are different and the outer diameter of the iron core at the lower side is smaller than the outer diameter of the iron core at the upper side, characterized in that: The iron core and electromagnetic wire at the lower side are covered with a protective shell to compensate for the outer diameter of the iron core so that the secondary winding at the lower side has the same outer dimensions as the secondary winding at the upper side, and the upper end surface of the protective shell is higher than or flush with the electromagnetic wire.
7. The current transformer according to claim 6, characterized in that: The upper end surface of the protective shell is 1-2 mm higher than the electromagnetic wire.
8. The current transformer according to claim 6, characterized in that: The protective shell, the iron core and the electromagnetic wire are wrapped into a whole through a film structure.
9. The current transformer according to any one of claims 6 to 8, characterized in that: The protective shell is a non-magnetic conductive protective shell.
10. The current transformer according to claim 9, characterized in that: The protective shell is an insulating protective shell or a stainless steel protective shell.