Current transformer for metering

Abstract

The utility model discloses a current transformer for metering, and relates to the technical field of power equipment, in particular to a current transformer for metering, which comprises a shell assembly, the shell assembly comprises an inner ring, a middle ring and an outer ring, the middle ring and the outer ring are both provided with clamping grooves, a secondary side wiring groove is arranged above the outer ring, and a secondary side wiring groove is arranged above the secondary side wiring groove. The secondary side wiring groove and the middle ring are provided with wire passing glue pouring holes, a connecting plate is arranged below the outer ring, an iron core is placed between the inner ring and the middle ring, a secondary side copper wire is wound on the periphery of the iron core, and arc-shaped cooling fins are embedded in a clamping groove between the middle ring and the outer ring. According to the current transformer for metering, the shell assembly, the arc-shaped heat dissipation fins and the organic silicon modified epoxy resin glue are arranged in a matched mode, so that the current transformer for metering has the effect of being good in heat dissipation effect, and the shell assembly and the organic silicon modified epoxy resin glue are arranged in a matched mode, so that the current transformer for metering has the effect of being good in anti-vibration performance.

Description

Technical Field

[0001] This utility model relates to the field of power equipment technology, specifically to a current transformer for metering. Background Technology

[0002] A current transformer is an electrical device that operates based on the principle of electromagnetic induction. It is mainly used to convert large currents in a power system into standardized small currents (usually 5A or 1A) to facilitate the connection of measurement, metering, and protection devices. It also achieves electrical isolation between the primary high-voltage system and the secondary low-voltage equipment. Because the working principle of a current transformer is based on the law of electromagnetic induction, the temperature will rise during use, which will lead to errors in the metering results. In addition, the iron core of existing current transformers is generally only limited by the structure of the shell. Even if glue is used for fixing, the amount of glue is relatively small, and the glue is quite hard after it hardens and can break. If the current transformer is installed in a vibrating environment such as on the top of a vehicle or power tower, the iron core, due to its large mass, can easily wear away the insulation layer of the secondary copper wire or damage the shell under such vibration. Utility Model Content

[0003] (a) Technical problems to be solved

[0004] To address the shortcomings of existing technologies, this utility model provides a current transformer for metering, which solves the problems mentioned in the background section.

[0005] (II) Technical Solution

[0006] To achieve the above objectives, this utility model is implemented through the following technical solution: A current transformer for metering includes a housing assembly, which includes an inner ring, a middle ring, and an outer ring. Both the middle ring and the outer ring have slots. A secondary side wiring slot is provided above the outer ring. The secondary side wiring slot and the middle ring have through-wire potting holes. A connecting plate is provided below the outer ring. An iron core is placed between the inner ring and the middle ring. Secondary side copper wire is wound around the periphery of the iron core. An arc-shaped heat dissipation fin is embedded in the slot between the middle ring and the outer ring. A housing cover plate is fixedly installed on the open side of the housing assembly. A secondary side wiring plate is fixedly installed above the secondary side wiring slot. Organosilicon modified epoxy resin is poured around the periphery of the iron core.

[0007] Preferably, the inner diameter of the secondary copper wire wound around the iron core is slightly larger than the outer diameter of the inner circle, so that when the iron core is placed between the inner and middle circles after being wound with the secondary copper wire, it can be centered by the inner circle and its movement is restricted.

[0008] Preferably, the secondary side terminal block is embedded above the secondary side terminal slot and fixed with countersunk screws. Two symmetrical terminals are installed in the middle of the secondary side terminal block. Each terminal includes a double-headed hexagonal screw and a hexagonal nut. The lower end of the terminal is connected to both ends of the secondary side copper wire through the nut. The two ends of the secondary side copper wire pass through the wire through the glue hole from bottom to top. The upper end of the terminal is connected to the positive and negative terminals of the ammeter through the nut.

[0009] Preferably, the silicone-modified epoxy resin adhesive combines the high strength of epoxy resin with the flexibility of silicone, has good impact resistance and good thermal conductivity. The silicone-modified epoxy resin adhesive is injected into the space between the inner ring and the middle ring through the wire filling hole and wraps the iron core and the secondary side copper wire.

[0010] Preferably, the arc-shaped heat dissipation fins include an arc-shaped inner fin and an outer fin. The arc-shaped inner fin is a quarter circle with the same diameter as the middle ring, and the outer fin has the same thickness as the width of the slot.

[0011] Preferably, the opening side of the housing assembly is provided with a groove with the same depth as the thickness of the housing cover plate. The housing cover plate is embedded in the groove and fixedly connected by countersunk screws, and the mating surfaces are all coated with sealant. The housing cover plate and the housing assembly are provided with fan-shaped holes on both sides near the arc-shaped heat dissipation fins.

[0012] This utility model provides a current transformer for metering, which has the following advantages:

[0013] 1. This metering current transformer, through the combined arrangement of the housing assembly, arc-shaped heat dissipation fins, and silicone-modified epoxy resin, achieves excellent heat dissipation. The arc-shaped heat dissipation fins are installed close to the outside of the iron core through the internal structure of the housing assembly. The silicone-modified epoxy resin not only fixes the two together but also has excellent thermal conductivity, allowing the heat from the iron core to be quickly transferred to the arc-shaped heat dissipation fins, which have good thermal conductivity and a large contact area with the outside. This ensures that the heat from the iron core is absorbed and dissipated in a timely manner by the arc-shaped heat dissipation fins, thus achieving excellent heat dissipation.

[0014] 2. This metering current transformer, through the combination of the housing assembly and silicone-modified epoxy resin, achieves good vibration resistance. The iron core is fixed by the internal structure of the housing assembly, with certain spacing around its perimeter. Then, silicone-modified epoxy resin is poured around the iron core. Because silicone-modified epoxy resin has a certain degree of viscosity and elasticity after solidification, the iron core, after being fixed and supported by the silicone-modified epoxy resin, has a good vibration resistance. Attached Figure Description

[0015] Figure 1 This is a structural schematic diagram of the three-dimensional view of this utility model;

[0016] Figure 2 This is a schematic diagram of the structure of the present invention in an exploded view;

[0017] Figure 3 This is a structural schematic diagram of the first sectional view of the present invention;

[0018] Figure 4 This is a structural schematic diagram of the second sectional view of the present invention;

[0019] Figure 5 This is a schematic diagram of the housing assembly of this utility model.

[0020] In the diagram: 1. Housing assembly; 101. Inner ring; 102. Middle ring; 103. Outer ring; 104. Slot; 105. Secondary side wiring slot; 106. Wire pass-through glue hole; 107. Connecting plate; 2. Iron core; 3. Secondary side copper wire; 4. Arc-shaped heat dissipation fins; 5. Housing cover plate; 6. Secondary side wiring plate; 601. Terminal block; 7. Silicone-modified epoxy resin adhesive. Detailed Implementation

[0021] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments.

[0022] Example

[0023] Please see Figures 1 to 5 This utility model provides a technical solution for a current transformer for metering, including a housing assembly 1. The housing assembly 1 includes an inner ring 101, a middle ring 102, and an outer ring 103. Both the middle ring 102 and the outer ring 103 have slots 104. A secondary side wiring groove 105 is provided above the outer ring 103. The secondary side wiring groove 105 and the middle ring 102 have through-wire potting holes 106. A connecting plate 107 is provided below the outer ring 103. An iron core 2 is placed between the inner ring 101 and the middle ring 102. Secondary side copper wire 3 is wound around the periphery of the iron core 2. An arc-shaped heat dissipation fin 4 is embedded in the slot 104 between the middle ring 102 and the outer ring 103. A housing cover plate 5 is fixedly installed on the open side of the housing assembly 1. A secondary side wiring plate 6 is fixedly installed above the secondary side wiring groove 105. Organosilicon modified epoxy resin 7 is poured around the periphery of the iron core 2.

[0024] The main body of the specific housing assembly 1 and the housing cover plate 5 are integrally injection molded by an injection molding machine. The wall thickness of the inner ring 101 and the middle ring 102 is 2mm, and the wall thickness of the outer ring 103 is 4mm. The slot 104 is inserted into half the wall thickness of the outer ring 103.

[0025] Please see Figure 3The inner diameter of the secondary copper wire 3 after being wound around the iron core 2 is slightly larger than the outer diameter of the inner ring 101. Therefore, when the iron core 2 is placed between the inner ring 101 and the middle ring 102 after being wound around the secondary copper wire 3, it can be centered by the inner ring 101 and its movement is restricted.

[0026] Specifically, the radius of the inner circle of the iron core 2 is 2mm larger than the radius of the outer circle of the inner ring 101. The diameter of the secondary copper wire 3 is 1.6mm. When the secondary copper wire 3 is wound around the iron core 2 and placed between the inner ring 101 and the middle ring 102, the single-sided gap between the iron core 2 and the secondary copper wire 3 combined structure and the inner ring 101 is only 0.4mm. Therefore, the iron core 2 is basically concentric with the inner ring 101 and hardly moves back and forth or left and right.

[0027] Please see Figure 3 The secondary side terminal block 6 is embedded above the secondary side terminal groove 105 and fixed by countersunk screws. Two symmetrical terminals 601 are installed in the middle of the secondary side terminal block 6. The terminals 601 include double-headed hexagonal screws and hexagonal nuts. The lower end of the terminals 601 is connected to both ends of the secondary side copper wire 3 through the nuts. The two ends of the secondary side copper wire 3 pass through the wire through the glue hole 106 from bottom to top. The upper end of the terminals 601 is connected to the positive and negative terminals of the ammeter through the nuts.

[0028] Specifically, after the secondary side terminal block 6 is embedded in the secondary side terminal groove 105, its upper surface is flush with the upper surface of the housing assembly 1. A certain distance is provided between the two terminals 601 to facilitate wiring. The outer hexagonal prism in the middle of the terminal block 601 is embedded in the inner hexagonal groove opened on the upper part of the secondary side terminal block 6 to prevent rotation. Two hexagonal nuts are provided below the terminal block 601. The function of the upper hexagonal nut is to lock the terminal block 601 to the secondary side terminal block 6, and the function of the lower hexagonal nut is to press the secondary side copper wire 3 to facilitate connection. A hexagonal nut is provided below the terminal block 601 to press the terminal lug of the positive and negative terminal connection wires of the ammeter. The secondary side terminal groove 105 has a certain depth to store excess secondary side copper wire 3.

[0029] Please see Figures 3 to 5 The silicone-modified epoxy resin adhesive 7 combines the high strength of epoxy resin with the flexibility of silicone, has good impact resistance and good thermal conductivity. The silicone-modified epoxy resin adhesive 7 is injected into the space between the inner ring 101 and the middle ring 102 through the wire filling hole 106 and wraps the iron core 2 and the secondary side copper wire 3. The combination of the secondary side wiring groove 105 and the wire filling hole 106 is similar to a funnel, which facilitates the injection of silicone-modified epoxy resin adhesive 7 into the space between the inner ring 101 and the middle ring 102.

[0030] Specifically, good impact resistance gives the current transformer good vibration resistance, and good thermal conductivity makes it easy to transfer the heat of the iron core 2 to the arc-shaped heat dissipation fins 4 for heat dissipation.

[0031] Please see Figure 3 The arc-shaped heat dissipation fin 4 includes an arc-shaped inner fin and an outer fin. The arc-shaped inner fin is a quarter circle with the same diameter as the middle ring 102. The thickness of the outer fin is the same as the width of the slot 104.

[0032] Specifically, after the outer fins are inserted into the slot 104, their mating gap is very small, which can prevent the silicone-modified epoxy resin 7 from leaking out of the gap, and at the same time, the silicone-modified epoxy resin 7 can seal these gaps.

[0033] Please see Figures 3 to 4 The housing assembly 1 has a groove with a depth equal to the thickness of the housing cover plate 5 on the open side. The housing cover plate 5 is embedded in the groove and fixedly connected by countersunk screws. The housing cover plate 5 and the housing assembly 1 have fan-shaped holes on both sides near the arc-shaped heat dissipation fins 4.

[0034] Specifically, the housing cover plate 5 is fixed to the housing assembly 1 by four countersunk screws. After the housing cover plate 5 is embedded in the housing assembly 1, its outer side is coplanar with the side of the housing assembly 1. The screw heads of the countersunk screws are also embedded in the housing cover plate 5, which makes the current transformer more aesthetically pleasing. The fan-shaped holes opened in the housing cover plate 5 and the housing assembly 1 are used for airflow to facilitate heat dissipation of the arc-shaped heat dissipation fins 4, thereby better dissipating heat for the iron core 2. The material of the arc-shaped heat dissipation fins 4 is aluminum alloy.

[0035] In use, first, wrap the secondary copper wire 3 around the outer surface of the iron core 2 without overlapping. Then, leave about 100mm of length at both ends of the secondary copper wire 3. Next, thread both ends of the secondary copper wire 3 outwards from the wire pass-through glue hole 106. Simultaneously, place the iron core 2 into the groove between the inner ring 101 and the middle ring 102. Then, insert the arc-shaped heat dissipation fins 4 into the slots 104 formed between the middle ring 102 and the outer ring 103. Finally, use countersunk screws to secure the housing cover plate 5 to the housing assembly 1. The connection is fixed, and at this time, the iron core 2 and the secondary copper wire 3 are encapsulated in the housing assembly 1. At the same time, the fins of the arc-shaped heat dissipation fins 4 are exposed to the air through the fan-shaped holes on both sides of the housing assembly 1 and the housing cover plate 5. The two ends of the secondary copper wire 3 are gently straightened and bent to the outside of the secondary wiring groove 105. The silicone-modified epoxy resin 7 is then poured into the cavity formed between the inner ring 101 and the middle ring 102 through the wire filling hole 106 using a syringe. The cavity also contains... The cavity is filled with an iron core 2 and a secondary copper wire 3. The filling can be stopped when the silicone-modified epoxy resin 7 fills the cavity and overflows into the secondary wiring groove 105. If the silicone-modified epoxy resin 7 is sticky, it can be applied while vibrating. The silicone-modified epoxy resin 7 is then allowed to dry naturally. The two ends of the secondary copper wire 3 are then connected to the two terminals 601 with hexagonal nuts. The secondary wiring plate 6 is then fixed to the secondary wiring groove 105 with countersunk screws. In subsequent use, the primary high-voltage cable passes through the hole in the middle of the housing assembly 1. The positive and negative terminals of the ammeter are connected to the two terminals 601. The current transformer is fixed through the holes at both ends of the connecting plate 107. If used outdoors, the current transformer should be installed in a place with airflow. If installed indoors and the current or ambient temperature is high, an electric fan can be installed on one side to dissipate the heat generated by the iron core 2 through the arc-shaped heat dissipation fins 4.

[0036] In summary, this metering current transformer uses the internal structure of the housing assembly 1 to mount the arc-shaped heat dissipation fins 4 close to the outside of the iron core 2. The silicone-modified epoxy resin 7 not only fixes the two together but also has a good thermal conductivity, allowing the heat from the iron core 2 to be quickly transferred to the arc-shaped heat dissipation fins 4, which have good thermal conductivity and a large contact area with the outside. This allows the heat from the iron core 2 to be absorbed and dissipated in a timely manner by the arc-shaped heat dissipation fins 4, achieving a good heat dissipation effect. The iron core 2 is fixed by the internal structure of the housing assembly 1 with a certain spacing around it. Then, silicone-modified epoxy resin 7 is poured around the iron core 2. Since silicone-modified epoxy resin 7 has a certain degree of viscosity and elasticity after solidification, the iron core 2, after being fixed and supported by silicone-modified epoxy resin 7, has a good vibration resistance.

[0037] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. A current transformer for metering, comprising a housing assembly (1), characterized in that: The housing assembly (1) includes an inner ring (101), a middle ring (102), and an outer ring (103). Both the middle ring (102) and the outer ring (103) are provided with slots (104). A secondary side wiring groove (105) is provided above the outer ring (103). The secondary side wiring groove (105) and the middle ring (102) are provided with wire-passing glue holes (106). A connecting plate (107) is provided below the outer ring (103). The inner ring (101) and the middle ring... (102) A core (2) is placed between the two rings. The core (2) is surrounded by secondary copper wire (3). The groove (104) between the middle ring (102) and the outer ring (103) is inlaid with arc-shaped heat dissipation fins (4). The shell assembly (1) is fixedly installed with a shell cover plate (5). The secondary wiring plate (6) is fixedly installed above the secondary wiring groove (105). The core (2) is surrounded by silicone-modified epoxy resin glue (7).

2. The current transformer for metering according to claim 1, characterized in that: The inner diameter of the secondary copper wire (3) after winding around the iron core (2) is slightly larger than the outer diameter of the inner ring (101). Therefore, when the iron core (2) is placed between the inner ring (101) and the middle ring (102) after winding the secondary copper wire (3), it can be centered by the inner ring (101) and its movement is restricted.

3. The current transformer for metering according to claim 1, characterized in that: The secondary side terminal block (6) is embedded above the secondary side terminal groove (105) and fixed by countersunk screws. Two symmetrical terminals (601) are installed in the middle of the secondary side terminal block (6). The terminals (601) include double-headed hexagonal screws and hexagonal nuts. The lower end of the terminals (601) is connected to both ends of the secondary side copper wire (3) through the nuts. The two ends of the secondary side copper wire (3) pass through the wire potting hole (106) from below to the top. The upper end of the terminals (601) is connected to the positive and negative terminals of the ammeter through the nuts.

4. The current transformer for metering according to claim 1, characterized in that: The silicone-modified epoxy resin adhesive (7) combines the high strength of epoxy resin with the flexibility of silicone, has good impact resistance and good thermal conductivity. The silicone-modified epoxy resin adhesive (7) is injected into the space between the inner ring (101) and the middle ring (102) through the wire filling hole (106) and wraps the iron core (2) and the secondary side copper wire (3).

5. The current transformer for metering according to claim 1, characterized in that: The arc-shaped heat dissipation fins (4) include an arc-shaped inner fin and an outer fin. The arc-shaped inner fin is a quarter circle with the same diameter as the middle ring (102). The thickness of the outer fin is the same as the width of the slot (104).

6. The current transformer for metering according to claim 1, characterized in that: The opening side of the housing assembly (1) is provided with a groove with the same depth as the thickness of the housing cover plate (5). The housing cover plate (5) is embedded in the groove and fixedly connected by countersunk screws, and the mating surfaces are coated with sealant. The housing cover plate (5) and the housing assembly (1) are provided with fan-shaped holes on both sides near the arc-shaped heat dissipation fins (4).

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