Current transformer with built-in open circuit prevention device

Abstract

The utility model relates to a low-voltage electric energy metering and current measuring device of an electric power system, in particular to a current transformer with a built-in open circuit prevention device. Comprising a coil device body, a shell, a built-in open circuit prevention device, a base, a secondary wire holder and an insulating layer, the shell is of an annular structure with a bus round hole, the shell is vertically installed on the base, the built-in open circuit prevention device and the coil device body are contained in the shell, epoxy resin is encapsulated in the shell to form the insulating layer, and the secondary wire holder is arranged on the base. The built-in open circuit prevention device and the coil device body are sealed in the insulating layer, the secondary wire holder is embedded in the insulating layer at the bottom of the coil device body, the secondary wiring terminal of the coil device body is arranged on the secondary wire holder, two wires of the built-in open circuit prevention device are connected with the secondary wiring terminal, and the built-in open circuit prevention device is used for preventing secondary open circuit. The distribution box has the characteristics of small volume, compact structure, fast installation, convenient disassembly, electricity larceny prevention, intensification and the like, and is suitable for transformer area metering transformation and new construction.

Description

Technical Field

[0001] The utility model relates to a low-voltage electric energy metering and current measuring device for an electric power system, in particular to a current transformer with a built-in open circuit prevention device. Background Art

[0002] Cable-through current transformers are commonly used for indoor metering in power systems. They are used for energy metering and current measurement. That is, the primary inlet and outlet lines are insulated cables, and the matching current transformers are in the form of busbars and are installed outside the primary insulated cables to achieve current measurement. Because the secondary circuit of the current transformer is not allowed to be open when in use, the secondary open circuit will have the following adverse consequences: 1) High voltage will endanger personal and equipment safety; 2) High saturation of the core will produce a large residual magnetism in the core, increasing the error; 3) Long-term use may cause the core to overheat. Usually, the S2 of the current transformer needs to be grounded during use, and grounding is often forgotten. In line with the requirements of personal and equipment safety, the product structure needs to be further improved. Utility Model Content

[0003] In order to solve the problem of secondary ungrounding in indoor current transformers of existing power systems, the utility model aims to provide a current transformer with a built-in open circuit prevention device.

[0004] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0005] The utility model provides a current transformer with a built-in open circuit prevention device, comprising a coil body, a shell, a built-in open circuit prevention device, a base, a secondary wiring seat and an insulating layer, wherein the shell is a circular ring structure with a busbar circular hole, the shell is vertically installed on the base, the built-in open circuit prevention device and the coil body are accommodated in the shell, epoxy resin is poured in the shell to form an insulating layer, the built-in open circuit prevention device and the coil body are sealed in the insulating layer, the secondary wiring seat is embedded in the insulating layer at the bottom of the coil body, the secondary wiring terminal of the coil body is arranged on the secondary wiring seat, two wires of the built-in open circuit prevention device are connected to the secondary wiring terminal, and the built-in open circuit prevention device is used to prevent secondary open circuit.

[0006] A neck is provided on one side where the shell is connected to the base, one end of the secondary wiring seat is embedded in the insulating layer of the neck, and the other end is exposed outside the insulating layer.

[0007] The outer cover of the secondary wiring seat is provided with a secondary wiring cover, and the secondary wiring cover is provided with lead sealing nails.

[0008] The secondary wiring seat is a rectangular parallelepiped structure, and a protrusion is provided in the middle of the front end. The protrusion is provided with a threaded hole for connecting the secondary wiring cover, and the two secondary wiring terminals are respectively arranged on both sides of the protrusion.

[0009] The base is a rectangular structure, and a raised plane is provided in the middle, the raised plane is connected to the neck of the shell through screws, and waist-shaped fixing holes are provided at both ends of the base.

[0010] The shell and the secondary wiring seat are both made of ABS plastic.

[0011] The coil body comprises an iron core and a secondary winding, wherein the iron core is a ring structure, the secondary winding is wound on the iron core, and is buffer-wrapped by insulating material.

[0012] The advantages and beneficial effects of the utility model are:

[0013] 1. Prevent secondary open circuit: The utility model casts the built-in anti-open circuit device inside the product and organically combines it with the coil body, effectively avoiding the damage to the meter caused by the secondary overvoltage of the current transformer and the personal safety hazard to the operator. When the fault of the secondary circuit of the current transformer is eliminated, the built-in anti-open circuit device automatically exits the short-circuit state of the current transformer, thereby achieving the purpose of preventing secondary open circuit.

[0014] 2. Small size and compact structure: The utility model is made of potting epoxy resin by pouring and curing. The secondary terminal adopts the type of secondary wiring seat with secondary wiring cover. The product has a small size and a more compact structure, and the secondary wiring and outlet are very convenient.

[0015] 3. Quick installation and easy disassembly: The bottom plate fixing method designed in this utility model is very convenient and quick to install, disassemble and maintain, thus improving work efficiency.

[0016] 4. Anti-electricity theft and intensification: The secondary wiring of the utility model is fixed with lead-sealed screws and can be sealed, which fundamentally solves the possibility of complex wiring and easy electricity theft of the original transformer, significantly improves the degree of intensification, and improves the reliability of power supply metering; it is suitable for metering transformation and new construction projects in the substation area. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of the structure of a current transformer with a built-in open circuit prevention device according to the utility model;

[0018] Figure 2 for Figure 1 Left view of

[0019] Figure 3 for Figure 1 Bottom view of

[0020] Figure 4 This is a connection diagram of the built-in anti-open circuit device in the utility model;

[0021] Figure 5 for Figure 4 Left view of

[0022] Figure 6 for Figure 4 Rear view of.

[0023] In the figure: 1- iron core, 2- secondary winding, 3- shell, 4- built-in anti-open circuit device, 5- base, 6- secondary terminal block, 7- secondary terminal cover, 8- lead sealing nail, 9- busbar round hole, 10- insulation layer, 11- secondary terminal. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] like Figures 1 to 3 As shown, the utility model provides a current transformer with a built-in anti-open circuit device, including a coil body, a shell 3, a built-in anti-open circuit device 4, a base 5, a secondary wiring seat 6 and an insulating layer 10, wherein the shell 3 is a circular ring structure with a busbar circular hole 9, and the shell 3 is vertically installed on the base 5, that is, the axis of the busbar circular hole 9 is in the horizontal direction. The built-in anti-open circuit device 4 and the coil body are accommodated in the shell 3, and the shell 3 is filled with epoxy resin to form an insulating layer 10, the built-in anti-open circuit device 4 and the coil body are sealed in the insulating layer 10, the secondary wiring seat 6 is embedded in the insulating layer 10 at the bottom of the coil body, and the secondary wiring terminal 11 of the coil body is set on the secondary wiring seat 6, and the two wires of the built-in anti-open circuit device 4 are connected to the secondary wiring terminal 11, and the built-in anti-open circuit device 4 is used to prevent secondary open circuit.

[0026] like Figure 2 As shown, in an embodiment of the present invention, the coil body includes an iron core 1 and a secondary winding 2, wherein the iron core 1 is a ring structure, the secondary winding 2 is wound on the iron core 1, and is buffered and wrapped with insulating material.

[0027] like Figure 1 As shown, in the embodiment of the utility model, a neck is provided on one side where the shell 3 is connected to the base 5, one end of the secondary wiring seat 6 is embedded in the insulating layer 10 of the neck, and the other end is exposed outside the insulating layer 10 for wiring.

[0028] Furthermore, a secondary wiring cover 7 is provided on the outer side cover of the secondary wiring seat 6. The secondary wiring cover 7 has a lead sealing nail 8, which can seal the secondary wiring, thereby preventing the secondary wiring from being stolen.

[0029] like Figures 4 to 6As shown, in this embodiment, the secondary wiring seat 6 is a rectangular parallelepiped structure, and a protrusion is provided in the middle of the front end, and a threaded hole for connecting the secondary wiring cover 7 is provided on the protrusion, and the secondary wiring cover 7 is connected to the threaded hole on the protrusion by screws. Two secondary wiring terminals 11 are respectively arranged on both sides of the protrusion, and the two wires of the built-in anti-open circuit device 4 are respectively welded to the two secondary wiring terminals 11.

[0030] like Figure 1 , Figure 3 As shown, in the embodiment of the utility model, the base 5 is a rectangular structure, and a raised plane is provided in the middle, the raised plane is connected to the neck of the housing 3 by screws, and waist-shaped fixing holes are provided at both ends of the base 5, and the waist-shaped fixing holes are used to adjust the installation position of the current transformer. The base 5 achieves a through-type structure and realizes the purpose of pillar-type use.

[0031] Specifically, the shell 3 and the secondary wiring seat 6 are made of ABS plastic. The built-in anti-open circuit device 4 is a commercially available product purchased from Beijing Luhe Electric Power Technology Co., Ltd., model LH-FX-T0. The built-in anti-open circuit device 4 has the following advantages: the conduction voltage is about 30V, which is lower than the safety voltage of 36V; the conduction time is less than 20ms; the leakage current is less than 1mA when not conducting, which does not affect the accuracy of the transformer; it can work for a long time after conducting, and the thyristor and the temperature switch switch in turn to work, effectively preventing the temperature from being too high; the device is automatically disconnected after the transformer is connected to the secondary.

[0032] The utility model provides a current transformer with a built-in open circuit prevention device, and the preparation process is as follows:

[0033] The secondary winding 2 is evenly wound on the annular iron core 1, and the coil body is formed by buffering and wrapping with insulating materials. The corresponding shell 3 is used for molding, and the built-in anti-open circuit device 4 and the coil body are placed in the shell 3. The distance between the coil body is adjusted, and the two leads of the built-in anti-open circuit device 4 are respectively welded to the secondary wiring terminals 11, integrated with the coil body, and then potted with epoxy resin. The overall structure is a through-core pillar busbar form. When assembling the product, fix the base 5 with screws, install the secondary wiring screws, and install the secondary wiring cover 7 and lead seal nails on the product after the experiment. The built-in anti-open circuit device 4 is cast inside the product and organically bonded to the coil body. When the secondary circuit is open or an abnormal overcurrent occurs in the primary winding, the voltage generated in the secondary winding 2 is much higher than the normal operating voltage. At this time, the built-in open circuit prevention device 4 connected in parallel instantly enters the on state, thereby effectively avoiding the damage to the meter caused by the secondary overvoltage of the current transformer and the personal safety hazard to the operator. When the fault of the secondary circuit of the current transformer is eliminated, the built-in open circuit prevention device 4 automatically exits the short-circuit state of the current transformer, thereby achieving the purpose of preventing the secondary open circuit.

[0034] During installation and use, according to the structural characteristics of the project and supporting equipment, use the base 5 to fix the product, pass the primary cable through the busbar circular hole 9 of the product, remove the secondary wiring cover 7 and the lead sealing nail 8, connect the secondary lead, cover the secondary wiring cover 7, pass the lead through the secondary holes on both sides, install the lead sealing nail 8 on the product to achieve secondary sealing, and the installation is complete.

[0035] The utility model provides a current transformer with a built-in anti-open circuit device, which is a new product designed in full accordance with national standards. It is made of potting resin by pouring and curing, adopts a rolled iron core, and utilizes the electromagnetic conversion principle to enable the secondary current to accurately reflect the change of the measured primary current and transmit it to the secondary metering and control device for use as current and electric energy measurement. It solves the problems of inconvenient installation and disassembly and easy electricity theft of the existing power system cable through-type current transformer. The product has the characteristics of small size, compact structure, quick installation, convenient disassembly, anti-electricity theft, and intensiveness, and is suitable for metering transformation and new construction projects in substations.

[0036] The above description is only an implementation method of the utility model and is not intended to limit the protection scope of the utility model. Any modification, equivalent replacement, improvement, expansion, etc. made within the spirit and principle of the utility model are included in the protection scope of the utility model.

Claims

1. A current transformer with a built-in open circuit prevention device, characterized in that: The invention comprises a coil body, a shell (3), a built-in open circuit prevention device (4), a base (5), a secondary wiring seat (6) and an insulating layer (10), wherein the shell (3) is a circular ring structure having a busbar circular hole (9), the shell (3) is vertically mounted on the base (5), the built-in open circuit prevention device (4) and the coil body are accommodated in the shell (3), epoxy resin is poured into the shell (3) to form an insulating layer (10), the built-in open circuit prevention device (4) and the coil body are sealed in the insulating layer (10), the secondary wiring seat (6) is embedded in the insulating layer (10) at the bottom of the coil body, the secondary wiring terminal (11) of the coil body is arranged on the secondary wiring seat (6), two wires of the built-in open circuit prevention device (4) are connected to the secondary wiring terminal (11), and the built-in open circuit prevention device (4) is used to prevent secondary open circuit.

2. The current transformer with a built-in open circuit prevention device according to claim 1, characterized in that: A neck is provided on one side of the shell (3) connected to the base (5); one end of the secondary wiring seat (6) is embedded in the insulating layer (10) of the neck, and the other end is exposed outside the insulating layer (10).

3. The current transformer with a built-in open circuit prevention device according to claim 2, characterized in that: The outer cover of the secondary wiring seat (6) is provided with a secondary wiring cover (7), and the secondary wiring cover (7) is provided with a lead sealing nail (8).

4. The current transformer with a built-in open circuit prevention device according to claim 3, characterized in that: The secondary wiring seat (6) is a rectangular parallelepiped structure, and a protrusion is provided in the middle of the front end. The protrusion is provided with a threaded hole for connecting the secondary wiring cover (7), and the two secondary wiring terminals (11) are respectively arranged on both sides of the protrusion.

5. The current transformer with a built-in open circuit prevention device according to claim 2, characterized in that: The base (5) is a rectangular structure, and a raised plane is provided in the middle, the raised plane is connected to the neck of the shell (3) via screws, and waist-shaped fixing holes are provided at both ends of the base (5).

6. The current transformer with a built-in open circuit prevention device according to claim 1, characterized in that: The shell (3) and the secondary wiring seat (6) are both made of ABS plastic.

7. The current transformer with a built-in open circuit prevention device according to claim 1, characterized in that: The coil body comprises an iron core (1) and a secondary winding (2), wherein the iron core (1) is a ring-shaped structure, and the secondary winding (2) is wound on the iron core (1) and is buffer-wrapped by insulating material.

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