Current transformer for traction transformer

Abstract

The utility model discloses a current transformer for a traction transformer, which comprises an upper semi-circle body and a lower semi-circle body, the upper semi-circle body and the lower semi-circle body are respectively molded by casting and then are detachably connected, and a ring-shaped structure is formed after the connection; wherein an upper iron core and a secondary winding wound on the upper iron core are sealed in the upper semicircular body, a lower iron core is sealed in the lower semicircular body, and two ends of the upper iron core are butted with two ends of the lower iron core to form an annular iron core. According to the invention, the electromagnetic conversion principle is utilized, so that the secondary current can accurately reflect and measure the change condition of the primary current, and the change condition is transmitted to the secondary metering and control device for current and electric energy measurement; the problems that an existing electric power system cable straight-through type current transformer is inconvenient to install and dismantle, and electricity is prone to being stolen are solved.

Description

Technical Field

[0001] The utility model relates to the technical field of electric energy metering and current measuring devices in low-voltage areas of electric locomotive traction transformer power systems, and in particular to a current transformer for traction transformers. Background Art

[0002] The low-voltage substation of the electric locomotive traction transformer power system generally adopts cable-through current transformers for power metering and current measurement. That is, the primary incoming and outgoing lines are insulated cables, and the matching current transformer is in the form of a busbar and is installed on the outside of the primary insulated cable to achieve current measurement. Because the product structure is a busbar type and cannot be opened and closed, the primary cable must be removed for product installation, maintenance and replacement; in addition, the secondary terminal is in the form of a junction box, and a separate cable must be led out when the secondary is electrically connected to the electric energy meter; the product is difficult and cumbersome to install and disassemble on site, and the secondary wiring cable is a potential point where electricity theft is prone to occur. In line with the requirements of product intensification and anti-electricity theft, its product structure needs to be further improved. Utility Model Content

[0003] The utility model aims to provide a current transformer dedicated to the electric locomotive traction transformer power system, so as to solve the problems of inconvenient installation and disassembly, easy electricity theft and the like of the current transformer in the low-voltage section of the existing power system.

[0004] To achieve the above-mentioned purpose, the present application proposes a current transformer for a traction transformer, comprising an upper semicircular body and a lower semicircular body, wherein the upper semicircular body and the lower semicircular body are respectively cast and formed and then detachably connected, and a circular ring structure is formed after connection; wherein an upper iron core and a secondary winding wound on the upper iron core are sealed in the upper semicircular body, and a lower iron core is sealed in the lower semicircular body, and the two ends of the upper iron core and the lower iron core are butt-jointed to form a ring-shaped iron core.

[0005] Furthermore, stepped through holes are provided on both sides of the upper semicircular body, and anti-rotation and anti-pulling embedded nuts are provided on both sides of the lower semicircular body. The fastening bolts pass through the through holes and are connected to the embedded nuts, thereby fastening the upper semicircular body and the lower semicircular body.

[0006] Furthermore, a rectangular spring is sleeved on the upper portion of the fastening bolt, and a nut is sleeved on the lower portion, and the rectangular spring and the nut are respectively arranged in the stepped groove of the upper semicircular body.

[0007] Furthermore, a secondary junction box is provided on the top of the upper semicircular body, and a waterproof sealing nut and a waterproof breathable valve are provided on the side wall of the secondary junction box.

[0008] Furthermore, a secondary cover plate is provided on the secondary junction box, and the secondary cover plate and the secondary junction box are sealed by a sealing gasket.

[0009] Furthermore, the upper iron core and the lower iron core are made of Permalloy.

[0010] Furthermore, the joint surface between the upper semicircular body and the lower semicircular body is sealed by a sealing ring.

[0011] Furthermore, the secondary outlet terminal leads out the armored cable through the secondary junction box.

[0012] As a further feature, the outer sides of the upper core and the secondary winding are both wrapped with an insulating layer.

[0013] As a further feature, a bottom plate is also included, and the lower semicircular body is arranged on the bottom plate.

[0014] Compared with the prior art, the above technical solution adopted by the utility model has the following advantages:

[0015] 1. Small size and compact structure: The utility model is made of epoxy resin casting and curing, and realizes an open and close structure after segmentation. It has its own secondary cable. The product is small in size and more compact in structure, and can be directly used with low-level area metering.

[0016] 2. Quick installation and easy disassembly: The opening and closing structure, rectangular spring and fastening bolt fixing method designed in the utility model are very convenient and quick to install, disassemble and maintain, saving a lot of heavy additional auxiliary work such as removal of high-voltage insulated cables, and improving work efficiency.

[0017] 3. Anti-electricity theft and intensification: The utility model directly adopts armored cable to realize the transmission of electric energy signal in the secondary part, which is convenient for users to connect the wires, fundamentally solves the problem of complicated wiring and easy electricity theft of the original transformer, significantly improves the degree of intensification, and improves the reliability of power supply metering; the product is widely used in metering transformation and new construction projects in substations. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of a current transformer for a traction transformer;

[0019] Figure 2 This is a side view of a current transformer for a traction transformer;

[0020] Figure 3 This is the internal diagram of the current transformer for traction transformer;

[0021] Among them: 1 is the upper semicircular body, 2 is the lower semicircular body, 3 is the bottom plate, 4 is the upper iron core, 5 is the secondary winding, 6 is the lower iron core, 7 is the embedded nut, 8 is the rectangular spring, 9 is the fastening bolt, 10 is the sealing ring, 11 is the secondary cover plate, 12 is the sealing gasket, 13 is the waterproof sealing nut, 14 is the waterproof breathable valve, 15 is the flat gasket, and 16 is the nut. DETAILED DESCRIPTION

[0022] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0023] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0024] In the description of the present application, it should be understood that the terms "center", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0025] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0026] See also Figure 1-3 The present embodiment provides a current transformer for a traction transformer, comprising an upper semicircular body 1, a lower semicircular body 2 and a bottom plate 3, wherein the lower semicircular body 2 is arranged on the bottom plate 3, the upper semicircular body 1 and the lower semicircular body 2 are respectively cast and formed and then detachably connected, and a circular ring structure is formed after the connection, an upper iron core 4 and a secondary winding 5 wound on the upper iron core 4 are sealed in the upper semicircular body 1, a lower iron core 6 is sealed in the lower semicircular body 2, and the upper iron core 4 and the lower iron core 6 are in contact at both ends to form a ring iron core, thereby forming a closed magnetic circuit to realize electromagnetic conversion current measurement;

[0027] As a preferred implementation provided by this embodiment, stepped through holes are provided on both sides of the upper semicircular body 1, and embedded nuts 7 are provided on both sides of the lower semicircular body 2. The connection and fastening are carried out through rectangular springs 8, hexagon socket fastening bolts 9 and embedded nuts 7. A flat washer 15 is provided on the top of the hexagon socket fastening bolts 9 to ensure the flatness of the upper and lower semicircular bodies. The embedded nuts 7 are used to limit the depth of the bolts. The rectangular spring 8 reduces the influence of the external world on the stress of the upper and lower semicircular bodies. The nuts 16 prevent the hexagon socket fastening bolts 9 from falling during maintenance, ensuring sufficient mechanical strength and no loosening during product installation and disassembly. The joint surface between the upper semicircular body 1 and the lower semicircular body 2 is sealed by a sealing ring 10, which effectively prevents external rainwater from penetrating into the cross-section joints of the upper iron core 4 and the lower iron core 6 during normal use of the product, affecting the magnetic properties of the iron core. The outer sides of the upper iron core 4 and the secondary winding 5 are both wrapped with an insulating layer.

[0028] In this embodiment, a secondary junction box is provided on the top of the upper semicircular body 1, and a secondary cover plate 11 is provided on the secondary junction box. The secondary cover plate 11 and the secondary junction box are sealed by a sealing gasket 12, which effectively improves the sealing of the secondary terminal. The side wall of the secondary junction box is provided with an IP65 copper waterproof sealing nut 13 and a waterproof breathable valve 14 to avoid the phenomenon of user electricity theft, with a high degree of centralization, effectively ensuring the reliability of cable sealing;

[0029] The manufacturing process of the current transformer for the traction transformer is as follows: firstly, the ring-shaped iron core is wire-cut to form an upper iron core and a lower iron core, the secondary winding 5 is evenly wound on the upper iron core, and the buffering wrapping is performed using insulating materials, and the secondary cable is connected to the secondary winding, thereby forming a current transformer body with a secondary cable; the wrapped current transformer body and the lower iron core are horizontally placed in the mold, and the uniform distance around is adjusted by using the groove in the mold and the strong magnetic stone in the groove, and the upper semicircular body and the lower semicircular body are formed by vacuum casting with epoxy resin, and the two are fastened by the hexagon socket fastening bolts 9 and the embedded nuts. The upper iron core 4 and the lower iron core 6 are fixed so that they form a circular iron core, thereby forming a closed magnetic circuit and realizing electromagnetic conversion current measurement; a square sealing ring 10 is bonded at the joint of the two semicircular bodies, which effectively prevents external rainwater from penetrating into the joint of the iron core cross section during normal use of the product and affecting the magnetic properties of the iron core; the bottom plate 3 is fixed on the cast body, leaving a mounting hole, and the secondary cover plate 11 and the sealing gasket 12 are fixed on the secondary box, which effectively improves the sealing of the secondary terminal; the waterproof sealing nut 13 is fixed on the side of the secondary junction box to avoid the user stealing electricity, with a high degree of intensiveness, effectively ensuring the reliability of the cable sealing.

[0030] During installation and use, according to the structural characteristics of the project and supporting equipment, the primary cable can be installed in advance, and the transformer can be installed last. During installation, first open the two semicircular bodies of the transformer, and then put the transformer on the primary cable. After appropriate adjustment, tighten the hexagon socket fastening bolts 9. At the same time, use the primary line positioning clamp to clamp the primary cable at the inlet and outlet ends respectively. The product is fixed on the cable, and then the electrical and mechanical connections of the secondary cable are made, and the installation is completed.

[0031] The effect of this implementation is that the current transformer for traction transformer is formed by epoxy resin casting and curing, and the rolled iron core uses the electromagnetic conversion principle to enable the secondary current to accurately reflect the changes in the measured primary current and transmit it to the secondary metering and control device for use in 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, easy disassembly, anti-electricity theft, and intensiveness, and can be widely used in substation metering transformation and new construction projects.

[0032] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A current transformer for a traction transformer, comprising an upper semicircular body and a lower semicircular body, characterized in that: The upper semicircular body and the lower semicircular body are respectively cast and formed and then detachably connected to form a circular ring structure; wherein the upper semicircular body is sealed with an upper iron core and a secondary winding wound on the upper iron core, and the lower semicircular body is sealed with a lower iron core, and the two ends of the upper iron core and the lower iron core are butted together to form a ring-shaped iron core; The upper semicircular body is provided with stepped through holes on both sides, and the lower semicircular body is provided with anti-rotation and anti-pulling embedded nuts on both sides. The fastening bolts pass through the through holes and are connected with the embedded nuts, thereby fastening the upper semicircular body and the lower semicircular body.

2. The current transformer for traction transformer according to claim 1, characterized in that: The upper part of the fastening bolt is sleeved with a rectangular spring, and the lower part is sleeved with a nut. The rectangular spring and the nut are respectively arranged in the stepped groove of the upper semicircular body.

3. The current transformer for traction transformer according to claim 1, characterized in that: A secondary junction box is arranged on the top of the upper semicircular body, and a waterproof sealing nut and a waterproof breathable valve are arranged on the side wall of the secondary junction box.

4. The current transformer for traction transformer according to claim 3, characterized in that: The secondary junction box is provided with a secondary cover plate, and the secondary cover plate and the secondary junction box are sealed by a sealing gasket.

5. The current transformer for traction transformer according to claim 1, characterized in that: The upper iron core and the lower iron core are made of Permalloy.

6. The current transformer for traction transformer according to claim 1, characterized in that: The joint surface between the upper semicircular body and the lower semicircular body is sealed by a sealing ring.

7. The current transformer for traction transformer according to claim 3, characterized in that: The armored cable is led out from the secondary outlet through the secondary junction box.

8. The current transformer for traction transformer according to claim 1, characterized in that: The outer sides of the upper iron core and the secondary winding are both wrapped with an insulating layer.

9. The current transformer for traction transformer according to claim 1, characterized in that: It also includes a bottom plate, and the lower semicircular body is arranged on the bottom plate.

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