Current limiting protection device of current transformer

Abstract

The utility model discloses a current-limiting protection device of a current transformer, which comprises a saturable reactor, a protection box and a binding post, the saturable reactor is connected with a lead, the saturable reactor is fixed in the protection box through epoxy resin, the binding post comprises a conductive post, an inner insulation sleeve and an outer insulation sleeve, the inner insulation sleeve is embedded in the protection box, and the outer insulation sleeve is embedded in the protection box. The outer insulation sleeve is sleeved on the inner insulation sleeve on the inner side of the protection box and forms an accommodating hole for installing the conductive column, a nut I and a nut II are separately arranged on the conductive column in the protection box, two flat washers are arranged between the nut I and the nut II, and the lead is fixed between the two flat washers. The binding posts can be connected through a bridging lead, the bridging lead is fixed between the two flat washers, a limiting blocking piece is arranged on the conductive column outside the protective box, a rotary knob is assembled at the outer end of the conductive column, a rotary knob metal insert is embedded in the rotary knob, and an external equipment lead can be connected between the rotary knob metal insert and the limiting blocking piece. According to the utility model, internal and external leads can be quickly connected, the technology of pouring epoxy resin can be simplified, and the efficiency is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of electrical equipment, and more specifically to a current transformer current limiting protection device. Background Art

[0002] The secondary output of the current transformer is connected to the input of the current transformer current limiting protection device. The output of the current transformer current limiting protection device is connected to the background protection and measurement device as the input of the user end. When the current transformer operates at the rated current or the required current, the saturated reactor is equivalent to an infinite resistance, and no current flows through it. When a short-circuit current or overcurrent occurs in the primary part of the current transformer, the voltage at the secondary end of the current transformer will reach or exceed the protection voltage of the current transformer current limiting protection device. The saturated reactor is equivalent to a low-value resistor at this time. At the same time, a large part of the current of the current transformer secondary input will flow through the saturated reactor, thereby ensuring that the current at the input end of the current transformer current limiting protection device does not increase with the increase of the primary current of the current transformer, and maintains a certain secondary output current unchanged, thereby protecting the background protection and measurement device of the current transformer from being damaged by the impact of large current.

[0003] The existing current transformer current limiting protection device needs to lead out the lead wires to facilitate its access to the output end and connection with external devices. In order to effectively isolate the housing of the protection device from the reactor body, a plastic gland is generally used to lead out the lead wires. There is a through hole in the center of the plastic gland, and a large gap will be left when the lead wire passes through the center of the gland. During transportation and use, it is easy to cause the lead connection to loosen. When the external device is connected, the lead connection between the protection device and the external device is very inconvenient. In addition, when fixing the reactor body and the housing, it is necessary to use a tooling fixture to prevent the epoxy resin used for fixing from overflowing, which brings inconvenience to the production process and the production efficiency needs to be improved. Utility Model Content

[0004] In order to solve the above problems, the utility model provides a current transformer current limiting protection device, which can effectively fix the internal lead wire and quickly realize the connection with the external device. The improved structure is conducive to improving production efficiency.

[0005] According to one aspect of the utility model, a current transformer current limiting protection device is provided, which includes a saturated reactor, a protection box and a terminal;

[0006] The saturated reactor comprises a low-saturation microcrystalline iron core, an inner insulating layer, an enameled wire and an outer insulating layer. The inner insulating layer is wrapped around the low-saturation microcrystalline iron core, one or more layers of enameled wire are wrapped around the inner insulating layer, the outer insulating layer is wrapped around the enameled wire, and the inlet and outlet ends of the enameled wire are respectively connected to leads.

[0007] The protective box has a cavity for accommodating the saturated reactor, and the saturated reactor is fixed in the protective box by epoxy resin;

[0008] The terminal comprises a conductive post, an inner insulating sleeve and an outer insulating sleeve, wherein the inner insulating sleeve is embedded in a protective box, and one end of the inner insulating sleeve is inserted into the inner side of the protective box, the outer insulating sleeve is sleeved on the inner insulating sleeve on the inner side of the protective box, and a receiving hole is formed inside the outer insulating sleeve and the inner insulating sleeve, the conductive post is installed through the receiving hole, one side of the conductive post is located inside the protective box, and the other side extends outside the protective box, a nut 1 and a nut 2 which are separately arranged are provided on the conductive post in the protective box, two flat washers are provided between the nut 1 and the nut 2, a lead is fixed between the two flat washers, the terminal posts are connected by a jumper lead, and the jumper lead is fixed between the two flat washers.

[0009] Therefore, the inner insulating sleeve and the outer insulating sleeve are insulating parts, and the metal conductive column is located inside the insulating part, which can realize effective isolation of the protective box. The leads of the input and output terminals of the saturated inductor and the jumper leads between the terminal blocks are quickly fixed by the flat washers on the inside of the protective box in conjunction with nuts one and two. The joints of the internal leads and the jumper leads are firmly connected and are not loosened due to interference from the external environment. The safety performance is greatly improved, and the connection with the external equipment is through the conductive column, which has better stability.

[0010] In some embodiments, a limit stopper is provided on the conductive column outside the protective box, and the limit stopper is closely attached to the end surface of the inner insulating sleeve. A knob is installed at the outer end of the conductive column, and a knob metal insert is embedded in the knob. The knob metal insert is connected to the conductive column through a thread, and a gap is formed between the knob metal insert and the limit stopper for connecting the lead wire of the external device. Therefore, when it is necessary to connect an external device, the knob is turned, and the knob metal insert moves toward the limit stopper, and the lead wire of the external device is fixed between the limit stopper and the knob metal insert. It is very convenient to connect the external device through the terminal.

[0011] In some embodiments, the inner insulating sleeve has an annular retaining ring. When the inner insulating sleeve is embedded in the protective box, the annular retaining ring is located outside the protective box and is in close contact with the outer wall of the protective box. The outer insulating sleeve has a sleeve body and a sleeve top. When the outer insulating sleeve is arranged on the inner insulating sleeve, the inner insulating sleeve on the inner side of the protective box is embedded in the sleeve body and the sleeve top is in close contact with the second nut, and the protective box is clamped between the annular retaining ring and the sleeve body. Thus, the locking nut second, the limit retaining piece and the second nut firmly clamp the inner insulating sleeve, the outer insulating sleeve and the protective box, ensuring that the terminal and the protective box are firmly connected.

[0012] In some embodiments, the protective box includes an upper cover plate, a lower cover plate, a left end cover sealing plate and a right end cover sealing plate. The cross-sections of the upper cover plate and the lower cover plate are both U-shaped structures with one side high and the other side low. The upper cover plate and the lower cover plate are buckled together and the two sides are fixed by the left end cover sealing plate and the right end cover sealing plate respectively, and the saturated inductor is fixed on the lower cover plate. Therefore, after the saturated inductor is wrapped, it is placed in the lower half cover plate of the U-shaped structure, and the leads of the saturated inductor and the jumper leads that need to be connected are connected to the terminal posts on both sides of the input and output, and then the left end cover sealing plate and the right end cover sealing plate are fixed as a whole with the lower half cover plate, and epoxy resin is poured in the closed space formed by them to fix the saturated inductor. After the epoxy resin is cured, the upper half cover plate is buckled on and fixed to the left end cover sealing plate and the right end cover sealing plate. By using the protective box structure provided by the present application, when pouring epoxy resin to fix the saturated inductor, it is no longer necessary to configure additional tooling and fixtures, which saves costs, simplifies the process flow, and greatly improves work efficiency.

[0013] In some embodiments, the bottom of the left end cover sealing plate and the right end cover sealing plate is provided with a folded edge bent outward, a waist-shaped mounting hole is provided on the folded edge, and an anti-slip rib is provided on the periphery of the knob. Thus, the left end cover sealing plate and the right end cover sealing plate are provided with a folded edge with a waist-shaped mounting hole, so that the current transformer current limiting protection device can be quickly installed, and the knob is provided with an anti-slip rib for convenient operation.

[0014] Compared with the prior art, the beneficial effects of the utility model are as follows: the structure design of the current transformer current limiting protection device of the utility model is ingenious, and the terminal and the protective box are fixed by the inner insulating sleeve, the outer insulating sleeve, the nut 2 and the conductive column. The rotatable nut 1 and the knob on the conductive column are used to realize the quick connection of the leads of the saturated inductor inside the protective box, the jumper leads and the leads of the external device outside the protective box, so that the lead joints inside the protective box after connection will not be loosened by the influence of the external environment. By improving the structure of the protective box, the process of pouring epoxy resin is simplified, and the work efficiency is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a three-dimensional diagram of an implementation mode of the current transformer current limiting protection device of the utility model;

[0016] Figure 2 It is a schematic diagram of the internal structure of an implementation mode of the current transformer current limiting protection device of the utility model;

[0017] Figure 3 yes Figure 1 A side view schematic diagram of

[0018] Figure 4 yes Figure 1 Schematic diagram of top view;

[0019] Figure 5yes Figure 4 A magnified view of part A in FIG.

[0020] Figure 6 This is the installation diagram of the upper cover, lower cover and saturated reactor. DETAILED DESCRIPTION

[0021] The utility model is further described below in conjunction with specific implementation methods.

[0022] like Figure 1 and 2 As shown, a current transformer current limiting protection device according to one embodiment of the utility model includes a saturable reactor 1, a protection box 2 and a terminal 4.

[0023] The saturated reactor 1 includes a low-saturation microcrystalline iron core 11, an inner insulating layer 12, an enameled wire 13 and an outer insulating layer 14. The low-saturation microcrystalline iron core 11 is ring-shaped. A layer of insulating material is wrapped on the outside of the low-saturation microcrystalline iron core 11 to form the inner insulating layer 12. After the inner insulating layer 12 is wrapped, one or more layers of the low-saturation microcrystalline iron core 11 are wrapped along the ring direction on the cross section of the low-saturation microcrystalline iron core 11, that is, one or more layers of enameled wire 13 are wrapped outside the inner insulating layer 12. Finally, a layer of insulating material is wrapped on the outside of the enameled wire 13 to form the outer insulating layer 14. The inlet and outlet ends of the enameled wire 13 are respectively connected with leads 15.

[0024] The outer shape of the protective box 2 is a rectangular parallelepiped. The protective box 2 has a cavity for accommodating the saturated reactor 1 . The saturated reactor 1 is fixed in the protective box 2 by epoxy resin 3 .

[0025] The terminal 4 is a component for realizing the conduction of the internal and external power supplies. A current transformer current limiting protection device has four terminal posts 4, which are divided into two groups and are respectively arranged on the left and right sides of the protection box 2. Figure 4 and 5As shown, each terminal 4 includes a conductive column 41, an inner insulating sleeve 42 and an outer insulating sleeve 43. The specific installation of the terminal 4 is to open a through hole 20 on the protective box 2. The main body of the inner insulating sleeve 42 is cylindrical in shape. One end of the inner insulating sleeve 42 has an annular retaining ring 421. The other end of the inner insulating sleeve 42 is inserted into the inner side of the protective box 2 so that the inner insulating sleeve 42 is embedded in the through hole 20 of the protective box 2. When the inner insulating sleeve 42 is embedded in the protective box 2, the annular retaining ring 421 is located outside the protective box 2 and is close to the outer wall of the protective box 2; the outer insulating sleeve 43 is cylindrical in shape, and has a sleeve body 431 and a sleeve top 432. The sleeve body 431 of the outer insulating sleeve 43 is sleeved on the inner side of the protective box 2. On the inner insulating sleeve 42, the outer insulating sleeve 43 and the inner insulating sleeve 42 are all hollow structures, and a receiving hole 40 is formed inside to install the conductive column 41; the conductive column 41 is installed through the receiving hole 40, one side of the conductive column 41 is located inside the protective box 2, and the other side extends to the outside of the protective box 2. The conductive column 41 in the protective box 2 has an external thread, and a nut 1 44 and a nut 2 45 are separately provided on this section of the conductive column 41. Two flat washers 46 are sleeved on the conductive column 41 between the nut 1 44 and the nut 2 45. After the position of the nut 2 45 is fixed, the nut 1 44 can be rotated to adjust the distance between the two flat washers 46. The distance between the two flat washers 46 can be used to clamp and fix the lead 15. If adjacent terminals 4 need to be connected, they can be connected through jumper leads 5, and the two ends of the jumper leads 5 can also be fixed between the two flat washers 46 of the corresponding terminals 4. The specific wiring status of the product is as follows: the four terminals 4 can be marked as input A, a, output X, x respectively, the two leads 15 of the saturated reactor 1 are respectively connected to the input A and a, and then two jumper leads 5 are used, one of which is connected to the input A and the output X, and the other is connected to the input a and the output x, the uppercase and lowercase marks between the input and output are the reactor leads, the terminals and the jumper leads are connected in series, and there are two sets of symmetrical series connections.

[0026] The inner insulating sleeve 42 and the outer insulating sleeve 43 are insulating parts, and the metal conductive column 41 is located inside the insulating part, which can achieve effective isolation of the protective box 2. The leads 15 at the inlet and outlet ends of the saturated reactor 1 and the jumper leads 5 between the terminals 4 are quickly fixed through the flat washers 46 on the inside of the protective box 2 in conjunction with the nuts 1 44 and 2 45. The joints of the internal leads 15 and the jumper leads 5 are firmly connected and are not loosened due to external environmental interference, which greatly improves safety performance. The external device is connected through the conductive column 41, and the stability is better.

[0027] like Figure 5As shown, the conductive column 41 outside the protective box 2 has an annular stopper 411, and the stopper 411 is tightly attached to the annular retaining ring 421 on the end face of the inner insulating sleeve 42. When the outer insulating sleeve 43 is sleeved on the inner insulating sleeve 42, the inner insulating sleeve 42 on the inner side of the protective box 2 is embedded in the sleeve body 431 and the sleeve top 432 is tightly attached to the second nut 45, and the protective box 2 is clamped between the annular retaining ring 421 and the sleeve body 431. The second nut 45 is locked, and the stopper 411 and the second nut 45 firmly clamp the inner insulating sleeve 42, the outer insulating sleeve 43 and the protective box 2, ensuring that the terminal 4 and the protective box 2 are firmly connected. The outer end of the conductive column 41 is equipped with a knob 47 made of non-conductive material, and a knob metal insert 471 is embedded in the knob 47. The knob metal insert 471 is integrated with the knob 47, and the knob metal insert 471 is connected to the conductive column 41 through a thread. A gap 470 is formed between the knob metal insert 471 and the limit stopper 411 for connecting the lead wire of an external device. The knob 47 is turned to move the knob metal insert 471 away from or close to the knob metal insert 471. The outer periphery of the knob 47 has a circle of anti-slip ribs 472 ( Figure 1 If an external device needs to be connected, the knob 47 is turned, and the knob metal insert 471 moves toward the limit baffle 411, and the lead wire of the external device (not shown) is fixed between the limit baffle 411 and the knob metal insert 471. It is very convenient to connect the external device through the terminal 4.

[0028] As shown in Figures 1 and 6, the protective box 2 specifically includes an upper half cover plate 21, a lower half cover plate 22, a left end cover sealing plate 23 and a right end cover sealing plate 24. The cross-sections of the upper half cover plate 21 and the lower half cover plate 22 are both U-shaped structures with one side high and one side low. The upper half cover plate 21 and the lower half cover plate 22 are mutually buckled through male and female tenons, and the left end cover sealing plate 23 and the right end cover sealing plate 24 are respectively installed on both sides and fixed with flat head screws 26, and the saturated reactor 1 is fixed on the lower half cover plate 22. Four terminal blocks 4 are arranged on the left end cover sealing plate 23 and the right end cover sealing plate 24 in pairs.

[0029] In the specific assembly process of the protective box 2, after the saturated inductor 1 is wrapped, it is placed in the lower half cover plate 22 of the U-shaped structure, and the leads 15 of the saturated inductor 1 and the jumper leads 5 that need to be connected are connected to the terminals 4 on both sides of the input and output, and then the left end cover sealing plate 23 and the right end cover sealing plate 24 are fixed as a whole with the lower half cover plate 22 by flat head screws 26, and epoxy resin 3 is poured in the bottom closed space formed by them to fix the saturated inductor 1. After the epoxy resin 3 is cured, the upper half cover plate 21 is buckled on, and the upper half cover plate 21 is fixed to the left end cover sealing plate 23 and the right end cover sealing plate 24 by flat head screws 26. By using the protective box 2 structure provided by the present application, when pouring epoxy resin 3 to fix the saturated inductor 1, it is no longer necessary to configure additional tooling and fixtures, which saves costs, simplifies the process flow, and greatly improves work efficiency.

[0030] like Figure 1 As shown, the bottom of the left end cover sealing plate 23 and the right end cover sealing plate 24 are provided with a folded edge 25 bent outward, and each folded edge 25 is provided with two waist-shaped mounting holes 251. Therefore, the left end cover sealing plate 23 and the right end cover sealing plate 24 are provided with the folded edge 25 with the waist-shaped mounting holes 251, so that the current transformer current limiting protection device can be quickly installed.

[0031] The current transformer current limiting protection device provided by the utility model has an ingenious structural design. The terminal 4 and the protective box 2 are fixed by the inner insulating sleeve 42, the outer insulating sleeve 43, the second nut 45 and the conductive column 41. The lead 15 of the saturated reactor 1 inside the protective box 2, the jumper lead 5 and the lead of the external device outside the protective box 2 are quickly connected by the rotatable nut 44 and the knob 47 on the conductive column 41, so that the lead connector inside the protective box 2 after connection is not affected by the external environment and loosened. And by improving the structure of the protective box 2, the process of pouring epoxy resin 3 is simplified, and the work efficiency is improved.

[0032] The above are only some embodiments of the present invention. It should be pointed out that for ordinary technicians in this field, other modifications and improvements can be made without departing from the creative concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A current transformer current limiting protection device, characterized in that: include: A saturated reactor (1), the saturated reactor (1) comprising a low-saturation microcrystalline iron core (11), an inner insulating layer (12), an enameled wire (13) and an outer insulating layer (14); the low-saturation microcrystalline iron core (11) is wrapped with the inner insulating layer (12); the inner insulating layer (12) is wrapped with one or more layers of enameled wire (13); the enameled wire (13) is wrapped with the outer insulating layer (14); the inlet and outlet ends of the enameled wire (13) are respectively connected to leads (15); A protective box (2), the protective box (2) having a cavity for accommodating a saturated reactor (1), the saturated reactor (1) being fixed in the protective box (2) by epoxy resin (3); The terminal post (4) comprises a conductive post (41), an inner insulating sleeve (42) and an outer insulating sleeve (43), wherein the inner insulating sleeve (42) is embedded in the protective box (2), and one end of the inner insulating sleeve (42) is inserted into the inner side of the protective box (2), the outer insulating sleeve (43) is sleeved on the inner insulating sleeve (42) inside the protective box (2), and the inner parts of the outer insulating sleeve (43) and the inner insulating sleeve (42) form a receiving hole (40), the conductive post (41) is installed through the receiving hole (40), and the conductive post (41) is installed in the receiving hole (40). One side of the electric post (41) is located inside the protective box (2), and the other side extends outside the protective box (2); a nut (44) and a nut (45) are separately arranged on the conductive post (41) inside the protective box (2); two flat washers (46) are arranged between the nut (44) and the nut (45); the lead wire (15) is fixed between the two flat washers (46); the terminal posts (4) are connected by a jumper lead wire (5), and the jumper lead wire (5) is fixed between the two flat washers (46).

2. The current transformer current limiting protection device according to claim 1, characterized in that: A limit baffle (411) is provided on the conductive column (41) outside the protective box (2), and the limit baffle (411) is tightly attached to the end surface of the inner insulating sleeve (42). A knob (47) is mounted on the outer end of the conductive column (41), and a knob metal insert (471) is embedded in the knob (47). The knob metal insert (471) is connected to the conductive column (41) by a thread, and a gap is formed between the knob metal insert (471) and the limit baffle (411) for connecting the lead wire of an external device.

3. The current transformer current limiting protection device according to claim 2, characterized in that: The inner insulating sleeve (42) has an annular retaining ring (421). When the inner insulating sleeve (42) is embedded in the protective box (2), the annular retaining ring (421) is located outside the protective box (2) and is in close contact with the outer wall of the protective box (2). The outer insulating sleeve (43) has a sleeve body (431) and a sleeve top (432). When the outer insulating sleeve (43) is sleeved on the inner insulating sleeve (42), the inner insulating sleeve (42) on the inner side of the protective box (2) is embedded in the sleeve body (431) and the sleeve top (432) is in close contact with the nut 2 (45). The protective box (2) is clamped between the annular retaining ring (421) and the sleeve body (431).

4. The current transformer current limiting protection device according to claim 3, characterized in that: The protective box (2) comprises an upper cover plate (21), a lower cover plate (22), a left end cover sealing plate (23) and a right end cover sealing plate (24); the cross-sections of the upper cover plate (21) and the lower cover plate (22) are both U-shaped structures with one side high and one side low; the upper cover plate (21) and the lower cover plate (22) are mutually buckled and fixed at both sides by a left end cover sealing plate (23) and a right end cover sealing plate (24); and the saturated reactor (1) is fixed on the lower cover plate (22).

5. The current transformer current limiting protection device according to claim 4, characterized in that: The bottoms of the left end cover sealing plate (23) and the right end cover sealing plate (24) are provided with folded edges (25) bent outwards, the folded edges (25) are provided with waist-shaped mounting holes (251), and the outer periphery of the knob (47) is provided with anti-slip ridges (472).

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