Automatic line changing device for current transformer

Abstract

This utility model belongs to the field of power equipment technology, and in particular to an automatic switching device for current transformers. It includes a switching assembly and a housing for mounting the switching assembly. The bottom of the housing has a base plate with several posts inserted into it. Each post has a winding terminal at its top and an elastic pad on its upper part. A cover is rotatably connected to the housing, and the cover has through holes that expose the winding terminals. This utility model allows for direct insertion and removal of the winding terminals via posts, ensuring installation stability during use. Compared to current methods of fixing winding terminals with screws or adhesive, it significantly improves maintenance speed and makes maintenance operations more convenient.

Description

Technical Field

[0001] This utility model relates to the field of power equipment technology, specifically to an automatic switching device for current transformers. Background Technology

[0002] An automatic current transformer switching device, also known as an automatic CT switching device, is mainly used for ratio testing of current transformers. It includes input and output interfaces. The input interface connects to the power supply and the current transformer tester, while the output provides multiple terminals for connecting to the various secondary windings (e.g., 1S1-1S2, 2S1-2S2, ..., taps) of the current transformer (CT) under test. The core of the device consists of a set of controlled electronic switches or relays (usually with independent circuit breakers and short-circuit switches for each winding) and a switching controller (such as a PLC or microprocessor). The controller precisely controls the on / off state of each switching element according to a preset program or instructions.

[0003] When a specific winding (e.g., winding 1) is selected for testing, the controller automatically closes the circuit breaker connecting that winding (1S1-1S2) to the current source and the tester, thus connecting it to the test circuit. Simultaneously, it forcibly closes the short-circuit switches connecting all other windings (e.g., windings 2, 3, etc.) (or connects them to a low-impedance load), ensuring they are in a safe closed-circuit state and effectively preventing the risk of open circuits on the secondary side. After the current winding test is completed, the controller automatically performs a switching operation: disconnecting the circuit breaker for the currently tested winding, connecting the circuit breaker for the next winding to be tested (e.g., winding 2), and simultaneously maintaining a reliable short-circuit state for all other windings (including those already tested). This switching-testing-re-switching process is automatic, continuous, and executed in a preset sequence until the testing of all target windings is completed.

[0004] However, while the current automatic winding switching device has improved the problem of multiple insertions and removals of winding terminals during a single test, the winding terminals still suffer from significant wear after long-term operation of the ratio test. The conventional installation methods for winding terminals are mainly threaded or adhesive. Threaded installation is not convenient for maintenance, while adhesive installation is prone to falling off after long-term use, especially in the more humid south.

[0005] Therefore, this application proposes an automatic current transformer switching device that facilitates the maintenance of winding terminals. Utility Model Content

[0006] To address the shortcomings of existing technologies, this utility model provides an automatic current transformer switching device, which solves the problem that current automatic current transformer switching devices cannot simultaneously achieve both secure installation and quick-release of winding terminals.

[0007] To achieve the above objectives, the present invention provides the following technical solution: an automatic current transformer switching device, comprising a switching assembly and a housing for installing the switching assembly, wherein a base plate is provided at the bottom of the housing, and a plurality of posts are inserted into the base plate, each post having a winding terminal at its top and an elastic pad at its upper part, and a cover is rotatably connected to the housing, the cover having a through hole for exposing the winding terminal.

[0008] Preferably, the substrate is provided with pins for inserting the plug, and the inner wall of the housing is also fixedly connected with a retainer, which is provided with a hole through which the plug can pass.

[0009] Preferably, the insert has an outwardly protruding axial limiting piece on its axial sidewall above the retainer.

[0010] Preferably, the inner edge of the insertion hole is further provided with a limiting opening, and the axial side wall of the insertion post and below the limiting piece is provided with a limiting block that cooperates with the radial limiting opening.

[0011] Preferably, the retainer is U-shaped, and both ends of the retainer are connected to the inner wall of the box via corner plates.

[0012] Preferably, the relay, pass switch, and short-circuit switch in the line-changing assembly are all integrated on the plug, the substrate is a PCB board, and the substrate connects the plug to the tester interface and the controller control circuit through onboard circuitry.

[0013] Preferably, the pins include at least 6 pins.

[0014] Preferably, the elastic pad is conical and fixed to the outer wall of the winding terminal, and the bottom of the cover, located at the inner edge of the through hole, engages with the elastic pad.

[0015] Compared with the prior art, the present invention provides an automatic current transformer switching device, which has the following advantages:

[0016] This automatic current transformer switching device allows for direct plugging and unplugging of winding terminals via inserts, ensuring installation stability during use. Compared to the current method of fixing winding terminals with screws or adhesive, it significantly improves maintenance speed and makes maintenance operations more convenient. Attached Figure Description

[0017] Figure 1 This is a three-dimensional structural diagram of the automatic switching device for this current transformer.

[0018] Figure 2 This is a top view of the structure of the automatic switching device for this current transformer;

[0019] Figure 3This is a three-dimensional structural diagram of the automatic switching device for this current transformer after the cover is opened.

[0020] Figure 4 This is an assembly drawing of the plug and retainer in the automatic switching device of this current transformer.

[0021] In the diagram: 1. Housing; 11. Cover; 111. Through hole; 2. Base plate; 21. Pin; 3. Socket; 31. Winding terminal; 32. Elastic pad; 33. Axial limiting piece; 34. Limiting block; 4. Cage; 41. Socket; 411. Limiting port. Detailed Implementation

[0022] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0023] The core of existing automatic current transformer switching devices consists of a set of controlled electronic switches or relays (usually with independent on / off switches for each winding) and a switching controller (such as a PLC or microprocessor). The controller precisely controls the on / off state of each switching element according to a preset program or instructions. Some models can even achieve remote operation of CT testing via wireless communication modules.

[0024] While this improves the problem of excessive wear caused by the frequent plugging and unplugging of the winding terminal 31, it does not mean that there is no wear. Moreover, with the increasing demand for current transformers and the fact that some current transformer testers have been integrated with automatic switching devices, the wear of the winding terminal 31 still exceeds that of other interfaces.

[0025] However, currently, the winding terminals 31 of automatic wire-changing devices are basically fixed to the panel (corresponding to the cover 11 in this technical solution) by threads or adhesive for permanent fixation. This makes disassembly during maintenance cumbersome, and the number of winding terminals 31 can reach up to nine, with some wire-changing devices having even more, resulting in very time-consuming maintenance. Therefore, this technical solution aims to improve the convenience of maintaining the winding terminals 31. It should be understood that any technical parts not mentioned in the following technical solution can be directly considered as existing technical solutions. For example, the locking method of the cover 11 (clasp or lock), and the non-winding terminals 31 and their design layout are all considered prior art.

[0026] Please see Figure 1-4The present invention provides the following technical solution: an automatic current transformer switching device, including a switching assembly and a housing 1 for installing the switching assembly. The bottom of the housing 1 is provided with a base plate 2, and a plurality of plugs 3 are inserted into the base plate 2. Each plug 3 is provided with a winding terminal 31 at its top and an elastic pad 32 on its upper part. A cover 11 is rotatably connected to the housing 1, and the cover 11 is provided with a through hole 111 that exposes the winding terminal 31.

[0027] As an optional implementation of this utility model, when the cover 11 is closed, the inner edge of the through hole 111 abuts against the elastic pad 32 and applies pressure to the plug 3, so that the elastic pad 32 is squeezed and has good stability. When maintenance is required, the cover 11 can be opened and the plug 3 can be pulled out from the base plate 2 to repair the winding terminal 31, or a new plug 3 can be directly replaced. Compared with the current method of fixing the winding terminal 31 with screws or adhesive, this technical solution significantly improves the maintenance speed by directly plugging and unplugging the plug 3, making the maintenance operation more convenient.

[0028] In this technical solution, other components in the automatic current transformer switching device, such as batteries, charging interfaces, wireless communication modules, control modules, relays, circuit breakers, and short-circuit switches, can be directly integrated onto the PCB board (which can be regarded as the aforementioned substrate 2) inside the chassis. Therefore, this technical solution will not elaborate on these components.

[0029] By adopting this implementation method, the winding terminal 31 can be directly plugged in and unplugged through the plug 3, and the installation stability during use is guaranteed. Compared with the current method of fixing the winding terminal 31 with screws or adhesive, the maintenance speed is significantly improved and the maintenance operation is more convenient.

[0030] like Figure 3-4 As shown, the substrate 2 is provided with a pin 21 for inserting the plug 3. The inner wall of the housing 1 is also fixedly connected with a retainer 4. The retainer 4 is provided with a plug hole 41 through which the plug 3 can pass. The axial side wall of the plug 3 and above the retainer 4 is also provided with an outwardly protruding axial limiting piece 33. The inner edge of the plug hole 41 is also provided with a limiting opening 411. The axial side wall of the plug 3 and below the limiting piece is provided with a limiting block 34 that cooperates with the radial limiting opening 411.

[0031] As an optional implementation of this utility model, the axial limiting piece 33 and the limiting port 411 on the retainer 4 prevent radial slippage after the plug 3 is inserted into the plug 21, and prevent damage to the substrate 2 and onboard circuit due to excessive force applied by the operator when installing the plug 3. When the cover 11 is closed, it can effectively maintain the installation firmness of the plug 3, ensuring that the external test CT wiring operation can be carried out normally during use.

[0032] like Figure 3As shown, the retainer 4 is U-shaped, and both ends of the retainer 4 are connected to the inner wall of the housing 1 through corner plates, which improves the strength and installation stability of the retainer 4 itself, and also improves the shear resistance of the housing 1, thus improving the overall strength of the housing 1.

[0033] like Figure 3-4 As shown, the relay, pass switch and short circuit switch in the line switching assembly are all integrated on the plug 3. The substrate 2 is a PCB board. The substrate 2 connects the pin 21 to the tester interface and the control circuit of the controller through the onboard circuit. The pin 21 includes at least 6 pins.

[0034] As an optional implementation of this utility model, the existing automatic line changing device is designed to integrate power supply, tester interface, controller and relay through onboard circuit (i.e. PCB board).

[0035] To ensure the basic functions of the automatic line-changing device can be realized, at least 6 wires are designed in the plug 3 to adapt to at least 6 pins in the plug 21, realizing the onboard circuit integration tester S1 / S2 and the controller output circuit. All of them are connected to the wires in the plug 3 through the pins on the plug 21. Then, the wires in the plug 3 directly integrate two types of relays: short-circuit switch and pass switch. These wires are finally connected to the CT under test through the terminal at the top.

[0036] like Figure 4 As shown, the elastic pad 32 is conical and fixed to the outer wall of the winding terminal 31, and the bottom of the cover 11 and the inner edge of the through hole 111 cooperate with the elastic pad 32.

[0037] As an optional implementation of this utility model, the tapered fit provides a guiding function between the insert post 3 and the through hole 111, ensuring that the insert post 3 has high installation stability after the cover is closed and during the insertion and removal operation during testing.

[0038] The working principle and usage process of this utility model are as follows: When the cover 11 is closed, the inner edge of the through hole 111 abuts against the elastic pad 32 and applies pressure to the plug 3, so that the elastic pad 32 is squeezed and has good stability; when maintenance is required, the cover 11 is opened and the plug 3 is pulled out from the base plate 2 to repair the winding terminal 31, or a new plug 3 is directly replaced.

[0039] Finally, it should be noted that the above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. An automatic current transformer switching device, comprising a switching assembly and a housing for mounting the switching assembly, wherein a base plate is provided at the bottom of the housing, characterized in that, A number of pins are inserted into the substrate, and each pin has a winding terminal at its top. An elastic pad is provided on the upper part of the pin. A cover is rotatably connected to the housing, and the cover has a through hole that exposes the winding terminal.

2. The automatic current transformer switching device according to claim 1, characterized in that, The base plate is provided with pins for inserting into the socket, and the inner wall of the housing is also fixedly connected with a retainer, which is provided with a socket hole through which the insert can pass.

3. The automatic current transformer switching device according to claim 2, characterized in that, The insert has an outwardly protruding axial limiting piece on its axial side wall above the retainer.

4. The automatic current transformer switching device according to claim 3, characterized in that, The inner edge of the insertion hole is also provided with a limiting port, and the axial side wall of the insertion post and below the limiting piece is provided with a limiting block that cooperates with the radial limiting port.

5. The automatic current transformer switching device according to claim 2, characterized in that, The retainer is U-shaped, and its two ends are connected to the inner wall of the box via corner plates.

6. The automatic current transformer switching device according to claim 2, characterized in that, The relays, pass switches, and short-circuit switches in the line-changing assembly are all integrated on the plug. The substrate is a PCB board, and the substrate connects the plug to the tester interface and the controller control circuit through onboard circuitry.

7. The automatic current transformer switching device according to claim 6, characterized in that, The connector includes at least 6 pins.

8. The automatic current transformer switching device according to claim 1, characterized in that, The elastic pad is conical and fixed to the outer wall of the winding terminal, and the bottom of the cover, located on the inner edge of the through hole, engages with the elastic pad.

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