A three-phase integrated access type molded case low-voltage current transformer

Abstract

A three-phase integrated access type low-voltage molded case current transformer, comprising a base, a current transformer, and a housing. An abdominal cavity is arranged inside the base; the abdominal cavity is used for placing three current transformers for metering and three primary busbars. The three current transformers for metering respectively pass through the three primary busbars. The current transformer for metering comprises a current transformer iron core, and a current transformer coil is wound around the current transformer iron core. The three primary busbars are distributed in parallel; a secondary wire metering connection terminal is arranged on one side of the base. The secondary wire metering connection terminal comprises three-phase connection posts and a neutral connection post. Two ends of the current transformer coil of the current transformer for metering are respectively connected to the three-phase connection posts and the neutral connection post of the secondary wire metering connection terminal. The current transformer of the present invention has high overall mechanical strength, saves time and effort in installation, and prevents wiring chaos and incorrect wiring.

Description

Technical Field

[0001] The present invention relates to a three-phase integrated access type low-voltage molded case current transformer, belonging to the technical field of current transformers. Background Art

[0002] A current transformer is an important electrical appliance used in electrical measuring instruments, relay protection, electric energy metering and other electrical equipment in the power system. It is a sensor for obtaining the current value of the primary circuit, and undertakes the functions of isolation between high and low voltages and conversion of large current into small current. The stable operation of the current transformer is directly of great significance to the operation of equipment such as the safety, protection and measurement of the power system.

[0003] The types of low-voltage current transformers are diverse, and they are all a kind of electric quantity transmitter constructed based on the principle of electromagnetic induction, generally composed of a closed iron core and windings. With the development of electrical and electronic equipment, and the need for intelligence and integration, the requirements for anti-interference, neatness and easy connection are getting higher and higher.

[0004] Existing low-voltage current transformers are all single-phase one-piece through-type. When installed, they are crowded with each other, and it is very difficult to pass through; during manufacturing, use and replacement, there are often phenomena of incorrect matching of different models and different transformation ratios; because many wires are connected separately for each phase, it often causes incorrect wiring of protection metering or between phases; during operation, the secondary wiring terminals often have the phenomenon of loosening and open circuit to generate high voltage; the large space occupied by the current transformer also restricts the neatness and miniaturization of the distribution box. Summary of the Invention

[0005] In order to solve the above technical problems, the current transformer of the present invention adopts a three-phase integrated access type low-voltage molded case current transformer.

[0006] The purpose of the present invention is to solve the problems of inconvenient installation, replacement and chaotic wiring of existing current transformers, and proposes a three-phase integrated access type low-voltage molded case current transformer.

[0007] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0008] A three-phase integrated access type low-voltage molded case current transformer, comprising a base, a current transformer, and a housing. An abdominal cavity is provided inside the base; the abdominal cavity is used to place three metering current transformers and three primary busbars. The three metering current transformers respectively pass through the three primary busbars. The metering current transformer includes a current transformer core, and a current transformer coil is wound around the current transformer core. The three primary busbars are distributed in parallel; on one side of the base, there is a secondary line metering wiring terminal, and the secondary line metering wiring terminal includes three-phase connection terminals and a neutral connection terminal. The two ends of the current transformer coil of the metering current transformer are respectively connected to the three-phase connection terminals and the neutral connection terminal of the secondary line metering wiring terminal.

[0009] Further, the abdominal cavity also places three protective current transformers, and the three protective current transformers also respectively pass through the three primary busbars. The protective current transformer includes a current transformer core, and a current transformer coil is wound around the current transformer core; on the other side of the base, there is a secondary line protection wiring terminal, and the secondary line protection wiring terminal includes three-phase connection terminals and a neutral connection terminal. The two ends of the current transformer coil of the protective current transformer are respectively connected to the three-phase connection terminals and the neutral connection terminal of the secondary line protection wiring terminal.

[0010] Further, lead seal holes are provided on both the base and the housing, and the base and the housing are lead-sealed through lead seal tightening screws.

[0011] Further, four symmetrically arranged mounting holes are provided on the base, and the mounting holes penetrate the base for fixing and mounting the base on the mounting surface of the power distribution cabinet through mounting screws.

[0012] Further, the primary busbar is fixed on the base through primary incoming and outgoing line terminals at both ends thereof by tightening screws.

[0013] Further, the primary incoming and outgoing line terminals respectively serve as the primary incoming line terminal and the primary outgoing line terminal of the primary busbar for connecting the primary incoming line and the primary outgoing line.

[0014] Further, screw holes are provided at the four corners of the housing, and the base and the housing are fastened through fastening bolts.

[0015] Further, secondary line outlet holes are respectively provided on both sides of the housing, and the positions of the secondary line outlet holes correspond to the positions of the secondary line metering wiring terminal and the secondary line protection wiring terminal for the outlet of the secondary metering line and the secondary protection line.

[0016] Further, a primary line inlet and a primary line outlet are symmetrically provided on the upper side and the lower side of the housing respectively.

[0017] Further, the current transformer core is formed by winding silicon steel sheets and impregnated through heat treatment.

[0018] The advantages of the three-phase integrated access type low-voltage plastic case current transformer of the present invention are as follows:

[0019] 1. The primary incoming lines for phases A, B, and C are directly connected in a plug-in manner respectively. A core and a coil are installed on each primary busbar. This structural design fully embodies the three-phase integrated layout and has high overall mechanical strength.

[0020] 2. Four fastening bolts are provided at the four corners of the encapsulation housing to connect the housing to the base to form a seal. This fully solves the trouble of decentralized installation, saving time and effort.

[0021] 3. The metering secondary outgoing line and the protection secondary outgoing line are respectively arranged on both sides of the base, facilitating the routing of secondary wires and preventing wiring confusion and incorrect wiring.

[0022] 4. With the fixed turn number design of the winding and after the three-phase integrated assembly of the current transformer, it can not only fully ensure that the winding outputs a stable and reliable signal, but also effectively ensure the complete matching of the three-phase current transformers.

[0023] 5. The incoming and outgoing line type installation of this current transformer reduces the installation space and does not require passing the primary wire through, so the installation becomes simplified.

[0024] 6. When used as a metering current transformer, since there are incoming line terminals, the voltage line can be directly connected to the watt-hour meter, avoiding opening the primary wire for wiring. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 FIG. is the front view of the wiring when the three-phase integrated access type low-voltage plastic case current transformer of the present invention is used as a metering transformer.

[0026] Figure 2 FIG. is the front view of the wiring when the three-phase integrated access type low-voltage plastic case current transformer of the present invention is used as a protection transformer.

[0027] Figure 3 FIG. is the front view of the housing. DETAILED DESCRIPTION OF THE INVENTION

[0028] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0029] AsFigure 1 As shown in the figure, a three-phase integrated access type low-voltage molded case current transformer includes a base 1, a current transformer 2, and a housing 3. A cavity 4 is provided inside the base 1. The cavity is used to place three current transformers for metering LA, LB, and LC and three primary busbars 5. The three current transformers for metering respectively pass through the three primary busbars. The current transformer for metering includes a current transformer core 6, and a current transformer coil 7 is wound around the current transformer core. The three primary busbars are distributed in parallel. A secondary line metering connection terminal is provided on one side of the base. The secondary line metering connection terminal includes three-phase connection terminals A, B, C and a neutral connection terminal N. The two ends of the current transformer coil 7 of the current transformer for metering are respectively connected to the three-phase connection terminals A, B, C and the neutral connection terminal N of the secondary line metering connection terminal.

[0030] Among them, one end of the current transformer coil of the current transformer for metering LA is connected to the three-phase connection terminal A, and the other end is connected to the neutral connection terminal N. Similarly, one end of the current transformer coil of the current transformer for metering LB is connected to the three-phase connection terminal B, and the other end is connected to the neutral connection terminal N; one end of the current transformer coil of the current transformer for metering LC is connected to the three-phase connection terminal C, and the other end is connected to the neutral connection terminal N.

[0031] Under such connection conditions, the three-phase integrated access type low-voltage molded case current transformer can be used as a metering current transformer. However, in another embodiment of the present invention, the three-phase integrated access type low-voltage molded case current transformer can also be used as a protection current transformer, which is achieved through the following structure, as Figure 2 shown:

[0032] The cavity also places three current transformers for protection LA’, LB’, LC’. The three current transformers for protection also respectively pass through the three primary busbars. The current transformers for protection LA’, LB’, LC’ include current transformer cores, and current transformer coils are wound around the current transformer cores. A secondary line protection connection terminal is provided on the other side of the base. The secondary line protection connection terminal includes three-phase connection terminals A’, B’, C’ and a neutral connection terminal N’. The two ends of the current transformer coil of the current transformer for protection are respectively connected to the three-phase connection terminals A’, B’, C’ and the neutral connection terminal N’ of the secondary line protection connection terminal.

[0033] It can be seen that the secondary line metering connection terminal and the secondary line protection connection terminal are respectively arranged on the left and right sides of the base, so that the secondary line outgoing lines for metering and protection are respectively arranged on both sides of the base, which is convenient for the routing of the secondary lines and prevents wiring confusion and incorrect wiring.

[0034] In another embodiment of the present invention, the three-phase integrated access type low-voltage molded case current transformer can be used as both a metering transformer and a protection transformer. At this time, the connection methods of Figure 1 and Figure 2 should be implemented simultaneously, that is, both ends of the current transformer coil of the current transformer for metering are respectively connected to the three-phase terminals A, B, C and the neutral terminal N of the secondary line metering connection terminal, and both ends of the current transformer coil of the current transformer for protection are respectively connected to the three-phase terminals A', B', C' and the neutral terminal N' of the secondary line protection connection terminal.

[0035] As Figures 1-3 shown, seal holes 8 are provided on both the base and the housing, and the base and the housing are sealed by seal tightening screws.

[0036] Four symmetrically arranged mounting holes 9 are provided on the base, and the mounting holes penetrate the base for fixing and mounting the base on the mounting surface of the power distribution cabinet through mounting screws.

[0037] The primary busbar 5 is fixed on the base through the primary inlet and outlet terminals at both ends by tightening screws 10.

[0038] The primary inlet and outlet terminals are respectively used as the primary inlet terminal and the primary outlet terminal of the primary busbar for connecting the primary incoming line and the primary outgoing line.

[0039] Screw holes 11 are provided at the four corners of the housing, and the base and the housing are fastened by fastening bolts.

[0040] Secondary line outlet holes 12 are respectively provided on both sides of the housing, and the positions of the secondary line outlet holes correspond to the positions of the secondary line metering connection terminal and the secondary line protection connection terminal for the outlet of the secondary metering line and the secondary protection line.

[0041] A primary line inlet 13 and a primary line outlet 14 are symmetrically provided on the upper side and the lower side of the housing respectively.

[0042] The current transformer core 6 is wound by silicon steel sheets and impregnated through heat treatment.

[0043] During use, select the three-phase integrated low-voltage molded case current transformer that meets the transformation ratio requirements according to the transformation ratio requirements of the current transformer needed for the actual load. Open the housing of the current transformer, pass the installation screws through the base installation holes 9, align with the installation surface, insert the installation screws and tighten them; after insulating the primary incoming line terminals, connect the A, B, and C phases of the primary incoming line to the primary incoming line terminals, and after insulating the primary outgoing line terminals, connect the A, B, and C phases of the primary outgoing line to the primary outgoing line terminals; lead out the secondary wires from the secondary wire metering connection terminals and the secondary wire protection connection terminals and connect them to the secondary circuit; after tightening the housing and the base with screws, seal at the seal point.

[0044] As described above, it is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and should be covered within the protection scope of the present invention.

Claims

1. A three-phase integrated access type low-voltage molded case current transformer, comprising a base, a current transformer, and a housing, characterized in that: An abdominal cavity is provided inside the base; the abdominal cavity is used to place three current transformers for metering and three primary busbars. The three current transformers for metering respectively pass through the three primary busbars. The current transformer for metering includes a current transformer core, and a current transformer coil is wound around the current transformer core. The three primary busbars are distributed in parallel; a secondary line metering connection terminal is provided on one side of the base. The secondary line metering connection terminal includes three-phase connection terminals and a neutral connection terminal. The two ends of the current transformer coil of the current transformer for metering are respectively connected to the three-phase connection terminals and the neutral connection terminal of the secondary line metering connection terminal; three current transformers for protection are also placed in the abdominal cavity. The three current transformers for protection also respectively pass through the three primary busbars. The current transformer for protection includes a current transformer core, and a current transformer coil is wound around the current transformer core; a secondary line protection connection terminal is provided on the other side of the base. The secondary line protection connection terminal includes three-phase connection terminals and a neutral connection terminal. The two ends of the current transformer coil of the current transformer for protection are respectively connected to the three-phase connection terminals and the neutral connection terminal of the secondary line protection connection terminal; The three-phase integrated access type low-voltage molded case current transformer can be used as a metering transformer and a protection transformer at the same time; Secondary line outlet holes are respectively provided on both sides of the housing, and the positions of the secondary line outlet holes correspond to the positions of the secondary line metering connection terminal and the secondary line protection connection terminal respectively, for the outlet of the secondary metering line and the secondary protection line.

2. The three-phase integrated access type low-voltage molded case current transformer according to claim 1, wherein: Sealing holes are provided on both the base and the housing, and the base and the housing are sealed by sealing fastening screws.

3. The three-phase integrated access type low-voltage molded case current transformer according to claim 1, wherein: Four mounting holes that are symmetrically arranged up, down, left, and right are provided on the base. The mounting holes penetrate through the base and are used to fix and install the base on the mounting surface of the power distribution cabinet through mounting screws.

4. The three-phase integrated access type low-voltage molded case current transformer according to claim 1, wherein: The primary busbar is fixed to the base through the primary inlet and outlet terminals at both ends thereof by fastening screws.

5. The three-phase integrated access type low-voltage molded case current transformer according to claim 4, characterized in that: The primary inlet and outlet terminals respectively serve as the primary inlet terminal and the primary outlet terminal of the primary busbar, and are used to connect the primary inlet and the primary outlet.

6. The three-phase integrated access type low-voltage molded case current transformer according to claim 1, wherein: Screw holes are provided at the four corners of the housing, and the base and the housing are fastened by fastening bolts.

7. The three-phase integrated access type low-voltage molded case current transformer according to claim 1, characterized in that: A primary line inlet and a primary line outlet are symmetrically provided on the upper side and the lower side of the housing respectively.

8. The three-phase integrated access type low-voltage molded case current transformer according to claim 1, characterized in that: The current transformer core is rolled from silicon steel sheets and is impregnated through heat treatment.

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