CN108010812A - A kind of main circuit conductor distribution structure of zero sequence current mutual inductor - Google Patents

Abstract

The invention discloses a main circuit conductor wiring structure of a zero-sequence current transformer of a residual current protection circuit breaker. The insulator passes through the annular center cavity of the transformer from the load side and is fixedly connected with the transformer. The insulator is provided with a mutual inductance The cross-shaped ribs protruding from the annular central cavity of the transformer, the cross-shaped ribs divide the annular central cavity of the transformer into four equal insulation areas, the four-phase terminals of A, B, C, and N are all in a U-shaped structure, and the four terminals U The U-shaped bottom passes through a corresponding insulating area, and the A-phase terminal and the N-phase terminal are mirror-symmetrical, the B-phase terminal and the C-phase terminal are mirror-symmetrical, and the U-shaped bottom of the four terminals passes through the ring-shaped central cavity of the transformer The radial cross-sectional area of the zero-sequence current transformer is the same, which can realize that the magnetic flux generated by each current in the primary circuit in the iron core cancels each other, and improves the detection sensitivity and detection reliability of the zero-sequence current transformer.

Description

A main circuit conductor wiring structure of a zero-sequence current transformer

technical field

The invention belongs to a residual current protection circuit breaker in the technical field of low-voltage electrical appliances, and in particular relates to a wiring structure of a main circuit conductor of a zero-sequence current transformer on the circuit breaker.

Background technique

The zero-sequence current transformer detects the residual current of the main circuit and converts it into the output voltage of the secondary circuit, which is directly or indirectly applied to the tripping coil of the residual current release after amplifying the signal to realize the residual current release. The action of the button protects the entire circuit. Therefore, the detection accuracy and detection reliability of the residual current transformer are very important. When there is no ground fault, the magnetic flux generated in the iron core by each current passing through the primary circuit of the transformer should be able to cancel each other out, and the secondary circuit of the residual current transformer should have no voltage output.

The four-pole residual current circuit breaker is based on the three-pole plus the N-pole part corresponding to the neutral line, that is, the N-pole is added on the basis of the A-pole, B-pole, and C-pole. The configuration method of the primary circuit wire of the transformer is to bend the terminals of A, B, C, and N phases into a U shape and then pass through the zero-sequence current transformer.

Referring to Fig. 1, in the structure of the existing zero-sequence current transformer 1, the central through hole of the transformer 1 is provided with four areas, which are respectively No. 10, No. 20, No. 30, and No. 40 areas. The ABCN wires are generally as follows Arrangement through the central through hole of the transformer: the A-phase connection component is vertically arranged in the No. 10 area of the zero-sequence current transformer 1, the B-phase connection component is horizontally arranged in the No. The components are vertically arranged in the No. 30 area of the zero-sequence current transformer, and the N-phase connection components are vertically arranged in the No. 40 area of the zero-sequence current transformer. This structure leads to the existence of leakage flux due to the asymmetric arrangement of conductors passing through the central through hole of the transformer, that is, in the case of no ground fault in the main circuit, a voltage output will be generated on the secondary circuit side, and the output When the voltage is sufficient, it will cause the malfunction of the circuit breaker and affect the entire power supply circuit.

Contents of the invention

The purpose of the present invention is to provide a new layout structure of the connecting components of the primary circuit of the zero-sequence current transformer, that is, to provide the wiring structure of the main circuit conductor of the zero-sequence current transformer, so as to realize that each current of the primary circuit is in the iron core. The mutual cancellation of the magnetic flux generated in the residual current transformer improves the detection sensitivity and detection reliability of the residual current transformer.

The technical solution adopted in the present invention is: the insulator passes through the annular center cavity of the transformer from the load side and is fixedly connected with the transformer, the insulator is provided with a cross-shaped rib protruding toward the annular center cavity of the transformer, and the cross-shaped rib connects the transformer The ring-shaped central cavity is divided into four equal insulating areas. The four-phase terminals of A, B, C, and N are all in a U-shaped structure, and the U-shaped bottom of the four terminals passes through a corresponding insulating area, and the A-phase terminal It is mirror-symmetrical with the N-phase terminal, mirror-symmetrical with the B-phase terminal and the C-phase terminal, and the radial cross-sectional area of the U-shaped bottom of the four terminals passing through the annular center cavity of the transformer is the same.

Further, a transformer bracket is provided on the incoming line side of the current transformer, and the transformer bracket has a bracket U-shaped plate perpendicular to the central axis of the transformer annular center cavity, the opening of the bracket U-shaped plate faces the transformer, and the bracket The bottom of the U-shaped plate protrudes in the direction of the transformer with a bracket rib. The bracket rib divides the inside of the bracket U-shaped plate into the transformer area and the circuit board area. There are bracket through holes on the bottom surface of the U-shaped plate in the transformer area. The central axis of the through hole is collinear with the central axis of the transformer ring center cavity, and the inner diameter is equal to the inner diameter of the transformer ring center cavity. The insulator and terminal assembly pass through the through hole of the bracket, and the insulator is flush with the U-shaped plate of the bracket. , and the terminal assembly extends out of the through hole of the bracket and connects to the main circuit on the incoming line side.

Further, the end faces of the four incoming wire ends of the A, B, C, and N four-phase connection terminals are even and of the same height, and the end faces of the four outgoing wire ends are even and of the same height.

The beneficial effects of the present invention after adopting the above technical scheme are: the present invention can solve the cumbersome problem that the primary circuit wire needs to be wrapped with insulating tape, has excellent phase-to-phase insulation performance, and can realize the generation of each current in the primary circuit in the iron core. The magnetic flux cancels each other out to improve the detection sensitivity and detection reliability of the zero-sequence current transformer, and the A-phase terminal and the N-phase terminal are mirror-symmetrical, and the B-phase terminal and the C-phase terminal are mirror-symmetrical, which can reduce the number of molds and reduce cost.

Description of drawings

Fig. 1 is a schematic diagram of the layout of existing ABCN phase conductors passing through zero-sequence current transformers;

Fig. 2 is the wiring structure schematic diagram of the main circuit conductor of a kind of zero-sequence current transformer of the present invention;

Fig. 3 is an enlarged view of the front view structure of Fig. 2;

Fig. 4 is the radial sectional view of Fig. 3;

Fig. 5 is the structural enlargement diagram of transformer support in Fig. 2;

Fig. 6 is an enlarged view of the structure of the insulator in Fig. 2;

FIG. 7 is an enlarged view of the structure of the terminal assembly 2 in FIG. 2;

In the figure; 1. Zero-sequence current transformer; 2. Terminal assembly; 3. Transformer bracket; 4. Insulator; 22. U-shaped bottom of terminal; 31. U-shaped plate of bracket; 32. Rib plate of bracket; 33 .Bracket through hole; 41. Insulation board; 42. Cross rib; 311. Transformer area; 312. Circuit board area; 421, 422, 423, 424. Insulation area.

Detailed ways

Referring to Figures 2, 3, and 4, the zero-sequence current transformer 1 has a transformer ring-shaped central cavity in the middle, along both sides of the axial direction of the transformer ring-shaped central cavity, one side is the incoming line side, and the other side is the load side . The insulator 4 passes through the annular central cavity of the transformer from the load side and is fixedly connected with the zero-sequence current transformer 1. The terminal assembly 2 passes through the annular central cavity of the transformer. After the terminal assembly 2 passes through the annular central cavity of the transformer Connect the main circuit on the incoming line side, and connect the user load on the load side. The terminal assembly 2 is composed of four-phase terminals A, B, C, and N. The insulator 4 in the annular central cavity of the transformer separates four identical insulating areas from the annular central cavity of the transformer, A, B, C, The N four-phase terminals pass through a corresponding insulating area respectively, where the A-phase terminal and the N-phase terminal are mirror-symmetrical, the B-phase terminal and the C-phase terminal are mirror-symmetrical, and the A-phase terminal and the C-phase terminal have relative mutual inductance. The central axis of the annular central cavity of the transformer is symmetrically arranged, and the B-phase connecting terminal and the N-phase connecting terminal are symmetrically arranged relative to the central axis of the annular central cavity of the transformer. A transformer bracket 3 is provided on the incoming line side of the zero-sequence current transformer 1 , and the transformer bracket 3 is fixedly connected with the zero-sequence current transformer 1 , and the terminal assembly 2 passes through the transformer bracket 3 .

Referring to Fig. 5, the transformer bracket 3 is close to the zero-sequence current transformer 1, made of insulating material, and has a bracket U-shaped plate 31 perpendicular to the central axis of the ring-shaped central cavity of the zero-sequence current transformer 1, and the bracket U The opening of the type plate 31 faces the zero-sequence current transformer 1, and the bottom of the bracket U-shaped plate 31 protrudes in the direction of the zero-sequence current transformer 1. There is a bracket rib 32, and the bracket rib 32 divides the inside of the bracket U-shaped plate 31 into a transformer area 311 and the circuit board area 312, on the bottom surface of the U-shaped plate 31 of the transformer area 311, there is a bracket through hole 33, the central axis of the bracket through hole 33 is collinear with the central axis of the transformer annular center cavity, the bracket through hole 33 The inner diameter is equal to the inner diameter of the annular center cavity of the transformer. The zero-sequence current transformer 1 is placed in the transformer area 311 , and the circuit board area 312 is used for placing the circuit board. Both the insulator 4 and the terminal assembly 2 passing through the annular center cavity of the transformer pass through the through hole 33 of the bracket, the insulator 4 is flush with the U-shaped plate 31 of the bracket, and the terminal assembly 2 is stretched out after the through hole 33 of the bracket. The incoming side is connected to the main circuit.

Referring to Fig. 6, the insulator 4 has an insulating plate 41 perpendicular to the axis of the central cavity of the zero-sequence current transformer 1, the insulating plate 41 is located on the load side of the zero-sequence current transformer 1, and a mutual inductance is arranged on the insulating plate 41. The cross-shaped rib 42 protruding from the annular central cavity of the device. The cross-shaped rib 42 passes through the annular central cavity of the transformer, and the mutually perpendicular cross-shaped structure length L1 of the cross-shaped rib 42 is equal to the inner diameter of the annular central cavity of the transformer, and the insulator 4 is embedded in the annular central cavity of the transformer through the cross-shaped rib 42 , tightly fit and fixed together with the annular center cavity of the transformer. The cross-shaped rib 42 divides the annular center cavity of the transformer into four equal insulating areas, which are the insulating areas 421, 422, 423, and 424, respectively, and the four-phase terminals of A, B, C, and N pass through the ring of the transformer. Four insulating areas in the center cavity.

Referring to Fig. 7 and Fig. 3, in the terminal block assembly 2, the incoming terminal A2 of the A-phase terminal is used for connecting with the main circuit, the outgoing terminal A21 is used for connecting the user load side, and the incoming terminal B2 of the B-phase terminal is used for connecting with the main circuit. The main circuit connection, the outgoing terminal B21 is the user load side connection, the incoming terminal C2 of the C-phase terminal is used to connect with the main circuit, the outgoing terminal C21 is the user’s load side connection, and the incoming terminal N2 of the N-phase terminal is used for connecting with the main circuit. The main circuit is connected, and the outgoing terminal N21 is connected to the user's load side. The end faces of the four incoming wire terminals A2, B2, C2, and N2 are even and of the same height, and the end faces of the four outgoing wire ends A21, B21, C21, and N21 are even and of the same height. A, B, C, and N four-phase terminals all have a U-shaped structure, and the U-shaped bottom 22 of the terminal passes through the annular center cavity of the transformer, so that the zero-sequence current transformer 1 ring sets A, B, C, and N four The terminal U-shaped bottom 22 of the phase terminal. The four U-shaped bottoms 22 of the connecting terminals pass through the corresponding insulating regions 421, 422, 423, 424 respectively, and the U-shaped bottoms 22 of the connecting terminals of the A-phase connecting terminal and the U-shaped bottom 22 of the connecting terminal of the N-phase connecting terminal are mirror-symmetrical, The connecting terminal U-shaped bottom 22 of the B-phase connecting terminal and the connecting terminal U-shaped bottom 22 of the C-phase connecting terminal are mirror-symmetrical. The two U-shaped side walls of the four-phase terminals A, B, C, and N are respectively located on the incoming line side and the load side of the zero-sequence current transformer 1 .

Claims (4)

1. A main circuit conductor wiring structure of a zero-sequence current transformer. The insulator (4) passes through the annular center cavity of the transformer from the load side and is fixedly connected with the transformer. The insulator (4) is provided with a direction transformer The cross-shaped ribs (42) protruding from the annular central cavity, the cross-shaped ribs (42) divide the annular central cavity of the transformer into four equal insulation areas, and the characteristics are: A, B, C, and N four-phase terminals are all in the shape of U-shaped structure, the U-shaped bottom (22) of the four terminals passes through a corresponding insulating area respectively, and the A-phase terminal and the N-phase terminal are mirror-symmetrical, and the B-phase terminal and the C-phase terminal are mirror-symmetrical, four The radial cross-sectional areas of the U-shaped bottom (22) of the connecting terminal passing through the annular center cavity of the transformer are the same. 2. A main circuit conductor wiring structure of a zero-sequence current transformer according to claim 1, characterized in that: a transformer support (3) is provided on the incoming line side of the transformer, and the transformer support (3) There is a bracket U-shaped plate (31) perpendicular to the central axis of the transformer annular center cavity, the opening of the bracket U-shaped plate (31) faces the transformer, and the bottom of the bracket U-shaped plate (31) protrudes in the direction of the transformer. The support rib (32), the support rib (32) divides the inside of the support U-shaped plate (31) into the transformer area (311) and the circuit board area (312), and the support U-shaped plate in the transformer area (311) ( 31) There is a support through hole (33) on the bottom surface, the central axis of the support through hole (33) is collinear with the central axis of the transformer ring center cavity, and the inner diameter is equal to the inner diameter of the transformer ring center cavity, and the insulating part (4) and the terminal assembly (2) pass through the bracket through hole (33), the insulator (4) is flush with the U-shaped plate of the bracket (31), and the terminal assembly (2) protrudes out of the bracket through hole (33). The incoming side is connected to the main circuit. 3. The main circuit conductor wiring structure of a zero-sequence current transformer according to claim 1, characterized in that: the end faces of the four incoming wire ends of A, B, C, and N four-phase terminals are even and highly Consistent, the end faces of the four outlets are even and of the same height. 4. The main circuit conductor wiring structure of a zero-sequence current transformer according to claim 1, characterized in that: two U-shaped side walls of the A, B, C, and N four-phase terminals of the U-shaped structure They are respectively located on the incoming line side and the load side of the transformer.