阅读说明：本技术 一种三相电流互感器 (Three-phase current transformer ) 是由 王维贤 董国鹏 王峰 于 2019-09-12 设计创作，主要内容包括：一种三相电流互感器,上述A、B、C相互感器的结构相同,并且在外侧浇注有环氧树脂壳体。在测量级磁芯上缠绕有测量级绕组,二次保护级磁芯上缠绕有二次保护级绕组。在一次绕组的外侧包裹有半导体材料制成的一次绕组屏蔽层,一次绕组缠绕在测量级磁芯和二次保护级磁芯上。一次绕组的两个引线分别连接有P1和P2一次电流接线排。P1和P2一次电流接线排的另一端穿出环氧树脂壳体的外表面。在环氧树脂壳体的下端基座外表面上设置有二次接线端子组。A、B、C相互感器的绕组引线和二次接线端子组连接。本电流互感器为全封闭三相一体式结构,环氧树脂浇注绝缘,用于紧凑型开关柜中起到电流监测和继电保护作用,有效利用柜内空间使布局合理。(The A, B, C mutual inductors have the same structure, and an epoxy resin shell is poured outside. The measuring-level magnetic core is wound with a measuring-level winding, and the secondary protection-level magnetic core is wound with a secondary protection-level winding. And a primary winding shielding layer made of semiconductor materials is wrapped on the outer side of the primary winding, and the primary winding is wound on the measuring-grade magnetic core and the secondary protection-grade magnetic core. Two leads of the primary winding are respectively connected with P1 and P2 primary current wiring rows. The other ends of the P1 and P2 primary current terminal blocks extend out of the outer surface of the epoxy housing. And a secondary wiring terminal group is arranged on the outer surface of the lower end base of the epoxy resin shell. A. B, C the winding leads of the inductors are connected to the secondary terminal sets. The current transformer is of a totally-enclosed three-phase integrated structure, epoxy resin is poured and insulated, the current transformer plays a role in current monitoring and relay protection in a compact switch cabinet, and space inside the cabinet is effectively utilized to achieve reasonable layout.)

1. A three-phase current transformer comprises an A mutual inductor (3), a B mutual inductor (13) and a C mutual inductor (14), and is characterized in that:

the mutual sensor A (3), the mutual sensor B (13) and the mutual sensor C (14) have the same structure, and an epoxy resin shell (1) is poured outside the mutual sensor A (3), the mutual sensor B (13) and the mutual sensor C (14);

The mutual inductor A (3) comprises a measuring-level magnetic core (4), a secondary protection-level magnetic core (10) and a primary winding (7);

A measuring-level winding (5) is wound on the measuring-level magnetic core (4), and a secondary protection-level winding (11) is wound on the secondary protection-level magnetic core (10); a primary winding shielding layer (8) made of semiconductor materials wraps the outer side of the primary winding (7), and the primary winding (7) is wound on the measurement-level magnetic core (4) and the secondary protection-level magnetic core (10); two lead wires of the primary winding (7) are respectively connected with a P1 primary current wiring row (2) and a P2 primary current wiring row (9); the other ends of the P1 primary current line bank (2) and the P2 primary current line bank (9) penetrate out of the outer surface of the epoxy resin shell (1);

A secondary wiring terminal group (6) is arranged on the outer surface of the lower end base of the epoxy resin shell (1);

The secondary wiring terminal group (6) comprises two A-phase measuring secondary wiring terminals (6-a), two B-phase measuring secondary wiring terminals (6-B), two C-phase measuring secondary wiring terminals (6-C) and two protection secondary wiring terminals (6-o);

two lead wires of a measuring winding (5) on the A-phase mutual sensor (3) are respectively connected with two A-phase measuring secondary wiring terminals (6-a); two lead wires of a measuring-grade winding (5) on the mutual sensor B (13) are respectively connected with two secondary wiring terminals (6-B) of the measuring grade of the phase B; two lead wires of a measuring-grade winding (5) on the mutual C sensor (14) are respectively connected with two secondary C-phase measuring-grade wiring terminals (6-C); one lead of a secondary protection level winding (11) on the mutual inductor A (3), one lead of a secondary protection level winding (11) on the mutual inductor B (13) and one lead of a secondary protection level winding (11) on the mutual inductor C (14) are connected in parallel and then connected to one protection level secondary connecting terminal (6-o); the other lead of the secondary protection level winding (11) on the mutual inductor A (3), the other lead of the secondary protection level winding (11) on the mutual inductor B (13) and the other lead of the secondary protection level winding (11) on the mutual inductor C (14) are connected in parallel and then connected to the other protection level secondary connecting terminal (6-o).

2. A three-phase current transformer according to claim 1, characterized in that:

A plurality of mounting and fixing holes (12) are arranged on a base at the lower end of the epoxy resin shell (1).

3. a three-phase current transformer according to claim 1, characterized in that:

the P1 primary current wiring bar (2) and the P2 primary current wiring bar (9) are copper bars with through holes.

Technical Field

The invention belongs to the field of transformers, and particularly relates to a three-phase current transformer.

background

current transformers used at the present stage are of a three-phase split type, and the volume of each single-phase current transformer occupies the insulating inner space of the switch cabinet, so that the design of the inner insulation of the cabinet is not facilitated.

Disclosure of Invention

the invention aims to provide a three-phase current transformer. The current transformer is of a totally-enclosed three-phase integrated structure, is used in a compact switch cabinet, has the functions of current monitoring and relay protection, and is reasonable in layout by effectively utilizing the space in the cabinet.

in order to realize the purpose, the adopted technical scheme is as follows:

The utility model provides a three-phase current transformer, includes mutual inductor of A, mutual inductor of B, mutual inductor of C, its technical essential lies in:

The mutual sensor a, the mutual sensor B and the mutual sensor C have the same structure, and epoxy resin cases are poured outside the mutual sensor a, the mutual sensor B and the mutual sensor C.

The mutual sensor A comprises a measuring-grade magnetic core, a secondary protection-grade magnetic core and a primary winding.

The measuring-level magnetic core is wound with a measuring-level winding, and the secondary protection-level magnetic core is wound with a secondary protection-level winding. And a primary winding shielding layer made of semiconductor materials is wrapped on the outer side of the primary winding, and the primary winding is wound on the measuring-grade magnetic core and the secondary protection-grade magnetic core. The two leads of the primary winding are respectively connected with a P1 primary current terminal block and a P2 primary current terminal block. The other ends of the P1 primary current terminal block and the P2 primary current terminal block extend out of the outer surface of the epoxy housing.

And a secondary wiring terminal group is arranged on the outer surface of the lower end base of the epoxy resin shell.

The secondary wiring terminal group comprises two A-phase measurement secondary wiring terminals, two B-phase measurement secondary wiring terminals, two C-phase measurement secondary wiring terminals and two protection secondary wiring terminals.

Two lead wires of the measuring winding on the A-phase mutual sensor are respectively connected with two A-phase measuring secondary connecting terminals. Two lead wires of a measuring-grade winding on the B mutual sensor are respectively connected with two B-phase measuring-grade secondary connecting terminals. Two lead wires of a measuring-grade winding on the mutual C sensor are respectively connected with two secondary C-phase measuring-grade wiring terminals. One lead of the secondary protection winding on the mutual inductor A, one lead of the secondary protection winding on the mutual inductor B and one lead of the secondary protection winding on the mutual inductor C are connected in parallel and then connected to one protection secondary connecting terminal. The other lead of the secondary protection winding on the mutual inductor A, the other lead of the secondary protection winding on the mutual inductor B and the other lead of the secondary protection winding on the mutual inductor C are connected in parallel and then connected to the other protection secondary wiring terminal.

and a plurality of mounting and fixing holes are formed in the lower end base of the epoxy resin shell.

The P1 primary current terminal block and the P2 primary current terminal block are copper bars with through holes.

Compared with the prior art, the mutual inductor has the beneficial effects that:

The current transformer is of a totally-enclosed three-phase integrated structure, is insulated by epoxy resin pouring, plays a role in current monitoring and relay protection in a compact switch cabinet (650 cabinet width), and is reasonable in layout by effectively utilizing the space in the cabinet.

the iron-based amorphous alloy magnetic core with high magnetic permeability is adopted, so that high sensitivity and high reliability are realized, and the precision of a measurement signal is ensured.

And an additional current protection winding is adopted to monitor the line fault current.

the material adopts low-loss 0.27mm thickness silicon steel, makes it respond rapidly under the overcurrent condition, ensures that the device can reliably move.

the total volume is compacter than three original single-phase current transformers of the same parameter, saves the cubical switchboard space.

The primary winding is provided with a shielding layer to prevent mutual influence between three-phase currents during operation, so that inaccurate measurement and protection signals are caused.

drawings

Fig. 1 is a schematic structural diagram of a front view of the transformer.

Fig. 2 is a side view schematic diagram of the transformer.

Fig. 3 is a front external view of the transformer.

Fig. 4 is a side view of the instrument transformer.

Fig. 5 is a schematic view of the structure in the direction K in fig. 3.

In the figure, an epoxy resin shell 1, a P1 primary current wiring bar 2, an A mutual inductor 3, a measuring grade magnetic core 4, a measuring grade winding 5, a secondary wiring terminal group 6, an A phase measuring grade secondary wiring terminal 6-a, a B phase measuring grade secondary wiring terminal 6-B, a C phase measuring grade secondary wiring terminal 6-C, a protective grade secondary wiring terminal 6-o, a primary winding 7, a primary winding shielding layer 8, a P2 primary current wiring bar 9, a secondary protective grade magnetic core 10, a secondary protective grade winding 11, a mounting and fixing hole 12, a B mutual inductor 13 and a C mutual inductor 14.

Detailed Description

a three-phase current transformer comprises an A mutual inductor 3, a B mutual inductor 13 and a C mutual inductor 14.

The mutual sensor a 3, the mutual sensor B13, and the mutual sensor C14 have the same configuration, and the epoxy resin case 1 is cast outside the mutual sensor a 3, the mutual sensor B13, and the mutual sensor C14. A plurality of mounting and fixing holes 12 are formed in the lower base of the epoxy resin case 1.

The mutual inductor A3 comprises a measuring-level magnetic core 4, a secondary protection-level magnetic core 10 and a primary winding 7.

The measuring secondary winding 5 is wound on the measuring secondary magnetic core 4, and the secondary protection secondary winding 11 is wound on the secondary protection secondary magnetic core 10. The outer side of the primary winding 7 is wrapped with a primary winding shielding layer 8 made of semiconductor materials, and the primary winding 7 is wound on the measurement-level magnetic core 4 and the secondary protection-level magnetic core 10. The two legs of the primary winding 7 are connected to a P1 primary current terminal row 2 and a P2 primary current terminal row 9, respectively. The other ends of the P1 primary current terminal row 2 and the P2 primary current terminal row 9 extend out of the outer surface of the epoxy housing 1. The P1 primary current terminal block 2 and the P2 primary current terminal block 9 are copper bars with through holes.

A secondary wiring terminal group 6 is provided on the outer surface of the lower end base of the epoxy resin case 1.

the secondary wiring terminal group 6 comprises two A-phase measurement secondary wiring terminals 6-a, two B-phase measurement secondary wiring terminals 6-B, two C-phase measurement secondary wiring terminals 6-C and two protection secondary wiring terminals 6-o.

Two lead wires of a measuring-level winding 5 on the A mutual sensor 3 are respectively connected with two A-phase measuring-level secondary connecting terminals 6-a. Two leads of the measuring-level winding 5 on the B-phase mutual sensor 13 are respectively connected with two B-phase measuring-level secondary connecting terminals 6-B. Two leads of the primary winding 5 of the phase C mutual inductor 14 are connected to two secondary terminals 6-C of the phase C measuring secondary, respectively. One lead of the secondary protection winding 11 on the mutual inductor A3, one lead of the secondary protection winding 11 on the mutual inductor B13 and one lead of the secondary protection winding 11 on the mutual inductor C14 are connected in parallel and then connected to one protection secondary connecting terminal 6-o. The other lead of the secondary protection winding 11 on the mutual inductor A3, the other lead of the secondary protection winding 11 on the mutual inductor B13 and the other lead of the secondary protection winding 11 on the mutual inductor C14 are connected in parallel and then connected to the other protection secondary connecting terminal 6-o.

The measuring-level magnetic core 4 adopts an iron-based amorphous alloy magnetic core with high magnetic permeability, and the secondary protection-level magnetic core 10 adopts silicon steel with the thickness of 0.27 mm.

the transformer is a three-phase current transformer for incoming wires, the incoming wires at the high-voltage side are fixed on a P1 primary current wiring bar 2 during installation, the outgoing wires are fixed on a P2 primary current wiring bar 9, and the whole transformer is fixed on a switch cabinet body through an installation fixing hole 12. When the high-voltage three-phase current flows through the primary winding 3 during operation, magnetic fields are formed in the measuring-stage magnetic core 4 and the protective-stage magnetic core 10, the magnetic fields respectively form currents in the measuring-stage winding 4 and the secondary protective winding 11, signals are output through the secondary terminal group 6, and the primary winding 3 is provided with the primary winding shielding layer 8 made of semiconductor materials, so that mutual influence among the three-phase currents can be avoided, and the obtained three-phase current signals are accurate. The whole transformer is cast and insulated by epoxy resin and can be used for indoor environmental conditions.

The technical parameters of the mutual inductor are as follows: voltage class: 10 kV;

Current ratio: 50-1000/5;

Grading: 0.2S/10P;

Capacity: 10/15 VA;

Frequency: 50 Hz;

Device class: indoor.