阅读说明：本技术 三相电流合成型零序互感器 (Three-phase current synthesis type zero sequence 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：三相电流合成型零序互感器,包括绝缘壳体,其上开设三相穿线孔。A相穿线孔外侧的绝缘壳体内有A相电流线圈,A相电流线圈包括A相铁芯、外侧的A相电流线圈绕组和A相电流线圈绕组外侧的A相电流线圈绕组外屏蔽层。B相和C相处结构相同。三相电流线圈绕组的始端连接在一起,三相电流线圈绕组的末端连接在一起,对应连接二次接线端子。本型电流互感器为全封闭一体式结构,三相分相穿电缆,每相有独立绕组线圈,单独每一相电流信号可达到计量级精度,再进行三相电流合成,从而提高产品自身精度。可实现零序电流高精度监测,产品本体采用户内环氧树脂浇注绝缘,符合10～35kV系统零序电流互感器使用要求。(A three-phase current synthesis type zero sequence mutual inductor comprises an insulating shell, wherein three-phase threading holes are formed in the insulating shell. A phase A current coil is arranged in the insulating shell on the outer side of the phase A threading hole, and comprises a phase A iron core, a phase A current coil winding on the outer side and a phase A current coil winding outer shielding layer on the outer side of the phase A current coil winding. The structures of the B phase and the C phase are the same. The starting ends of the three-phase current coil windings are connected together, and the tail ends of the three-phase current coil windings are connected together and correspondingly connected with the secondary wiring terminals. The current transformer is of a totally-enclosed integrated structure, three phases are split in phase and penetrate through a cable, each phase is provided with an independent winding coil, each phase of current signal can reach the metering level precision independently, and then three-phase current synthesis is carried out, so that the precision of a product is improved. The high-precision monitoring of the zero-sequence current can be realized, the product body is insulated by adopting indoor epoxy resin casting, and the use requirement of the zero-sequence current transformer of a 10-35 kV system is met.)

1. The three-phase current synthesis type zero sequence transformer comprises an insulating shell (8); the method is characterized in that:

three holes are uniformly formed in the circumference of the surface of the insulating shell (8), namely an A-phase threading hole (2), a B-phase threading hole (9) and a C-phase threading hole (10);

an A-phase current coil is arranged in the insulating shell (8) at the outer side of the A-phase threading hole (2), and the A-phase threading hole (2) is positioned at the inner side of the A-phase current coil;

the A-phase current coil comprises an A-phase iron core (5), an A-phase current coil winding (1) on the outer side and an A-phase current coil winding outer shielding layer (7) on the outer side of the A-phase current coil winding (1);

a B-phase current coil is arranged in the insulating shell (8) at the outer side of the B-phase threading hole (9), and the B-phase threading hole (9) is positioned at the inner side of the B-phase current coil;

the B-phase current coil comprises a B-phase iron core (12), an outer B-phase current coil winding (11) and an outer B-phase current coil winding shielding layer (13) outside the B-phase current coil winding (11);

a C-phase current coil is arranged in the insulating shell (8) at the outer side of the C-phase threading hole (10), and the C-phase threading hole (10) is positioned at the inner side of the C-phase current coil;

the C-phase current coil comprises a C-phase iron core, a C-phase current coil winding (6) on the outer side and a C-phase current coil winding outer shielding layer on the outer side of the C-phase current coil winding (6);

the starting end of the C-phase current coil winding (6), the starting end of the B-phase current coil winding (11) and the starting end of the A-phase current coil winding (1) are connected together and connected with one end of the secondary wiring terminal (4);

the tail end of the C-phase current coil winding (6), the tail end of the B-phase current coil winding (11) and the tail end of the A-phase current coil winding (1) are connected together and connected with the other end of the secondary connecting terminal (4).

2. The three-phase current synthesis type zero-sequence transformer of claim 1, characterized in that:

the circumferential edge of the disk surface of the insulating shell (8) is provided with a plurality of mounting holes (3).

3. The three-phase current synthesis type zero-sequence transformer of claim 1, characterized in that: the insulating shell (8) is an epoxy resin insulating shell.

4. The three-phase current synthesis type zero-sequence transformer of claim 1, characterized in that: the A-phase iron core (5), the B-phase iron core (12) and the C-phase iron core are composite iron cores formed by alternately laminating silicon steel sheets and microcrystalline alloy sheets.

5. The three-phase current synthesis type zero-sequence transformer of claim 4, characterized in that: the thickness of the silicon steel sheet is 0.23mm, and the thickness of the microcrystal alloy sheet is 0.23 mm.

6. The three-phase current synthesis type zero-sequence transformer of claim 1, characterized in that: the A-phase iron core (5), the B-phase iron core (12) and the C-phase iron core are all annular iron cores;

the A-phase threading hole (2), the B-phase threading hole (9) and the C-phase threading hole (10) are all round holes.

Technical Field

The invention belongs to the field of mutual inductors, and particularly relates to a three-phase current synthesis type zero-sequence mutual inductor.

Background

When the existing zero-sequence current transformer is used, a three-phase cable simultaneously penetrates through the same current coil, the zero-sequence current of a line is monitored by utilizing the principle that the three-phase current generates magnetic potential balance, and a secondary signal of a product of the principle is high in excitation loss due to the inherent principle of the secondary signal, so that high-precision measurement is difficult to achieve.

Disclosure of Invention

The invention aims to provide a three-phase current synthesis type zero-sequence transformer, wherein three phases are split and penetrate through a cable, each phase current signal can reach the metering level precision independently, and then three-phase current synthesis is carried out.

The technical scheme is as follows:

a three-phase current synthesis type zero sequence mutual inductor comprises an insulating shell.

The technical key points are as follows:

three round holes are uniformly formed in the circumference of the surface of the insulating shell, namely an A-phase threading hole, a B-phase threading hole and a C-phase threading hole.

An A-phase current coil is arranged in the insulating shell outside the A-phase threading hole, and the A-phase threading hole is located on the inner side of the A-phase current coil.

The A-phase current coil comprises an A-phase iron core, an outer A-phase current coil winding and an outer A-phase current coil winding shielding layer outside the A-phase current coil winding.

A B-phase current coil is arranged in the insulating shell outside the B-phase threading hole, and the B-phase threading hole is positioned inside the B-phase current coil.

The B-phase current coil comprises a B-phase iron core, an outer B-phase current coil winding and an outer B-phase current coil winding shielding layer outside the B-phase current coil winding.

And a C-phase current coil is arranged in the insulating shell outside the C-phase threading hole, and the C-phase threading hole is positioned inside the C-phase current coil.

The C-phase current coil comprises a C-phase iron core, an outer C-phase current coil winding and an outer C-phase current coil winding shielding layer outside the C-phase current coil winding.

The starting end of the C-phase current coil winding, the starting end of the B-phase current coil winding and the starting end of the A-phase current coil winding are connected together and connected with one end of the secondary connecting terminal.

The tail end of the C-phase current coil winding, the tail end of the B-phase current coil winding and the tail end of the A-phase current coil winding are connected together and connected with the other end of the secondary wiring terminal.

The A-phase iron core, the B-phase iron core and the C-phase iron core can be composite iron cores formed by alternately laminating silicon steel sheets and microcrystalline alloy sheets.

The advantages are that:

the current transformer is of a totally-enclosed integrated structure, three phases are split in phase and penetrate through a cable, each phase is provided with an independent winding coil, each phase of current signal can reach the metering level precision independently, and then three-phase current synthesis is carried out, so that the precision of a product is improved. The high-precision monitoring of the zero sequence current can be realized, the product can be directly fixed at a lower wire inlet of a switch cabinet in a split-phase threading mode of a three-phase cable without additionally reserving a position for installation, and the product body is cast and insulated by indoor epoxy resin and meets the use requirement of a 10-35 kV system zero sequence current transformer.

Drawings

Fig. 1 is a front view of the present invention.

Fig. 2 is a cross-sectional view taken along line D-D in fig. 1.

Fig. 3 is a schematic circuit diagram.

Fig. 4 is a front view of the outer shape.

Fig. 5 is a profile side view.

The phase-A current coil winding comprises a phase-A current coil winding 1, a phase-A threading hole 2, a mounting hole 3, a secondary wiring terminal 4, a phase-A iron core 5, a phase-C current coil winding 6, a phase-A current coil winding outer shielding layer 7, an insulating shell 8, a phase-B threading hole 9, a phase-C threading hole 10, a phase-B current coil winding 11, a phase-B iron core 12 and a phase-B current coil winding outer shielding layer 13.

Detailed Description

The three-phase current synthesis type zero sequence transformer comprises an insulating shell 8.

The insulating shell 8 is in a disc shape, three round holes are uniformly formed in the circumference of the disc surface, and the three round holes are an A-phase threading hole 2, a B-phase threading hole 9 and a C-phase threading hole 10 respectively.

An A-phase current coil is arranged in the insulating shell 8 at the outer side of the A-phase threading hole 2, and the A-phase threading hole 2 is positioned at the inner side of the A-phase current coil.

The A-phase current coil comprises a circular A-phase iron core 5, an A-phase current coil winding 1 and an A-phase current coil winding outer shielding layer 7. The A-phase threading hole 2 and the A-phase iron core 5 are arranged concentrically.

The phase A iron core 5 is wound with a phase A current coil winding 1, and the outer side of the phase A current coil winding 1 is provided with a phase A current coil winding outer shielding layer 7.

A B-phase current coil is arranged in the insulating shell 8 outside the B-phase threading hole 9, and the B-phase threading hole 9 is positioned inside the B-phase current coil.

The B-phase current coil comprises a circular B-phase iron core 12, a B-phase current coil winding 11 and a B-phase current coil winding outer shielding layer 13. The B-phase threading hole 9 and the B-phase iron core 12 are arranged concentrically.

The phase B iron core 12 is wound with a phase B current coil winding 11, and a phase B current coil winding outer shielding layer 13 is arranged outside the phase B current coil winding 11.

A C-phase current coil is arranged in the insulating shell 8 at the outer side of the C-phase threading hole 10, and the C-phase threading hole 10 is located at the inner side of the C-phase current coil.

The C-phase current coil comprises a circular C-phase iron core, a C-phase current coil winding 6 and a C-phase current coil winding outer shielding layer. The C-phase threading hole 10 and the C-phase iron core are concentrically arranged.

And a C-phase current coil winding 6 is wound on the C-phase iron core, and an outer shielding layer of the C-phase current coil winding is arranged on the outer side of the C-phase current coil winding 6.

The a terminal (start terminal) of the C-phase current coil winding 6, the a terminal (start terminal) of the B-phase current coil winding 11, and the a terminal (start terminal) of the a-phase current coil winding 1 are connected together, and the S1 terminal of the secondary connection terminal 4 is connected.

The B-terminal (end) of the C-phase current coil winding 6, the B-terminal (end) of the B-phase current coil winding 11, and the B-terminal (end) of the a-phase current coil winding 1 are connected together, and the S2 terminal of the secondary connection terminal 4 is connected.

That is, the a-phase current coil winding 1, the B-phase current coil winding 11, and the C-phase current coil winding 6 are connected in parallel.

The secondary connection terminal 4 is located on the surface of the insulating housing 8. The periphery edge of the disk surface of the insulating shell 8 is provided with a plurality of mounting holes 3. The insulating housing 8 is an epoxy insulating housing.

The phase A iron core 5, the phase B iron core 12 and the phase C iron core are composite iron cores of silicon steel sheets and microcrystalline alloy sheets, the silicon steel and the microcrystalline alloy sheets are commercially known materials, and the silicon steel sheets (with the thickness of 0.23 mm) and the microcrystalline alloy sheets (with the thickness of 0.23 mm) are alternately laminated to obtain the iron core. The thick silicon steel and amorphous alloy composite iron core is adopted, the sensitivity can be ensured when the zero-sequence fault current is very small, and the failure of the relay protection device caused by saturation can be prevented when the instantaneous fault current is too large.

The A-phase cable passes through the A-phase threading hole 2, the B-phase cable passes through the B-phase threading hole 9, and the C-phase cable passes through the C-phase threading hole 10.

The principle of the product is that current is synthesized into zero sequence current value when three-phase current is normal, and when the three-phase current of the circuit is unbalanced, current balance is broken, and then zero sequence current is generated to monitor the state of the circuit.

This product is that the three-phase cable divides the hole to pass and wears a hole simultaneously than original with parameter three-phase cable and has reduced alternate interference, and mounting hole 3 is the circumference overall arrangement, and is the same with the cable trend, and the direct inlet that can fix under the cubical switchboard.

Each phase of current coil winding is provided with an outer shielding layer, so that the inaccuracy of a zero sequence signal caused by mutual influence caused by a three-phase current alternating magnetic field is prevented.

This product is zero sequence current transformer for the inlet wire, and the three-phase cable passes from the cable through wires hole that corresponds respectively, and the inlet wire hole under the cubical switchboard is fixed through a plurality of mounting holes 3 to the product body (insulating housing 8). When the circuit is normal, the current generated by each phase of current coil winding is the same, the signal parallel composite magnitude value output by the three phases is zero, and no signal is output by the secondary wiring terminal 4. When the three-phase currents are inconsistent, the original three-phase synthesis is broken, unbalanced currents occur at the secondary output terminal 4, the current coil comprises an iron core, a current coil winding and a current coil winding outer shielding layer (the material of the outer shielding layer is a conventional known material), the current coil winding outer shielding is used for preventing the three phases from being influenced mutually, the synthetic value of the three-phase currents is accurate, the whole product is cast and formed by epoxy resin to serve as an insulating shell 8, the insulating edge of a 10-35 kV line is met, and the indoor environment condition is met.

The technical parameters are as follows: voltage class: 10-35 kV, current ratio: 20-150/1, grade: class 0.2S, capacity: 5VB, frequency: 50/60Hz, device class: indoor.