CN216388935U

CN216388935U - Novel Rogowski coil for integrating metering and protection of low-voltage circuit breaker

Info

Publication number: CN216388935U
Application number: CN202220469040.0U
Authority: CN
Inventors: 范建华; 贾鹤; 陈景峰; 丁明亮; 张勋
Original assignee: Qingdao Topscomm Communication Co Ltd
Current assignee: Qingdao Topscomm Communication Co Ltd
Priority date: 2022-03-07
Filing date: 2022-03-07
Publication date: 2022-04-26
Anticipated expiration: 2032-03-07

Abstract

The utility model relates to the technical field of current sensors of low-voltage circuit breakers, and discloses a novel Rogowski coil for integrating metering and protection of a low-voltage circuit breaker. Novel rogowski coil replaces low-voltage circuit breaker's measurement CT and protection CT as measurement and protect function in the current sensor of an organic whole to the realization is to the accurate monitoring of low-voltage circuit breaker busbar circuit heavy current, and then realizes the measurement and the protect function of circuit breaker. The metering and protecting integrated novel Rogowski coil designed by the utility model can completely offset the interference magnetic field generated by equivalent large wire turns without calculating return turns, improves the accuracy of current measurement, can complete wiring by only two layers of PCBs at least, and reduces the design difficulty and cost of the low-voltage circuit breaker.

Description

Novel Rogowski coil for integrating metering and protection of low-voltage circuit breaker

Technical Field

The utility model relates to the technical field of current sensors of low-voltage circuit breakers, in particular to a novel Rogowski coil for integrating metering and protection of a low-voltage circuit breaker.

Background

The low-voltage circuit breaker is an extremely important electrical device in a power distribution link, is also a widely used electrical appliance, and refers to a switching device which can close, bear and break current under normal loop conditions and can close, bear and break current under abnormal loop conditions within a specified time.

The primary side of a Current Transformer (CT) is connected in series in a bus loop of the low-voltage circuit breaker, and the secondary side of the CT is connected in series in a measuring and protecting circuit of the low-voltage circuit breaker to realize the functions of metering and protecting. When the circuit is normal, the circuit breaker monitors the circuit current by means of the metering CT and protects the CT to obtain energy for the main circuit of the circuit breaker. When the circuit has serious overload or short circuit, undervoltage and other faults, the protection CT can also measure the loop current, and the circuit is processed by the main circuit of the circuit breaker to command the switching-on/off mechanism to cut off the loop. Therefore, the CT is required to be able to accurately measure the loop current regardless of whether the loop is normal or not. However, the CT may cause overcurrent saturation due to the magnetic core, which causes deviation of the current of the bus loop of the breaker, and further causes the overcurrent protection of the breaker to be misaligned. In order to solve the problem, at present, a Rogowski coil without a magnetic core is generally adopted to replace a metering CT, so that the situations of overcurrent saturation and inaccurate metering can be avoided.

At present, the Rogowski coil comprises a common Rogowski coil and a PCB Rogowski coil, the common Rogowski coil is wound manually or by a machine, the winding is not uniform enough, and the quality of products in the same batch is uneven. Although the traditional PCB Rogowski coil uses the printed circuit board as a framework to improve the manufacturing accuracy, the radius of a return turn needs to be calculated to be strictly equal to the equivalent radius of an equivalent large turn formed by the Rogowski coil, so that a magnetic field generated by the return turn can just reversely offset an interference magnetic field generated by the equivalent large turn (the interference magnetic field is perpendicular to the plane of the Rogowski coil, namely along the axial direction of the Rogowski coil), and the magnetic field generated by the strictly calculated return turn still cannot completely offset the interference magnetic field. In addition, the conventional PCB Rogowski coil is provided with return turns, so the number of layers of the PCB is at least four, and the practical application cost is higher. Meanwhile, the traditional Rogowski coil has low utilization rate of a PCB (printed Circuit Board) routing line, small routing coverage area and few winding turns, thereby causing low precision.

SUMMERY OF THE UTILITY MODEL

In order to solve the problems, the utility model provides a novel Rogowski coil which is used for integrating metering and protection of a low-voltage circuit breaker.

The purpose of the utility model can be realized by the following technical scheme:

the utility model provides a be used for low voltage circuit breaker measurement and integrative novel rogowski coil of protection, includes anticlockwise PCB rogowski coil and clockwise PCB rogowski coil, and anticlockwise PCB rogowski coil and clockwise PCB rogowski coil superpose each other, print on same circuit board, and wherein printed circuit board is two-layer or multilayer PCB structure, and novel rogowski coil skeleton is annular PCB, and the platykurtic, annular PCB center reservation have the generating line of circuit breaker to walk the line hole. The novel Rogowski coil is provided with PCB through holes, the diameters of all the through holes are the same, two external through holes are reserved on the outermost side of the annular PCB and are used for being connected with an external circuit, one external through hole is a wire inlet hole, and the other external through hole is a wire outlet hole; all via holes except the wire inlet hole and the wire outlet hole are mounting holes, and the mounting holes are divided into an outer ring mounting hole, a middle ring mounting hole, a secondary inner ring mounting hole and an inner ring mounting hole.

Furthermore, the novel Rogowski coil is provided with a PCB wiring, the wiring is distributed on the top layer and the bottom layer of the PCB, and the top layer wiring and the bottom layer wiring are sequentially connected through the mounting holes.

Furthermore, the novel Rogowski coil is provided with 3N-1 or 3N outer ring mounting holes, and the mounting holes are arranged on an outer ring circle which takes the center of the bus wire routing hole as the circle center at an equal angle of 120/N degrees; the number of the middle ring mounting holes, the number of the secondary inner ring mounting holes and the number of the inner ring mounting holes are N, the middle ring mounting holes, the secondary inner ring mounting holes and the number of the inner ring mounting holes are arranged on different circles which take the center of the bus wire routing hole as the circle center at equal angles of 360/N degrees, and the radiuses of the circles are different; the middle ring mounting holes are located near the middle position of the annular PCB, and the mounting holes of the two innermost rings are close to each other as much as possible but do not contact with each other, so that more routing wires can be contained, and the number of turns is increased.

Furthermore, the turns of the counterclockwise PCB Rogowski coil are equal to those of the clockwise PCB Rogowski coil.

Further, the counterclockwise PCB rogowski coil and the clockwise PCB rogowski coil are connected in series only at the tail and the head.

Furthermore, the metering CT and the protection CT of the low-voltage circuit breaker are replaced by the novel Rogowski coil, metering and protection integration is realized, a low-voltage circuit breaker loop bus passes through a bus wire routing hole reserved by the novel Rogowski coil, an alternating current induction voltage signal is induced on the novel Rogowski coil at the moment, and the signal sequentially passes through a wire inlet hole, an anticlockwise PCB Rogowski coil, a clockwise PCB Rogowski coil and a wire outlet hole.

The beneficial technical effects of the utility model are as follows:

through the measurement CT and the protection CT that replace low-voltage circuit breaker, can realize measurement and protection integration, save circuit breaker structural space, the structure is small and exquisite, can solve the problem of measuring in the narrow and small space of low-voltage circuit breaker to low-voltage circuit breaker lightweight design.

Compare traditional PCB Rogowski coil, novel Rogowski coil need not to calculate the radius that returns the circle, and convenient design, the produced interference magnetic field of anticlockwise PCB Rogowski coil and clockwise PCB Rogowski coil can offset each other along coil axial both ends, can also improve low voltage circuit breaker's measurement accuracy and sensitivity through improving the wire winding number of turns.

Drawings

Fig. 1 is a structural schematic diagram of a novel metering and protecting integrated rogowski coil for a low-voltage circuit breaker.

Fig. 2 is a schematic diagram of a counterclockwise PCB rogowski coil structure of the present invention.

Fig. 3 is a schematic diagram of the clockwise PCB rogowski coil structure of the present invention.

Reference numerals: the bus-bar wiring hole is 1, the wire inlet hole is 2, the wire outlet hole is 3, the outer ring mounting hole is 4, the middle ring mounting hole is 5, the secondary inner ring mounting hole is 6, the inner ring mounting hole is 7, the top layer wiring is 8, the bottom layer wiring is 9, the tail part is 10, and the head part is 11.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the utility model and do not limit the utility model.

Example 1:

as shown in fig. 1, a novel rogowski coil for integrating metering and protection of a low-voltage circuit breaker comprises a counterclockwise PCB rogowski coil, a clockwise PCB rogowski coil, an amplifying circuit module, an integrating circuit module, a blocking circuit module, a metering module and a protection module.

The novel Rogowski coil is formed by mutually overlapping a counterclockwise PCB Rogowski coil and a clockwise PCB Rogowski coil, and is finally printed and manufactured on the same PCB.

The novel Rogowski coil is manufactured into a printed circuit board shape and is of a two-layer PCB structure, as shown in figure 1, the whole novel Rogowski coil framework is an annular PCB and is flat, and a bus wiring hole 1 of a circuit breaker is reserved in the center so that a lead of a measured bus loop current can pass through.

The novel Rogowski coil is provided with PCB through holes, wherein the diameters of all the through holes are the same, and only the outermost side of the annular PCB is reserved with two external through holes for being connected with an external circuit. One is a wire inlet hole 2 and one is a wire outlet hole 3. All the through holes except one wire inlet hole 2 and one wire outlet hole 3 are mounting holes, wherein the mounting holes are divided into an outer ring mounting hole 4, a middle ring mounting hole 5, a secondary inner ring mounting hole 6 and an inner ring mounting hole 7.

The novel Rogowski coil is provided with a PCB (printed Circuit Board) wire which is distributed on the top layer and the bottom layer of a two-layer plate of the PCB, as shown in figure 1, a solid line is a top layer wire 8, a dotted line is a bottom layer wire 9, and the top layer wire 8 and the bottom layer wire 9 are only connected in sequence through mounting holes.

The novel Rogowski coil is shown in figure 1, wherein the number of the outer ring mounting holes 4 is 35, and the mounting holes are arranged on an outer ring circle which takes the center of the bus wiring hole 1 as the circle center at an equal angle of 10 degrees, so as to achieve the purpose of coil symmetry. The number of the middle ring mounting holes 5, the number of the secondary inner ring mounting holes 6 and the number of the inner ring mounting holes 7 are 12, the middle ring mounting holes, the secondary inner ring mounting holes and the inner ring mounting holes are arranged on different circles which take the center of the bus wiring hole 1 as the center of a circle at equal angles of 30 degrees, the radiuses of the circles are different, and the circles are selected according to specific conditions. The middle ring mounting hole 5 is located near the middle position of the annular PCB, the purpose of placing the middle ring mounting hole 5 at the proper position of the annular PCB is to utilize the space between turns of the coil and utilize the narrow PCB space to the maximum extent, and the mounting holes of the two innermost rings are close to each other as much as possible but are not contacted so as to accommodate more routing, increase the number of turns and improve the measurement sensitivity and precision of the coil.

The forward direction of the winding of the anticlockwise PCB Rogowski coil is anticlockwise, namely the trend of current in the coil, the current flows from the wire inlet hole 2 to one via hole of the inner ring mounting hole 7 connected with the solid line through the solid line (namely PCB top layer routing), flows to the PCB bottom layer through the via hole, is transmitted to one via hole of the outer ring mounting hole 4 connected with the dotted line through the dotted line (namely PCB bottom layer routing), flows to the solid line (namely PCB top layer) again, and then is taken as circulation to move anticlockwise to the tail part 10 of the anticlockwise PCB Rogowski coil and flow out.

The forward direction of the winding of the clockwise PCB Rogowski coil is clockwise, namely the trend of current in the coil, the current flows from the head 11 of the clockwise PCB Rogowski coil to one of the through holes of the outer ring mounting hole 4 along the periphery of the coil through a dotted line (namely PCB bottom layer routing), flows to the top layer of the PCB through the through hole, is transmitted to one of the through holes of the inner ring mounting hole 7 through a solid line (namely PCB top layer routing), flows to the dotted line (namely PCB bottom layer) again, and then the current is taken as circulation to continuously and clockwise advance to the outlet hole 3 of the clockwise PCB Rogowski coil to flow out.

The turns of the counterclockwise PCB Rogowski coil and the clockwise PCB Rogowski coil are equal, when the turns of the coils are increased, the better the symmetry of the counterclockwise PCB Rogowski coil and the clockwise PCB Rogowski coil is, the interference magnetic field can be completely offset, the measurement precision can be improved accordingly, and the turns of the counterclockwise PCB Rogowski coil and the clockwise PCB Rogowski coil are increased as much as possible during manufacturing.

The counterclockwise PCB rogowski coil and the clockwise PCB rogowski coil are not connected at any other places except for the tail 10 and the head 11 which are connected in series. As shown in fig. 2, corresponds to winding a rogowski coil without return turns counterclockwise. As shown in fig. 3, a rogowski coil without a return turn is wound clockwise, the length of the connected novel rogowski coil is twice as long as that of the original rogowski coil, and the directions of interference magnetic fields generated by the counterclockwise PCB rogowski coil and the clockwise PCB rogowski coil which are symmetrically designed are just opposite to each other, and the interference magnetic fields are directly counteracted.

Novel luo shi coil replaces low-voltage circuit breaker's measurement CT and protection CT, realizes measurement and protection integration, and low-voltage circuit breaker return circuit generating line passes novel luo shi coil and reserves generating line wiring hole 1, and the induction of this moment goes up the alternating current induced voltage signal on the novel luo shi coil, and the signal loops through entrance hole 2, anticlockwise PCB luo shi coil, clockwise PCB luo shi coil and wire hole 3.

The amplifying circuit module amplifies the alternating current induction voltage output by the novel Rogowski coil.

And the integration circuit module performs integration processing on the amplified alternating current induction voltage signal and restores the amplified alternating current induction voltage signal into a current signal of a tested loop bus.

And the DC blocking circuit module filters and restores DC components in the loop current.

The metering module processes the current signal of the detected loop with the direct-current component filtered out, and is used for metering voltage and current, filtering and the like of the circuit breaker.

And the protection module processes the detected loop current signal with the direct-current component filtered out for relay protection of the circuit breaker.

The above-mentioned embodiments are illustrative of the specific embodiments of the present invention, and are not restrictive, and those skilled in the relevant art can make various changes and modifications to obtain corresponding equivalent technical solutions without departing from the spirit and scope of the present invention, so that all equivalent technical solutions should be included in the scope of the present invention.

Claims

1. A novel Rogowski coil for integrating metering and protection of a low-voltage circuit breaker is characterized in that the novel Rogowski coil comprises a counterclockwise PCB Rogowski coil and a clockwise PCB Rogowski coil, the counterclockwise PCB Rogowski coil and the clockwise PCB Rogowski coil are mutually superposed and printed on the same circuit board, the printed circuit board is of a two-layer or multi-layer PCB structure, a framework of the novel Rogowski coil is an annular PCB which is flat, and a bus wiring hole of the circuit breaker is reserved in the center of the annular PCB;

the novel Rogowski coil is provided with PCB through holes, the diameters of all the through holes are the same, two external through holes are reserved on the outermost side of the annular PCB and are used for being connected with an external circuit, one external through hole is a wire inlet hole, and the other external through hole is a wire outlet hole; all via holes except the wire inlet hole and the wire outlet hole are mounting holes, and the mounting holes are divided into an outer ring mounting hole, a middle ring mounting hole, a secondary inner ring mounting hole and an inner ring mounting hole.

2. The novel Rogowski coil for low-voltage circuit breaker measurement and protection integration according to claim 1, wherein the novel Rogowski coil is provided with PCB traces, the traces are distributed on the top layer and the bottom layer of the PCB, and the top layer trace and the bottom layer trace are sequentially connected only through mounting holes.

3. The novel Rogowski coil for the metering and protecting of the low-voltage circuit breaker is integrated as claimed in claim 1 or 2, and is characterized in that the novel Rogowski coil is provided with 3N-1 or 3N outer ring mounting holes, and the mounting holes are arranged on an outer ring circle which takes the center of a bus wire routing hole as a circle center at an equal angle of 120/N degrees; the number of the middle ring mounting holes, the number of the secondary inner ring mounting holes and the number of the inner ring mounting holes are N, the middle ring mounting holes, the secondary inner ring mounting holes and the number of the inner ring mounting holes are arranged on different circles which take the center of the bus wire routing hole as the circle center at equal angles of 360/N degrees, and the radiuses of the circles are different; the middle ring mounting holes are located near the middle position of the annular PCB, and the mounting holes of the two innermost rings are close to each other as much as possible but do not contact with each other, so that more routing wires can be contained, and the number of turns is increased.

4. The integrated new rogowski coil for metering and protection of low-voltage circuit breakers according to claim 3, characterized in that said counter-clockwise and clockwise PCB rogowski coils have equal number of turns.

5. A novel Rogowski coil for metering and protection integration of a low voltage circuit breaker according to claim 4, wherein the counterclockwise PCB Rogowski coil and the clockwise PCB Rogowski coil are connected in series only at the tail and the head.