Electronic tripping section of a circuit breaker

Abstract

The present invention relates to an electronic tripping unit for a circuit breaker, and more particularly to an electronic tripping unit for a circuit breaker having a phase interference prevention function. According to the electronic tripping unit for a circuit breaker according to one embodiment of the present invention, a magnetic field absorbing material is provided to cover the Rogowski coil in the current detection unit, so that the magnetic field does not spread to adjacent phases.

Description

Technical Field

[0001] The present invention relates to an electronic trip unit of a molded case circuit breaker, and more particularly, to an electronic trip unit of a molded case circuit breaker having an inter-phase current interference prevention function.

Background Art

[0002] Generally, a molded case circuit breaker (MCCB) is an electrical device that automatically interrupts a circuit to protect the circuit and loads in the event of an electrical overload or short-circuit accident. It generally comprises a terminal portion connected to the power side or the load side, a contact portion composed of a fixed contact and a movable contact, an opening / closing mechanism portion that provides driving force to mechanically bring the movable contact into contact with the fixed contact, a trip portion that detects overcurrent or short-circuit current generated in the circuit and induces the tripping operation of the opening / closing mechanism portion, and an arc extinguishing portion that extinguishes an arc generated when an abnormal current is interrupted.

[0003] FIG. 1 is a longitudinal sectional view of a conventional molded case circuit breaker. The conventional molded case circuit breaker comprises, inside a casing 1 formed of an insulating material, fixed contacts 2a, 2c and a movable contact 2b which constitute a contact portion provided for connecting or interrupting a circuit from the power side to the load side, an opening / closing mechanism portion 3 that provides power for rotating the movable contact 2b, an arc extinguishing portion 4 provided for extinguishing an arc generated when a fault current is interrupted, and a detection mechanism portion that detects abnormal current. Here, the detection mechanism portion is composed of an electronic trip unit 5.

[0004] FIG. 2 is a perspective view of a conventional electronic trip unit 5. The electronic trip unit is composed of a trip stator 6 that supplies current from the load-side fixed contact 2c to a current transformer (CT) 7, a current transformer 7 that converts the supplied current into a small current, a current transformer accommodating portion 8, and a control unit (PCB) 9 that drives a circuit by the current converted by the current transformer 7 and activates a trip coil (not shown) when an abnormal current occurs.

[0005] When an abnormal current occurs in circuit 10, the trip coil, having received a control signal from the control unit 9, activates the switching mechanism 3 to interrupt the circuit. The circuit breaker trips, and the arc (ARC) is extinguished in the arc extinguishing unit 4.

[0006] Figure 3 is a block diagram showing the fault current interruption mechanism.

[0007] In the electronic trip unit 5, the parts mainly related to the current detection function consist of a current detection unit (Signal CT) 7a, a power generation unit (Power CT) 7b, and a control unit 9.

[0008] The control unit 9 operates on power supplied from the power generation unit 7b. The control unit 9 determines whether or not there is a fault based on the magnitude and phase of the current input from the current detection unit 7a, activates the trip coil, activates the switching mechanism unit 3, and shuts off the circuit. Thus, it plays the role of separating and shutting off the faulty section from the healthy section in the circuit.

[0009] Here, the control unit 9 measures the amount of electricity using the current detection unit 7a and voltage generation unit 7c of the electronic trip unit 5, and then makes a determination of the fault current based on that measurement. These data require high measurement accuracy so that they can replace the metering and measuring instruments of the power system.

[0010] However, in the current transformer 7, errors in current measurement may occur due to interference between phase currents.

[0011] The current transformer 7 will be explained in more detail below.

[0012] The current detection unit 7a and the power generation unit 7b have a structure through which the busbar (either the R phase, S phase, or T phase) of the circuit 10 passes.

[0013] As shown in Figure 4, the current detection unit 7a uses a Rogowskii coil, which has the advantages of being small in size and not having saturation characteristics.

[0014] Conversely, the power generation unit 7b uses a CT with an iron core having saturation characteristics, as shown in Figure 5. Typically, the current detection unit 7a and the power generation unit 7b are configured as shown in Figures 6a and 6b at the same location through which the busbar passes, in order to effectively utilize the small size of the circuit breaker, and are arranged as shown in Figure 7 according to the number of poles of the circuit breaker (three in the case of three phase).

[0015] Within the small size of a circuit breaker, the current flowing through each phase distorts the magnitude and phase of the current in other phases. This phenomenon is called inter-phase current interference, and it must be eliminated to improve measurement accuracy.

[0016] In order to reduce such inter-phase current interference phenomena, conventional techniques have involved managing various factors such as uniform winding control of the Rogowski coil, control of the start and end points of the Rogowski coil winding, and separation of lead wires. However, these methods have the drawback of increasing the manufacturing time of the current transformer and making the equipment more complex, and therefore do not have a significant effect in reducing inter-phase current interference phenomena in practice.

[0017] As a prior art document related to the present invention, Patent Document 1, "Circuit Breaker for Wiring," is disclosed. [Prior art documents] [Patent Documents]

[0018] [Patent Document 1] Korean Registered Utility Model Publication No. 20-0487464 [Overview of the project] [Problems that the invention aims to solve]

[0019] The present invention was made to solve the above problems and aims to provide an electronic tripping unit for a circuit breaker that reduces interphase interference caused by the magnetic fields of adjacent phases and minimizes errors in the measured current. [Means for solving the problem]

[0020] An electronic trip unit of a wiring breaker according to an embodiment of the present invention, wherein the wiring breaker has a circuit connected from a power supply side to a load side, and an alternating current having a plurality of phases flows through the circuit, wherein each of the plurality of phases is provided with a current transformer for measuring the alternating current, the current transformer includes a current detection unit that measures the current of any one of the plurality of phases on which the current transformer is installed, and the current detection unit is provided with a magnetic field absorbing material that absorbs a magnetic field generated in the any phase to prevent the magnetic field from spreading to other phases.

[0021] Here, the current transformer further includes a power generation unit that generates a voltage by an induced electromotive force generated in any one of the plurality of phases on which the current transformer is installed.

[0022] The electronic trip unit further includes a control unit that operates by receiving power supplied from the power generation unit, and cuts off the circuit when it is determined that a current signal transmitted from the current detection unit is a fault current.

[0023] Furthermore, a trip unit case forming a housing of the electronic trip unit is provided with a current transformer accommodating portion that accommodates the current transformer.

[0024] Furthermore, the current transformer accommodating portion is provided with a connection conductor insertion portion in which a connection conductor connected to the circuit is installed.

[0025] Furthermore, the current detection unit includes a Rogowski coil having a through hole, and a first magnetic field absorbing material that covers the Rogowski coil among the magnetic field absorbing materials.

[0026] Furthermore, the current detection unit further includes a first magnetic field absorbing material fixing member fixed to the current transformer accommodating portion, the Rogowski coil is accommodated inside the fixing member, and the first magnetic field absorbing material is installed outside the fixing member.

[0027] Further, a current transformer mounting portion is protruded from the current transformer accommodating portion, and a central hole into which the current transformer mounting portion is fitted is formed in the first magnetic field absorbing material fixing member.

[0028] Further, the first magnetic field absorbing material fixing member has a front surface portion and a side surface portion, and the side surface portion has a curved surface portion and a flat surface portion.

[0029] Further, an inner diameter of the central hole is formed to be smaller than an inner diameter of the Rogowski coil.

[0030] Further, a width of a side surface portion of the first magnetic field absorbing material fixing member is formed to be larger than a width of a side surface portion of the Rogowski coil.

[0031] Further, the Rogowski coil, the first magnetic field absorbing material fixing member and the first magnetic field absorbing material are coupled to each other by a molding method.

[0032] Further, the power generating portion includes an iron core and a coil, and the magnetic field absorbing material includes a second magnetic field absorbing material covering the iron core and the coil.

[0033] Further, the magnetic field absorbing material is formed of a material with high magnetic permeability.

[0034] Further, the magnetic field absorbing material is formed of permalloy or Nano-crystalline.

Effect of the Invention

[0035] According to the electronic trip unit of a wiring circuit breaker according to an embodiment of the present invention, since the current detecting portion is provided with the magnetic field absorbing material covering the Rogowski coil, the spread of a magnetic field to adjacent phases is prevented.

[0036] Further, since the power generating portion is provided with the magnetic field absorbing material covering the iron core and the coil, the spread of a magnetic field to adjacent phases is prevented.

[0037] Therefore, when an abnormal current occurs in the circuit, current measurement errors due to interphase interference are minimized.

[0038] Furthermore, since inter-phase interference is prevented, the inter-phase distance can be shortened, and the overall size can be reduced. [Brief explanation of the drawing]

[0039] [Figure 1] This is a longitudinal cross-sectional view of a conventional circuit breaker. [Figure 2] This is a perspective view of an electronic tripping mechanism applied to a conventional circuit breaker. [Figure 3] This is a block diagram of a conventional electronic trip unit. [Figure 4] This diagram shows the current detection section of a conventional electronic tripping device. [Figure 5a] This diagram shows the power generation section of a conventional electronic trip circuit. [Figure 5b] This diagram shows the power generation section of a conventional electronic trip circuit. [Figure 6a] This diagram shows a current transformer in an electronic trip section using conventional technology. [Figure 6b] This diagram shows a current transformer in an electronic trip section using conventional technology. [Figure 7] This diagram shows a conventional electronic trip section with a current transformer installed, and the occurrence of phase interference. [Figure 8] This is a longitudinal cross-sectional view of a circuit breaker according to one embodiment of the present invention. [Figure 9] This is a perspective view of an electronic tripping unit applied to a circuit breaker according to one embodiment of the present invention. [Figure 10] This is a perspective view of an electronic tripping unit applied to a circuit breaker according to one embodiment of the present invention. [Figure 11] Figure 10 is a separated perspective view of the electronic tripping unit. [Figure 12] This is a rear view of the electronic trip unit. The electronic trip unit cover has been removed. [Figure 13] This is a perspective view of a current transformer applied to the electronic trip section of the present invention. [Figure 14] Figure 13 is a separated perspective view of the current detection unit. [Figure 15] Figure 13 is a separated perspective view of the power generation unit. [Modes for carrying out the invention]

[0040] Preferred embodiments of the present invention will be described below with reference to the attached drawings. However, this is intended to describe the invention in enough detail that a person with ordinary skill in the art to which the present invention pertains can easily carry it out, and it does not limit the technical idea or scope of the present invention.

[0041] In this invention, the terms "member" or "part" used to indicate a component are not used for any specific purpose and may be omitted.

[0042] The electronic tripping sections of the circuit breakers according to each embodiment of the present invention will be described in detail below with reference to the drawings. Figure 8 is a longitudinal cross-sectional view of a circuit breaker according to one embodiment of the present invention, and Figures 9 and 10 are perspective views of the electronic tripping section applied to the circuit breaker according to one embodiment of the present invention. Figure 11 is a separated perspective view of the electronic tripping section of Figure 10.

[0043] An electronic tripping unit for a circuit breaker according to one embodiment of the present invention is applied to a circuit breaker through which an alternating current having multiple phases R, S, and T flows from the power source P side to the load L side, wherein each of the multiple phases R, S, and T is provided with a current transformer 300 for measuring the alternating current, and the current transformer 300 includes a current detection unit 310 that detects (senses) the current of any of the multiple phases R, S, and T on which the current transformer 300 is installed, and a power generation unit 350 that generates a voltage due to the induced electromotive force generated in any of the phases, and the current detection unit 310 or the power generation unit 350 is provided with magnetic field absorbing materials 330 and 370 that absorb the magnetic field generated in any of the phases and prevent it from spreading to other phases.

[0044] Figure 8 is a longitudinal cross-sectional view of a circuit breaker 100 according to one embodiment of the present invention.

[0045] The basic configuration of the circuit breaker according to the present invention is the same as that of a general circuit breaker.

[0046] The circuit breaker is provided with a housing 101 made of an insulating material. The housing 101 houses and supports the components inside.

[0047] Contact points are provided inside the housing 101 for connecting or disconnecting the circuit from the power supply side to the load side. The contact points include fixed contacts 111 and 112 and a movable contact 113 that moves toward and away from them.

[0048] The opening / closing mechanism 120, located above the contact point, supplies power to rotate the movable contact 113.

[0049] The arc extinguishing section 130 is provided to extinguish the arc that occurs when the fault current is interrupted.

[0050] Furthermore, a detection and tripping unit for detecting abnormal currents is provided. Here, the detection and tripping unit consists of an electronic tripping unit 200.

[0051] Here, the trip unit 200 includes a trip unit stator 198 and a connecting conductor 220 connected to the fixed contact 112, a current transformer 300 that converts the current flowing through the connecting conductor 220, and a control unit 240 that operates using the current supplied from the current transformer 300 to operate the switching mechanism unit 120.

[0052] Figures 9 and 10 are perspective views of the electronic trip unit. Figure 9 shows the front part of the electronic trip unit, and Figure 10 shows the rear part of the electronic trip unit. On the other hand, Figure 11 is a separated perspective view of the electronic trip unit.

[0053] The trip section case 201 is formed from an injection-molded product. In other words, the trip section case 201 is composed of a molded housing.

[0054] A control unit housing 202 is provided on the upper part of the trip unit case 201, and a current transformer housing 203 is provided on the lower part of the trip unit case 201. Here, the control unit housing 202 and the current transformer housing 203 are integrally formed. On the other hand, a current transformer housing cover 210 is provided on the rear part of the trip unit case 201.

[0055] The control unit 240 is installed in the control unit housing 202. The control unit 240 is made up of a circuit board (PCB). The control unit 240 receives a current signal from the current transformer 300.

[0056] The current transformer housing 203 has a current transformer housing section 205 into which the current transformer 300 is inserted. The current transformer housing section 205 occupies most of the space of the current transformer housing 203. A current transformer housing cover 210 covers the current transformer housing section 205. The current transformer 300 is inserted into the current transformer housing section 205. The current transformer housing 203 is provided with a current transformer housing section 205 for each phase. For example, in a three-phase circuit of R, S, and T, the current transformer housing 203 is provided with three current transformer housing sections 205 for the R phase, S phase, and T phase.

[0057] The current transformer 300 is provided to convert the current flowing through the circuit into a current of a magnitude that can be applied to an ammeter (not shown) of the control unit 240.

[0058] The current transformers 300 and current transformer housings 205 are provided in quantities equal to the number of phases. For example, if the alternating current flowing through the circuit is three-phase (R phase, S phase, T phase), then three current transformers 300 and three current transformer housings 205 are provided.

[0059] The front surface of the trip section case 201 is provided with isolation grooves 204 between each phase. The isolation grooves 204 increase the creepage distance and improve the insulation performance between phases.

[0060] A voltage sensor insertion groove 215 is formed on the front of the trip unit case 201. A voltage sensor (not shown) is installed in the voltage sensor insertion groove 215. The voltage sensor detects the voltage generated on the connecting conductor 220 and transmits it to the control unit 240.

[0061] Further explanation will be given with reference to Figure 12. Figure 12 is a rear view of the electronic trip unit. Here, the current transformer housing cover 210 has been removed. Also, in the S phase, the power generation unit 350 of the current transformer 300 has been removed. Furthermore, in the T phase, the connecting conductor 220 and the current transformer 300 have been removed.

[0062] A connecting conductor 220 is provided at the center of the current transformer 300. The connecting conductor 220 connects the trip section stator 198, which is connected to the power supply side, and the load-side terminal 199, which is connected to the load side. The current transformer 300 reduces the current flowing through the connecting conductor 220 and sends it to the control unit 240.

[0063] A connecting conductor insertion section 207 is provided protruding from the current transformer housing 203. The connecting conductor insertion section 207 extends in the front-to-back direction from the center of the current transformer housing section 205. The connecting conductor insertion section 207 is manufactured in a tubular shape, and a connecting conductor insertion hole 208 is formed inside it. A connecting conductor 220 is inserted into the connecting conductor insertion hole 208. The current transformer 300 is installed around the connecting conductor insertion section 207.

[0064] The connecting conductor insertion portion 207 is made of insulating material. The connecting conductor insertion portion 207 is integrally formed from the same material as the current transformer housing 203. The connecting conductor insertion portion 207 insulates the current transformer 300 from the connecting conductor 220.

[0065] The connecting conductor 220 is installed in the trip section 200 and electrically connects the power supply side and the load side. The current flowing through the connecting conductor 220 is measured by a current transformer, and the trip is activated when an abnormal current occurs.

[0066] The connecting conductor 220 has coupling grooves 222 formed on both sides for connecting the trip stator 198 or the load-side terminal 199.

[0067] The trip stator 198 is coupled to one end of the connecting conductor 220. The trip stator 198 connects the load-side fixed contact 112 and the load-side terminal 199 via the connecting conductor 220.

[0068] The current transformer housing 201 has a current transformer mounting section 230 formed around the connecting conductor insertion section 207 for fixing the current transformer 300. The current transformer mounting section 230 protrudes from the bottom surface of the current transformer housing section 205. The current transformer mounting section 230 is formed to be circular overall.

[0069] Figure 13 is a perspective view of the current transformer applied to the electronic trip section of the present invention, Figure 14 is a separate perspective view of the current detection section of Figure 13, and Figure 15 is a separate perspective view of the power generation section of Figure 13.

[0070] The current transformer 300 consists of a current detection unit 310 and a power generation unit 350.

[0071] The current detection unit 310 (or signal generation unit) includes a Rogowski coil 311, a first magnetic field absorbing material fixing member 320, and a first magnetic field absorbing material 330. The current detection unit 310 outputs a current signal to the control unit 240.

[0072] The Rogowski coil 311 is formed in a donut shape. The Rogowski coil 311 is formed in a form in which the coil is wound along the outer surface of the donut. Alternatively, it can be made by rolling a long, straight coil into a circle. Therefore, the Rogowski coil 311 is also called an air-core coil. The Rogowski coil 311 has the advantages of being small in size and not having saturation characteristics.

[0073] The Rogowski coil 311 has a hole in its center. A connecting conductor 220 is inserted into the through hole 313 of the Rogowski coil 311. The Rogowski coil 311 detects the current flowing through the connecting conductor 220.

[0074] The first magnetic field absorber fixing member 320 is provided to support the first magnetic field absorber 330. The first magnetic field absorber fixing member 320 ensures that the first magnetic field absorber 330 is installed at a predetermined distance from the Rogowski coil 311. The first magnetic field absorber fixing member 320 mechanically supports the first magnetic field absorber 330 so that it does not deform.

[0075] The first magnetic field absorbing material fixing member 320 is formed to a size that covers the periphery of the Rogowski coil 311. Here, the first magnetic field absorbing material fixing member 320 is formed to be larger than the diameter of the front part and the width of the side part of the Rogowski coil 311. Therefore, a space is formed between the Rogowski coil 311 and the first magnetic field absorbing material fixing member 320.

[0076] The first magnetic field absorber fixing member 320 is formed in an overall short cylindrical shape.

[0077] The first magnetic field absorbing material fixing member 320 has a front portion 321 and a side portion 322 consisting of a curved portion 323 and a flat portion 324.

[0078] The front portion 321 of the first magnetic field absorber fixing member 320 has a mounting hole 325 formed in the center. The mounting hole 325 occupies most of the area of ​​the front portion 321. The current transformer mounting portion 230 is fitted into the mounting hole 325.

[0079] The front portion 321 of the first magnetic field absorbing material fixing member 320, excluding the mounting hole 325, is formed to be larger than the thickness of the Rogowski coil 311, and the width of the side portion 322 of the first magnetic field absorbing material fixing member 320 is formed to be larger than the width of the side portion of the Rogowski coil 311. Therefore, the first magnetic field absorbing material fixing member 320 completely shields the Rogowski coil 311 from the front and sides.

[0080] The inner diameter of the central hole 325 of the first magnetic field absorber fixing member 320 is formed to be smaller than the inner diameter of the Rogowski coil 311. Therefore, when the current transformer mounting portion 230 of the current transformer housing portion 205 is fitted into the central hole 325 of the first magnetic field absorber fixing member 320, the Rogowski coil 311 is positioned inside the current transformer housing portion 205 at a predetermined distance from the central hole 325.

[0081] An open groove 326 is formed in the flat portion 324 of the side portion 322. The open groove 326 is provided to prevent interference with surrounding parts.

[0082] A work groove 327 is provided in a part of the curved surface 323 of the side portion 322, with an inclination formed on the inner circumferential surface. With the components of the current detection unit 310 housed in the current transformer housing 205 and temporarily assembled, the worker adjusts the position of the Rogowski coil 311 using the work groove 327.

[0083] The first magnetic field absorbing material fixing member 320 has an open back and accommodates the Rogowski coil 311.

[0084] The first magnetic field absorber 330 has open front and back surfaces. Therefore, the first magnetic field absorber 330 is short and tubular in shape. The first magnetic field absorber 330 has a curved portion 323 and a flat portion 324 that correspond to the shape of the side portion 322 of the first magnetic field absorber fixing member 320. The first magnetic field absorber 330 covers the side portion of the Rogowski coil 311.

[0085] The first magnetic field absorbing material 330 is formed to surround the first magnetic field absorbing material fixing member 320. Since the Rogowski coil 311 is inserted inside the first magnetic field absorbing material fixing member 320, the first magnetic field absorbing material 330 absorbs the generated magnetic field by covering the Rogowski coil 311.

[0086] The magnetic field absorbing materials 330 and 370 use materials with high magnetic permeability. In other words, the materials used for the magnetic field absorbing materials are those that effectively absorb the magnetic field generated around the Rogowski coil 311. In electromagnetism, magnetic permeability is a value that indicates how much a medium is magnetized in response to a given magnetic field. The usual symbol is the Greek letter μ. The international unit is henry per meter (H / m).

[0087] Using materials with high magnetic permeability as magnetic field absorbing materials 330 and 370 means the following:

[0088] Firstly, the magnetic field absorbing materials 330 and 370 are easily magnetized. In other words, magnetic induction occurs well, resulting in a high magnetic flux density.

[0089] Secondly, it stores a large amount of magnetic energy. In other words, it has a large magnetic energy storage capacity.

[0090] Thirdly, the magnetic flux flows smoothly. In other words, the magnetic field flows smoothly within the magnetic field absorbing material.

[0091] Because of these effects, the magnetic field generated in the Rogowski coil 311 is absorbed by the first magnetic field absorber 330 and does not spread outwards, thus not affecting neighboring phases.

[0092] Permalloy or nanocrystalline are used as materials with such high magnetic permeability. Permalloy is an alloy of approximately 80% nickel and 20% iron, and is an excellent magnetic material with very high magnetic permeability and low magnetic hysteresis loss. Nanocrystalline has the characteristic of having even better magnetic permeability than permalloy, but it is easily crushed, so care must be taken when using it.

[0093] As previously mentioned, the current detection unit 310 includes a Rogowski coil 311, a first magnetic field absorber fixing member 320, and a first magnetic field absorber 330. The Rogowski coil 311, the first magnetic field absorber fixing member 320, and the first magnetic field absorber 330 are joined by a molding method. For example, the Rogowski coil 311, the first magnetic field absorber fixing member 320, and the first magnetic field absorber 330 are inserted into the current transformer housing 205 and, in a temporarily assembled state, a molding liquid such as epoxy resin is injected and solidified.

[0094] The current transformer mounting portion 230 within the current transformer housing portion 205 is fitted into the central hole 325 of the first magnetic field absorber fixing member 320.

[0095] The first magnetic field absorber 330 is fitted onto the outer surface of the first magnetic field absorber fixing member 320, and the Rogowski coil 311 is inserted into the interior of the first magnetic field absorber fixing member 320.

[0096] The power generation unit 350 generates current due to the induced electromotive force of the iron core 351, and the control unit 240 is driven by the power supply using this current. In addition, the power generation unit 350 also generates current due to the induced electromotive force during normal operation, and the current generated here functions as a power source that keeps the control unit 240 running at all times.

[0097] The power generation unit 350 includes an iron core 351, a coil 360, and a second magnetic field absorbing material 370.

[0098] The core 351 is made of cold-rolled grain-oriented silicon steel sheet. Multiple silicon steel sheets are bonded together in layers using a lap bonding method. The assembled steel sheets are wrapped with insulating tape that has excellent thermal and mechanical properties, and the core surface is treated with rust-preventive paint for protection.

[0099] A hollow section 352 is formed in the center of the iron core 351, into which the connecting conductor 220 and the connecting conductor insertion section 207 are inserted.

[0100] A coil 360 is formed in a portion of the iron core 351. An electric current is generated in the coil 360 by electromagnetic induction.

[0101] When the rated current (several hundred amperes) flows through the small size of a circuit breaker, a magnetic field is generated around the busbar of each phase, causing distortion in the output of the current detection unit 310 of the other phases.

[0102] Thus, interphase interference, which distorts the signals of other phases due to magnetic fields, negatively affects the measurement accuracy of circuit breakers. Therefore, when attempting to achieve high-precision measurement functions within a circuit breaker, interphase interference must be minimized.

[0103] A second magnetic field absorber 370 is provided to prevent the magnetic field generated around the power generation unit 350 from affecting adjacent phases.

[0104] The second magnetic field absorbing material 370 is formed in such a way that it covers the side surfaces of the iron core 351 and the coil 360.

[0105] The characteristics and structure of the second magnetic field absorber 370 are the same as those of the first magnetic field absorber 330. The second magnetic field absorber 370 is made of the same material as the first magnetic field absorber 330.

[0106] The control unit 240 operates using power supplied from the power generation unit 350. When the control unit 240 determines that the current supplied from the current detection unit 310 is an abnormal current, it activates a trip coil (not shown) to shut off the circuit.

[0107] According to the electronic tripping section of a circuit breaker according to one embodiment of the present invention, a magnetic field absorbing material is provided to cover the Rogowski coil in the current detection section, thereby preventing the magnetic field from spreading to adjacent phases.

[0108] Furthermore, since the power generation section is equipped with a magnetic field absorbing material that covers the iron core and coil, the spread of the magnetic field to adjacent phases is prevented.

[0109] Therefore, when an abnormal current occurs in the circuit, current measurement errors due to interphase interference are minimized.

[0110] Furthermore, since inter-phase interference is prevented, the inter-phase distance can be shortened, and the overall size can be reduced.

[0111] The embodiments described above are examples of carrying out the present invention, and any person with ordinary skill in the art to which the present invention pertains may make various modifications and alterations without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed herein illustrate the technical idea of ​​the present invention and do not limit the scope of the technical idea of ​​the present invention. That is, the scope of protection of the present invention should be interpreted as defined in the claims, and all technical ideas within the scope equivalent thereto should be interpreted as being included in the present invention. [Explanation of symbols]

[0112] 100 Circuit breakers 200 Electronic trip unit 205 Current transformer housing 220 Connecting Conductor 240 Control Unit 300 Current Transformer 310 Current detection unit 311 Logoski Coil 320 First magnetic field absorbing material fixing member 330 First magnetic field absorber 350 Power Generation Unit 351 Iron Heart 360 coils 370 Second Magnetic Field Absorber

Claims

1. In the electronic tripping section of a circuit breaker, where the circuit is connected from the power supply side to the load side and multiple phases of alternating current flow through the circuit, Each of the aforementioned multiple phases is provided with a current transformer for measuring the alternating current, and the current transformer is It includes a current detection unit that measures the current of any of the multiple phases on which the current transformer is installed, The current detection unit is characterized by being equipped with a magnetic field absorbing material. Electronic tripping mechanism of a circuit breaker.

2. The current transformer is, The power supply generation unit further includes a power supply unit that generates a voltage due to an induced electromotive force generated in any of the aforementioned phases. The electronic tripping section of the circuit breaker according to claim 1.

3. The control unit further includes a control unit that operates by receiving power supplied by the power generation unit and shuts off the circuit when it determines that the current signal transmitted from the current detection unit is a fault current. The electronic tripping section of the circuit breaker according to claim 2.

4. The trip section case forming the housing of the electronic trip section is provided with a current transformer housing section in which the current transformer is housed. The electronic tripping section of the circuit breaker according to claim 1.

5. The current transformer housing is provided with a connecting conductor insertion section into which a connecting conductor connected to the circuit is installed. The electronic tripping section of the circuit breaker according to claim 4.

6. The current detection unit includes a Rogowski coil having a through hole, Among the magnetic field absorbing materials, the first magnetic field absorbing material covering the Rogowski coil is included. The electronic tripping section of the circuit breaker according to claim 4.

7. The current detection unit is The first magnetic field absorbing material fixing member is fixed to the current transformer housing, houses the Rogowski coil inside, and has the first magnetic field absorbing material installed outside. The electronic tripping section of the circuit breaker according to claim 6.

8. The current transformer housing portion is provided with a protruding current transformer mounting portion, and the first magnetic field absorbing material fixing member has a central hole into which the current transformer mounting portion is fitted. The electronic tripping section of the circuit breaker according to claim 7.

9. The first magnetic field absorbing material fixing member has a front portion and a side portion, and the side portion has a curved portion and a flat portion. The electronic tripping section of the circuit breaker according to claim 7.

10. The inner diameter of the central hole is formed to be smaller than the inner diameter of the Rogowski coil. The electronic tripping section of the circuit breaker according to claim 8.

11. The width of the side surface of the first magnetic field absorbing material fixing member is formed to be greater than the width of the side surface of the Rogowski coil. The electronic tripping unit of the circuit breaker according to claim 9.

12. The Rogowski coil, the first magnetic field absorber fixing member, and the first magnetic field absorber are joined to each other by a molding method. The electronic tripping section of the circuit breaker according to claim 7.

13. The aforementioned power generation unit is It includes an iron core and a coil, The magnetic field absorbing material includes a second magnetic field absorbing material that covers the iron core and the coil. The electronic tripping section of the circuit breaker according to claim 2.

14. The magnetic field absorbing material is formed from a material with high magnetic permeability. The electronic tripping section of the circuit breaker according to claim 1.

15. The magnetic field absorbing material is formed of permalloy or nanocrystalline. The electronic tripping unit of the circuit breaker according to claim 14.

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