JP2009133783A - Current sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To facilitate setting for correction of a current to be measured, in a current sensor for processing a signal by using in common each current to be measured by two Rogowski coils by a single signal processing circuit. <P>SOLUTION: This current sensor 1 is equipped with a printed board 2, coils 3, 4 having openings 31, 41, respectively, and a signal processing circuit 5 which is used in common for signal processing of each detection current detected by the coils 3, 4. The coils 3, 4 and the signal processing circuit 5 are formed on the same substrate 2. Output ends 32, 42 of the coils 3, 4 for outputting each detection current signal are connected, respectively, to the input end 51 of the signal processing circuit 5 through transmission lines 11, 12 having substantially the same length L1 and formed on the printed board 2. As a result, since each unnecessary detection current, based on an external magnetic field detected respectively by the transmission lines 11, 12 can be adjusted to be substantially the same, each measurement error, based on the external magnetic field of each current to be measured detected by the coils 3, 4, becomes approximately the same; and when correcting the current to be measured, setting for correction is facilitated. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a current sensor for measuring a current flowing through a branch circuit or the like of a domestic distribution board.

  In recent years, Rogowski coils that are less affected by external magnetic fields are often used in current sensors for non-contact measurement of the amount of alternating current that is passed through wires such as power transmission and transformation equipment and household distribution boards. In order to measure this, a plurality of Rogowski coils and a signal processing circuit for signal-processing detected currents from these Rogowski coils have been integrated on a printed circuit board. Moreover, in such a current sensor, signal processing is performed by connecting the current detection output from two Rogowski coils to one common signal processing circuit in each transmission line provided on the printed circuit board for miniaturization and cost reduction. ing.

  By the way, when an unnecessary external magnetic field is incident on the printed circuit board, such a current sensor is affected by the external magnetic field in the transmission line from the Rogowski coil to the signal processing circuit, and is generated in each transmission line based on the external magnetic field. The unnecessary detection current is input to the signal processing circuit and becomes a measurement error of the current to be measured. At this time, if the lengths of the transmission lines from the two Rogowski coils are different, a difference occurs in the unnecessary detection current due to the external magnetic field in each transmission line, and the measurement error of the measured current detected by each Rogowski coil is not constant. . For this reason, when the measurement error is to be corrected, the correction amount differs for each current to be measured, which complicates the correction setting.

By the way, each detection output from the two Rogowski coils is input to the sensor unit via each transmission line on the printed circuit board, and a current sensor that generates each detection data based on each detection output by switching the input of the sensor unit. It is known (see Patent Document 1). However, in this current sensor, there is no disclosure regarding the transmission line length as a countermeasure against the influence of the external magnetic field in each transmission line.
JP 2007-195294 A

  The present invention has been made in order to solve the above problem, and in a current sensor in which two Rogowski coils and a signal processing circuit shared for signal processing of each detected current from these coils are formed on the same substrate. The measurement error based on the external magnetic field of the current to be measured is corrected by making the influence of the external magnetic field in each transmission line connecting the output ends of the two Rogowski coils and the input end of the signal processing circuit substantially the same. It is an object to provide a current sensor that facilitates the setting of correction.

  In order to achieve the above object, the invention of claim 1 is characterized in that at least two Rogowski coils having openings through which electric wires to be measured through which current flows pass, and signal processing shared by signal processing of each detected current detected by these Rogowski coils. A current sensor in which the Rogowski coil and the signal processing circuit are formed on the same substrate, an output end from which each detected current signal of the Rogowski coil is output, and an input end of the signal processing circuit Are connected by transmission lines of substantially the same length formed on the substrate.

  According to a second aspect of the present invention, in the AC current detection coil according to the first aspect, each input end of the signal processing circuit is disposed adjacent to each other, and each input end and each input end Are arranged at substantially equal distances from the center of each opening of the Rogowski coil having an output end connected by the transmission line.

  According to a third aspect of the present invention, in the AC current detection coil according to the first or second aspect, the signal processing circuit includes an amplification circuit and an integration circuit for amplifying and integrating the detection current, and the amplification Additional circuit components for assisting amplification and integration in the circuit and the integration circuit are connected adjacent to the amplification circuit and the integration circuit, and disposed on the same substrate surface.

  According to a fourth aspect of the present invention, in the current sensor according to any one of the first to third aspects, the signal processing circuit includes a correction processing unit that corrects a value of a detected current detected by the Rogowski coil. It is a thing.

  According to a fifth aspect of the present invention, in the current sensor according to any one of the first to fourth aspects, a correction logoski coil for detecting a correction amount necessary for correcting the value of the detection current is provided. In addition, the correction processing unit corrects the value of the detection current based on a correction amount detected by the correcting Rogowski coil.

  According to the first aspect of the present invention, the influence of the external magnetic field on each transmission line connecting the output ends of the two Rogowski coils and the input ends of the signal processing circuit becomes substantially the same. The unnecessary detection current of the transmission line is also substantially the same, and when the current to be measured is corrected, each current to be measured can be corrected with substantially the same correction amount, and the setting of the correction becomes easy.

  According to the invention of claim 2, by arranging each output end of the Rogowski coil near the line connecting each input end of the signal processing circuit and the center of each opening, each transmission line is connected to each center of the opening. It can arrange | position substantially symmetrically about the straight line which is equidistant from. As a result, each coil and the signal processing circuit can be approached at a substantially shortest distance while keeping each transmission line substantially the same length, so that the length of the transmission line can be shortened, the influence of the external magnetic field is reduced, and the same correction is performed. The amount of correction can be made small, and the correction error can be reduced.

  According to the invention of claim 3, since the length of the transmission line connecting the amplifier circuit, the integrating circuit, and the additional circuit components connected to them can be shortened, the influence of the external magnetic field can be reduced.

  According to the invention of claim 4, since the influence of the external magnetic field can be corrected and reduced, the current measurement accuracy is improved.

  According to the invention of claim 5, since the correction amount can always be detected by the correction logoski coil, the detection current detected by the logoski coil under measurement can be corrected in real time, and the current measurement accuracy is further improved.

  Hereinafter, a current sensor 1 according to a first embodiment of the present invention will be described with reference to FIGS. 1 to 4. As shown in FIG. 1, a current sensor 1 of the present embodiment includes a printed circuit board 2 having a multilayer structure, two Rogowski coils (hereinafter referred to as coils) 3 and 4 for detecting a current flowing through a measured wire, and a coil. The signal processing circuit 5 performs signal processing of the detected currents 3 and 4, and the Rogowski coils 3 and 4 and the signal processing circuit 5 are formed on the same substrate.

  Openings 31 and 41 serving as through holes for forming the coils 3 and 4 are formed in the printed circuit board 2, and signal processing is performed on the output terminals (output end portions) 32 and 42 of the coils 3 and 4 on the surface. Transmission lines 11 and 12 connected to the input end 51 (51a and 51b) of the circuit 5 are formed. The output terminals 32 and 42 are each provided with a signal terminal for each detected current signal and a ground terminal. The input end 51 is provided with input terminals 51a and 51b arranged adjacent to each other, to which input signals from the respective detection current signals are input. The input terminals 51a and 51b each have a signal terminal and a ground terminal. Have.

  Here, the output end 32 from which the respective detection current signals of the Rogowski coils 3 and 4 are output and the input end 51 of the signal processing circuit 5 are formed on the printed circuit board 2 and have substantially the same length L1 of the transmission lines 11 and 12. Are connected to each other. Also, here, the input terminals 51a and 51b of the input end 51 of the signal processing circuit 5 are disposed adjacent to substantially the same position, and from the centers 30 and 40 of the openings 31 and 41 of the two Rogowski coils, respectively. They are arranged at approximately the same distance. The transmission lines 11 and 12 include two signal lines and a ground line, and are connected to the signal terminals and the ground terminals of the input terminals 51a and 51b and the output terminals 32 and 42, respectively. The printed board 2 is not limited to the multilayer board as described above, and a double-sided board may be used.

  The coils 3 and 4 detect currents flowing through the wires under test 20 disposed through the openings 31 and 41 formed in the printed circuit board 2, and these detected currents are output terminals of the coils 3 and 4. 32 and 42. The output currents from the output terminals 32 and 42 are connected to the input terminals 51a and 51b of the input end 51 via the transmission lines 11 and 12 connected to the output terminals 32 and 42, respectively.

  Here, the coils 3 and 4 used in the present embodiment will be described with reference to FIGS. Since the coils 3 and 4 have the same configuration, only the coil 3 will be described here.

  The coil 3 includes a plurality of radial lines 33 formed radially on the conductive foils 22 and 23 on both the front and back surfaces of the insulating substrate 21 around the opening 31 of the printed circuit board 2, and insulation is formed at both ends of the radial lines 33. And a through hole 34 penetrating through the conductive substrate 21 in the thickness direction. The through hole 34 includes through through holes 34a, 34b, and 34c that penetrate the insulating substrate 21 and penetrate both the front and back surfaces of the printed board 2 in the thickness direction. Through the through-holes 34a, 34b, 34c, the radial lines 33 on both the front and back surfaces of the insulating substrate 21 are electrically connected to each other at their ends to form a toroidal coil 35. This toroidal coil 35 is formed in a double manner by a winding advance coil 36 and a rewind coil 37 in a rewind direction that are prevented from contacting each other by a connecting portion 38, and the rewind coil 36 and the rewind coil. The coil 3 is configured by continuously connecting 37. With this coil 3, the detected current of the current flowing through the measured electric wire 20 that passes through the opening 31 is taken out from the output terminal 32. The sum of the induction currents generated in the winding advance coil 36 and the rewinding coil 37 is obtained, and an induction current proportional to the number of turns of all the coils is obtained. For the unnecessary external magnetic field, the winding advance coil 36 and the rewinding coil 37 are obtained. The difference between the induced currents detected at 1 is detected, and the unnecessary external magnetic field is reduced.

  As shown in FIG. 4, the signal processing circuit 5 includes an amplifying unit 6, an integrating unit 7, and a data output unit 8. The amplifying unit 6 includes an input switching circuit 61 and an amplifying circuit 62. The input switching circuit 61 amplifies the input signals of the detection currents from the coils 3 and 4 input from the input terminals 51a and 51b by temporally switching. Send to circuit 62.

  The amplifier circuit 62 includes an operational amplifier 63 for amplification, and an input resistor 91 and a feedback resistor 92 that are additional circuit components 9 that assist the amplification operation of the operational amplifier 63 are connected to the periphery thereof. The amplifier circuit 62 amplifies the input signal sent from the input switching circuit 61 and sends it to the integrating unit 7. The integration unit 7 includes an integration circuit 71, and the integration circuit 71 includes an operational amplifier 72 for integration. Around the operational amplifier 72, an input resistor 93, a feedback resistor 94, and a feedback capacitor 95, which are additional circuit components 9 that assist the integration of the operational amplifier 72, are connected. The integrator 7 integrates the detection output output by the coils 3 and 4 in a differential form and amplified by the amplifier circuit 62 to generate a current waveform that is easy to process signals. The data output unit 8 also calculates an effective value calculation unit 81 that calculates an effective value from the current waveform obtained by the integration unit 7 and an effective value (detection data) obtained by the effective value calculation unit 81 from an analog signal. An A / D conversion unit 82 that converts to a digital signal and a memory unit 83 that stores detection data converted into a digital signal by the A / D conversion unit 82 are provided.

  In the current sensor 1 configured as described above, when a current flows through each measured wire 20 that passes through the openings 31 and 41 of the coils 3 and 4, the detected currents that the coils 3 and 4 flow through each measured wire 20. Is output from the output terminals 32 and 42. Each detected current taken out from these output terminals 32 and 42 is input to the input end 51 of the signal processing circuit 5 through the transmission lines 11 and 12 having the line length L1.

  Each detected current input to the input terminals 51 a and 51 b of the input end 51 becomes an input signal of the signal processing circuit 5 and is switched in a time division manner by the input switching circuit 61, and signal processing is performed in the signal processing circuit 5. And detection data is generated. This detection data is output from the data output unit 8 as measurement current data to a control device of the switchboard and the like. Thus, the detected currents of the coil 3 and the coil 4 are switched and processed by the same signal processing circuit 5. For this reason, the processing errors generated in the signal processing circuit 5 are the same, and variations in detection data are suppressed.

  Here, when a current to be measured is detected, for example, if a large current flows through an external electric wire existing far away to generate a magnetic field, the remote external magnetic field becomes an unnecessary external magnetic field for the current sensor 1. Since this unnecessary external magnetic field is a far magnetic field, the magnetic field distribution has substantially the same level on the current sensor 1. Therefore, the transmission lines 11 and 12 receive an unnecessary external magnetic field having the same magnetic field level. Here, if the transmission lines 11 and 12 receive an unnecessary external magnetic field, an unnecessary detection current due to the external magnetic field is added to the transmission lines 11 and 12 and flows. As a result, a mixed current in which an unnecessary detection current is superimposed on each detected current flows through the transmission lines 11 and 12. When these mixed currents are input, the signal processing circuit 5 generates detection data based on the mixed currents. Therefore, the detection data includes a measurement error corresponding to the unnecessary detection current.

  At this time, in this embodiment, since the lengths of the transmission lines 11 and 12 are substantially the same, the transmission lines 11 and 12 have an unnecessary covering with substantially the same size due to the external magnetic field having a substantially uniform magnetic field distribution. Detection current flows. Therefore, when the current to be measured is corrected, it is only necessary to correct the same error amount for each current to be detected detected by the coil 3 and the coil 4, so that the correction can be easily set.

  In addition, since the distance between the input end 51 of the signal processing circuit 5 and the centers 30 and 40 of the opening 31 and the opening 41 is substantially equal, the input end 51 of the signal processing circuit 5 and each of the openings 31 and 41 are arranged. By arranging the output ends of the coils 3 and 4 in the vicinity of the line connecting the centers of the transmission lines 11 and 12, the transmission lines 11 and 12 are approximately connected to the straight lines that are equidistant from the centers 30 and 40 of the openings 31 and 41. They can be arranged in line symmetry. As a result, the coils 3 and 4 and the signal processing circuit 5 can be approached at a substantially shortest distance while keeping the transmission lines 11 and 12 substantially the same length, so that the length of the transmission lines 11 and 12 can be shortened. The influence of the magnetic field is reduced. As a result, each current to be measured can be corrected with the same correction amount, and the correction amount itself is reduced, so that a correction error is reduced and measurement accuracy is improved.

  Thus, according to the current sensor 1 of the present embodiment, the lengths of the transmission lines 11 and 12 that connect the output ends of the coils 3 and 4 and the input end of the signal processing circuit 5 are configured to be substantially the same. Since the measurement error due to the external magnetic field of the detection current of the coils 3 and 4 can be made the same, the measurement error can be made substantially the same. Therefore, for example, when a measurement error is detected and stored in advance and correction is performed using the stored error data, it is not necessary to set a correction value for each measured current of the coils 3 and 4, and Correction can be made with a common correction value. Accordingly, when correction is performed, the correction setting is simplified, the amount of correction data to be stored is small, the amount of memory can be reduced, and the price can be reduced.

  In addition, since the signal processing circuit 5 can be approached to the coils 3 and 4 at a substantially shortest distance while keeping the transmission lines 11 and 12 the same, the length of the transmission line can be shortened, and the influence of the external magnetic field is reduced. The correction amount can be reduced, thereby reducing the correction error.

  Next, a modification of the current sensor according to the second embodiment of the present invention will be described with reference to FIG. The current sensor 1 of this modification is formed by forming transmission lines 11 and 12 at L-shaped line-symmetric positions, and other configurations are the same as those of the first embodiment.

  According to the current sensor 1 of this modification, the transmission lines 11 and 12 have substantially the same total length L2, and the portions parallel to the L-shaped orthogonal portion have substantially the same length. As a result, the transmission lines 11 and 12 can maintain the same reception level even when the direction of the external magnetic field changes, and the correction amount can be made substantially the same when correcting each measured current.

  Next, a current sensor 1 according to a second embodiment of the present invention will be described with reference to FIG. In the current sensor 1 of the present embodiment, an additional circuit component 9 for assisting amplification and integration in the amplification circuit 62 and the integration circuit 71 is connected adjacent to the amplification circuit 62 and the integration circuit 71, and It is disposed on the same substrate surface 2a. Other configurations are the same as those in the first embodiment.

  The amplifier circuit 62 and the integration circuit 71 are provided with a semiconductor LSI 60 including operational amplifiers 63 and 72 for amplification or integration. Around the LSI 60, there are additional circuit components 9 (an input resistor 91, a feedback resistor 92, an input resistor 93, and a feedback circuit). A resistor 94, a feedback capacitor 95, a power supply noise countermeasure capacitor 96, and the like are connected adjacently, and the LSI 60 and the additional circuit component 9 are mounted on the same board surface 2a of the printed board 2. As described above, since the additional circuit component 9 is disposed close to the same plane without using a through hole or the like, the connection wiring for connecting the LSI 60 and the additional circuit component 9 is shortened, and the external magnetic field in the connection wiring is reduced. The influence of can be reduced. Here, the transmission lines 11 and 12 are formed by connecting the metal foil wires on the front and back of the printed circuit board 2 through the through holes 33p.

  Next, a current sensor 1 according to a third embodiment of the present invention will be described with reference to FIG. In the current sensor 1 of the present embodiment, the signal processing circuit 5 includes a correction processing unit 84 that corrects the value of the detected current detected by the coils 3 and 4. This is the same as the embodiment.

  The correction processing unit 84 includes a correction value acquisition unit 85 that is formed in the data output unit 8 and acquires a correction value, and a correction value storage unit 86 that stores the correction value acquired by the correction value acquisition unit 85. When measuring the current of the measured wire 20, the correction value acquisition unit 85 first turns off the current of the measured wire 20 while passing the measured wire 20 through the openings 31 and 41, and loads the measured wire 20 in an unloaded state. A measurement current is detected, and the detected current to be measured is stored in advance in the correction value storage unit 86 as a correction value. Next, the current to be detected is measured when the current of the wire 20 to be measured is turned on (in the load state). The correction processing unit 84 performs correction by subtracting the detected current in the no-load state, which is a correction value, from the detected current in the loaded state. That is, the detected current in the no-load state is regarded as a detected current based on an external magnetic field. Thereby, it can correct | amend easily in the state according to the measurement actual condition.

  In addition, the current flowing through the transmission lines 11 and 12 includes a detected current detected by the coils 3 and 4 and an unnecessary detected current that flows based on an external magnetic field. If the phases of these currents are different, The combined current increases or decreases depending on the phase of each other. For this reason, here, a phase detection unit (not shown) is provided, the phase flowing through the wire 20 to be measured and the phase of the current due to the external magnetic field are detected in advance, and the current phase information is stored in the correction value storage unit 86. Keep it. The phase of the unnecessary detection current due to the external magnetic field can be detected from the detected current in the load state. Thereby, the correction in the case where the detected current and the unnecessary detected current are in phase is corrected by subtracting the unnecessary detected current from the detected current, and in the opposite phase, the correction is performed by adding the unnecessary detected current to the detected current. Thereby, correction with higher accuracy can be performed.

  Next, a current sensor 1 according to a fourth embodiment of the present invention will be described with reference to FIG. The current sensor 1 of the present embodiment further includes correction logoski coils 3b and 4b for detecting a correction amount necessary for correcting the value of the detected current, and the correction processing unit 84 includes the correction logoski coils 3b and 4b. The value of the detected current is corrected based on the correction amount detected in step (1). Other configurations are the same as those in the first embodiment.

  The current sensor 1 of the present embodiment is provided with other measurement coils 3a and 4b and correction coils 3b and 4b, which have the same configuration as the measurement coils 3 and 4 on the same printed circuit board 2. Yes. Here, the case where the electric current of the four adjacent to-be-measured electric wires 20 is measured is shown. The other measuring coils 3a and 4b and correction coils 3b and 4b have openings 31a and 41a and openings 31b and 41b, respectively, and their detected currents are transmitted through the transmission lines 11 and 12, respectively. The signals are input to the signal processing circuits 5a and 5b and processed.

  The correction logoski coils 3b and 4b are used in a state where the measured electric wire 20 is not inserted into the openings 31b and 41b. That is, the correcting Rogowski coils 3b and 4b can measure the current under measurement in a no-load state under substantially the same conditions as when no current is flowing through the wire under measurement 20. As shown in FIG. 8, when a large current I flows through the external electric wire 100 in the direction of the arrow X in the distance, a magnetic field H is generated around the external electric wire 100 by the current I. When this magnetic field H is incident on the current sensor 1, the measurement coils 3, 4, the coils 3a, 4a, and the correction coils 3b, 4b are similarly affected. Therefore, the measured currents of the measuring coils 3 and 4 and the coils 3a and 3b can be corrected based on the unnecessary detection current of the external magnetic field detected by the correcting Rogowski coils 3b and 4b.

  The signal processing circuit 5b includes a correction value calculation unit 87 for calculating a correction value. The correction value calculation unit 87 calculates the effective value from the current waveform output by processing the current to be measured (corresponding to the current in the no-load state) detected by the correction logoski coils 3b and 4b by the amplification unit 6 and the integration unit 7. To calculate correction value data. The correction value data is transmitted to the correction processing unit 84 of the data output unit 8 of the signal processing circuits 5 and 5a. The correction processing unit 84 rewrites the initial correction value stored in the correction value storage unit 86 based on the received correction value data. At this time, the correction value calculation unit 87 can send the correction value data calculated in real time even when the coils 3 and 4 and the coils 3a and 4b are measuring the measured current. Thereby, even if the magnitude of the external magnetic field changes, the correction value stored in the correction value storage unit 86 can be immediately corrected, and the corrected current data can be sent from the data output unit 8. Further, the correction value calculation unit 87 is also configured to detect the phase of the unnecessary detection current based on the external magnetic field. Even when the phase of the unnecessary detection current based on the external magnetic field is changed, this phase information is used as the data output unit. By sending to 8, the plus / minus correction direction can be determined based on the phase information.

  As described above, according to the current sensor 1 of the present embodiment, correction can be performed so as to remove the influence of the external magnetic field in real time, so that the current measurement accuracy can be further improved. Further, the correction value calculation unit 87 performs calculation including the unnecessary detection current based on the external magnetic field received by the additional circuit component of the amplification unit 6 and the integration unit 7 of the signal processing circuit 5b. The currents to be measured can be corrected including the influence of the external magnetic field in the signal processing circuits 5 and 5a on the third and fourth sides, and the current measurement accuracy is further improved.

  In addition, this invention is not limited to the structure of said various embodiment, A various deformation | transformation is possible suitably in the range which does not change the meaning of invention. In the various embodiments described above, since the coil and the signal processing circuit are formed on the same substrate, they can be shielded by covering them together with a metal case, thereby preventing the influence of an external magnetic field on the coil and performing signal processing. It is possible to suppress unnecessary radiation interference to external electronic equipment due to digital processing signals generated in the circuit and harmonics thereof. Although the case where the current sensor and the signal processing circuit are on the same substrate has been described here, the transmission line connecting the coil and the signal processing circuit circuit may be the same length even if they are not on the same substrate. Further, the number of the correcting logo ski coil may be one.

The block diagram of the current sensor which concerns on the 1st Embodiment of this invention. The top view of the Rogowski coil of the said current sensor. The perspective view of the Rogowski coil of the said current sensor. The block diagram of the signal processing circuit of the said current sensor. The block diagram of the modification of the current sensor which concerns on the said 1st Embodiment. The block diagram of the current sensor which concerns on the 2nd Embodiment of this invention. The block diagram of the signal processing circuit of the current sensor which concerns on the 3rd Embodiment of this invention. The block diagram of the current sensor which concerns on the 4th Embodiment of this invention.

Explanation of symbols

1 Current sensor 2 Printed circuit board (board)
3, 3a Rogowski Coil 3b Correction Rogowski Coil 4, 4a Rogowski Coil 4b Rogowski Coil for Correction 5 Signal Processing Circuit 6 Amplification Unit 62 Amplification Circuit 7 Integration Unit 71 Integration Circuit 8 Data Output Unit (Correction Processing Unit)
9, 91, 92, 93, 94, 95, 96 Additional circuit components 11 Transmission line 12 Transmission line 20 Wire under test 30 Center 31, 31a, 31b Opening 32 Output terminal (output end)
40 Center 41, 41a, 41b Opening 42 Output terminal (output end)
51 Input end 51a, 51b Input terminal (input end)
84 Correction processing section

Claims (5)

At least two Rogowski coils having openings through which the wire under test through which current flows passes;
A signal processing circuit shared by the signal processing of each detected current detected by these Rogowski coils, the Rogowski coil and the signal processing circuit are current sensors formed on the same substrate,
The output end portion of each of the detected current signals of the Rogowski coil and the input end portion of the signal processing circuit are connected to each other by a transmission line having substantially the same length formed on the substrate. The current sensor according to claim 1.   Each input end of the signal processing circuit is arranged adjacent to each other, and each input end and the center of each opening of the Rogowski coil having an output end connected to each input end by the transmission line. The current sensors according to claim 1, wherein the current sensors are arranged at substantially equal distances from each other. The signal processing circuit includes an amplification circuit and an integration circuit for amplifying and integrating the detection current,
Additional circuit components for assisting amplification and integration in the amplification circuit and integration circuit are connected adjacent to the amplification circuit and integration circuit and disposed on the same substrate surface. The current sensor according to claim 1 or claim 2.   4. The current sensor according to claim 1, wherein the signal processing circuit includes a correction processing unit that corrects a value of a detection current detected by the Rogowski coil. 5. A correction logoski coil for detecting a correction amount necessary for correcting the value of the detection current is further provided,
5. The current sensor according to claim 1, wherein the correction processing unit corrects the value of the detection current based on a correction amount detected by the correction logoski coil. .

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