Rogowski current sensor with a printed circuit board

Abstract

The invention relates to a sensor (1) for measuring an electric current through an electrical element, the sensor (1) comprising a printed circuit (10), said printed circuit (10) comprising: at least two upper tracks (12', 12'') extending along a first plane (P1): at least one lower track (14') extending along a second plane (P2), the upper tracks (12', 12'') and said at least one lower track (14') being configured to surround the electrical element;and vias (16, 16', 16'') connecting the upper tracks (12', 12'') to said at least one lower track (14'), the sensor (1) further comprising a conducting wire comprising several turns, each turn comprising an upper portion, a lower portion and an intermediate portion connecting the upper portion to the lower portion, the sensor (1) being characterized in that each lower track among the at least one lower track (14') comprises a first portion (146) opposite an upper track (12'), and a second portion (148) opposite an upper track adjacent (12'') to said upper track (12'). Figure for the abstract: Fig. 1;

Description

Title of the invention: Rogowski current sensor comprising a printed circuit board

[0001] The invention relates to the field of current measurement at the level of an electrical element, in particular to that of Rogowski type sensors or coils.

[0002] As is known, current measurement through an electrical element can be performed in various ways. This can be achieved, for example, using a measuring shunt adapted to measure the current flowing through said electrical element. It is also possible to use a Hall effect measuring sensor inserted in a magnetic circuit or coupled to a magnetic flux concentrator, or even a Neel effect measuring sensor consisting of a super-paramagnetic circuit, a measuring coil, and electronics enabling spectral analysis of this measurement.

[0003] Another way to measure the current in an electrical element is to use a Rogowski current sensor consisting of a winding and a high-impedance load that measures the change in current flowing through the sensor. A Rogowski current sensor comprises a helical winding of conductive wire wound, for example, around an annular tube. One end of the conductive wire returns through the center of the winding to the other end of the wire, so that the two ends of the winding are adjacent. The Rogowski current sensor is positioned around the electrical conductor, namely the electrical element, whose current is to be measured.

[0004] The Rogowski type measuring sensor has many advantages such as its low weight and wide frequency band.

[0005] Alternatively, the annular tube of the Rogowski coil can be replaced by a printed circuit board. The coil of the coil is deposited on faces of the printed circuit board through holes in said printed circuit board.

[0006] If a current variation passes through the sensor cross-section perpendicular to the plane formed by all the turns of the sensor, then this current variation generates an electromagnetic field parallel to the plane formed by all the turns of the conducting wire. This electromagnetic field generates a measurable voltage across the terminals or ends of the Rogowski coil.

[0007] However, any external electromagnetic field to the Rogowski current sensor that is perpendicular to the electromagnetic field generated by the current variation becomes a disturbance for the Rogowski current sensor. Indeed, this external electromagnetic field is superimposed on the sensor's own electromagnetic field, which is generated by the current variation flowing through the sensor, and modifies the measurable voltage. at the terminals of the sensor. Such a Rogowski current sensor is therefore very susceptible to electromagnetic disturbances from its environment.

[0008] The invention aims to provide a Rogowski type current sensor made on a printed circuit board or PCB ("Printed Circuit Board") which is little or not sensitive to electromagnetic interference.

[0009] To this end, the invention relates to a Rogowski-type sensor configured to measure an electric current flowing through an electrical element, the sensor comprising a printed circuit board, said printed circuit board comprising: - at least two upper tracks extending along a foreground plane; - at least one lower track extending along a second plane parallel to the first plane, the upper tracks and said at least one lower track being configured to surround the electrical element; and - vias connecting the upper tracks to said at least one lower track, the sensor further comprising a conducting wire comprising several turns, each turn comprising an upper portion, a lower portion and an intermediate portion connecting the upper portion to the lower portion, the upper portion of each turn extending over an upper face of an upper track among the upper tracks, the lower portion of each turn extending over an lower face of a lower track among the at least one lower track, and the intermediate portion passing through one of the vias connecting said upper track to said lower track, the sensor being characterized in that each lower track among the at least one lower track comprises a first portion opposite an upper track among said at least two upper tracks,and a second section opposite an upper runway adjacent to said upper runway.

[0010] This arrangement of the lower and upper tracks has the advantage of allowing an overlap of a lower track by an upper track and vice versa, so as to limit any electromagnetic disturbance oriented perpendicularly to the upper and lower tracks.

[0011] According to one aspect of the invention, the sensor comprises a return track between said at least two upper tracks and said at least one lower track, the return track extending along a third plane parallel to the first and second planes, the return track being configured to surround the electrical element, the conducting wire passing through the return track.

[0012] According to one aspect of the invention, the first portion of the at least one lower track represents two-thirds of the at least one lower track and the second portion of the at least one lower track represents one-third of the at least one lower track.

[0013] According to one aspect of the invention, the first portion and the second portion each represent half of at least one lower track.

[0014] According to one aspect of the invention, at least one lower track and the upper tracks are identical to each other.

[0015] According to one aspect of the invention, the first portion of at least one lower track comprises a first via among said vias and the second portion of at least one lower track comprises a second via among said vias.

[0016] According to one aspect of the invention, the at least one lower track comprises four vertices, the first via and the second via being positioned close to two vertices not adjacent to each other.

[0017] According to one aspect of the invention, a lower track comprises four sides, two sides out of the four sides being straight and two sides out of the four sides being curved, one curved side connecting the two straight sides.

[0018] According to one aspect of the invention, the at least two upper tracks are separated from the at least one lower track by a distance of less than 5 millimeters, and preferably equal to 1.5 millimeters.

[0019] According to one aspect of the invention, the at least two upper tracks and the at least one lower track are made of copper.

[0020] The invention will be better understood and other advantages will become apparent upon reading the detailed description of an embodiment given by way of example, a description illustrated by the accompanying drawing in which:

[0021] [Fig-1] [Fig.1] represents a schematic top view of a type sensor Rogowski according to an embodiment of the invention;

[0022] [Fig.2] [Fig.2] is a simplified schematic side view of [Fig.1] showing a coil passing through a printed circuit board of the sensor;

[0023] [Fig.3] [Fig.3] represents a view similar to [Fig.2] in which a track of The sensor return is represented;

[0024] [Fig.4] [Fig.4] represents a schematic top view of part of the sensor showing the coil passing through the printed circuit board;

[0025] [Fig. 5] [Fig. 5] shows a schematic exploded view of part of the sensor showing the coil passing through the printed circuit board;

[0026] [Fig.6] [Fig.6] represents an exploded schematic view of the sensor part of the [Fig. 5] repeated twice; and

[0027] [Fig.7] [Fig.7] represents a schematic side view of [Fig.6].

[0028] For the sake of clarity, the same elements will bear the same markings in the different different figures.

[0029] Figure 1 shows a schematic top view of a Rogowski current sensor 1 configured to measure a current flowing through an electrical element. The current sensor 1 at least partially surrounds the electrical element. The current sensor 1 is preferably in contact with the electrical element. In a configuration In the preferred configuration, the current sensor 1 surrounds the electrical element such that the surface enclosed by the current sensor 1 in a first PI plane corresponds to a current measurement section 2 of the electrical element. In other words, the measurement section 2 is a surface bounded by the current measurement sensor 1 in the first PI plane parallel to the current measurement sensor 1.

[0030] The current measuring sensor 1 comprises a printed circuit board 10 shown more precisely in [Fig.2]. The printed circuit board 10 is configured to surround the electrical element so as to delimit the measuring section 2.

[0031] The printed circuit board 10 comprises at least two upper tracks, namely at least a first upper track 12' and a second upper track 12", extending along the first plane PI and at least one lower track 14' extending along a second plane P2 parallel to the first plane PI, the upper tracks 12' and 12" and said at least one lower track 14' being configured to surround the electrical element.

[0032] The printed circuit 10 then extends from the first plane PI to the second plane P2. The upper tracks 12' and 12" are thus superimposed on said at least one lower track 14'.

[0033] The printed circuit board 10 also includes at least one via 16 connecting the upper tracks 12' and 12" to said at least one lower track 14'. The at least one via 16 takes the form of an opening in one of the at least two upper tracks 12' and 12" and the at least one lower track 14' extending towards the other of the at least two upper tracks 12' and 12" and the at least one lower track 14'. The printed circuit board 10 is traversed by the at least one via 16.

[0034] The current measuring sensor 1 comprises a conducting wire 18 having several turns 19. Each turn 19 comprises an upper portion 182, a lower portion 186, and an intermediate portion 184 connecting the upper portion 182 to the lower portion 186. The upper portion 182 extends over an upper face 122 of the upper track, as shown in [Fig. 2], among at least two upper tracks 12' and 12", such as, for example, the first upper track 12'. The lower portion 186 extends over a lower face 142 of the lower track among at least one lower track 14'. And the intermediate portion 184 passes through one of the vias 16.

[0035] The turns 19 surround the printed circuit 10 and each turn is adjacent to at least one other turn 19 so that the turns 19 form a winding 20 around the printed circuit 10.

[0036] Therefore, when an electric current passes through the electrical element and in particular the measuring section 2 perpendicular to the plane PI, an electromagnetic field CE is generated in the winding 20 perpendicular to the plane formed by each turn 19.

[0037] In a preferred configuration, the at least two upper tracks 12' and 12" comprise a defined number, greater than or equal to 2, of upper tracks in the PI plane. And, the at least one lower track 14' comprises a defined number, greater than or equal to 1, of lower tracks in the second plane P2 parallel to the PI plane.

[0038] Each lower track of the at least one lower track 14' comprises a first portion 146 opposite an upper track among said at least two upper tracks, such as for example the first upper track 12', and a second portion 148 opposite an upper track adjacent to said upper track, such as for example the second upper track 12'.

[0039] In other words, the first lower track 14' is positioned between the first upper track 12' and the second upper track 12”. Thus, the projection of the first lower track 14' lies between the first upper track 12' and the second upper track 12” in the first plane PI. The first lower track 14' is therefore offset relative to the first upper track 12' by means of a rotation whose center is substantially close to the center of the section to be measured 2.

[0040] And, similarly, the printed circuit 10 may include, in addition to the first lower track 14', a second lower track 14”. The first lower track 14' and the second lower track 14” are included in the second plane P2 parallel to the plane PI coinciding with the lower track 14. And, similarly, each upper track of the at least two upper tracks 12' and 12” includes a first portion 126 opposite a lower track among said at least one lower track, and a second portion 128 opposite a lower track adjacent to said at least one lower track.

[0041] In other words, the second upper track 12” is arranged between the first lower track 14’ and the second lower track 14”, as shown in [Fig. 1]. And, a first portion 126 of the second upper track 12” is opposite the first lower track 14’ while a second portion 128 of the second upper track 12” is opposite the second lower track 14”.

[0042] Thus, the projection of the second upper track 12" is located between the first lower track 14" and the second lower track 14" in the second plane P2. The second upper track 12" is therefore offset relative to the second lower track 14" by means of a rotation whose center is substantially close to the center of the section to be measured 2.

[0043] And, similarly, the printed circuit board 10 may include a third upper track 12” included with the first upper track 12” and the second upper track 12” in the first plane PL. And, the second lower track 14” may then be disposed between the second upper track 12” and the third upper track 12”. And, as previously stated, a first portion of the second track in lower 14” is opposite the second upper 12” runway while a second portion of the second lower 14” runway is opposite the third upper 12” runway.

[0044] Thus, the projection of the second lower track 14'' can be included between the second upper track 12" and the third upper track 12" so that there is the offset.

[0045] The first upper track 12' is at a distance from the second upper track 12”. In other words, there is a spacing 13 between the first upper track 12' and the second upper track 12”.

[0046] The printed circuit board 10 may also include, as shown in [Fig. 3], a return track 17 extending along a third plane P3 parallel to the first plane P1 and the second plane P2. The return track 17 is configured to surround the electrical element. The third plane P3 lies between the first plane P1 and the second plane P2 along a fourth plane P4 perpendicular to the first plane P1, the second plane P2, and the third plane P3. The conductive wire 18 passes through the return track 17.

[0047] The return track 17 is a layer of the printed circuit board 10 in which the conductive wire 18 extends. The return track 17 is also traversed by the conductive wire 18 such that an intermediate portion 188 of the conductive wire 18 is positioned between the upper portion 182 and the lower portion 186 of the conductive wire according to the fourth plane P4. The winding 20 comprises two ends 202 and 204, the first end 202 being connected to a turn 19. The second end 204 is connected to the return track 17. The return track 17 allows the conductive wire 18 to return, thus enabling the measurement of a voltage and a current in the measuring sensor 1.

[0048] In the plane P4 shown in [Fig.3], the return track 17 is narrower than the at least two upper tracks 12' and 12" and the at least one lower track 14'. The vias 16 are thus on either side of the return track 17, which allows the conductor wire 18 to pass through the printed circuit board 10 without crossing the return track 17.

[0049] Generally, each lower track of at least one lower track 14' is arranged opposite a spacing 13. And, each upper track of at least two upper tracks 12' and 12" is arranged opposite a spacing 13.

[0050] Advantageously, the first portion 146 of the at least one lower track 14' represents one half of the at least one lower track 14' and the second portion 148 of the at least one lower track 14' represents the other half of the at least one lower track 14'. Alternatively, the first portion 146 of the at least one lower track 14' may represent two-thirds of the at least one lower track 14' and the second portion 148 of the at least one lower track 14' may represent one-third of the at least one lower track 14'.

[0051] The at least two upper tracks 12' and 12" and the at least one lower track 14' then have the advantage of magnetically isolating the printed circuit board 10 from any external electromagnetic field to the current measuring sensor 1. More precisely, any interfering magnetic flux CEP passing through the printed circuit board 10 and perpendicular to the first plane PI, i.e., orthogonal to the electromagnetic field CE, is blocked by one of the upper tracks of the at least two upper tracks 12' and 12" if this interfering electromagnetic flux CEP must pass through one of the upper tracks of the at least two upper tracks 12' and 12" before passing through the printed circuit board 10, or by the at least one lower track 14' if this interfering electromagnetic flux CEP must pass through the at least one lower track 14' before passing through the printed circuit board 10.The at least two upper tracks 12' and 12" and the at least one lower track 14' thus ensure a magnetic isolation function in the fourth plane P4.

[0052] More specifically, the disturbing electromagnetic flux CEP crossing perpendicularly the PI plane at the level of the current measuring sensor 1 is blocked at least by one upper track of at least two upper tracks 12' or 12" or by at least one lower track 14' so as not to be able to disturb the measuring sensor 1. This offset architecture also has the advantage of reducing the dimensions of the at least two upper tracks 12 and the at least one lower track 14'.

[0053] The at least two upper tracks 12 and / or the at least one lower track 14 may also be an electrically conductive track so as to facilitate the electrical connection between each via 16. It may therefore be envisaged that the at least two upper tracks 12 and / or the at least one lower track 14 be made of a material comprising copper which is an excellent magnetic insulator and a good electrical conductor, thus enabling the at least two upper tracks 12' and 12" and / or the at least one lower track 14' to ensure the two functions of magnetic isolation from the external electromagnetic field of the current measuring sensor 1 and electrical conduction around the printed circuit board 10. The printed circuit board 10 may also include an electrical insulator between the at least two upper tracks 12' and 12" and the at least one lower track 14'.

[0054] As shown in [Fig.4], the offset of the first upper track 12' relative to the first lower track 14' induces misalignment of the upper portion 182 arranged against the first upper track 12' and of the lower portion 186 arranged against the first lower track 14'.

[0055] As shown in [Fig. 5], each upper 12', 12" or even 12" track of the at least two upper 12' and 12" tracks such as the first upper 12' track or the second upper 12" track of the upper 12' track and each lower track of the at least one lower 14' track such as the first lower 14' track or the The second lower track 14” includes two vias 16 so as to allow the turns 19 to be connected together. It is thus possible to repeat the same elementary pattern, namely the turn 19 of conductor wire 18 as shown in [Fig.6].

[0056] As stated previously, the measuring sensor 1 surrounds the electrical element. Preferably, the measuring sensor 1 has an annular shape.

[0057] In addition, each track of at least one lower 14' track, such as the first lower 14' track or the second lower 14" track, and each track of at least two upper tracks, such as the first upper 12' track or the second upper 12" track, are identical.

[0058] In a ring-shaped measuring sensor 1 configuration, the first upper track 12' may be trapezoidal or a solid arc in the first plane PI. The first lower track 14' may also be trapezoidal or an arc in the first plane PI. Alternatively, the measuring sensor 1 may be elliptical or bar-shaped. However, any other geometric shape, such as a triangle, may be considered.

[0059] A solid arc is understood to mean that the at least one lower track 14' comprises four sides 1400, 1401, 1402, and 1403 in the second plane P2, as shown in [Fig. 1]. Two sides 1400 and 1402 of the four sides 1400, 1401, 1402, and 1403 are straight, and two sides 1401 and 1403 of the four sides 1400, 1401, 1402, and 1403 are curved. And, a curved side, for example, the first curved side 1401, is adjacent to the two straight sides 1400 and 1402.

[0060] Similarly, the at least two lower tracks 12' or 12" comprise four sides 1200, 1201, 1202, and 1203 in the first plane PI. Two sides 1200 and 1202 of the four sides 1200, 1201, 1202, and 1203 are straight, and two sides 1201 and 1203 of the four sides 1200, 1201, 1202, and 1203 are curved. And, a curved side, for example, the first curved side 1201, is adjacent to the two straight sides 1200 and 1202.

[0061] As stated previously, each run of the at least two upper 12' runs or of the at least one lower 14' run comprises two 16' vias. The first portion of the at least one lower 14' run may comprise a first 16' via and the second portion of the at least one lower 14' run comprises a second 16' via. And, similarly, the first portion of an upper run of the at least two upper 12' runs may comprise a first via and the second portion of the upper run of the at least two upper 12' runs comprises a second via.

[0062] The via of the first portion of at least one lower runway 14', i.e. the first via 16', is arranged next to a first straight side 1400 of the two straight sides and a first curved side 1401 of the two curved sides and the via of the second portion of at least one lower runway 14', namely the second via 16', is arranged next to the other right side 1402 of the two right sides, namely the second right side 1402, and to the other curved side 1403 of the two curved sides, namely the second curved side 1403.

[0063] In other words, each track among the at least one lower track 14' comprises four vertices 1410, 1412, 1414, 1416. The first via 16' and the second via 16" are positioned near two vertices that are not adjacent to each other. As an illustrative example, the first via 16' may be positioned near a first side 1410, and the second via 16" is then positioned near a third side 1414 that is not adjacent to the first side 1410. By "not adjacent," it is understood that the two vertices are not consecutive.

[0064] Similarly, each of the at least two upper tracks comprises four vertices. The first via of said upper track and the second via of said upper track are positioned near two vertices that are not adjacent to each other.

[0065] As shown in [Fig.7], the first upper track 12' is in contact, along the first right side 1200, with a spacing 13 and, along the second right side 1202, with another spacing 13'. And, the first lower track 14' is in contact, along the first right side 1400, with a third spacing 13" and, along the second right side 1402, with a fourth spacing 13"'.

[0066] In other words, each track of the upper track of the at least two upper tracks 12' and 12" is arranged between two spacings 13 in the first plane PI and each track of the lower track of the at least one lower track 14' is arranged between two spacings 13 in the second plane P2.

[0067] However, as stated previously, the surface area of ​​the first portion and the surface area of ​​the second portion are identical.

[0068] In other words, each spacing 13 is arranged opposite the center of an upper track of at least two upper tracks 12' or 12" such as the first upper track 12' or opposite the center of a lower track of at least one lower track 14' such as the first lower track 14'.

[0069] Thus, the second 13' spacing arranged between the first upper 12' track and the second upper 12" track faces the center of the first lower 14' track. And, the fourth 13" spacing arranged between the first lower 14' track and the second lower 14" track also faces the center of the second upper 12" track in the first plane PL. The at least one lower 14' track, as well as the at least two upper 12' tracks, comprise a mean angular length lam, which is defined as the mean length of the sum of the two curved sides 1402 and 1404. Therefore, the offset between the at least two upper 12' tracks, such as the first upper 12' track or the second upper 12" track, and the at least one lower track such as the first lower track 14' or the second lower track 14'' is of a length equal to .

[0070] The first lower track 14' is offset from the first upper track 12' by an arc of a circle of length equal to . Any other offset along an arc of a circle of defined length, such as for example or 2k, may be considered. 3 4

[0071] Advantageously, the distance separating the first plane PI, and therefore the at least two upper tracks 12' and 12", from the second plane P2, and therefore the at least one lower track 14', is less than 5 millimeters, so that the thickness of the measuring sensor 1, defined by this distance between the first plane PI and the second plane P2, is small. Very advantageously, the distance separating the first plane PI from the second plane P2 is less than 2 millimeters and preferably equal to 1.5 millimeters, so that the thickness of the measuring sensor 1 is small.

[0072] The measuring sensor 1, surrounding the electrical element, may advantageously include an internal diameter RI between 20 millimeters and 200 millimeters, defining the measuring section 2 and an external diameter R2 between 40 millimeters and 400 millimeters so that the measuring sensor is suitable for wide size ranges of the electrical element.

[0073] The first upper track 12', the second upper track 12”, the first lower track 14' or even the second lower track 14” advantageously comprises an average angular length lam between 10 millimeters and 1.5 millimeters so that the number of turns 19 surrounding the printed circuit 10 can be defined.

[0074] The diameter of at least one via 16 can also be between 0.3 millimeters and 5 millimeters.

[0075] Advantageously, it can be envisaged that each track of the at least one lower track 14' and each track of the at least two upper tracks 12' and 12" are identical. Machining each track is then facilitated.

[0076] The offset arrangement of the upper track 12 and the lower track 14 thus has the advantage of having an overlap of one track by the other so as to reduce the electromagnetic sensitivity of the measuring sensor 1.

Claims

Claims

1. Rogowski type sensor (1) configured to measure an electric current passing through an electrical element, the sensor (1) comprising a printed circuit (10), said printed circuit (10) comprising: - at least two upper tracks (12', 12”) extending along a first plane (PI): - at least one lower track (14') extending along a second plane (P2) parallel to the first plane (PI), the upper tracks (12', 12”) and said at least one lower track (14') being configured to surround the electrical element; and - vias (16, 16', 16”) connecting the upper tracks (12', 12”) to said at least one lower track (14'), the sensor (1) further comprising a conductive wire (18) comprising several turns (19), each turn (19) comprising an upper portion (182), a lower portion (186) and an intermediate portion (184) connecting the upper portion (182) to the lower portion (186), the upper portion (182) of each turn (19) extending on an upper face (122) of an upper track (12', 12”) among the upper tracks (12', 12”), the lower portion (186) of each turn (19) extending on a lower face (142) of a lower track (14') among the at least one lower track (14'), and the intermediate portion (184) passing through one of the vias (16, 16', 16”) connecting said upper track (12', 12”) to said lower track (14'),the sensor (1) being characterized in that each lower track among the at least one lower track (14') comprises a first portion (146) facing an upper track (12') among said at least two upper tracks (12', 12”), and a second portion (148) facing an upper track adjacent (12”) to said upper track (12').,

2. Rogowski type current sensor (1) according to claim 1, comprising a return track (17) between said at least two upper tracks (12', 12”) and said at least one lower track (14), the return track (17) extending along a third plane (P3) parallel to the first plane (PI) and to the second plane (P2), the return track (17) being configured to surround the electrical element, the conductive wire (18) passing through the return track (17).

3. Rogowski type current sensor (1) according to one of claims 1 or 2, in which the first portion (146) of the at least one lower track (14') represents two thirds of the at least one lower track (14') and the second portion (148) of the at least one lower track (14') represents one third of the at least one lower track (14').

4. Rogowski type current sensor (1) according to one of claims 1 or 2, in which the first portion (146) and the second portion (148) each represent a half of the at least one lower track (14').

5. Rogowski type current sensor (1) according to one of claims 1 to 4, in which the at least one lower track (14') and the upper tracks (12', 12”) are identical to each other.

6. Rogowski type current sensor (1) according to one of claims 1 to 5, wherein the first portion (146) of the at least one lower track (14') comprises a first via (16') among said vias (16, 16', 16”) and the second portion (148) of the at least one lower track (14') comprises a second via (16”) among said vias (16, 16', 16”).

7. Rogowski type current sensor (1) according to one of claims 1 to 6, wherein the at least one lower track (14') comprises four vertices, the first via (16') and the second via (16”) being positioned near two vertices not adjacent to each other.

8. A Rogowski-type current sensor (1) according to claim 5, wherein the at least one lower track (14') comprises four sides (1400, 1401, 1402, 1403), two sides (1400, 1402) among the four sides being straight and two sides (1401, 1403) among the four sides being curved, one curved side (1401) connecting the two straight sides (1400, 1402).

9. Rogowski type current sensor (1) according to one of the preceding claims, in which the at least two upper tracks (12', 12”) are spaced from the at least one lower track (14') by a distance of less than 5 millimeters, and preferably equal to 1.5 millimeters.

10. Rogowski type current sensor (1) according to one of the preceding claims, in which the at least two upper tracks (12', 12”) and the at least one lower track (14') are made of copper.

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