"Constructive System Regarding a Capacitive Voltage Sensor"

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Field of the Invention

_The present invention relates to a constructive system comprising a capacitive voltage sensor, wherein said sensor detects the electric field generated by a voltage element of the same capacitive sensor, for example, to determine the voltage value of said live element.

_More particularly, the present invention relates to a constructive system comprising a capacitive voltage sensor, in which said sensor detects the electric field generated by a voltage element of the same sensor without affecting any surrounding electric and/or magnetic fields, such as, for example, the electromagnetic fields generated by other conductors and/or other nearby bars.

Background of the Invention

_At the present the known capacitive voltage sensors have a number of drawbacks.

_A first drawback is due to the fact that the resin of dielectric material disposed around the sensor components includes vacuoles (air bubbles) with consequent phenomena of unwanted partial discharges.

_Another disadvantage is due to the fact that the same resin is detached from the elements that make up the capacitive sensor with consequent phenomena of unwanted partial discharges.

_A third drawback is due to the fact that said resin is not perfectly adherent and/or not perfectly clamped and/or constrained with respect to the organs constituting the capacitive sensor and, therefore, as a result of aging, there are discontinuities between said resin and the organs quoted, with consequent phenomena of unwanted partial discharges. _This disadvantage is particularly present when the capacitive sensor is used in an environment where the operating temperature (hot/cold) varies cyclically.

_With reference to the facts of the invention, the following documents are cited: WO_2010 / 070.693.A1 , CN_105.588.966.A and US_6.252.388.B1.

Exposure of the Invention

Jt is therefore the object of the present invention to solve the aforementioned drawbacks.

_The invention, which is characterized by the claims, solves the problem of creating a constructive system regarding a capacitive sensor of electric voltage, in which said capacitive sensor extends axially along an axis defined longitudinal, in which said capacitive sensor comprises: >_a source electrode, jn which said source electrode has an elongated shape that extends longitudinally along a longitudinal axis, jn which said source electrode configures a first axial end portion and a second axial end portion opposite to the first axial end portion; >_a tubular body shielding, _in which said tubular body shielding has an elongated shape which extends longitudinally along a longitudinal axis, _jn which said tubular body shielding configures a first axial portion and a second axial portion opposite to said first axial portion, _in which said tubular body shielding configures a shell having an inner face and an outer face; >_an electric field sensor, _in which said electric field sensor is positioned radially spaced around said source electrode, _jn which said electric field sensor is positioned within said tubular body shielding, _in which said electric field sensor is positioned between the first axial end portion and the second axial end portion; >_a mass of dielectric insulating material, in which said mass is able to encompass said tubular body shielding, said source electrode and said electric field sensor; in which said constructive system is characterized by the fact that said electric field sensor comprises at least a first inner sheet and a second outer sheet overlapped and joined together; by the fact that said first inner sheet is made by an electrically conductive material; by the fact that said second outer sheet is made by an electrically insulating material; by the fact that said second outer sheet made by insulating material is constrained with respect to the inner face of the tubular shielding.

Brief description of the drawings

_Further features and advantages of the present invention will be more evident from the following description of some of its preferred embodiments, here given merely by way of non-limiting example, with reference to the accompanying drawings in which:

>_Figure 1 illustrates a first embodiment of the constructive system object of the present invention, wherein said system is used to produce a capacitive voltage sensor; >_Figure 2 illustrates a second embodiment of the constructive system object of the present invention, wherein said system is used to make a feedthrough able to also perform the function of capacitive voltage sensor;

>_Figures 3, 4 and 5 illustrate in schematic manner and as planarly view a possible and preferred embodiment of a structure for forming an electric field sensor prior to its insertion into a shielding tubular body, in which Fig. 4 is a cross-sectional view with respect to the line 4-4 of Fig. 3;

>_Figure 1A illustrates a constructive variation of the system of the first embodiment of FIG. 1 ;

>_Figure 2A illustrates a constructive variation of the system that relates to the second embodiment of Fig. 2;

>_Fig. 6 illustrates schematically a constructive detail regarding the constructive variants of Figs. 1 A and 2A. Exemplifying Description of Some Preferred Embodiments

_With reference to the accompanying drawings, the constructive system object of the present invention is able to provide a capacitive electrical voltage sensor, wherein said sensor extends along an axis Y defined longitudinal.

_With reference to Fig. 1 and 2, this system substantially comprises a source electrode 110/210, a shielding tubular body 120/220, an electric field sensor 130/230, and a mass of dielectric insulating material 140/240.

_With reference to said source electrode 110/210 it has an elongated shape extending longitudinally along a longitudinal axis Y, in such a way as to configure a first axial end portion 111/211 and a second opposite axial end portion 112/212, in which the latter is opposite with respect to the first axial end portion 111/211.

_With reference to the shielding tubular body 120/220, it has an elongate shape extending longitudinally along a longitudinal axis Y, so as to configure a first axial end portion 121/221 and a second opposite axial end portion 122/222.

_The shielding tubular body 120/220 is preferably grounded and it is able to shield the electric field sensor 130/230 with respect to the field lines generated by live voltage conductors positioned externally with respect to the capacitive sensor, so that the field sensor 130/230 detects the field lines generated by the source electrode 110/210.

_Said shielding tubular body 120/220 comprises a tubular mantle 123/223, wherein said mantle 123/223, configures an inner face 124/224 and an outer face 125/225 with respect to the central axis Y.

_With reference to the electric field sensor 130/230, said electric field sensor 130/230 is radially spaced with respect and around said source electrode 110/210 as well as positioned within said shielding tubular body 120/220 and preferably positioned in a intermediate point comprised between the first axial end portion 121/221 and the second axial end portion 122/222 of said screening tubular body 120/220.

_With reference to the mass of dielectric insulating material 140/240, said mass is able to incorporate the various elements of the sensor and, primarily and substantially, said shielding tubular body 130/230, said source electrode 110/210 and said electric field sensor 130/230, in order to positioning said elements and in order to form an electrically insulated carrier structure.

_Also referring to Figures 3, 4, 5 and 6, said electric field sensor 130/230 comprises at least one first inner sheet 131/231 and a second external sheet 132/232 which are superimposed and joined together, preferably as a monolithic structure, as best described below, wherein the first inner sheet 131/231 is made by means of an electrically conductive material (metallic) and the second external sheet 132/232 is made by means of an electrically insulating material.

_With reference to the second outer sheet 132/232 made by insulating material it is preferably bonded to the inner face 124/224 of the shielding element 120/220, for example, by glue points positioned on the outer face of the sheet 132/232 and on the internal face 124/224 of the shielding tubular body 120/220, or by other systems as described below.

_With reference to the first internal sheet 131/231 made by conductive material, it is able to detect the electric field lines generated by the source electrode 110/210 and, more particularly, it is intended to form a capacitive coupling between said source electrode 110/210 and said first sheet 131/231.

Jn this context, said first sheet 131/231 may take various forms and/or dimensions and/or sizes which can be different with respect to those illustrated in the figures, without departing from the inventive concept of the present invention.

_With reference to the second outer sheet 132/232 made by insulating material, it is able to support the inner sheet 131/231 in place, as well as able to electrically insulating the inner sheet 131/231 with respect to the shielding tubular body 120/220 and therefore, said second sheet 132/232 may take shapes and/or thickness and/or size and/or conformations different with respect of those illustrated in the Figures without departing from the inventive concept of the present invention.

_With particular reference to Figures 1A, 2A and 6, the shielding tubular body 120/220 is provided with first through holes 126/226, wherein said first through holes 126/226 have a width such that the resin can pass through the same first through holes 126/226 during the casting of the same resin while forming the sensor.

_With reference to Figs. 3, 4 and 5, said electric field sensor 130/230 is provided with second through holes 133/233, wherein said second through holes 133/233 have a width able to allow the passage of the resin through the same second holes 133/233 during its casting for forming the sensor.

_With particular reference to Figure 6, said first through holes 126/226 and said second through holes 133/233 are axially and mutually communicating, preferably axially aligned with each other, and in any case disposed in such a way as to allow the passage of the resin through said first 126/226 and said second 133/233 through holes during the casting of the same resin while forming the sensor.

_With reference to Fig. 5, said electric field sensor may further comprise optional fixing means 150, which are applied to the external face 133/233 of the second outer sheet 132/232, wherein said fixing means 150 are designed to form a bond between the second sheet 132/232 and the inner face 124/224 of the shielding tubular body 120/220.

Jf the fixing means 150 are not present, the electric field sensor comprises only the inner sheet 131/231 and the external sheet 132/232, associated with them, provided with through holes 133/233, and in this case it is provided to fix the outer foil 132/232 with respect to and/or against the inner face 124/224 of the shielding tubular body 120/220 by points of glue or other systems.

_With particular reference to Figures 3, 4 and 5, they illustrate in detail a particular electric field sensor 130/230, wherein said first inner sheet 131/231 is provided with respective through holes defined by a respective perimeter 134/234, said second outer sheet 132/232 is provided with respective through holes defined by a respective perimeter 135/235, wherein said through holes in said first inner sheet 131/231 have a greater amplitude than the through holes in the second outer sheet 132/232, in such a way as to create between said two perimeters 134_135 / 234_235 (i.e., between said two through holes) an annulus 136/236 of insulating material.

_With reference to Figures 1 and 2, the capacitive coupling between the source electrode 110/210 and the electric field sensor 130/230 detects the electric field generated by the source electrode 110/210, and the relative signal by the cable 160/260 can be transmitted to a processing device 170/270, for example to estimate the value of the voltage present in said source electrode 110/210.

_With reference to the above description, as the electric field sensor 130/230 is formed by a monolithic body comprising at least one first internal sheet 131/231 and a second external sheet 132/232 overlapped and joined together (glued, associated, bound) before of the their insertion into the shielding tubular body 120/220, there is no undesirable delamination dislocation/separation between said two sheets, thus solving the above-mentioned problems as well as solving other problems associated with the assembling of the sensor components before the casting, as the electric filed sensor 130/230 is easily and quickly secured/fixed in position by means of points of glue between the external face 137/237 of the external sheet 132/232 of the electric field sensor 130/230 and the internal face 124/224 of the shielding tubular body 120/220. _With reference to the particular embodiment of Figure 6, the resin can pass and flow through the holes 133/233 executed in the two sheets 131/231 and 132/232 of the electric field sensor 130/230 during its casting, and some resin can also and flow through the holes 126/226 of the screening tubular body 120/220, and in this manner the characteristics of filling and of gripping of the resin are improved, no undesired vacuoles are formed, and no undesired dislocation/separation shall occur between the shielding body 120/220 and the electric field sensor 130/230, thus solving the above-mentioned problems.

_The description of the various embodiments of the constructive system for a capacitive sensor are provided solely by ways of non-limiting example, and clearly, therefore, said system can be modified or varied in any way suggested by experience and/or by its use or application within the scope of the following claims. _ The following claims also form an integrative part of the above description.