Patent Publication Number: US-2023143620-A1

Title: Constructive system regarding a capacitive sensor

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 17/031,021, filed Sep. 24, 2020, issued as U.S. Pat. No. 11,543,436, which is a continuation of International Application No. PCT/IT2019/000023, filed on Mar. 19, 2019, which claims priority to Italian Patent Application No. 102018000004114, filed Mar. 30, 2018, the entire contents of all of which are incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to a constructive system regarding a capacitive voltage sensor, wherein said sensor is able to detect the electric field generated by a voltage element of the same capacitive sensor, in order, for example, to be able to estimate the value of the voltage of said live element. 
     More particularly, the present invention relates to a constructive system regarding a capacitive voltage sensor, wherein said sensor provides for detecting the electric field generated by the voltage element of the same sensor without undergoing the influence of any surrounding electric and/or magnetic fields, such as, for example, electro/magnetic fields generated by other conductors and/or other bars arranged nearby. 
     BACKGROUND 
     Currently the current capacitive voltage sensors have a series of drawbacks. 
     A first drawback is due to the fact that the resin dielectric material arranged around the components of the sensor includes vacuoles (air bubbles) with consequent phenomena of undesired partial discharges. 
     A second drawback is due to the fact that the same resin is detached with respect to the elements that make up the capacitive sensor with consequent phenomena of undesired partial discharges. 
     A third drawback is due to the fact that the aforementioned resin is not perfectly adherent and/or not perfectly clinging and/or constrained with respect to the elements making up the capacitive sensor and, therefore, as a result of aging, detachments take place between said resin and the aforementioned elements, with consequent phenomena of unwanted partial discharges. This drawback is particularly present when the capacitive sensor is used in an environment where the operating temperature (hot/cold) varies cyclically. 
     A fourth drawback is due to the fact that the components that make up the sensors are expensive to make. 
     A fifth drawback is due to the fact that the components that form the sensors after their correct positioning can move during the subsequent assembly or transport operations that take place before the resin is poured, with consequent realization of a non-conforming product and/or of a product to be discarded. 
     SUMMARY 
     The invention provides, in one aspect, a capacitive voltage sensor assembly including a first electrode extending along a longitudinal axis, the first electrode including a first end and a second end opposite the first end, a second electrode surrounding the second end of the first electrode, the second electrode including a tubular portion having a first end and a second end opposite the first end, and a base portion coupled to the first end of the tubular portion, and a mass of dielectric insulating material at least partially encapsulating the first electrode and the second electrode. The tubular portion includes a plurality of cantilevered tabs interconnected at the first end of the second electrode. Each tab of the plurality of cantilevered tabs is circumferentially separated from an adjacent tab of the plurality of cantilevered tabs to define a gap therebetween at the second end of the second electrode. 
     The invention provides, in another aspect, a capacitive voltage sensor assembly including a first electrode extending along a longitudinal axis, the first electrode including a first end and a second end opposite the first end, a second electrode surrounding the second end of the first electrode, the second electrode including a tubular portion having a first end and a second end opposite the first end, and a mass of dielectric insulating material at least partially encapsulating the first electrode and the second electrode. The tubular portion includes a plurality of cantilevered tabs interconnected at the first end of the second electrode. Each tab of the plurality of cantilevered tabs circumferentially separated from an adjacent tab of the plurality of cantilevered tabs to define a gap therebetween at the second end of the second electrode. The plurality of cantilevered tabs is configured to flex during curing of the mass of dielectric insulating material. 
     The invention provides, in another aspect, a capacitive voltage sensor assembly including a first electrode extending along a longitudinal axis, a second electrode including a tubular portion arranged coaxially with the longitudinal axis and a base portion located at an end of the tubular portion, the base portion extending transverse to the longitudinal axis, and a mass of dielectric insulating material at least partially encapsulating the first electrode and the second electrode. The tubular portion and the base portion each include a plurality of through holes, and the tubular portion is configured to flex during curing of the mass of dielectric insulating material. 
     Other features and aspects of the invention will become apparent by consideration of the following detailed description and accompanying drawings. 
    
    
     
       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 practical embodiments, given here purely by way of non-limiting example, made with reference to the figures of the enclosed drawings in which: 
         FIG.  1    shows schematically and in axial section a first embodiment of the constructive system object of the present invention; 
         FIG.  2    is an exploded view from above downwards of the components relating to the first embodiment; 
         FIG.  3    is an exploded view from the bottom upwards of the components relating to the first embodiment; 
         FIG.  4    shows schematically and in axial section a second embodiment of the construction system object of the present invention; 
         FIG.  5    is an exploded view from above downwards of the components relating to the second embodiment; 
         FIG.  6    is an exploded view from the bottom upwards of the components relating to the second embodiment. 
         FIG.  7    illustrates schematically a constructive detail of the second embodiment; 
         FIG.  8    schematically illustrates a construction detail of the second embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     With reference to the attached figures, a constructive system according to an embodiment of the present invention concerns a capacitive electric voltage sensor, indicated with S. 100  in  FIGS.  1 ,  2  and  3   , and with S. 200  in  FIGS.  4 ,  5  and  6   , in which said system extends axially along an axis Y_S. 100 /Y_S. 200 , defined longitudinal, configuring a first axial end portion, Ya_S. 100 /Ya_S. 200 , here defined for descriptive reasons as vicinal without limiting intent, and a second axial end portion, Yb_S. 100 /Yb_S. 200 , here defined for descriptive reasons as distal without limiting intent, in which said sensor extends transversely along a transverse axis X. 
     Said system substantially comprises: a first electrode  110 / 210  (made completely or partially with conductive material as better understood in the following), a second electrode  120 / 220  (made completely or partially with conductive material as better understood later), and a mass of dielectric insulating material,  130 / 230 . 
     The first electrode  110 / 210  is positioned near said first axial end portion Ya_S. 100 /Ya_S. 200  and preferably has an elongated shape which extends axially along its axis Y_ 110 /Y_ 210  arranged coaxially with respect to the axis Y_S. 100 /Y_S. 200  of the sensor S. 100 /S. 200 , in order to configure a first axial portion  110 . v / 210 . v  defined vicinal and a second axial portion  110 . d / 210 . d  defined distal and opposite with respect to the first axial portion  110 . v / 210 . d.    
     The second electrode  120 / 220  has a tubular shape that extends longitudinally along a longitudinal axis thereof Y_ 120 /Y_ 220  arranged coaxially with respect to the axis of the sensor Y_S. 100 /Y_S. 200  of the sensor S. 100 /S. 200 . Said second electrode  120 / 220  is positioned around said first electrode  110 / 210 , more particularly around the distal portion  110 . d / 210 . d  of said first electrode  110 / 210 , and also said second electrode  120 / 220  configures a first axial portion  120 . v / 220 . v  defined vicinal and a second axial portion  120 . d / 220 . d  defined distal which is opposite with respect to said first axial portion  120 . v / 220 . v.    
     With reference to the mass of dielectric insulating material  130 / 230 , it is intended to at least partially enclose said first electrode  110 / 210  and said second electrode  120 / 220 . The aforementioned first electrode  110 / 210  preferably has a funnel-like shape, with its distal portion  100 . d / 210 . d  lying within the vicinal portion  120 . v / 220 . v  of the tubular body defined by the second electrode  120 / 220 . 
     With particular reference to the second electrode  120 / 220 , it comprises a plurality of first elements,  121   a,    121   b,    121   c,  etc./ 221   a / 221   b,    221   c,  etc., which have an axially elongated shape intended to define for each of them a vicinal axial end,  121   a.v / 221   a.v , and a distal axial end  121   a.d / 221   a.d.    
     These first elements  121   a,    121   b,  etc./ 221   a,    221   b,  etc. are arranged circumferentially side by side with each other, in order to configure a tubular body  120 / 220  and, again these first elements  121   a,    121   b,  etc./ 221   a / 221   b,  etc. are supported in a cantilevered manner, with their distal ends  121   a.d / 221   a.d  joined to each other by means of a circular ring  123 / 223  which acts as a support foot, so that the respective vicinal ends  121   a.v / 221   b.v  are free to oscillate (move) with a certain degree of freedom, in which said degree of freedom has a magnitude such as to allow said elements  121   a,    121   b,  etc./ 221   a,    221   b,  etc. cantilevered and more particularly supported by said respective vicinal ends  121   a.v / 221   a.v  to flex and/or move during the solidification steps of the resin used for forming the sensor, i.e. to follow the thermal extensions and contractions of the same resin during the casting and cooling phases of the same resin. 
     Again with reference to the attached figures, the system can further comprise a second element  150 / 250 , wherein said second element  150 / 250  is positioned near the distal ends  121   a.d ,  121   b.d , etc./ 221   a.d ,  221   b.d , etc. of said plurality of first elements  121   a,    121   b,  etc./ 221   a,    221   b,  etc., as for example inside the circular ring  123 / 223  which acts as a support foot. 
     Preferably, said first elements  121   a,    121   b,  etc./ 221   a / 221   b,  etc. are circumferentially spaced apart, in order to form openings  122   a,    122   b,  etc./ 222   a,    222   b,  etc., in which said openings have a width such as to allow the resin, in its liquid/pasty state, and therefore during the pouring thereof, to flow between said openings  122   a,    122   b,  etc./ 222   a ,  222   b,  etc. from the outside towards the inside of the tubular body  120 / 220  as well as from the inside towards the outside of the same tubular body  120 / 220  and, therefore, allowing to the same resin to perfectly arrange itself around the individual elements. In this context, optionally, said first elements  121   a,    121   b,  etc./ 221   a,    221   b,  etc. can also be equipped with through holes  124 / 224 . Preferably, said first elements  121   a,    121   b,  etc./ 221   a,    221   b,  etc. can be laminar elements having an elongated shape which extends along a respective longitudinal axis  121   a.y / 221   a.y , in which the latter axis can be oriented parallel to the longitudinal axis Y_S. 100 /Y_S. 200  of the sensor S.  100 /S. 200 . In this context, this parallelism is a preferred but not a limiting characteristic. 
     Preferably, the distal ends  121   a.d ,  121   b.d , etc./ 221   a.d ,  221   b.d , etc. of said first elements  121   a,    121   b,  etc./ 221   a / 221   b,  etc. are associated/constrained to the external perimeter  151 / 2510   f  said second element  150 / 250 , and said second element  150 / 250  is preferably provided with through openings  154   a,    153   b / 253   a,    253   b,  near the external perimeter  151 / 251  (having a shape in the form of a half-moon) or within said external perimeter  151 / 251 , for the same reasons as previously indicated with respect to the openings  124 / 224 . 
     With particular reference to the figures, as also better described below, said first electrode  120 / 220  having a tubular shape and said second element  150 / 250  having a disc-like shape can form an electrode having the shape of a “glass/cup”, in which said first elements  121   a ,  121   b,  etc./ 221   a / 221   b,  etc. form the tubular portion of said glass and in which the second element  150 / 250  forms the bottom portion of the same glass. 
     With reference to the system illustrated in  FIGS.  1 ,  2  and  3   , two different operating configurations can be implemented. To implement the first operating configuration, the first electrode  110  is connected to a voltage potential, such as for example a live bar by a conductive connection, in such a way that said first electrode  110  performs the function of source electrode  110  electric field generator. In this first configuration, the second electrode  120 , positioned around said source electrode  110 , acts as an electric field sensor electrode  120  and, more particularly, as an electric field sensor electrode  120  able to detect the electric field generated by said source electrode  110 , wherein also the second element  150  is present, wherein said second element  150  can also act as an electric field sensor. 
     To implement the second operating configuration, the second electrode  120  is connected to a voltage potential, such as for example a live bar by a conductive connection, so that said second electrode  120  performs the function of source electrode  120  electric field generator. In this second configuration, the first electrode  110 , positioned within said second source electrode  120 , acts as an electric field sensor electrode  110  and, more particularly, as an electric field sensor electrode  110  able to detect the electric field generated by said source electrode  120 . 
     With reference to  FIGS.  4 ,  5 ,  6 ,  7  and  8   , they illustrate a variant embodiment of the system object of the present invention, wherein, optionally, said first elements  221   a,    221   b,    221   c , etc. comprise respective first laminae  224  in insulating material designed to form a self-supporting support structure and respective first thin layers  225  of conductive material applied on the respective inner surfaces of said first laminae  224 , wherein the set of the various layers  225  made of conductive material of the various first elements  221   a,    221   b,    221   c,  etc. form the second electrode  220 _ 225  having a tubular shape. 
     Optionally, said first elements  221   a,    221   b,    221   c,  etc. may further comprise respective second thin layers  226  of conductive material applied on the outer surface of said first sheets  224 , electrically insulated with respect to the first thin layers  225  and preferably connected to ground, in which the set of the various layers  226  form an electromagnetic screen, having tubular form, which is adapted to prevent electric field lines external to the sensor  5 _ 200 , such as for example electric field lines generated by conductors arranged nearby, to close on the first internal electrode  210  or on the second electrode  220 _ 225 , in such a way that the capacitive coupling between the first electrode  210  and the second electrode  220 _ 225  is immune to the external electric fields. 
       FIGS.  4 ,  5 ,  6 ,  7  and  8    illustrate a variant embodiment of the system object of the present invention in which said second element  250  comprises a first lamina  254  made of insulating material stretched to form a self-supporting supporting structure and a first thin layer of conductive material  255  applied to the inner surface of said first lamina  254 , wherein said first thin layer  255  of conductive material is stretched to form a further component for second electrode  220  of the capacitive sensor S_ 200 , for example electrically connecting said layer inner/upper  255  with the first conductive inner layer  225  of the second electrode  220 . 
     Optionally, said second element  250  may further comprise a second thin layer  256  of conductive material (preferably connected to ground) applied on the outer surface of said first lamina  254  and electrically insulated with respect to the first thin layer  255 , stretched to form an electromagnetic shield adapted to prevent to the electric field lines external to the sensor S_ 200  (such as for example electric field lines generated by conductors arranged nearby) to close on the first internal electrode  210  or on the second electrode  220 _ 225 , so that the capacitive coupling between the first central electrode  210  and the second tubular electrode  210 _ 225  is immune to external electric fields. 
     With reference to  FIG.  7    it illustrates a flat coppered base  81  which can be rolled up, comprising a base  223  and “petals”  221   a,    221   b,  etc., in which the said base  81  is able to form the second electrode  220  having a tubular shape. 
     The flat base  81  comprises a first lamina  224  of insulating material intended to form a self-supporting support structure and a first thin layer  225  of conductive material applied on the inner surface of said first lamina  224 , in such a way that by wrapping said base in the manner of a ring with the first layer  225  inside the second electrode  220  is obtained. 
     Optionally, if desirable, said base  81  may also comprise a second thin layer  226  of conductive material applied to the outer surface of said first lamina  224 , wherein said second thin layer  226  is electrically insulated with respect to the first thin layer  225 , in order to form, throughout the winding in the form of a ring as aforesaid, an electromagnetic shield having a tubular shape in relation to the second electrode  220  as specified above. 
     With reference to  FIG.  8   , the second element  250  can also be obtained by means of a copper-plated base  82 , comprising a first lamina  254  made of insulating material intended to form a self-supporting supporting structure and a first thin layer of conductive material  255  applied to the inner/upper surface of said first lamina  254 , in which said first thin layer  255  of conductive material is stretched to form a further component for the second electrode  220  as aforesaid. 
     Optionally, said second element  250  may further comprise a second thin layer  256  of conductive material applied to the outer/lower surface of said first lamina  254 , wherein said second layer  256  is electrically insulated with respect to the first layer  255 , as well as a third layer of conductive material  257 , applied on the outer/lower face of said lamina  254 , electrically isolated with respect to the second layer  256 , wherein said third layer  257  is connected by one or more “via”  258  with the first layer of inner and upper conductive material  255 . 
     With reference to the above description the capacitive sensor S_ 200  can provide a first and a second operative configuration. 
     With reference to the first operating configuration, said first electrode  210  can act as a source electrode and the second electrode  220 , more particularly the inner conductive layer  225  (and also the optional inner conductive layer  255  of the second element  250 ) can perform the function of an electric field sensor electrode adapted to detect the electric field emitted by the first electrode  210  ( 225 , 255 ). 
     With reference to the second operating configuration, said second electrode  220 , more particularly the inner conductive layer  225  (and also the optional internal conductive layer  255  of the second element  250 ) can perform the function of an electric field source electrode and said first electrode  210  can act as an electric field sensor electrode able to detect the electric field emitted by the second electrode  220  (i.e. from the layer  225  and/or the layer  255 ). 
     The description of the various embodiments of the constructive system for a capacitive sensor is given purely by way of an example without limiting, and therefore all the modifications or variants suggested by the practice and/or falling within the scope of the following claims can be applied to said system. The following claims are also an integrative part for the above description.