EP3394862A1

EP3394862A1 - High-voltage electric insulator

Info

Publication number: EP3394862A1
Application number: EP16809126.2A
Authority: EP
Inventors: Florent MOREL; Olivier FABRÈGUE
Original assignee: Centre National de la Recherche Scientifique CNRS; Ecole Centrale de Lyon; SuperGrid Institute SAS
Current assignee: Centre National de la Recherche Scientifique CNRS; Ecole Centrale de Lyon; SuperGrid Institute SAS
Priority date: 2015-12-22
Filing date: 2016-11-03
Publication date: 2018-10-31
Anticipated expiration: 2036-11-03
Also published as: CN108604486A; FR3045917A1; WO2017109302A1; EP3394862B1; FR3045917B1

Abstract

The invention relates to a high-voltage electric insulator (1) comprising an elongate insulating element (11) that extends along an axis and has first and second ends (117, 118) at a distance from each other along said axis, and further comprising at least first and second resonant circuits (122, 123) that are galvanically insulated from each other by the insulating element (11), the first and second resonant circuits each comprising at least one winding extending about the axis, said windings being at a distance from each other along the axis and being magnetically coupled.

Description

HIGH VOLTAGE ELECTRIC ISOLATOR

The invention relates to equipment for high voltage networks, in particular the supply of control or control circuits to be connected to a high voltage equipment.

Equipment used in high voltage networks, such as power lines, transformers or power converters, require local electronic circuits. These electronic circuits are used either to control electronic power components or to perform measurements and control operations on the equipment. The supply voltages of this electronic circuit are much lower than the potential difference between the ground and the high voltage level of the equipment to which the electronic circuit is contiguous.

The power supply of such an electronic circuit by battery makes it possible to avoid a wiring between the ground and the circuit, and makes it possible to feed this circuit with few constraints of galvanic isolation with respect to the ground or the high voltage. However, since the battery life is limited, regular maintenance operations are necessary. Such maintenance operations are problematic at high voltage, or require the shutdown of the equipment associated with the electronic circuit, which can be economically disabling.

A supply of the electronic circuit from a source connected to the earth poses problems of galvanic isolation between the ground and the high voltage, all the more annoying that the voltage level is high. The sizing constraints of the circuit can then make its cost prohibitive.

Power supplies of such electronic circuits by energy collectors have also been proposed. However, such solutions are inappropriate in direct current, and do not allow to collect sufficient energy to supply the electronic circuit, if the high voltage equipment on which the energy is taken is not crossed by a sufficient current.

FR738101 discloses a high voltage electrical insulator. This insulator is designed to divert energy from a high-voltage conductor through the insulator. A primary winding passes through the insulator along its axis and connects its input to its output. The primary winding is surrounded by an insulating sleeve. A secondary winding surrounds the insulating sleeve.

Fiber optic feeds have also been proposed. Such power supplies are based on a light emitted by the power supply to the earth, the transmission of this light by an optical fiber, and the conversion of this light into electricity by a converter attached to the electronic circuit. However, such power supplies are particularly expensive and provide only a very limited power. The invention aims to solve one or more of these disadvantages. There is thus a need for a simple and safe solution for supplying electronic circuits connected to high voltage, from a ground potential, without limitation of autonomy. The invention thus relates to a high voltage electrical insulator, as defined in appended claim 1.

The invention also relates to the subject of the appended dependent claims. The various features of the dependent claims may also be independently combined with the features of claim 1, without constituting an intermediate generalization.

It may be noted that the windings of the different resonant circuits are advantageously spaced apart from one another along the axis of the insulator.

The invention also relates to a system, comprising:

an insulator as defined above;

an AC power supply generating a supply potential from a ground potential, said power supply being connected to a third resonant circuit provided with a winding for generating a magnetic flux, said winding generating a magnetic flux being positioned at the first end of the body. Other characteristics and advantages of the invention will emerge clearly from the description which is given hereinafter, by way of indication and in no way limitative, with reference to the appended drawings, in which:

FIG 1 is a schematic representation of an insulator according to an exemplary implementation of the invention;

FIG. 2 is a schematic representation of an example of a power transmission circuit integrated in the isolator of FIG. 1;

FIG 3 is a sectional view of a first variant of fixing a resonant circuit on an insulator body;

FIG 4 is a sectional view of a second variant of fixing a resonant circuit on an insulator body;

FIG 5 is a third sectional view first variant of fixing a resonant circuit on an insulator body;

FIG 6 is a sectional view of a fourth variant of fixing a resonant circuit on an insulator body;

FIG 7 is a sectional view of a fifth variant of fixing a resonant circuit on an insulator body.

Figure 1 is a schematic representation of an electrical system including a high voltage electrical insulator 1 according to an exemplary implementation of the invention. The insulator 1 is here illustrated for illustrative purposes in a application of support of a high-voltage line 94. An insulator according to the invention can of course also be used with other types of high voltage equipment, such as transformers or converters for example in the form of isolated bushings or arresters.

An electrical isolator 1 is fixed at the top of a pole 91. The post 91 has at its upper part an arm 92. The electrical insulator 1 is fixed cantilevered to the post 91 via the arm 92. A power supply circuit 2 is attached to the post 91 or arm 92, or isolator 1. The power supply 2 is configured to generate an alternating voltage on an output interface, from a ground reference potential 93.

The electrical insulator 1 comprises, in a manner known per se, fastening supports 13 and 14 at opposite ends. The electrical insulator 1 further comprises an insulating body 1 1 elongated along an axis, in a manner known per se. The fixing supports 13 and 14 are attached to respective axial ends 11 and 18 of the insulating body 11. The fixing brackets 13 and 14 are here metal parts. The fixing supports 13 and 14 are electrically insulated in a manner known per se through the insulating body 11. In particular, the electrical insulator 1 advantageously comprises at least one cross section between the axial ends 1 17 and 1 18 containing only electrically insulating material (this cross section containing for example only the insulating body 1 1, or for example the body insulation 1 1 and air). The insulator 1 then does not include an electrical conductor extending right through between the axial ends 1 17 and 1 18.

The fixing support 13 is fixed to the arm 92. The fixing support 14 comprises a bow 141 crossed by a high-voltage line 94. An electronic circuit 3 is for example fixed to the support 14. The electronic circuit 3 is connected to the high line. voltage 94. The electronic circuit 3 is for example configured to measure an electrical parameter on the high voltage line 94, for example the current passing through it or its potential.

The electrical insulator 1 further comprises a device for transmitting wireless electrical energy 12. The energy transmission device 12 comprises an input connected to the supply circuit 2, and an output connected to the electronic circuit 3. The device power transmission 12 comprises several resonant circuits galvanically isolated from each other magnetically coupled. Each of these resonant circuits comprises at least one respective winding around the axis of the body January 1. These windings are spaced apart from each other along said axis and are magnetically coupled. Thus, electrical energy can be transmitted between the resonant circuits along the axis of the insulator 1. In this case, the energy transmission device 12 comprises an input resonant circuit 121, a first intermediate resonant circuit 122, a second intermediate resonant circuit 123, and an output resonant circuit 124. The resonant circuits 121 to 124 are distributed along the axis of the body 1 1 of the insulator. The resonant input circuit 121 is connected to the supply circuit 2. The resonant output circuit 124 is connected to the electronic circuit 3.

Figure 2 is an electrical diagram corresponding to an example of energy transmission device 12 according to the invention. The resonant circuit 121 comprises at least one conductive winding connected to the supply circuit 2. This winding is positioned at the end 1 17 of the insulating body 1 January. This winding is intended to generate a magnetic flux, part of which passes through a winding of an adjacent resonant circuit. The winding of the resonant circuit 121 comprises at least one turn whose axis is substantially collinear with the axis of the insulating body 1 January. The inductance and the resistance of the winding of the resonant circuit 121 are here modeled by an inductance 161 and a resistor 171. The resonant circuit 121 here includes a capacitor 151 connected in series with the inductor 161. Discrete components can of course be added to adapt the values of inductance and resistance in the resonant circuit 121.

The resonant circuit 122 comprises at least one conductive winding. The winding of the resonant circuit 122 comprises at least one turn whose axis is substantially collinear with the axis of the insulating body 1 January. The inductance and the resistance of the winding of the resonant circuit 122 are here modeled by an inductor 162 and a resistor 172. Discrete components can of course be added to adapt the inductance and resistance values in the resonant circuit 122. The resonant circuit 122 is here of the series RLC type and includes a capacitor 152 connected in series with the inductor 162 and the resistor 172. The capacitor 152 is here a discrete component.

The resonant circuit 123 comprises at least one conductive winding. The winding of the resonant circuit 123 comprises at least one turn whose axis is substantially collinear with the axis of the insulating body 1 January. The inductance and the resistance of the winding of the resonant circuit 123 are here modeled by an inductance 163 and a resistor 173. Discrete components can of course be added to adapt the inductance and resistance values in the resonant circuit 123. The resonant circuit 123 is here of series RLC type and includes a capacitor 153 connected in series with the inductor 163 and the resistor 173. The capacitor 153 is here a discrete component. The resonant circuit 124 comprises at least one conductive winding connected to the electronic circuit 3. This winding is positioned at the end 1 18 of the insulating body 1 January. This winding is intended to receive a magnetic flux from a winding of an adjacent resonant circuit. The electronic circuit 3 is here illustrated in the form of an electric charge. The winding of the resonant circuit 124 comprises at least one turn whose axis is substantially collinear with the axis of the insulating body 1 January. The inductance and the resistance of the winding of the resonant circuit 124 are here modeled by an inductance 164 and a resistor 174. Discrete components can of course be added to adapt the inductance and resistance values in the resonant circuit 124. The resonant circuit 124 here is of the series RLC type and includes a capacitor 154 connected in series with the inductor 164 and the resistor 174. The capacitor 154 is here a discrete component.

The windings of two adjacent resonant circuits along the body 1 1 are magnetically coupled. The windings of the resonant circuits are for example made of conductive wire, for example copper or aluminum. Advantageously, the supply frequency generated by the supply circuit 2 is equal to the resonance frequencies of the resonant circuits.

When the supply circuit 2 applies an AC voltage to the resonant circuit 121, a variable current flows in this circuit 121, the winding of which creates a variable magnetic flux. Part of this magnetic flux will pass through the winding of the resonant circuit 122 by mutual coupling. The variable flux in the winding of the intermediate resonant circuit 122 creates a variable induced voltage in the winding. A variable current appears in this winding and in the capacitor 152. This current then creates another variable magnetic flux. Thus, electrical energy is transferred step by step to the resonant circuit 124.

An insulator 1 according to the invention thus makes it possible in a simple way to transfer, with a galvanic isolation, electrical energy between a supply circuit and an electronic circuit with very different potentials. Such an insulator 1 remains compact and the use of the insulating body insulating properties 1 1 as a resonant circuit support reduces the distance between the resonant end circuits, which further improves the transmission efficiency.

Advantageously, the intermediate resonant circuits 122 and 123 have the same resonance frequency. Advantageously, the resonant input circuit 121 and the resonant output circuit 124 have the same resonance frequency as the intermediate resonant circuits. These different configurations make it possible to improve the energy transmission efficiency of the device 12. It is particularly difficult to obtain good yields when the distance between the transmitter and the receiver is important, but in a context of high voltage equipment, this distance is important to ensure galvanic isolation. Advantageously, the resonant frequency of the resonant circuits 121 to 124 is at least equal to 5 kHz, or even at least 20 kHz, or even at least 100 kHz, for example up to 1 GHz. Such resonance frequency levels allow:

reduce the size of the capacitors of the resonant circuits, or even eliminate them;

to reduce the number of turns of each winding of a resonant circuit.

In the example illustrated, the resonant circuits 121, 122, 123 and 124 each include a capacitor. Such a component is optional, the parasitic capacitance of the windings of the resonant circuits being sufficient to obtain an appropriate resonant frequency for each of these resonant circuits. The capacitors of the resonant circuits may preferentially be of the film or ceramic type.

To increase the mutual coupling between the windings of the resonant circuits 121 to 124, the windings are advantageously concentric with an axis coinciding with that of the insulating body 11. The use of concentric windings having an axis coincident with that of the insulating body 1 1 makes it possible to maintain these windings parallel to the equipotential lines. The windings thus do not alter the voltage withstand of the insulator 1. In order to further increase the efficiency of the energy transmission device 12, each of said windings comprises several turns wound around the axis of the insulating body 11.

For the sake of simplification, the transmission device 12 here comprises only two intermediate resonant circuits. However, it is possible to envisage using a larger number of intermediate resonant circuits in order to reduce the distance between two adjacent resonant circuits and thus to improve the transmission efficiency of this transmission device 12. The number of intermediate resonant circuits may, for example, be to be defined according to the length of the insulating body 1 1, as well as its geometry.

The insulating body 11 is for example made of a usual insulating material, such as ceramic, porcelain or glass. The insulating body 11 may also be made in composite form as a fiberglass shaft and a silicone sheath. The insulating body 1 1 retains the usual function of an insulator, namely to galvanically isolate the supports 13 and 14, placed at very different electrical potentials.

The windings of the resonant circuits are here circular, to adapt to an insulating body 1 1 having a symmetry of revolution.

Figure 3 is a schematic sectional view in a longitudinal plane of a first variant of the insulator according to the invention. FIG. 3 is only a detail view at a resonant circuit 120 of the energy transmission device 12. The insulating body 1 1 here has a shape of revolution about the axis 1 15, defining an alternation of 1. The winding of the resonant circuit 120 has several turns 160 wound around the axis 1 15 and connected to a capacitor 150. The turns 160 and the capacitor 150 are here positioned at the bottom of the coil. the groove 1 12, which allows them to provide greater mechanical and electrical protection.

Grooves 1 14 are advantageously formed in the groove 1 12.

The grooves 1 14 have the same pitch as the turns 160 of the winding of the resonant circuit 120. The turns 160 of this winding are housed in these grooves 1 14, which allows in particular to ensure a better mechanical retention of these turns 160.

The capacitor 150 is fixed to the insulating body 1 1 by any appropriate means, for example by gluing. The capacitor 150 is here housed in a respective groove or in a recess. Advantageously, the winding of the resonant circuit 120 (and if necessary the capacitor 150) is covered by an electrically insulating material 18. Thus, the maintenance of the insulator 1 will be facilitated, for example by allowing a projection of water to avoid the formation of a conduction path on the surface of the insulating body January 1, without altering the resonant circuit 120. The insulating material 18 here forms a sleeve around the turns 160. The insulating material is for example an insulating synthetic resin.

Figure 4 is a schematic sectional view in a longitudinal plane of a second variant of the insulator according to the invention. FIG. 4 is only a detail view at a resonant circuit 120 of the energy transmission device 12. The insulating body 1 1 here has a shape of revolution about the axis 1 15, defining an alternation of 1. The winding of the resonant circuit 120 comprises several turns 160 wound around the axis 1 15 and connected to a capacitor 150. The turns 160 and the capacitor 150 are here positioned at the periphery. of a projecting ring January 1, which increases the mutual coupling between the adjacent resonant circuits. Grooves 11 are provided at the periphery of the projecting ring 11 1. The grooves 1 14 have the same pitch as the turns 160 of the winding of the resonant circuit 120. The turns 160 of this winding are housed in these grooves 1 14, which allows in particular to ensure a better mechanical retention of these turns 160.

Figure 5 is a schematic sectional view in a longitudinal plane of a third variant of the insulator according to the invention. FIG. 5 is only a detail view at a resonant circuit 120 of the energy transmission device 12. The insulating body 1 1 here has a shape of revolution around the axis 1 15, defining an alternation of 1. 1 1 1 is defined by the junction between a projecting ring January 1 and a groove 1 12. The winding of the resonant circuit 120 has several turns 160 wound around the axis 1 15 and connected to a capacitor 150. The turns 160 and the capacitor 150 are here positioned in the junction between a projecting ring January 1 and a groove January 12.

Grooves 1 14 are formed in the junction 1 13. The turns 160 are positioned substantially in the same plane and concentric. The turns 160 of this winding are housed in these grooves 1 14, which in particular makes it possible to guarantee a better mechanical hold of these turns 160.

The capacitor 150 is fixed to the insulating body 1 1 by any appropriate means, for example by gluing. The capacitor 150 is here housed in a respective groove or in a recess. Advantageously, the winding of the resonant circuit 120 (and if necessary the capacitor 150) is covered by an electrically insulating material 18. Thus, the maintenance of the insulator 1 will be facilitated, for example by allowing a projection of water to avoid the formation of a conduction path on the surface of the insulating body 1 1, without altering the resonant circuit 120. The insulating material is for example an insulating synthetic resin. Another variant of the insulator 1 of FIG. 5 can also be envisaged. The turns of a winding being in the same plane, they can be included in a printed circuit. The capacitor 150 can then be a discrete component soldered on such a printed circuit.

In the illustrated examples, the windings of the resonant circuits are reported on the insulating body 11. However, it is also possible to drown the windings of the resonant circuits inside the material of the insulating body 11.

Another variant of the insulator 1 of the FIG.

5. The turns of a winding being in the same plane, they can be made in the form of tracks on a single or double-sided printed circuit or tracks in a multilayer printed circuit. The capacitor 150 can then be a discrete component soldered on such a printed circuit.

The variants illustrated in FIGS. 6 and 7 correspond to embodiments of resonant circuit windings embedded inside the material of the insulating body 11 and with a winding produced by tracks on a printed circuit.

Figure 6 is a schematic sectional view in a longitudinal plane of a fourth variant of the insulator according to the invention. FIG. 6 is only a detail view at a resonant circuit 120 of the energy transmission device 12. The insulating body 1 1 here has a shape of revolution about the axis 1 15, defining an alternation of 1. The winding of the resonant circuit 120 comprises several turns 160. The turns 160 are here made in the form of tracks on a printed circuit substrate 19. The printed circuit 19 is here embedded in the FIG. material of the insulating body 1 1, and extends in particular radially in a projecting ring 1 1 1. The turns 160 are wound around the axis 1 15. The turns 160 are here connected to a capacitor 150. The capacitor 150 is fixed to the printed circuit 19.

Figure 7 is a schematic sectional view in a longitudinal plane of a fifth variant of the insulator according to the invention. FIG. 7 is only a detail view at a resonant circuit 120 of the energy transmission device 12. The insulating body 1 1 here has a shape of revolution around the axis 1 15, defining an alternation of 1. The winding of the resonant circuit 120 comprises several turns 160. The turns 160 are here made in the form of tracks on the two opposite faces of a printed circuit substrate 19. The circuit board 19 is embedded in the material of the insulating body 1 1, and extends in particular radially in a projecting ring January 1 January. The turns 160 are wound around the axis 1 15. In the illustrated examples, the turns of the windings are housed in grooves of the insulator 1. It is also possible to envisage other variants, for example simply fixed turns on the surface of the insulating body 11.

In the example illustrated, the insulating body 1 1 has an alternation of projecting rings and grooves. However, the invention can also be applied to an insulator 1 comprising an insulating body whose outer surface is cylindrical.

Claims

High voltage electrical insulator (1), comprising an insulating body (1 1) elongated along an axis (1 15), having first and second remote ends (1 17, 18) along said axis, characterized in that it comprises in addition :

at least first and second resonant circuits (122, 123) galvanically isolated from each other by said insulating body (1 1), the first and second resonant circuits comprising at least one respective winding (160) around said axis, said windings being distant from each other along said axis and magnetically coupled.

Insulator (1) according to claim 1, wherein the insulating body (1 1) has a shape of revolution defining an alternation of salient rings (1 1 1) and grooves (1 12), said windings (160) being arranged in respective grooves (1 14).

An insulator (1) according to claim 1 or 2, wherein grooves (1 14) are formed in the insulating body (1 1) and wherein said windings (160) are accommodated in said grooves.

An insulator (1) according to any one of the preceding claims, wherein said windings (160) are covered with an electrically insulating material (18).

An insulator (1) according to any one of the preceding claims, wherein said windings (160) each comprise a plurality of turns wound around said axis (1 15), said windings being concentric.

An insulator (1) according to any preceding claim, comprising two conductive supports (13,14) respectively fixed to the first and second ends of the body (1 17,1 18).

An isolator (1) according to any one of the preceding claims, wherein the resonant frequencies of said first and second resonant circuits (122,123) are between 50 Hz and 1 GHz.

An insulator (1) according to any one of the preceding claims, wherein each of said first and second resonant circuits (122,123) comprises a capacitor (152,153) connected in series with a respective winding, said capacitor being fixed to the body (1 1) of the insulator.

9. The insulator (1) according to any one of the preceding claims, further comprising a third resonant circuit galvanically isolated from the first and second resonant circuits by said insulating body, the third resonant circuit comprising at least one respective winding about said axis, said winding being spaced apart from the windings of the first and second resonant circuits along said axis and being magnetically coupled to a winding of the third resonant circuit.

An insulator (1) according to any one of the preceding claims, comprising first and second fixing supports (13, 14) respectively fixed to the first and second ends (1 17, 1 18) of the insulating body (1 1), the first and second fixing supports being electrically insulated by the insulating body (1 1). 1 1. An insulator (1) according to any of the preceding claims, wherein at least one cross section of the insulator contains only electrically insulating material.

12. System, comprising:

an isolator (1) according to any one of the preceding claims;

an AC power supply (2) generating a supply potential from a ground potential (93), said power supply (2) being connected to a fourth resonant circuit (121) provided with a winding (161) for generating a magnetic flux, said winding for generating a magnetic flux being positioned at the first end (1 17) of the body (1 1).

13. The system of claim 12, wherein the power supply (2) generates a supply potential at a frequency identical to the resonance frequency of said first, second and fourth resonant circuits.

The system of claim 12 or 13, comprising:

an electronic circuit (3) intended to be connected to a high voltage equipment (94), connected to a fifth resonant circuit (124) provided with a magnetic flux receiving winding (164), said receiving winding being positioned at the second end (1 18) of the body (1 1).