DRONE PROTECTION AGAINST HIGH-VOLTAGE ELECTRICAL DISCHARGES AND CORONA EFFECT

Abstract

A remotely controlled flying device is intended to approach and contact a high-voltage overhead power line for operation thereon. The flying device includes a mechanical structure bearing propellers and an aircraft body containing at least a power hub, a flight controller, and radio communication means. An electrical shield encapsulates the mechanical structure. The remotely controlled flying device also has a surge protector or the like designed to locally capture and guide toward the electrical shield possible electric discharges in the phase of power line approaching and/or contacting and to render the electrical shield equipotential with the power line.

Claims

1. A remotely-controlled flying device intended to approach and contact a high-voltage overhead power line for operation thereon, said flying device comprising: a plurality of propellers (8); a mechanical structure (1) bearing the plurality of propellers (8) and an aircraft body (4) containing at least a power hub, a flight controller, and radio communication means; and an electrical shield (2, 7) encapsulating said mechanical structure (1) and comprising an assembly of electrically-conductive bars (20) interconnected with electrically-conductive connectors (21) according to a truss or a lattice; wherein the remotely-controlled flying device also comprises on its top at least two anchoring spots, at least one thereof provided with a surge protector or the like (3), comprising a mechanical part, having a V-shape open to the exterior of the device, for guiding the power line in the phase of power line approaching and contacting, as well as for attracting possible electric discharges towards the electrical shield (2, 7); wherein at least two linearly-disposed automatic clamping devices (6), also located on the top part of the flying device (1), are provided for attaching the flying device to the power line and are located in the vicinity of the V-shape mechanical part(s), being capable to attach the flying device to the power line, once the flying device has approached upwards the power line so that the latter is located sufficiently close to the bottom of the V-shape mechanical part; and wherein the clamping devices (6) are claws mounted rotary in a plane orthogonal to the power line direction in use, said claws being in permanent rotation until they grip the power line and stop.

2. The remotely-controlled flying device according to claim 1, wherein said electrically-conductive bars (20) and connectors (21) have a round shape.

3. The remotely-controlled flying device according to claim 1, wherein said electrically-conductive bars (20) and connectors (21) are polished.

4. The remotely-controlled flying device according to claim 1, wherein each of said clamping devices (6) is coupled with one of said surge protectors or the like (3).

5. The remotely-controlled flying device according to claim 1, wherein an additional electrically-conductive element (3) is connected to the V-shaped mechanical part and configured to ensure that, once a first contact has been established with the high-voltage power line, contact remains active or permanent during subsequent operations/phases.

6. The remotely-controlled flying device according to claim 1, further comprising a metallic mesh (7) covering the top part and the lateral part of said assembly of electrically-conductive bars (20) interconnected with connectors (21) according to a truss or a lattice, wherein the metallic mesh is configured to allow unimpeded air flow created by the rotation of the propellers.

7. The remotely-controlled flying device according to claim 6, wherein a bottom side of the flying device has reduced or partial metallic mesh (7) covering or has a metallic mesh (7) with increased mesh size, wherein the metallic mesh is configured to assure proper communication with a remote control on earth.

8. The remotely-controlled flying device according to claim 1, wherein the electronics in the aircraft body (4) comprise conventional electronics not having special protection against high-intensity electromagnetic fields.

9. The remotely-controlled flying device according to claim 1, wherein the electrically conductive bars (20) and the connectors (21) are made of an electrically conductive material having a surface configured to be small enough so as not to hinder air flow.

10. The remotely-controlled flying device according to claim 9, wherein the electrically-conductive material is carbon, aluminum, titanium, copper, or a material with an outside layer of copper.

11. The remotely-controlled flying device according to claim 1, wherein the device is configured to bear a sensor (5) also provided with dedicated clamps able to automatically fixate the sensor (5) onto the power line, once the flying device has been firstly anchored to the power line and put at the electric potential thereof.

12. The remotely-controlled flying device according to claim 1, wherein a transient suppressor is further connected in parallel with the ground and a main power supply bus.

13. The remotely-controlled flying device according to claim 1, wherein the electrical shield (2) is fitted to the external envelope of the mechanical structure (1) or makes the external envelope thereof.

14. A system comprising: the remotely-controlled flying device according to claim 1, and a hosted payload.

15. A method for anchoring a payload to a high-voltage overhead power line, the method comprising: causing the remotely controlled flying device of claim 1 to approach a power line by remote control; anchoring the flying device by guiding the high-voltage overhead power line into or towards the surge protectors or the like (3); clamping the flying device to the power line using the automatic clamping devices (6); anchoring a payload device (5) using a dedicated anchoring mechanism; releasing the automatic clamping devices (6) and freeing the flying device (1) from the power line; and bringing back the flying device to earth by remote control.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0054] FIG. 1A is a complete schematic view in perspective of a controlled flying device intended to approach and contact a high-voltage power line for operation thereon, according to the present disclosure (propellers and batteries not shown for sake of clarity). FIG. 1B is a similar view but showing only the metallic structure and the propellers.

[0055] FIG. 2 is another perspective view of the device of FIG. 1B, showing in particular the metallic mesh partly covering the structure encasing the UAV and contributing to the efficiency of the Faraday cage.

[0056] FIG. 3 is a detailed view of a rounded corner in the metallic structure supporting the shielding mesh.

[0057] FIG. 4 is a detailed view of the surge arrester and clamping system also shown on FIG. 1A.

DETAILED DESCRIPTION

[0058] As shown on FIGS. 1A, 1B and 2, the novel concept of the present disclosure is embodied in: [0059] 1) a protective frame 2 surrounding the mechanical structure 1 of a flying device; [0060] 2) this protective frame 2 being electrically conductive and; [0061] 3) this protective frame 2 being designed to guide electrical arcs outside the sensitive electrical parts of the flying device, such as electronics, sensors, antennas, etc. Protective frame 2 constitutes a Faraday cage.

[0062] In addition of providing a Faraday cage, said protecting frame 2 is supplemented, according to the present disclosure, at least by two anchoring spots 3 on its top, employed for connecting the flying device onto the energized conductors as well as for attracting possible electrical discharges towards the protective frame, in the approaching phase(s) of the conductor. This configuration implies that the flying device is designed to exclusively approach the power line from underneath. The anchoring spots may be provided with basic lightning arresters (rods) or may contain more sophisticated surge protection devices (for example according to the definitions given above). More advantageously, at least part of these anchoring spots shall be provided with two custom surge protectors or the like, preferably having a V-shape, not only for attracting possible electrical discharges but also for self-guiding the final phase of UAV landing on the power line. Once the power line is guided and engaged inside the V-shape of the surge protectors, an automatic closing and connection may be carried out, for example via clamps 6, known per se in prior art.

[0063] In an embodiment, the surrounding frame 2 has a common, electrically-connected grounding scheme. Then the energy of the surge just brings the right amount of charge to put the shield at the same potential as the power line. This energy is partially dissipated in the shielding and partially stored therein, without impacting the electronics functionality of the device. It should be noted that, when the device is anchored to the power line, the ground is then at the voltage of the line.

[0064] As a result, the improved protective frame according to the present disclosure is suitable to attract, guide and safely annihilate electrical arcs, through a path to ground via the Faraday cage, outside the perimeter or envelope of the flying device sensitive elements (e.g. electronics, sensors, propellers).

[0065] Accordingly, the present disclosure advantageously allows to use devices simply equipped with conventional electronics so that said devices will be protected in the phase of approaching and further when brought and maintained in contact with energized lines, but without compromising or impair the electrical and electronic functions of the device.

[0066] Further, to avoid possible residual spikes on the power supply of the flying device, a transient suppressor can be specifically connected in parallel with the ground and main power supply bus.

[0067] According to the embodiment shown on FIG. 2, a metallic mesh 7 deployed on the external conductive bars 20 is provided to further protect the sensitive electronic parts of the flying device by causing uniform distribution of the electrical arc paths across the mesh structure 7. This additional protection will ensure that the UAV is protected also when the device is approaching the line with a less ideal trajectory, such as by a lateral approach. It is to be noted that the metallic mesh 7 could be made of a regular wire mesh material surface, such as a thin copper foil, stretched over the frame of external conductive bars 20, but when the mesh covering is to be reduced for example (see below), it can also be made of a couple of wires linking the bars.

[0068] Advantageously, the mesh structure 7 shall cover at least the top part of the drone protective frame 2. On the bottom side of the drone protective frame 2 there is reduced mesh covering or with the mesh size is increased, because the power line approach is performed at proximity of the drone top and also in order to ensure optimal communication with the remote control on ground, while still needing some kind of conductive elements (to make a closed Faraday cage) on any side of the outer shield.

[0069] According to the present disclosure, the design of the protective frame 2 shall specially be conceived with consideration of corona effect. Consequently, the edges thereof shall be particularly neat, and in particular shall not present any sharp point or spike and, where possible, round shapes could be preferred. For example, as shown on FIG. 3, special rounded corners could be provided as neat finish at the edges of the protective frame.

[0070] The frame design possibly including a metallic mesh embeds the flight engines and propellers 4, 8 allowing unimpeded air flow generated by the propellers through the device and ensuring, as mentioned above, that electrical arcs do not easily reach the most sensitive parts of the flying device (rotors, control unit, communication, inertial measurement unit-IMU, and GPS for example).

[0071] According to the preferred embodiment depicted in FIG. 1, the protective frame 2 shall consist in some kind of truss or lattice made of bars assembled according to a specific geometric layout and preferably built from carbon material, to ensure very good electrical conductivity. In flying applications (drone/UAV flights), such a light material is also considered in order not to penalize the payload of the device.

[0072] According to an embodiment, the junction parts of protective frame 2, as also shown on FIG. 1 and FIG. 2, are preferably made of polished aluminum, with round shapes to minimize corona discharges, connecting all the carbon bars together and ensuring a sufficiently good conductivity. The assembled bars in the frame are thereby supposed to be finished with round shapes and no sharp edge so as to reduce corona effect (see above). The carbon bars being made of multiple carbon fibers, surrounding them with the junction parts permits to ensure that all the fibers contribute to the conductivity, which allows to achieve a resistance between two extremities of the drone as low as possible, preferably below 1.5-2 Ohm, and more preferably below 1 Ohm.

[0073] The electrically conductive material composing the bars and connectors should be light, rigid, possibly 3D-printable and having a surface small enough, so as not to block air flow through the flying device. In addition to carbon and aluminum, for example titanium that can be 3D-printed or a material with an outside layer of copper can be used as well. However solid copper has the disadvantage to be heavier. Alternately the bars can be composed of non-conductive material coupled to some conductive material, for example plastic bars with metal wires incorporated in a groove thereof or with metal wire strapping.

[0074] Once the drone has been safely guided into the above-mentioned surge protectors opening, and provided to come into equipotential contact with the energized line, a firm connection of the drone can performed for example through closing with clamps, as described in prior art and in particular in patent application EP 3 832 822 A1, to the same Applicant.

[0075] In the embodiment shown on FIG. 4, the mechanical parts with V-shape 3 are shown as well as the clamping devices 6 (any additional surge arrester or the like is not shown for sake of clarity). The clamping devices 6 have here the form of rotary claws, moving perpendicularly to the power line direction and clamping the line once it comes sufficiently close to the claws. In one embodiment, the clamping operation could be done automatically using some line detection device. In another embodiment, the claws are continuously rotating and clamp the line, once they come to grip with it and stop. In case there are two clamping claws, they will advantageously rotate in opposite directions.

LIST OF REFERENCE SYMBOLS

[0076] 1 mechanical structure of the flying device [0077] 2 electrical shield [0078] 3 surge protector [0079] 3 additional conductive element [0080] 4 aircraft body [0081] 5 payload device-sensor (provided space shown) [0082] 6 automatic clamping device [0083] 7 metallic mesh [0084] 8 propeller [0085] 9 rounded corner bar connector [0086] 10 overhead power line [0087] 20 conductive bar (carbon) [0088] 21 connector (aluminum)