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EP-3794358-B1 - SYSTEM FOR SPIKING, I.E. EXPLORING VOLTAGE, IN ELECTRIC CABLES

EP3794358B1EP 3794358 B1EP3794358 B1EP 3794358B1EP-3794358-B1

Inventors

  • BAREZZANI, GUALTIERO
  • LIVI, Leonardo

Dates

Publication Date
20260513
Application Date
20190517

Claims (15)

  1. A system (1) for "spiking", i.e. exploring voltage, in electric cables (5) comprising: A) an exploring apparatus (2) having: - a first clamping jaw (3) and a second clamping jaw (4), shaped to receive therebetween a portion of an electric cable (5) to be explored, - a reversible tightening device (6) associated with the clamping jaws (3, 4) and adapted to allow an opening of the clamping jaws (4, 5) to receive the electric cable portion therebetween and to tighten the clamping jaws (3, 4) one against the other to clamp the electric cable portion (5) in a clamping position (7), - an elongated metal blade (8) connected to the first clamping jaw (3) and displaceable between a retracted position, in which the blade (8) does not interfere with the clamping position (7), and an extended position, in which the blade (8) extends into the clamping position (7), so as to penetrate the electric cable portion (5) and to put individual conductors of the electric cable (5) in electrical contact with one another, - a hydraulic actuator (9) connected to the first clamping jaw (3) and configured to displace the blade (8), with respect to the first and second clamping jaws (3, 4), from the retracted position into the extended position, in response to a pressure increase of a hydraulic liquid, - a pump (10) adapted to increase a pressure of a hydraulic liquid, - a flexible pressure hose (11) connected between the pump (10) and the hydraulic actuator (9) so as to communicate the hydraulic liquid pressure from the pump (10) to the hydraulic actuator (9), wherein the voltage exploring system (1) further comprises: B) a manual remote controller (12) for a remote actuation and control of the pump (10), C) actuation communication means (13) adapted to provide pump actuation signals from the remote controller (12) to the pump (10), wherein: - the manual remote controller (12) is physically separate from the exploring apparatus (2) and from any accessories physically connected thereto, so as to allow a positioning of the remote controller (12) at a safety distance from the exploring apparatus (2), - the actuation communication means (13) comprise a wireless connection (71, 72) exceeding said safety distance wherein the exploring apparatus (2) further comprises: - a blade position detector (14) connected to the first clamping jaw (3) and configured to detect the arrival of the blade (8) into the extended position and to provide an exploring confirmation signal confirming the reaching of the extended position of the blade (8), - exploring confirmation communication means (15) connected to the position detector (14) and adapted to transmit the exploring confirmation signal, wherein the exploring confirmation communication means (15) comprise a wireless transmitter (68), wherein the blade position detector (14) comprises a movable member (57), directly or indirectly displaceable by means of an actuation piston (27) of the hydraulic actuator (9) so as to actuate, upon reaching the extended position of the blade (8), a pressure button of the pressure detector (14) to generate the exploring confirmation signal, wherein a part of the displacement energy of the movable member (57) is used to power and actuate the exploring confirmation transmitter (68), wherein the blade position detector (14) and the exploring confirmation transmitter (68) are both battery-free.
  2. A system (1) according to claim 1, comprising sound and/or light signaling means (69, 70) signaling the arrival of the blade (8) in the extended position.
  3. A system (1) according to any one of the preceding claims, wherein the pump (10) comprises: - a pump housing (16), - optionally, an accumulator seat (17) adapted to receive an accumulator (18) and having electrical terminals which make an electrical contact with the accumulator (18), - a motor (19) supported by the pump housing (16) and, optionally, powered by means of the accumulator (18), - a pumping unit (20) supported by the pump housing (16) and connected to the motor (19) so as to increase, in response to the movement of the motor (19), the hydraulic liquid pressure, - an electronic control circuit (21) connected to the motor (19) and, optionally, to the accumulator (18), to control the motor (19), - a maximum pressure valve (23) which, upon reaching a maximum set pressure in the hydraulic fluid acting on the hydraulic actuator (9), automatically opens a return duct (25) from the hydraulic actuator (9) to a tank (22) of the pump (10) to discharge at least part of the pressure fluid into the tank (22), - a pressure sensor (66) in signal connection with the electronic control circuit (21) and configured to detect the hydraulic liquid pressure.
  4. A system (1) according to any one of claims 1 to 3, wherein the electronic control circuit (21) is configured to automatically switch off the motor (19) depending on the exploring confirmation signal.
  5. A system (1) according to any one of the preceding claims, wherein the clamping jaws (3, 4), the hydraulic actuator (9), the tightening device (6) and the blade (8) are connected to a supporting structure (29) and together form an exploring head (26) of the exploring apparatus (2) positioned at a variable distance from the pump (10).
  6. A system (1) according to any one of the preceding claims, wherein the first clamping jaw (3) is connected in a stationary manner with respect to an actuation cylinder (24) of the hydraulic actuator (9) and forms: - a first cable seat (30) with at least one concavity to accommodate and hold the electric cable portion (5) in the clamping position (7), - a first passage channel (39) for the blade (8) to pass through the first clamping jaw (3) into the clamping position (7).
  7. A system (1) according to claim 6, wherein the first cable seat (30) or a further first cable seat (30') is formed in an adapter (32) reversibly lockable to a base portion (33) of the first clamping jaw (3), or wherein the first cable seat (30) or a further first cable seat (30') is formed in an adapter (32) reversibly lockable to a base portion (33) of the first clamping jaw (3) and the reversible connection of the adapter (32) is a snap connection, without the aid of tools, comprising a plurality of spherical portions (34), elastically supported in the base portion (33) of the first clamping jaw (3) and adapted to snap-engage corresponding cavities (34') formed in the adapter (32), or vice versa, and at least one fixed centering projection (35) of the base portion (33) receivable in a corresponding centering cavity (36) of the adapter (32), wherein the exploring system (1) comprises one or more of said different adapters (32) for electric cables (5) having different shapes and sections.
  8. A system (1) according to any one of the preceding claims, wherein the second clamping jaw (4) forms: - a second cable seat (37) with a concavity to accommodate and hold the electric cable portion (5) in the clamping position (7), - a second passage channel (38) or a recess to allow the blade (8) to penetrate inside the second clamping jaw (4). - a further second cable seat (37'), having a shape different from the shape of the second cable seat (37), wherein the second clamping jaw (4) may be positioned and tightened with respect to the first clamping jaw (3) in: - a first position in which the second cable seat (37) faces the first clamping jaw 3, - a second position in which the further second cable seat (37') faces the first clamping jaw (3).
  9. A system (1) according to any one of the preceding claims, wherein the elongated blade (8) comprises an elongated cutting portion (50) with a sharp free end and with sharp longitudinal edges (52), as well as a connecting portion (48) configured for a reversible snap-connection of the blade (8) to the hydraulic actuator (9), wherein, optionally, the blade connecting portion (48) is enlarged with respect to the elongated cutting portion (50) so as to allow the blade connecting portion (48) to be gripped during an extraction of the blade (8) from the electric cable (5) following the completion of the voltage exploring.
  10. A system (1) according to any one of the preceding claims, wherein the actuation communication means (13) comprise an actuation transmitter (71), connected and mounted to the remote controller (12), as well as an actuation receiver (72), connected and mounted to the pump (10) and which provide together said wireless actuation connection (71, 72), said actuation transmitter (71) and said actuation receiver (72) being selected from the group consisting of radio wave, infrared radiation and laser transmitters/receivers and transceivers.
  11. A system (1) according to any one of claims 1 to 10, wherein the exploring confirmation communication means (15) comprise a wireless exploring confirmation transmitter (68) connected to the blade position detector (14) and mounted to the first clamping jaw (3), as well as a wireless exploring confirmation receiver (73) mounted and connected to the pump (10), which together make a wireless exploring confirmation connection, wherein said exploring confirmation transmitter (68) and said exploring confirmation receiver (73, 73') are selected from the group consisting of radio wave, infrared radiation and laser transmitters/receivers and transceivers.
  12. A system (1) according to claim 5, wherein the control electronics (21) of the pump (10) is configured to switch off the pump (10) automatically when the following two conditions simultaneously occur: - the blade (8) has reached the extended position, - the hydraulic fluid pressure, detected by means of the pressure sensor (66), exceeds a predetermined reference pressure.
  13. A system (1) according to any one of the preceding claims, further comprising a blade extraction device (60), comprising: - a resting seat (61) shaped for the resting against the electric cable (5), - a blade hooking portion (62) shaped to engage the blade (8) in a shape connection, said blade hooking portion (62) being guided in a displaceable manner with respect to the resting seat (61), - a traction mechanism (63) connected to the resting seat (61) and acting on the blade hooking portion (62) to drag the blade hooking portion (62) from a first position at the resting seat (61) towards a second position away from the resting seat (62) so as to extract the blade (8) hooked to the blade hooking portion (62) out of the electric cable (5).
  14. A system (1) according to any one of claims 1 to 12, wherein the manual remote controller (12) comprises an ON/OFF button (74) of the remote controller (12), a pumping button (75) to actuate the pump (10), a release button (76) to switch off the pump (10) and to release the hydraulic fluid pressure, as well as a light indicator (77) to indicate the switch on status and the battery status of the remote controller (12), or wherein the exploring apparatus (2) comprises a colored marking (67) visible outside the exploring apparatus (2) and moving together with the displacement of an actuation piston (27) of the hydraulic actuator (9).
  15. A system (1) according to any one of claims 1 to 12, wherein the tightening device (6) comprises two traction bars (42) having first ends connected in an articulated manner to two side ends of the second clamping jaw (4) and second ends, threaded and equipped with a tightening nut (43), for engaging with corresponding tightening seats (44) of the first clamping jaw (3) to tighten the second clamping jaw (4) in the direction of the first clamping jaw (3).

Description

The present invention relates to a system for spiking, i.e. exploring voltage in electric cables. When preparing for cutting or connection operations of electric cables, e.g. medium voltage cables, it is essential to explore the presence or absence of electric voltage in the cable. The voltage exploration operation is usually performed by means of an exploring apparatus called "spike tool", which clamps a portion of externally isolated electric cable in a position which prevents a displacement of the single conductors of the cable, e.g. of the three individual conductors of a triplex, and which pushes a metal blade through the external insulation of the locked cable so as to put the individual conductors into electric contact with one another. If there is no voltage in the electric cable, the penetration of the metal blade into the cable has no effects except locally damaging the cable. If there is voltage in the electric cable, the penetration of the metal blade into the cable creates a short circuit and the formation of an electric arc which can be detected as an explosion. A known voltage exploring apparatus comprises: two clamping jaws, shaped to receive a portion of an electric cable to be explored between each other,tightening means associated with the clamping jaws and adapted to allow an opening of the clamping jaws to receive the electric cable portion between each other and to tighten the clamping jaws against each other to clamp the electric cable portion in a clamping position,a metal blade connected to one of the jaws in displaceable manner between a retracted position, in which the blade does not interfere with the clamping position of the portion of electric cable, and an extended position, in which the blade extends through the clamping position of the portion of electric cable, so as to put individual conductors of the electric cable into electrical contact with one another,an explosive capsule associated with the metal blade, the explosion of which moves the blade from the retracted position into the extended position,a remote ignition device, connected by means of an ignition wire to the explosive capsule which can be actuated to explode the explosive capsule. The known voltage exploring apparatuses allows, by virtue of the instantaneous effect of the explosion, an almost instantaneous (non-progressive) electric contact of the conductors of the explored electric cable. However, the need to store, transport and handle the explosive capsules is regarded as problematic and requires skilled and certified labor. The exploration noise similar to a firearm shot and the explosion fumes are considered very annoying. Furthermore, after a limited number of explorations by detonation actuating, the exploring apparatus must be subjected to maintenance because of the destructive effect of the explosion on the blade and on the other components of the apparatus. Finally, the material connection of the operator with the electric cable during the voltage exploration, because of the ignition wire and the explosion of the explosive capsule itself are subjectively perceived as dangerous. lf the exploration operation shows no effect (presumably due to lack of electric voltage in the conductors) it is still necessary to check that the metal blade has truly penetrated in a complete manner through the electric cable. With the apparatus of the prior art, this verification requires a visual inspection of the position of the blade after the explosion of the explosive capsule and, hence, an approach of the operator to the cable damaged by the blade but without the absolute certainty that the exploration has been performed correctly and completely. CN 104 701 782 B discloses a system comprising a remote-controlled hydraulic cable puncturing device which can be considered a closest state of the art for the present invention. lt is thus the object of the present invention to provide a system for spiking, i.e. exploring voltage in electric cables, having such features as to overcome at least some of the drawbacks mentioned with reference to the prior art. These and other objects are achieved by means of a voltage exploring system according to claim 1. The dependent claims relate to advantageous embodiments. According to the invention, a system for spiking, i.e. exploring voltage in electric cables is provided. The provided exploring system avoids the need to hold, carry and handle explosive detonators, and the related risks, reduces acoustic and air pollution in the voltage exploration site and physically separates (electric isolation barrier) the exploring apparatus from the operator, thereby protecting the operator from any risk of electrocution and also overcoming the even only subjective perception of operating in condition of risk. Finally, the wireless transmission of commands for actuating the exploring apparatus allows the operator to be effectively sheltered from the exploration zone. According to the invention,