DEVICE AND METHOD FOR SIMULTANEOUSLY HEATING AND APPLYING HIGH VOLTAGE TO AN ELECTRICAL CABLE
The device with an induction and high-voltage transformer replicates in-service heating conditions, addressing the issue of external liquid heating methods by maintaining cable properties and achieving homogeneous temperature.
Patent Information
- Application Number
- FR2022011409
- Authority / Receiving Office
- FR · FR
- Patent Type
- Patents
- Current Assignee / Owner
- Filing Date
- 2022-11-02
- Publication Date
- 2025-12-12
- Estimated Expiration
- 2042-11-02
AI Technical Summary
Existing methods for heating electrical cables during development fail to replicate in-service conditions, as they use external liquid mediums that can alter mechanical and electrical properties, and the heating source differs from the in-service conductor-based heating.
A device comprising an induction transformer for heating and a high-voltage transformer for applying voltage directly to the cable, allowing 'dry' heating without external liquids, with optional water immersion for temperature homogeneity.
Replicates in-service heating conditions, maintaining cable properties and ensuring homogeneous temperature without altering mechanical and electrical characteristics.
Smart Images
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Abstract
Description
Title of the invention: DEVICE AND METHOD FOR HEATING AND SIMULTANEOUSLY APPLYING HIGH VOLTAGE TO AN ELECTRICAL CABLE
[0001] The present invention relates to a device and a method for simultaneously heating and applying high voltage to an electrical cable.
[0002] The invention relates to the field of electrical cables intended for the transport of energy and / or the transmission of data. It is particularly applicable in the field of the development of high-voltage transmission cables.
[0003] During the development phase of a high-voltage transmission cable, in order to reproduce the operating conditions that the cable will encounter once it is in service, it is necessary to heat the cable when it is subjected to stress related to the application of high alternating or direct voltage.
[0004] The heating of the tested cable samples is generally carried out by immersing these samples in a heated liquid, which may be water or a dielectric oil.
[0005] However, when a liquid medium is used to heat a cable, particularly in the case of oil, it is not known how this liquid medium is likely to affect the mechanical and / or electrical properties of the cable. Furthermore, the heating source is located outside the cable, whereas when the cable is actually in service, the heating generally comes from its main conductor, which constitutes significantly different operating conditions.
[0006] The present invention aims to remedy the aforementioned drawbacks of the prior art.
[0007] To this end, the present invention proposes a device for simultaneously heating and applying high voltage to an electrical cable, remarkable in that it comprises: the electrical cable; an induction transformer connected to the electrical cable, suitable for heating the electrical cable to a predetermined initial temperature; and a high voltage transformer connected between the electrical cable and ground, suitable for applying a predetermined voltage of between 100 kV and 300 kV to the electrical cable.
[0008] Thus, the superposition, on the cable, of the induction transformer for heating the cable and the high-voltage transformer for applying the high-voltage stress allows for "dry" heating through the core of the cable, without the presence of oil. which could alter the mechanical and / or electrical properties of the materials constituting the cable.
[0009] In a particular embodiment, the device further comprises a reservoir containing water, in which the electrical cable is at least partially immersed.
[0010] This ensures a homogeneous temperature for the electrical cable, without using oil as a liquid medium.
[0011] In a particular embodiment, this water is heated to a second predetermined temperature.
[0012] This helps to increase the heating of the cable.
[0013] In a particular embodiment, the second predetermined temperature is equal to the first predetermined temperature.
[0014] In a particular embodiment, the first predetermined temperature is between 30°C and 110°C.
[0015] For the same purpose as indicated above, the present invention also proposes a method for simultaneously heating and applying high voltage to an electrical cable by means of a device such as is briefly described above, remarkable in that it comprises steps consisting of: heat the electrical cable to the said first predetermined temperature by means of the induction transformer; apply simultaneously to the electrical cable the said predetermined voltage between 100 kV and 300 kV by means of the high voltage transformer.
[0016] The special characteristics and advantages of the process being similar to those of the device, they are not repeated here. Brief description of the drawings
[0017] Other aspects and advantages of the invention will become apparent from the following detailed description of particular embodiments, given by way of non-limiting examples, with reference to the accompanying drawings, in which:
[0018] [Fig-1] is a schematic representation of a device according to the present invention, in a particular embodiment. Description of method(s) of implementation
[0019] The electrical diagram in [Fig. 1] represents, in a particular embodiment, a device 10 according to the present invention, for simultaneously heating and applying high voltage to an electrical cable 12 during development, as a test. The invention applies in particular, but not exclusively, to medium- or high-voltage cables, whether alternating or direct current.
[0020] The device 10 includes the electrical cable 12, which is for example wound in a loop, the two ends of the loop being connected to each other.
[0021] The device 10 further includes an induction transformer 14 connected to the electrical cable 12. The induction transformer 14 is traversed by a current which creates a magnetic field which, by induction, creates a higher current in the electrical cable 12. Thus, the induction transformer 14 is adapted to heat the electrical cable 12 to a first predetermined temperature.
[0022] By way of non-limiting example, the first predetermined temperature may be between 30°C and 110°C.
[0023] The device 10 also includes a high-voltage transformer 16 connected between the electrical cable 12 and ground, adapted to apply a predetermined voltage of between 100 kV and 300 kV to the electrical cable 12. Specifically, the high-voltage transformer 16 transforms a three-phase voltage of 440 V AC into a high voltage of 100 kV to 300 kV AC.
[0024] The high-voltage transformer 16 is connected to a conductor of the electrical cable 12, for example, by means of a lug. The ends of the electrical cable 12 are therefore exposed. For example, at the ends of the electrical cable 12, the semiconductor layer(s) and the electrically insulating layer(s) of the electrical cable are removed, so as to expose the aforementioned conductor at the ends of the electrical cable 12.
[0025] Optionally, as in the particular embodiment illustrated, the device 10 may further comprise a reservoir 18 containing water, in which the electrical cable 12 is at least partially immersed. In [Fig. 1], the water level is designated by reference numeral 180. This water is optionally heated to a second predetermined temperature, for example, equal to the first predetermined temperature.
[0026] Optionally, the mass 20 is connected to the water in order to ground the water, so that the outer layer of the electrical cable 12 in contact with the water is grounded, this outer layer being for example a semiconducting layer.
[0027] Thus, the method according to the present invention, of heating and simultaneously applying a high voltage to the electric cable 12 by means of the device 10, comprises steps consisting of heating the electric cable 12 to the first predetermined temperature by means of the induction transformer 14 and simultaneously applying to the electric cable 12 the predetermined voltage of between 100 kV and 300 kV by means of the high voltage transformer 16.
Claims
Demands
1. Device (10) for simultaneously heating and applying high voltage to an electrical cable (12), said device (10) comprising: said electrical cable (12); an induction transformer (14) connected to said electrical cable (12), adapted to heat said electrical cable (12) to a first predetermined temperature; and a high-voltage transformer (16) connected between said electrical cable (12) and ground, adapted to apply to said electrical cable (12) a predetermined voltage of between 100 kV and 300 kV, said device (10) being characterized in that it further comprises a reservoir (18) containing water, in which said electrical cable (12) is at least partially immersed, in that the water is heated to a second predetermined temperature and in that said second predetermined temperature is equal to said first predetermined temperature.
2. Device (10) according to claim 1, characterized in that said first predetermined temperature is between 30°C and 110°C.
3. A method for simultaneously heating and applying high voltage to an electric cable (12) by means of a device (10) according to any one of the preceding claims, characterized in that it comprises steps consisting of: heating said electric cable (12) to said first predetermined temperature by means of said induction transformer (14); simultaneously applying said electric cable (12) said predetermined voltage of between 100 kV and 300 kV by means of said high voltage transformer (16).