The present invention relates to an apparatus for measuring the distance from the ground of overhead electric power line conductors.
The present invention is advantageously used for effecting the optical measurement of the ground clearance, i.e. the distance that separates the ground from the lowest conductor of an overhead electric power line, in particular on critical spans in specific periods, to which the following description will make explicit reference, at the same time maintaining its generic characteristics.
The measurement of the height or ground clearance of spans of overhead lines is generally particularly important for allowing the optimization of the transporting capacity of overhead electric power lines.
As is known, the ground clearance of conductors of energy transporting lines depends on the temperature reached by the conductor, which in turn depends on the current circulating, the atmospheric temperature, wind, solar radiation and humidity. In addition to this, there is the case of the formation of sleeves of snow/ice on the conductors, a condition that can also cause significant reductions in the ground clearance.
In order to guarantee the safe operability of overhead electric power lines, cautionary capacity limits are currently imposed, based on the use of deterministic or statistical evaluations based on national regulations.
Due to the growing demand for energy and the difficulty in upgrading the power supply network, it is extremely useful to have detailed information that can allow an increase in the electric current supply under these conditions and at the same time maintain a high safety level.
A great advantage has been obtained from an optimum knowledge of the real behaviour of electric power lines in relation to environmental conditions and the charge, i.e. the current circulating on the same electric power line.
Direct measurement techniques of the temperature of the conductor currently known comprise the use of various measuring apparatuses, whose installation requires complex work on the part of electrical experts, as it must generally be effected on live line conductors.
Furthermore, as mentioned above, another phenomenon that leads to both a reduction in the ground clearance and a possible interruption of the line is the formation of agglomerates or ice sleeves on the conductors.
At present, exhaustive experimental data that allow the validation of growth models of the sleeve on the basis of the environmental conditions and load of the line, are unavailable.
It should also be pointed out that the possibility of effecting ground clearance measurements without interacting with the electric power line would allow a prompter intervention capacity and a more effective collection of data necessary for defining more accurate safety regulations for the production and management of electric power lines.
An objective of the present invention is to solve and overcome the problems of the known art indicated above.
In particular, an objective of the present invention is to provide an optical measurement apparatus capable of effecting, automatically and with a high time frequency, the ground clearance measurement of overhead electric power line conductors, without the necessity of interacting with the same line by the installation of complex instrumentations or with active or passive targets.
A further objective of the present invention is to provide an apparatus capable of effecting ground clearance measurements with great precision, and characterized by reduced dimensions in order to allow its portability.
The structural and functional characteristics of the present invention and its advantages with respect to the known art will appear more evident from the claims provided hereunder, and in particular from the following description, referring to the enclosed drawings, which show the schematization of a preferred but non-limiting embodiment of a measurement apparatus, in which:
- figure 1 represents a schematic view of the measurement apparatus object of the invention; and
- figure 2 is an enlarged view in scale of a component of the apparatus of figure 1.
With reference to figure 1, 1 indicates as a whole an optical apparatus for measuring the distance from the ground of an overhead electric power line (known and not illustrated).
The apparatus 1 is suitable for operating, starting from the detection of the intensity peak of the back-scattered signal from one or more electric power line conductors when it is reached by an infrared laser beam (characterized by so-called eye-safe emission), which is moved angularly on a vertical plane perpendicular to that containing the conductor under examination.
If the angle formed by the propagation direction of the beam with respect to the horizontal plane when the infrared signal scattered by the conductor has been received and detected, is known, it is therefore possible to determine the ground clearance, whose absolute value can be calculated with a precision of 5 cm, once an initial reference measurement has been effected.
More specifically, according to what is illustrated in figure 1, the apparatus 1 comprises a unit 2 for the generation and management of infrared laser radiation (generation unit), and a sending and receiving unit 3 of the infrared laser radiation towards an electric power line conductor under examination, said unit 3 being moved angularly according to a vertical plane (sending and receiving unit).
The two units 2 and 3 are connected to each other by means of suitable cables 4, electrical and in optical fiber.
According to what is illustrated in figure 1, the unit 3 is assembled on a motorized angular movement and positioning precision system 13 and is equipped with a double-axis precision inclinometer 11.
Said unit 3 comprises a formation optics 8 of an infrared laser beam through an infrared lens 9 and an optical reception system 10 of the infrared signal back-scattered from the conductor.
This system 10 is defined by an infrared optics, a band pass interferential filter centered on the emission wavelength of the infrared laser and an infrared detector.
The unit 3 in particular has reduced dimensions to allow it to be easily transported and can be assembled on a support 12 defined for example by a tripod for cameras.
According to what is illustrated in figure 2, the unit 2 comprises a portable container C containing, in its interior, the infrared laser source 5 whose radiation is sent to the collimator lens 9 of the unit 3 through the above-mentioned cables 4 made of optical fiber, and also comprises a control computer 6 provided with a data acquisition card connected via USB cable to the unit 3, power supplies and batteries 7 for autonomous functioning.
The unit 3 is therefore suitable, when in use, for directing the infrared laser beam towards a conductor of the above-mentioned overhead electric power line, and receiving the optical signal scattered by the conductor itself by means of the optical system 10 of the unit 3.
The laser beam emitted by the unit 3 is periodically moved angularly with a constant angular rate, upwards and downwards on a vertical plane by means of the above movement system 13.
The signal coming from the infrared detector of the optical system 10 is then acquired by the computer 6 and processed.
The above optical signal scattered by the conductor under examination is registered in relation to the lighting angle, measured by means of the precise angular positioner of the system 13 and biaxial inclinometer 11.
The absolute angular position of the conductor itself with respect to the gravity acceleration direction can be obtained from the position of the peak of the signal scattered by the conductor under examination, and consequently also the ground clearance, whose absolute value can be determined with a precision of 5 centimeters.
The diameter of the same conductor can also be defined from the measurement of the angular dimension of the peak of the signal scattered by the conductor under examination, with a precision of ±5 mm.
In both cases, when effecting an onsite detection, the distance of the apparatus 1 from the ground vertical of the conductor of the electric power line, must be known.
The apparatus 1 also comprises a remote control-management and display unit 14, connected to the unit 2 by means of a wireless connection.
The unit 14 comprises, for example, a personal computer 15, or alternatively a PC tablet 16 with a touch-screen type screen.
It should also be pointed out that, with the apparatus described above, it is also advantageously possible to measure the ground clearance in the case of bad weather, with rain and snow, and regardless of variations in the orientation of the above-mentioned tripod support 12.
1. An apparatus (1) for measuring the distance from the ground of an overhead electric power line, characterized in that it comprises a generation and management unit (2) of an infrared laser radiation, and a sending and receiving unit (3) of infrared radiation, connected to said generation unit (2); said sending and receiving unit (3) being suitable for launching an infrared laser beam towards at least one conductor of said electric power line and intercepting the optical signal scattered by the same conductor.
2. The apparatus according to claim 1, characterized in that said generation unit (2) and said sending and receiving unit (3) of infrared radiation has a reduced size and weight to allow their transportability.
3. The apparatus according to claim 1 or 2, characterized in that said generation unit (2) and said sending and receiving unit (3) are connected to each other by means of electrical and optical fiber cables (4).
4. The apparatus according to any of the previous claims 1 to 3, characterized in that said generation unit (2) comprises a container (C) containing, in its interior, an infrared laser source (5) to be sent to said sending and receiving unit (3), a computer (6) connected to said sending and receiving unit (3), and a battery power supply (7).
5. The apparatus according to any of the previous claims 1 to 4, characterized in that said sending and receiving unit (3) comprises optical means (8) for forming an infrared laser beam, infrared collimator means (9), infrared filtering means (10), movement and tilt-regulation means (13) and tilt-measurement means (11) of said sending and receiving unit (3).
6. The apparatus according to claim 5, characterized in that said sending and receiving unit (3) is movably assembled on supporting means (12); said movement and tilt-regulation means (13) being assembled on said supporting means (12) for angularly moving said sending and receiving unit (3).
7. The apparatus according to any of the previous claims 1 to 6, characterized in that it also comprises a remote control-management and display unit (14) suitable for remotely controlling said generation unit (2).
8. The apparatus according to claim 7, characterized in that said remote control-management and display unit (14) comprises a personal computer (15) connected to said generation unit (2) via wireless connection.
9. The apparatus according to claim 7, characterized in that said remote control-management and display unit (14) comprises a PC tablet (16) connected to said generation unit (2) via wireless connection.