ELECTRICAL SAFETY DEVICE AND METHOD OF OPERATION OF SAID DEVICE

Description

ELECTRICAL SAFETY DEVICE AND METHOD OF OPERATION OF THE SAID DEVICE DESCRIPTION Scope of application 5 The present invention relates to an electrical safety device and a method of operation of said device, according to the preamble of the respective claims independent. The safety device according to the invention can be used in maintenance work on power lines in both industrial and residential environments. 10 In particular, the device in question is intended to be applied to an operator (for example example mounted on the latter's harness) to detect the presence of a field dangerous electrical generated by the power line where the operator is working, in in order to guarantee the necessary safety conditions during maintenance work. The safety device according to the invention can be advantageously used for a 15 power line at any voltage level. Therefore, the device in question fits into the sector of production of devices safety for electrical systems and for electrical transmission and distribution systems electricity. State of the art 20 AC power lines are subject to more or less periodic maintenance frequent, during which they are usually previously sectioned upstream of the tract to be maintained, so as to place this section at zero potential. This way, an operator can approach the line without incurring the risk of a electric shock and therefore carry out maintenance operations safely. 25 Otherwise, the operator would run the risk of electric shock not only because contact with a conductor of the power line, but also in proximity to the latter, due to the electric field generated by the voltage to which the conductor is placed, which can lead to electric shocks to the operator depending on the intensity of the electric field same and air conditions (e.g. humidity, temperature, etc.). 5 To prevent such risk, for example in the case where the section of line that is to be subjected to maintenance has not been properly sectioned, are known in the sector of reference to electrical safety devices, which are intended to be worn by the operator, for example mounted on the latter's harness, to detect the presence of the electric field in the vicinity of the line to be maintained. 10 Such devices of known type are configured to measure a quantity representative of the electric field, for example its intensity measured in kV / m, and to signal during the operator's approach to electrical conductors, for example by means of a signal acoustic, when this quantity exceeds a predetermined threshold value, beyond which the operator himself is advised not to get any closer. 15 In this way, the devices of the prior art allow safe operations on the line which must be maintained by the operator, who can therefore get close to the line without incurring the risk of an electric shock. However, the above-described prior art safety devices have proven to be unsuitable in practice. free from inconveniences. 20 The main drawback is that these devices are equipped with poor application flexibility. In fact, each known type of electrical safety device can be used for the operations in a specific line at a specific voltage level, for example 132 kV, 220 kV, 380 kV, etc. 25 In particular, as explained above, the aforementioned devices detect the exceeding of a value electric field threshold, which threshold value is predetermined on the basis of the application for which the device itself is intended, i.e. based on the field expected electrical power at a certain distance for the voltage level of the specific power line for which the device is designed. 5 Therefore, each device can only be used for the power line for which it was designed. specifically designed. This drawback makes maintenance operations on multiple lines at different levels costly. of voltage by a company managing the power lines of distribution and / or transmission, as it requires that each operator be equipped with many devices 10 safety how many voltage levels are there that the company is responsible for subjecting to maintenance. A further drawback of the known safety devices lies in the fact that these the latter have a preferential arrangement in which they must be arranged to detect the electric field correctly. 15 In fact, such prior art devices generally employ a plate capacitor as sensor for detecting and measuring the electric field, which, however, requires that the aforementioned plates are arranged orthogonally to the generated electric field lines from the line conductor. Therefore, the above devices must be used by the operator in one direction 20 preferential approach to the conductors of the line to be maintained, making laborious the operations of approaching the line. Furthermore, if the operator does not assume the necessary position, the safety device may not correctly detect the electric field and therefore not reliably signal dangerous conditions. Presentation of the invention 25 In this situation, the problem underlying the present invention is to overcome the drawbacks of the above-mentioned known solutions, by making available a device of electrical safety and a method of operation of said device which may be used for different types of power lines (in particular characterised by different voltage levels). 5 A further aim of the present invention is to provide a device of electrical safety and a method of operation of said device which are capable to detect an electric field regardless of the position assumed by the operator or the directions of approach to the power line. A further aim of the present invention is to provide a device 10 of electrical safety and a method of operation of said device which are capable to reliably detect the electric field. A further aim of the present invention is to provide a device of detection which is compact and easy to use. A further aim of the present invention is to provide a device 15 detection which is simple and economical to implement. Brief description of the drawings The technical characteristics of the invention, according to the above-mentioned purposes, are clearly can be seen from the content of the claims below and the advantages thereof will become more evident in the detailed description that follows, made with 20 reference to the attached drawings, which represent a purely practical embodiment by way of example and not by way of limitation, where: − Figure 1 shows a perspective view of the electrical safety device in question. present invention; − Figure 2 shows a further perspective view of the safety device of Figure 1 25 with some parts removed to better highlight others; − Figure 3 shows a cross-sectional view of a spherical capacitor of the device safety in question; − Figure 4 shows a schematic top view of an electronic board of the safety device in question; 5 − Figure 5 shows a block diagram representing the method of operation of the device in question; − Figure 6 shows an example of electric field distribution lines for a line extra high voltage at 380 kV near a pole. Detailed description of a preferred embodiment example 10 With reference to the attached drawings, an electrical safety device has been indicated with 1 according to the invention. This device can be advantageously used by an operator during work on maintenance on power lines, specifically alternating current power lines. In particular, in the continuation of the description with the expression power lines must 15 means both overhead power lines, in particular transmission and / or distribution lines, both ground-based power lines and industrial and / or residential electrical systems. The electrical safety device 1 in question comprises a support element 2 designed to be applied to an operator. Preferably, the device 1 is advantageously worn by the operator, in particular 20 is applied to the harness worn by the latter, for example at a shoulder, or, alternatively, on the operator's protective helmet. Advantageously, the support element 2 is made at least partially of material electrically insulating, such as a plastic material. In particular, as illustrated in the example of figure 2, the support element 2 comprises 25 a support frame 23 which preferably extends along a development direction main X between a first end 21 and an opposite second end 22. The device 1 further comprises an electric field sensor 3, which is mounted on the support element 2 and is arranged to measure at least one electric field generated by at least one power line. 5 Advantageously, the electric field sensor 3 is mounted at the first end 21 of the support frame 23. In particular, the electric field sensor 3 protrudes from the first end of the support element 2 along the main development direction X. The device 1 further comprises a position sensor 4, which is mounted on the element 10 support 2 and is designed to detect operator movements. Advantageously, the support element 2 comprises an electronic board 7, which door mounted position sensor 4 and is preferably mounted on the support frame 23. In particular, the supporting frame 23 is made in the form of a frame, which delimits the 15 inside it a central opening 24 inside which the electronic board 7 is located. In more detail, the electronic board 7 is provided with a mechanically external edge connected to the frame of the support frame 23. The device 1 further comprises a processing unit 5, which is operationally connected to the electric field sensor 3 to detect E-field measurements containing at least 20 values ​​of electric field strength. Advantageously, the processing unit 5 is mounted on the electronic board 7 and preferably includes a microprocessor. The processing unit 5 is also operationally connected to the position sensor 4 for detect position measurements S associated with corresponding field measurements E. 25 The processing unit 5 is also able to calculate, at least from the E field measurements and from the position measurements S, variations V associated with displacements. In particular, the above mentioned V variations are calculated as variations of the field measurements And with respect to the (contemporaneous) variations of the S position measurements. For example, processing unit 5 is configured to acquire an E-field measurement and 5 a corresponding position measurement S, performed respectively by the field sensor electric 3 and from the position sensor 4 preferably at the same time and acquire then a new measurement of the field E and of the position S at a later time, calculating then the variations V based on these measurements. The processing unit 5 is also arranged to generate a warning signal A in 10 function of the variations V. In particular, this warning signal A is indicative of a dangerous condition for the operator, indicating for example a limiting electric field, or a limiting distance from a line conductor (calculated in particular on the basis of the measured electric field), in addition to the which the operator would no longer be in a safe condition. 15 In this way, the warning signal A generated by the processing unit 5 of the device 1 of electrical safety is generated as a function not only of the E field measurements, but also from the position measurements S and, more precisely, from a correlation of the latter. Therefore, device 1 is able to signal to the operator a limit condition, beyond the which the operator himself is in a dangerous condition, taking into account the movement 20 of the operator inside an electric field, and more precisely inside the field electricity generated by the line that needs to be maintained. In particular, the trend of the electric field as a function of the displacement made allows the operator to identify dangerous conditions regardless of the specific power line where the operator is working, as it allows to obtain characteristics 25 of the electric field that allow us to recognize the type of power line that has it generated and identify the corresponding dangerous conditions. Advantageously, the electric field sensor 3 is an electric field sensor omnidirectional. In this way, the operator can approach the line under maintenance assuming any 5 position and from any direction, with the 3 omnidirectional electric field sensor that is able to correctly measure the electric field without being oriented in a particular direction, for example perpendicular, to the electric field lines. Advantageously, the electric field sensor 3 comprises a spherical capacitor 30. In particular, with reference for example to figure 3, the spherical capacitor 30 comprises 10 an external armature 31, of hollow spherical shape, defining an internal volume 310, made in conductive material. In more detail, this external armor 31 has a diameter between 10 and 30 mm, preferably 20 mm. Advantageously, the spherical capacitor 30 comprises an internal armature 32, of shape 15 spherical, which is contained in the internal volume 310 defined by the external frame 31. Preferably, the internal armature 32 is concentric with the external armature 31, and in particular is distanced from the latter. In more detail, this internal armor 32 has a smaller diameter than the aforementioned external armour 31, preferably between 3 and 20 mm, for example 8 mm. 20 Advantageously, the spherical capacitor 30 comprises a spacer layer 33, which it is interposed between the external armature 31 and the internal armature 32 and is preferably made in electrically insulating material, and even more preferably in dielectric material, in particular in plastic material, obtained for example by 3D printing. Preferably, the spherical capacitor comprises an outer shell 34, which is placed at 25 external armor cover 31. In particular, this external shell 34 has a hollow spherical shape, containing inside it the external armor 31, and is preferably made of electrically insulating material, such as example in plastic material. In more detail, the outer shell 34 is fixed to the support frame 23, in particular in 5 correspondence of the first end 21 of the latter. Preferably, the support element 2 of the device 1 comprises a hooking bracket 25, mechanically connected to the support frame 23 at the first end 21 of the latter. In more detail, the outer shell 34 of the spherical capacitor 30 is mechanically connected 10 to the mounting bracket 25, to mount the electric field sensor 3 on the mounting element support 2. Advantageously, the position sensor 4 comprises at least one altimeter 40, which is preferably mounted on the electronic board 7. In particular, the altimeter 40 (e.g. manometric type) is configured to detect 15 a vertical movement of the operator. In more detail, the processing unit 5 is configured to detect 40 measurements from the altimeter of quota representing the operator's quota variation, in particular in approaching the power line. In other words, the above position measures S advantageously include at least 20 a change in operator quota. In this way, the V variations calculated by the processing unit 5 are representative at least of the variation of the electric field generated by the power line with respect to the operator share change. Advantageously, the position sensor 4 comprises at least one accelerometer 41, the 25 which is preferably mounted on the electronic board 7 and is specifically configured for detect operator acceleration. In more detail, the processing unit 5 is configured to detect from the accelerometer 41 acceleration measurements representative of the operator's speed variation, in especially during the latter's approach to the power line. 5 In this way, the V variations calculated by the processing unit 5 are representative at least of the variation of the electric field generated by the power line with respect to the difference in speed at which the operator is approaching the power line. In other words, if a trader is moving too quickly (in terms of acceleration) within the electric field generated by the power line under maintenance, 10 the processing unit 5 can generate a warning signal A to warn the operator. Advantageously, the electrical safety device 1 comprises an emitter 6, operationally connected to the processing unit 5 to receive the warning signal A, the which warning signal A is capable of triggering the emitter 6 to emit an alarm signal AL. 15 Preferably, the emitter 6 is mounted on the support element 2, in particular on the electronic board 7. In particular, the emitter 6 is of the acoustic type, capable of emitting an alarm signal AL sound, and / or optical, capable of emitting an AL alarm signal, light, and / or optical vibrational, capable of emitting a vibrational AL alarm signal. 20 Advantageously, the emitter 6 is a combination of the emitter types listed above, being capable of emitting, for example, an AL alarm signal in audible and acoustic form, or sound and vibrational, etc. Advantageously, the alarm signal AL emitted by the emitter 6 is susceptible to be perceived by the operator, who is therefore made aware of the device 1 25 electrical safety of being in proximity to a dangerous condition, for example due to of the intensity of the electric field to which it is subjected (which could generate a discharge electric) with respect to the power line that the operator is approaching, determined on the basis of the V variations, as described in detail below. In accordance with an embodiment not illustrated in the attached figures, the emitter is 5 mechanically separated from the support element 2 of the device 1, and is arranged for be applied to a different point of the operator's body or integrated into another device of the latter (such as a communication device). Advantageously, the device is equipped with a communication unit connected to the processing unit 5 for receive the warning signals A and communicate (wireless or wired) with the emitter 6 for 10 send to the latter such warning signals A. Appropriately, the communication unit It can be set up to send the warning signal also to remote devices, for example supplied to other operators or at a control centre. Advantageously, with reference to figure 2, the device 1 comprises at least one power source 8, equipped in particular with one or more batteries 80, arranged at 15 example in series, to power at least the processing unit 5 and, preferably, the position sensor 4 and, more preferably, the electronic board 7 and the mounted components on it. In more detail, the support element 2 comprises a base plate 26, which is placed at the second end 22 of the supporting frame 23, substantially orthogonally to the 20 to the main development direction X of the latter. In particular, the base plate 26 is provided with a first face 26' fixed to the second end of the supporting frame 23, and of an opposite second face 26'', to which it is fixed the power source 8. Advantageously, the power source 8 comprises a battery cartridge 81, 25 which is mechanically connected to the second face 26'' of the base plate 26 and protrudes projecting from the latter along the main development direction X. In particular, the battery cartridge 81 is equipped with one or more housing seats in which 80 batteries are inserted. Advantageously, the device 1 comprises a power input 70, arranged 5 on the electronic board 7 and ready to be connected to the power source 8, and in particular to the 80 batteries, by means of electric cables. Preferably, the device 1 comprises a DC / DC converter 73, which is arranged on the electronic board 7 and is connected to the input of the power source 8 for through the power input 70, and output to other components arranged on the board 10 electronics 7, such as the processing unit 5, the position sensor 4 and the emitter 6, to convert the input voltage waveform into a waveform voltage adequate for the correct functioning of the latter. Advantageously, the support element 2 of the device 1 comprises a casing of cover 27, internally hollow, which is placed to contain the field sensor 15 electric 3, of the position sensor 4, of the processing unit 5, and, advantageously, of the power source 8 and of the support frame 23 and of the electronic board 7 arranged on the latter. In particular, the covering casing 27 comprises a first shell 270, placed as a covering of the electronic board 7 and of the electric field sensor 3, and a second shell 271, placed 20 to cover the power source 8. Advantageously, the first shell 270 is mechanically connected, e.g. in a removable, to the first face 26' of the base plate 26, and the second shell 271 is mechanically connected, for example in a removable manner, to the second 27'' face of the base plate 26. 25 Preferably, the first shell 270 of the covering element 27 is provided with at least a slot 272, arranged in correspondence with the emitter 6, and designed to facilitate the release of the AL alarm signal emitted by the latter, for example in the form of sound signal. Advantageously, with reference to the example in figure 5, the device 1 comprises a 5 data memory 50, which is advantageously mounted on the electronic board 7 and, for for example, it can be integrated into the processing unit 5. In particular, data memory 50 contains multiple CL identification classes, each of which which is associated with a corresponding power line, for example an overhead line in high voltage (in particular it operates at 132 kV or 150 kV) or in very high voltage (in particular 10 operates at 220 kV or 380 kV). In more detail, each CL identification class contains reference parameters P representative of a spatial distribution of a generated reference electric field from the corresponding power line. For example, such reference parameters P are determined by the line voltage at which it is 15 operates the power line of the corresponding identification class CL, the height of the pole of the power line, the distribution of the phase conductors of the power line, etc. Preferably, the reference parameters P include at least the field lines (in (in particular their distribution and the relative intensity) of the electric field generated by the power line. 20 An example of the electric field distribution lines is shown in figure 6, which is relating to a 380 kV very high voltage line in the vicinity of a pole or pylon support. Advantageously, each CL identification class contains at least one threshold value VS electric field strength representative of a dangerous condition. 25 In particular, the threshold value VS of a given identification class CL can differ from the threshold value of a different CL identification class. For example, with reference to a very high voltage overhead power line it exerts 380 kV, the high voltage to which the conductors of the latter are placed causes a ionization of the surrounding air (known in technical jargon as the corona effect), 5 making it more conductive. Therefore, the threshold value VS of a class of CL identification relating to this power line will be different than the VS threshold value of a class of information CL relating to a power line with different voltage in which not the corona effect is present. Advantageously, the processing unit 5 is arranged to compare the variations V 10 with the reference parameters P of the CL identification classes. In particular, the reference parameters P of each identification class CL contain information (given in particular by the field lines) relating to the electric field at a certain distance from the conductor, or at a certain height. So, in particular, the reference parameters P contain field strength values 15 electric in the space around the power line, which then report the variations of the field electric in that space and which, therefore, can be compared with the variations V calculated by the device 1 in question. Advantageously, the processing unit 5 is arranged to select a class of CL identification in whose reference parameters P the variations V fall. 20 In other words, the processing unit 5 is configured to detect a match between the variations V, calculated from the measurements detected by the electric field sensor 3 and by the position sensor 4, and the reference parameters P of the CL identification classes. For example, if the V variations are within (advantageously within tolerance ranges) in the variations of the electric field given by the reference parameters P of a given 25 identification class CL, processing unit 5 selects this identification class CL and then uses the latter's VS threshold values ​​to detect the conditions of danger, as discussed in detail below. Advantageously, the processing unit 5 is arranged to compare the measurements of field E with the threshold value VS of the selected identification class CL. 5 In particular, the processing unit 5 is arranged to generate the warning signal A in function of the above comparison between the field measurements E acquired by the field sensor electric 3 with the threshold value VS. In more detail, the processing unit 5 is configured to generate the above signal. warning A if the E field measurements are higher than the VS threshold value. 10 Preferably, as above, such warning signal A is received by the emitter 6, the which is capable of emitting the AL alarm signal to inform the operator of the conditions of danger. In this way, the warning signal A, and advantageously the alarm signal AL, do not depend on the electric field intensity in an absolute sense, but on the field intensity 15 electrical referring to the CL identification class and, therefore, to the electrical line subjected to maintenance. Advantageously, the electrical safety device 1 can therefore be used for multiple lines electrical, in particular operated at different voltage levels, as it is capable of select the CL identification class relating to a specific power line and 20 selecting a VS threshold value based on the determined power line. Advantageously, the processing unit 5 is programmed to implement a state of continuous measurement, in which it continuously acquires E-field measurements and position S, via the electric field sensor 3 and the position sensor 4, respectively. In particular, at each acquisition instant, the processing unit 5 25 acquires a field measurement E and a corresponding position measurement S. In this measurement state, the processing unit 5 compares each field measurement E with a minimum field threshold. If the field measurement E is greater than the minimum field threshold, the processing unit 5 implements a first (online) verification state, in which, based on the E-field measurements, 5 Check if the electric field increases. More specifically, if the intensities associated with the measurements of field E exceed a certain field value, the processing unit 5 implements a first classification state, in which it selects the CL identification class on the basis of of the E-field measurements and the S-position measurements. For example, the reference parameters P of each CL identification class include a corresponding first value of 10 intensity and a corresponding first value of altitude (used in this first state of verification). In particular, if the E field measurements exceed the first intensity value and the position measurements S exceed the first value of the parameters of a given CL identification class, the processing unit 5 selects this identification class CL. 15 If the field measurement E is not greater than the minimum field threshold, the unit of Processing 5 compares the corresponding position measurement S with a height value minimum. If the position measurement S is less than this minimum height value, the unit of processing 5 performs a new acquisition (of a new E field measurement and of a corresponding new position measure S). If the position measure S is greater than this 20 minimum quota value, processing unit 5 implements a second verification state (on pole), in which, on the basis of the position measurements S, it checks whether the operator's height increases. More specifically, if the position measurements S exceed a certain value of quota, the processing unit 5 implements a second classification state, in which select the CL identification class based on the E field measurements and the measurements 25 of position S. For example, the reference parameters P of each identification class CL include a corresponding second intensity value and a corresponding second quota value (used in this second verification state). If the field measurements And they exceed the second intensity value and the position measurements S exceed the second share value of the parameters of a given CL identification class, the unit of 5 processing 5 selection of this identification class CL. Essentially, the first verification state is implemented to check whether the operator is approaching to the power line along the line spaced from the poles and the second verification state is implemented to check if the operator approaches the power line in the vicinity of the pole (where the electric field conditions are generally different from those far away 10 from the pole, for example with substantially lower field strength values, as visible from the example in figure 6). Advantageously, the electric field sensor 3 is arranged to generate signals of output U electrics as a function of the detected electric field and, preferably, transmit them to the electronic board 7. 15 In particular, with reference to figure 4, the device 1 comprises a circuit of acquisition 71, which is composed for example of passive electrical components, such as resistors and / or capacitors, is mounted on the electronic board 7 and is designed for acquire and condition the electrical output U signals generated by the electric field sensor 3, to allow for subsequent processing. 20 Advantageously, the electrical safety device 1 comprises an amplifier variable gain 51, which is electrically connected to the electric field sensor 3 for receive the above output signals U and generate corresponding amplified measurement signals. In particular, the variable gain amplifier 51 is mounted on the electronic board 7 and is preferably connected to the electric field sensor 3 via the circuit 25 acquisition 71, so as to receive the output signals U already conditioned by the latter. Advantageously, the processing unit 5 is operationally connected to the field sensor electric 3 through the variable gain amplifier 51 to calculate, based on the amplified measurement signals, E-field measurements. Advantageously, the processing unit 5 is arranged to set different gains 5 in the variable gain amplifier 51. In this way, the device 1 is able to detect electric fields in a range of several orders of magnitude, for example it is able to detect electric fields of tens of Volts / meter is tens of thousands of Volts / meter, by setting a different gain in the variable gain amplifier 51. 10 In particular, this feature allows the device 1 to be used both for the maintenance on high and very high voltage lines as well as on low voltage lines, for example at 230 V, as described in detail below. Advantageously, the processing unit 5 is equipped with at least one search program in which sets a minimum gain as the gain of the variable gain amplifier 15 51, for example equal to 1. Advantageously, in the above mentioned search program the processing unit 5 acquires the amplified measurement signals and processes them to calculate the E-field measurements. If the processing unit 5 detects that the values ​​of these E-field measurements are not significant, it implements the loop operation described below, aimed at selecting 20 a gain suitable for the measured electric field, to allow obtaining reliable values and precise E-field measurements. In particular, in the above mentioned research program the processing unit 5 performs iteratively, for a maximum number of cycles, until the field measurements E contain significant values, the following operations: 25 − increases the gain by a certain increment, − acquires new amplified measurement signals, and − processes the new amplified measurement signals to calculate the E-field measurements. So, if the new measurement signals allow to calculate significant values ​​of the measurements of field E, the processing unit 5 in the search program selects the gain 5 current and terminates the loop operation. Instead, if the new measurement signals do not allow to calculate significant values ​​of the E-field measurements, the processing unit 5 in search program performs a new cycle of the loop operation by incrementing the current gain by reacquiring new amplified measurement signals to recalculate the measurements of the field with the new profit. 10 This allows you to select an appropriate gain without the risk of providing out-of-range values. E-field measurement scale, allowing to obtain the advantages better described in the discussion of the method of operation of the device 1 in question. In particular, significant values ​​must be understood as electric field intensity values which deviate from a null value, barring background noise, in a way that is known per se 15 for a technician in the sector. Advantageously, the maximum number of cycles is between 32 and 1,024, e.g. 64. In particular, the gain increases at each iteration (until the E field measurements do not contain significant values) until reaching a maximum gain at of the last cycle, that is, of the last iteration performed by the search program. 20 Preferably, the maximum gain is between 100 and 20,000, e.g. 1,000 or 10,000. Advantageously, the processing unit 5 comprises an analog-to-digital converter (ADC) 71, which is mounted on the electronic board 7 and is designed to receive the signals of amplified measurement and in analog format and convert them to digital format at the output, in 25 manner known to a technician in the sector, to then transmit them to the unit of processing 5. The present invention also relates to a method of operation of a electrical safety device 1 of the type described above and referred to below, for simplicity of exhibition, the same nomenclature and the same references will be maintained. 5 The operating method in question comprises a measurement phase, in which the sensor of electric field 3 measures the electric field generated by at least one power line, a displacement detection phase, in which the position sensor 4 detects displacements of the operator and an acquisition phase. In the above acquisition phase, the processing unit 5 detects from the field sensor 10 electric 3 E field measurements containing at least electric field strength values ​​and from the position sensor 4 the position measurements S associated with the corresponding measurements of field E. The method in question also comprises a processing phase, in which the unit of processing 5 calculates, at least from the E field measurements and the S position measurements, the 15 V variations of the electric field associated with the above displacements, and a signaling phase, wherein the processing unit 5 generates a warning signal A as a function of the variations V. In this way, device 1 signals to the operator a limit condition, beyond which the operator himself is in a dangerous condition, taking into account the movement of the operator within the electric field generated by the line that is to be subjected 20 per maintenance. Advantageously, the method in question includes an assembly phase, preferably preceding the above measurement phase, in which the operator wears device 1, for example by placing it on your harness or protective helmet. Advantageously, the operating method in question comprises a first phase of 25 comparison, where the processing unit 5 compares the variations V with the parameters of reference P of the CL identification classes, and a selection phase, in which the unit of processing 5 selects a aforementioned identification class CL in whose parameters reference P includes the V variations. In particular, the operating method includes a second comparison phase, in which 5 The processing unit 5 compares the E-field measurements with the threshold value VS of the selected identification class CL. Advantageously, in the signaling phase, the processing unit 5 generates the signal A warning when the E field measurements exceed the VS threshold value of the selected CL identification class. 10 In this way, the device 1 can be used on multiple power lines, which differ between their voltage level, arrangement of the conductors, height of the latter from the ground, etc., allowing economic savings to a company that manages multiple lines electrical equipment requiring maintenance. Advantageously, the operating method includes a setup phase, in which 15 the variable gain amplifier 51 receives the output signals U generated by the sensor electric field 3 and generates corresponding amplified measurement signals. Advantageously, in the setup phase the processing unit 5 sets a gain minimum in variable gain amplifier 51, acquires the amplified measurement signals and processes the amplified measurement signals to calculate the E-field measurements. 20 In particular, as long as the E-field measurements do not contain significant values, the unit of Processing 5 iteratively performs, for the maximum number of cycles, the following operations: increases the minimum gain by the above-mentioned determined increment, acquires new signals amplified measurement signals and processes the new amplified measurement signals to calculate the measurements of field E. 25 In this way, device 1 is able to detect the presence of electric fields whose intensity is included in a range of several orders of magnitude, for example from a few tens of Volts / meter to tens of thousands of Volts / meter by adjusting the gain of the variable gain amplifier 51 to accurately acquire the measurements of field E. 5 Therefore, the method of operation in question allows the device 1 to be used in both high voltage and low voltage applications. For example, when the operator approaches a low voltage power line, in particularly in a domestic system and, therefore, not at high altitude, the processing unit 5 set a high gain (e.g. 100, 1,000, or 10,000) in the amplifier 10 variable gain 51, in order to detect a relatively low electric field. In particular, when the operator approaches the conductor of such power line, the unit of Processing 5 acquires the calculated E-field measurements with a high gain and, at the at the same time, it acquires the position measurements S, which, however, do not detect any movement of the operator himself at a higher level. 15 The processing unit then calculates the variations V, which are representative of electric field variations (referring to a low electric field, the measurement of which is obtained by means of a high gain) compared to a zero change in altitude, detected from altimeter 40. Therefore, the high gain and zero altitude variation allow the unit to 20 processing to identify the CL identification class relating to a power line low voltage earth, such as that of a domestic system and to identify a corresponding threshold value VS. Advantageously, the operating method of the device 1 also allows to detect correctly the presence of the electric field generated by a power line even during 25 the ascent of an operator along a pylon. In fact, along the pylon the electric field can be null and, therefore, the processing unit 5 can detect from the field sensor electric 3 measurements of zero intensity E field alternating with measurements of high intensity E field intensity. However, the processing unit 5 itself detects position measurements S, in particular 5 elevation measurements representing the operator's elevation change measured from the altimeter 40, which are processed by the processing unit 5 which correlates the proximity between the acquisition of the above-mentioned measurements of zero and high intensity E-fields intensity and altitude measurements, recognizing that the operator is approaching the power line conductors climbing up the pylon. 10 Consequently, the processing unit 5 neglects the zero intensity E field measurements. in order to correctly report the detected electric field and be able to communicate to the operator of any dangerous condition through the warning signal A and the AL alarm signal emitted by emitter 6. Advantageously, the operating method of the device 1 is able to signal 15 to the operator a dangerous condition even when the power line under maintenance is been correctly sectioned, especially if the sectioned power line is arranged in parallel to another unconnected power line (e.g. for power lines high and very high voltage lines). In this situation, the electric current flowing in the undisconnected power line is 20 likely to induce a voltage on the conductors of the sectioned power line, in particular starting from the sectioning point. Therefore, the conductors of the sectioned line could not be at zero potential, but rather have a voltage that can reach some hundred volts. In this case, as the operator approaches the conductors of the sectioned power line 25 while climbing in altitude, the processing unit 5 of the device 1 detects the presence of a field weaker electrical output than expected if the power line had not been sectioned (which is advantageously detected by setting a high gain of the gain amplifier variable 51), but not attributable to a low voltage domestic electrical system, in how much the position sensor 4, and in particular the altimeter 40, detects variations in 5 share by the operator as the measured electric field increases. In this way, the device 1 and its method of operation allow a operator to work safely even in the aforementioned situation. Advantageously, the E field measurements detected by the processing unit 5 starting from the Electric field measurements performed by electric field sensor 3 contain values ​​of 10 frequency of the electric field, which frequency values ​​allow the unit to 5 same processing to detect the operating frequency of the voltage on a specific power line. In particular, the processing unit 5 is able to detect both the fundamental component of the operating frequency, both the presence of any harmonic components, at a 15 multiple frequency of the fundamental component, or of any components subharmonics, at a frequency lower than the fundamental component. Advantageously, the presence of certain voltage harmonics, such as the second harmonic (which in a system operated at 50 Hz has a value of 100 Hz), can indicate the presence of a photovoltaic system connected to the power line, for example downstream of the 20 sectioning point of the latter, which could be dangerous for the operator during maintenance operations on the power line itself. Therefore, the method of operation of the device 1 allows the latter to detect the dangerous condition described above, by detecting the harmonic components present in the electric field measured by the electric field sensor 3, with the unit of 25 processing 5 which generates the warning signal A and the emitter 6 which emits the warning signal AL alarm. The invention thus conceived therefore achieves the intended purposes.

Claims

CLAIMS 1. Electrical safety device (1), which comprises: - a support element (2) arranged to be applied to an operator; - an electric field sensor (3), which is mounted on said support element (2) and is arranged to measure at least one electric field generated by at least one power line; - at least one position sensor (4), which is mounted on said support element (2) and is arranged to detect movements of said operator;- at least one processing unit (5), which is operatively connected to said electric field sensor (3) to detect field measurements (E) containing at least intensity values ​​of said electric field, is operatively connected to said position sensor (4) to detect position measurements (S) associated with corresponding said field measurements (E), and is capable of calculating, at least from said field measurements (E) and from said position measurements (S), variations (V) of said electric field associated with said displacements; said processing unit (5) being arranged to generate a warning signal (A) as a function of said variations (V).; 2. Electrical safety device (1) according to claim 1, characterised in that said electric field sensor (3) is an omnidirectional electric field sensor.

3. Electrical safety device (1) according to claim 2, characterised in that said electric field sensor (3) comprises a spherical capacitor (30).

4. Electrical safety device (1) according to any of the preceding claims, characterised in that said at least one position sensor (4) comprises at least one altimeter (40).

5. Electrical safety device (1) according to any of the preceding claims 27 - 27, characterised in that said at least one position sensor (4) comprises at least one accelerometer (41).

6. Electrical safety device (1) according to any of the preceding claims, characterised in that it comprises an emitter (6), operatively connected to said processing unit (5) to receive said warning signal (A), which warning signal (A) is capable of actuating said emitter (6) to emit an alarm signal (AL).

7. Electrical safety device (1) according to any of the preceding claims, characterised in that it comprises a data memory (50), which contains multiple identification classes (CL), each of which is associated with a corresponding power line and contains: - reference parameters (P) representing a spatial distribution of a reference electric field generated by the corresponding said power line; - at least one threshold value (VS) of electric field intensity representative of a dangerous condition; said processing unit (5) being arranged to: - compare said variations (V) with the reference parameters (P) of said identification classes (CL); - select a said identification class (CL) in which said reference parameters (P) said variations (V) fall;- compare said field measurements (E) with said at least one threshold value (VS) of the selected said identification class (CL); - generate said warning signal (A) based on said comparison.; 8. Electrical safety device (1) according to any of the preceding claims, wherein said electric field sensor (3) is arranged to generate electrical output signals (U) as a function of said detected electric field; characterised in that it comprises a variable gain amplifier (51), which is electrically connected to said electric field sensor (3) to receive said output signals (U) and generate corresponding amplified measurement signals; said processing unit (5) being operatively connected to said electric field sensor (3) through said variable gain amplifier (51) to calculate, on the basis of said amplified measurement signals, said field measurements (E); said processing unit (5) being arranged to set different gains in said variable gain amplifier (51).

9. Electrical safety device (1) according to claim 8, characterised in that said processing unit (5) is equipped with at least one search program in which: - sets a minimum gain as said gain in said variable gain amplifier (51); - acquires said amplified measurement signals; - processes said amplified measurement signals to calculate said field measurements (E); until said field measurements (E) do not contain significant values, iteratively, for a maximum number of cycles: - increases said gain by a given increment; - acquires new said amplified measurement signals; - processes said new amplified measurement signals to calculate said field measurements (E).

10. Method of operation of an electrical safety device (1) according to any of the preceding claims, comprising: - a measurement step, wherein said electric field sensor (3) measures at least one said electric field generated by at least one said power line; - a displacement detection step, wherein said position sensor (4) detects - 29 displacements of said operator; - an acquisition step, wherein said processing unit (5) detects: - from said electric field sensor (3) said field measurements (E) containing at least the intensity values ​​of said electric field; - from said position sensor (4) said position measurements (S) associated with corresponding said field measurements (E); - a processing step, wherein said processing unit (5) calculates, at least from said field measurements (E) and from said position measurements (S), said variations (V) of said electric field associated with said displacements;- a signalling phase, in which said processing unit (5) generates said warning signal (A) as a function of said variations (V).; 11. Operating method according to claim 10 of an electrical safety device (1) according to claim 7, characterised in that it comprises: - a first comparison phase, wherein said processing unit (5) compares said variations (V) with the reference parameters (P) of said identification classes (CL); - a selection phase, wherein said processing unit (5) selects a said identification class (CL) in which said reference parameters (P) said variations (V) fall; - a second comparison phase, wherein said processing unit (5) compares said field measurements (E) with said at least one threshold value (VS) of the selected said identification class (CL); wherein, in said signalling phase, said processing unit (5) generates said warning signal (A) when said field measurements (E) exceed said at least one threshold value (VS) of the selected said identification class (CL).

12. A method of operation according to claim 10 or 11 of an electrical safety device (1) according to claim 9, characterised in that it comprises a setting step, wherein: - said variable gain amplifier (51) receives said output signals (U) generated by said electric field sensor (3) and generates the corresponding said amplified measurement signals 5; - said processing unit (5): - sets said minimum gain in said variable gain amplifier (51); - acquires said amplified measurement signals; - processes said amplified measurement signals to calculate said field measurements (E); 10 wherein, as long as said field measurements (E) do not contain significant values, said processing unit (5) iteratively performs, for said maximum number of cycles, the following operations: - increases said minimum gain by said given increment; - acquires new said amplified measurement signals;15 - processes said new amplified measurement signals to calculate said field measurements (E).;