System and method for measuring voltage in an intermediate cable - Patents.com

Abstract

A system, method, and / or computer program for measuring a voltage between an electrical cable of an electrical grid and a reference point without electrical contact to the reference point, the voltage measuring device may include a first plate having a first area and providing a first capacitance between the first plate and the reference point, a second plate having a second area and providing a second capacitance between the second plate and the reference point, at least one current measuring device for measuring current through the first plate and the second plate to provide respective first and second current measurements, and a processor electrically coupled to the current measuring device for receiving the current measurements and calculating the voltage between the electrical cable and the reference point by comparing the current measurements between the reference point and each of the first plate and the second plate.

Description

[Technical field]

[0001] The present invention relates generally to the field of electrical grids, more particularly, but not exclusively, to electrical transmission and distribution networks, more particularly, but not exclusively, to detecting defects in electrical grids using sensors mounted on electrical cables, and more particularly, but not exclusively, to measuring various electrical parameters in intermediate cables. [Background technology]

[0002] An electrical grid may have many defects. Various components of the grid may fail, and the failures may be instantaneous, gradual, or intermittent. Some defects may be caused by the environment, such as humidity, smoke, dust, wind, trees, etc. Various defects and failures may have different characteristics and affect the network in different ways. Characterizing, detecting, identifying, and locating defects in an electrical grid is a known problem with various solutions including various types of sensors mounted on the cables of the electrical grid.

[0003] One important parameter that needs to be measured is the voltage at various points in the intermediate cable. Other important parameters associated with the intermediate cable voltage are the capacitance between the cable and the reference point, the reactance between the cable and the reference point, and the impedance between the cable and the reference point, as measured in the intermediate cable. The problem with measuring such parameters is that the measurement equipment, when mounted in the intermediate cable, may not have an electrical contact to the reference point, or the neutral line, or the common cable, or any other reference point to measure the potential difference. Summary of the Invention [Means for solving the problem]

[0004] According to an exemplary embodiment of the present invention, a system, method, and / or computer program is provided for measuring a voltage between an electric cable of an electric grid and a reference point such as ground. Such an exemplary embodiment of a voltage measuring device may include a plurality of plates including a first plate having a first area and providing a first capacitance between the first plate and the reference point, and at least one second plate having a second area and providing a second capacitance between the second plate and the reference point. Such an exemplary embodiment of a voltage measuring device may also include at least one current measuring device for measuring a current through each of the first plate and the at least one second plate to provide respective first and second current measurements (or more), and a processor electrically coupled to the one or more current measuring devices for receiving the first and second current measurements (or more) and for calculating a voltage between the electric cable and the reference point by comparing the first and second current measurements and, if provided, the current through the other plate.

[0005] According to another exemplary embodiment, the voltage measurement device may be mounted on an electrical cable of the electrical grid in an intermediate cable and may not be electrically connected by a wire to a similar reference point such as a ground or a common line or a neutral line.

[0006] According to yet another exemplary embodiment of the voltage measurement device, the first plate and the second plate may face a reference point and may be rounded such that when the voltage measurement device or the plates may move, such as yaw, pitch, and / or roll, at least one of the first plate and the second plate faces the reference point.

[0007] According to yet another exemplary embodiment of the voltage measuring device, the first plate and the second plate may be interleaved with each other.

[0008] Furthermore, according to another exemplary embodiment of the voltage measuring device, the voltage measuring device may additionally comprise an accelerometer and / or a gyroscope for measuring at least one of the yaw, pitch, and roll of the voltage measuring device and / or the plate. The processor of the voltage measuring device may then calculate the voltage between the electric cable and the reference point taking into account the measured yaw, pitch, and / or roll.

[0009] Still further, according to another exemplary embodiment of the voltage measurement device, the processor may monitor one or more relationships between the current measurements to detect defects and / or weather conditions such as humidity, rain, and ice.

[0010] Furthermore, according to another exemplary embodiment of the voltage measurement device, the processor may calculate a fast change in voltage between the electrical cable and the reference point using the current measurement, the calculated voltage between the electrical cable and the reference point, and the capacitance between the plate and the reference point.

[0011] Still further, according to another exemplary embodiment, the voltage measurement device may additionally include an internal capacitance between each of the plates and the electrical cable, and a step in which the internal capacitance is measured in the laboratory, and then used by the processor to calculate a voltage between the electrical cable and a reference point.

[0012] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the relevant art.The materials, methods, and examples provided herein are illustrative only and are not intended to be limiting.No particular order of steps or stages of the methods and processes described in this disclosure, including the figures, is intended or implied, except to the extent necessary or essential in the process itself.In many cases, the order of process steps can be varied without changing the purpose or effect of the method described. [Brief description of the drawings]

[0013] Various embodiments of the present invention are described herein by way of example only, with reference to the accompanying drawings. Now, with specific reference to the drawings in detail, it is emphasized that the details shown are presented by way of example and for the purpose of illustrative discussion of the embodiments only, in order to provide what is believed to be a useful and easily understood explanation of the principles and conceptual aspects of the invention. In this regard, no attempt is made to show the structural details of the embodiments in more detail than is necessary for a fundamental understanding of the invention, and the description taken in conjunction with the drawings will make apparent to those skilled in the art how some forms and structures may be embodied in practice. [Figure 1] FIG. 1 is a simplified diagram of cable devices mounted on respective electrical cables of an electrical grid, each cable device including a cable voltage measurement system. [Diagram 2] FIG. 2 is a first simplified electrical diagram of a voltage measurement system including two plates of different sizes. [Diagram 3] FIG. 3 is a second, more detailed, simplified electrical diagram of a voltage measurement system including two plates of different sizes. [Figure 4A] FIG. 4A is a simplified diagram of a printed circuit board (PCB) that includes a pair of plates of different sizes. [Figure 4B] FIG. 4B is a simplified diagram of a printed circuit board (PCB) including a pair of curved plates of different sizes. [Figure 4C] FIG. 4C is a simplified diagram of a printed circuit board (PCB) containing pairs of interleaved plates of different sizes. [Diagram 5] FIG. 5 is a simplified diagram of a cut through cable device mounted on an electrical cable and including a voltage measurement system. [Figure 6] FIG. 6 is a simplified diagram of a side cutaway of box 36 showing the PCB (ie, pair of plates) curved downwards. [Figure 7] FIG. 7 is a simplified diagram of a side cutaway of box 36 showing the PCB (ie, pair of plates) curved upwards. [Figure 8] FIG. 8 is a simplified diagram of a computing device that is included in a cable device mounted on an electrical cable and includes a processor of a voltage measurement system for calculating the cable voltage in an intermediate cable. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] A method and system are provided for measuring the voltage between an electric cable and a reference point without the measuring device having an electrical contact with the reference point for measuring the potential difference. The measuring device may be an electric sensor that operates to measure one or more electric parameters. The measuring device may be mounted anywhere on the electric cable, i.e. in the intermediate cable, which may be anywhere between two poles or two insulators that support or support the cable. The cable may be an overhead cable or an underground cable. For example, for an underground cable, the measuring device may be installed where the underground cable is exposed and / or where there is no shielding, such as a maintenance hole (manhole) or a division point.

[0015] The principles and operation of systems and methods for measuring electrical cable voltage at an intermediate cable according to certain exemplary embodiments described herein may be better understood with reference to the following drawings and accompanying description.

[0016] Before describing at least one embodiment in detail, it is to be understood that the embodiments are not limited in their application to the details of construction and arrangement of components set forth in the following description or illustrated in the drawings. Other embodiments may be practiced or carried out in various ways. It is also to be understood that the phraseology and terminology employed herein is for the purpose of description and should not be regarded as limiting.

[0017] Elements of the drawings labeled with numbers not described within the drawings but described in a previous drawing have the same purpose and description as in the previous drawing. Similarly, elements identified in the text by numbers that do not appear in a drawing described by the text have the same purpose and description as in the previous drawing in which they are described.

[0018] The drawings in this document may not be intended to be to scale: different figures may use different scales, and different scales may even be used within the same figure, for example, different scales for different views of the same object, or different scales for two adjacent objects.

[0019] The measuring device can measure various electrical parameters at multiple locations in the electrical network and by comparing the multiple measurements, determine the presence of a fault, the type or characteristics of the fault, and its location. One important electrical parameter is the voltage at a point on the electrical cable, which may be in an intermediate cable that is away from any poles or insulators supporting the cable, and the voltage measuring device may not have any electrical contact with a reference point such as ground, or zero, or neutral, or common line.

[0020] In this regard, the voltage measurement device may be electrically coupled to the electrical cable as a first reference point for measuring a potential difference (e.g., voltage), but may lack a second electrical contact to a second reference point (i.e., neutral, ground, common line, etc.).

[0021] The terms "grid" or "electricity grid" may refer to an electric power transmission network and / or distribution network, and any portion of such a network between a generating station or stations and loads or consumers.

[0022] The term "cable" or "electrical cable" may refer to any single cable, or wire, or power line of an installed network, such as a phase carrier cable.

[0023] The term "cable device" may refer to any device mounted on or off an electrical cable of an installed network, including sensors, measurement devices, communication devices, etc. As a non-limiting example, a cable device may derive power from electric and / or magnetic fields surrounding the electrical cable, which may be generated by currents flowing in the electrical cable.

[0024] The term "measurement" or "electrical measurement" may refer to any type of measurement of any electrical parameter, such as voltage, current, electric field, magnetic field, resistance, capacitance, inductance, charge, etc. The term "physical measurement" or "mechanical measurement" may refer to any type of measurement of any physical parameter other than an electrical parameter. Such parameters may be temperature, wind, humidity, movement, height, (cable) depression, (cable) angle, etc. Such measurements are typically performed by cable devices mounted on the electrical cable.

[0025] The term "intermediate cable" may refer to any location or point along an electrical cable where a cable device, or voltage sensor, or voltage measurement device may be mounted on the electrical cable, and the cable device, or voltage sensor, or voltage measurement device may not have access to or electrical contact with a reference potential, such as ground, zero line, common line, neutral line, etc.

[0026] The term "reference point" may refer to any such reference potential, such as ground, zero line, common line, neutral line, different phase power lines, reference plane, etc.

[0027] The terms "electrically coupled," or "electrically connected," or simply "connected," can refer to direct or indirect electrical contact (galvanic contact).

[0028] The term "ungrounded voltage measurement" may refer to measuring the voltage or potential of an electrical element, such as an electrical cable, that is a first electrical reference point, without contacting a second electrical reference point, such as a reference point, zero voltage line, common line, neutral line, a power line of a different phase, etc. For simplicity, all such versions of a second electrical reference point may be referred to herein as a "reference point."

[0029] Reference is now made to FIG. 1, which is a schematic diagram of a cable device 10 mounted on each electrical cable 11 of an electrical grid 12 according to one exemplary embodiment, each cable device 10 including a cable voltage measurement system 13.

[0030] FIG 1 shows three independent cable devices 10 mounted in three different geographic locations of respective cables 11 in an intermediate cable. The cables 11 may be supported by poles (not shown) via insulators (not shown). FIG 1 shows the cables 11 between the poles or insulators. Each of the cable devices 10 may include a slot 14 or similar arrangement through which the cables 11 may be inserted into the cable device 10 when mounting the cable device 10 on the current carrying cable 11. Each of the cable devices 10 includes a voltage measurement system, as will be further described below.

[0031] 1, cable devices 10 and their respective voltage measurement systems 13 are coupled to their respective cables 11 but are not connected to any other reference point such as ground, zero voltage line, common line, neutral line, etc. In this respect, the voltage measurement systems are ungrounded voltage measurement systems.

[0032] Reference is now made to FIG. 2, which is a first simplified electrical diagram of a voltage measurement system 13 according to one exemplary embodiment.

[0033] As an option, the simplified electrical diagram of Figure 2 may be viewed in the context of the details of the previous figures. However, it will be appreciated that the simplified electrical diagram of Figure 2 may be viewed in the context of any desired environment. Moreover, the above definitions may be equally applied to the following description.

[0034] 2, the voltage measurement system 13 may include at least two conductive plates 15 of different areas, which form an (external) parasitic capacitance 16 between each plate and a ground reference point 17. A current measurement device 18 or a controlled current source 18 is connected between the electrical cable 11 and each of the plates 15. The voltage measurement system 13 may calculate the voltage between the plates 15 and the ground reference point 17 by comparing the two currents as measured by the current measurement device 18 or as provided by the controlled current source 18.

[0035] Reference is now made to FIG. 3, which is a second or detailed simplified electrical diagram of voltage measurement system 13 according to one exemplary embodiment.

[0036] As an option, the simplified electrical diagram of Figure 3 may be viewed in the context of the details of the previous figures. However, it will be appreciated that the simplified electrical diagram of Figure 3 may be viewed in the context of any desired environment. Moreover, the above definitions may be equally applied to the following description.

[0037] 2, the voltage measurement system 13 may include at least two conductive plates 15, typically formed of metal layers or materials. A first plate 15, designated by number 19, has an area A19 that is smaller (or larger) than an area A20 of a second plate 15, designated by number 20. It should be understood that the number of plates 15 may be more than two plates, and that the areas of the various plates may vary accordingly.

[0038] Each plate 15 has an internal parasitic capacitance between the respective plate and cable 11, designated in Figure 2 as internal parasitic capacitors 21 and 22. Different areas of capacitors 21 and 22 may result in different capacitances of capacitors 21 and 22, designated as C17 and C18, respectively. Each plate 15 has an external parasitic capacitance between the respective plate and reference point 17, designated in Figure 2 as external parasitic capacitors 23 and 24.

[0039] 2, each plate may be connected to electrical cable 11 by a resistor. Resistor 25 may be connected between plate 19 and cable 11, and resistor 26 may be connected between plate 20 and cable 11.

[0040] Each resistor may be connected to an input terminal of a respective electrical input network or buffer circuit 27 and 28, as shown in FIG. 2. Each such buffer circuit may include an operational amplifier. The outputs of buffer circuits 27 and 28 may be connected to inputs of respective analog-to-digital converters (ADCs) 29 and 30. The outputs of ADCs 29 and 30 may be connected to a processor (or microcontroller, etc.) 31. Each resistor, its buffer circuit, and its ADC may be considered as current measurement device 18 of FIG. 2.

[0041] Processor 31 may use buffer circuit 27 and ADC 29 to make a measurement of voltage V25 across resistor 25, and similarly buffer circuit 28 and ADC 30 to make a measurement of voltage V26 across resistor 26. Processor 31 may then calculate current 125 through resistor 25 and current 126 through resistor 26. Processor 31 may then calculate the voltage of cable 11 relative to the potential of reference point 17 by comparing currents 125 and 126 (optionally by adding the voltages measured across resistors 25 and 26, respectively). Processor 31 may then communicate the calculated cable voltages via output 32 to any other type of computing device.

[0042] It should be appreciated that, alternatively, a single ADC may be used with switching circuitry connecting the single ADC to two (or more) buffer circuits (27 and 28). The processor 31 may control the switching circuitry to select the appropriate buffer circuit 27 in an alternating fashion to obtain current and / or voltage measurements of the respective resistors (25 and 26).

[0043] It should be appreciated that the currents and / or voltages for resistors 25 and 26 may be calculated instantaneously or by averaging repeated measurements over time, for example by calculating the RMS (root mean square) value of each of the currents and / or voltages. The RMS values ​​may be calculated by processor 31 or using dedicated hardware.

[0044] Reference is now made to Figures 4A, 4B and 4C, which are simplified diagrams of pairs of plates 15 according to three exemplary embodiments.

[0045] As an option, the simplified electrical diagrams of Figures 4A, 4B, and 4C may be viewed in the context of the details of the previous figures. However, it will be appreciated that the simplified electrical diagrams of Figures 4A, 4B, and 4C may be viewed in the context of any desired environment. Moreover, the preceding definitions may be equally applied to the following description.

[0046] 4A shows a printed circuit board (PCB) 33 that may include a pair of plates 15 of different sizes (such as plates 19 and 20 in FIG. 3). Two or more plates 15 may be formed on a single PCB with a space of a few millimeters between the plates. Two or more plates 15 may be formed on a single PCB as thin layers of metal or any other conductive material.

[0047] 4B shows a printed circuit board 34 that may include a pair of plates 15 of different sizes, such as plates 19 and 20, similar to those in FIG. 3 and FIG. 4A. However, the printed circuit board 34 is curved. On the one hand, the curved PCB 34 may conform to the shape of the external box of the cable device 10. On the other hand, the curved PCB 34 may retain the same or similar external parasitic capacitance as the reference point when the cable device 10 may tilt, such as when the cable 11 sways sideways due to wind blowing. Thus, the PCB 34 may provide more stable measurements in various weather conditions.

[0048] Figure 4C, similar to Figure 3 and to Figures 4A and 4B, shows a printed circuit board 35 that may include pairs of plates 15 of different sizes, such as plates 19 and 20. However, plates 19 and 20 of printed circuit board 35 are interleaved. Interleaving two or more plates in any shape and form of interleaving may further promote stable capacitance and accurate measurements in various weather conditions and cable movements such as a galloping line.

[0049] Other shapes and configurations of the plates are also envisioned.

[0050] Reference is now made to FIG. 5, which is a simplified diagram of a cut through cable device 10 mounted on an electrical cable 11 according to one exemplary embodiment.

[0051] As an option, the illustration of cable device 10 in Fig. 5 may be viewed in the context of the details of the previous figures. However, it will be appreciated that the illustration of cable device 10 in Fig. 5 may be viewed in the context of any desired environment. Moreover, the previous definitions may be equally applied to the following description.

[0052] 5, cable device 10 may include a box or body 36 through which electrical cable 11 passes. Electrical cable 11 may be part of an electrical grid, transmission network, or distribution network, such as that maintained by a power company to provide electricity to the public, factories, etc. Cable device 10 may thus be mounted on energized cable 11, i.e., when cable 11 is fully powered and / or carrying voltage and / or current.

[0053] Box 36 may be constructed in two pieces that can be opened and then closed around cable 11. Alternatively, box 36 may be constructed in one piece that encloses most of the cable diameter and has an opening on one side, such as slot 14 (not shown in FIG. 5), for inserting cable 11 and attaching the box to cable 11. Other configurations and shapes of box 36 are also envisioned.

[0054] 5, cable device 10 may include a power supply module 37, a controller module 38, one or more power measurement devices 39, one or more physical measurement devices 40, and a backhaul communication module 41. Optionally, cable device 10 may also include a local area communication module 42, a remote sensing module 43, and a propulsion control module 44. Optionally, cable device 10 may also include a cable clamping unit 21 and a GPS module 45. Electrical measurement device 39 may include at least the electronic circuitry of a cable voltage measurement system 13, such as the electrical circuitry shown and described with reference to FIG.

[0055] 5, cable device 10 may include a magnetic core 46 on which at least one coil is wound to form a winding 47. Core 46 may be mounted around electrical cable 21. Core 46 may be constructed of two parts (one in each of the two parts of box 36) that are closed around electrical cable 11 when box 36 is attached to electrical cable 11. However, optionally, particularly for high voltage cables, core 46 may be open in the sense that it has a slot through which electrical cable 11 may be inserted.

[0056] The magnetic core 46 typically derives a magnetic field from the current flowing in the electrical cable 11. The windings 47 may derive a current from the magnetic flux in the magnetic core 46. The windings 47 may typically be electrically coupled to a power source module 37, which provides a voltage to the other modules of the cable device 46. It should be understood that the cable device 10 may derive power from a single electrical cable 11.

[0057] Alternatively, for example when used with insulated high voltage cables and / or underground cables and / or low voltage utility networks, the power supply module 37 may be connected to sensors attached to the electrical cable, the electrical cable deriving its power supply from another source (such as a main unit connected to a low voltage output of a transformer, a battery, photovoltaic (PV) elements, etc.) Such a configuration of the cable device 10 may have only one part with an opening at the bottom.

[0058] Each and / or both of the backhaul communication module 41 and the local area communication module 42 may be coupled to one or more antennas 48. The remote sensing module 43 may be coupled to and control various sensors, one or more cameras 49, one or more microphones 50, etc. It should be understood that the cameras may be mounted on a system of axles that provide three-dimensional rotation. Alternatively, multiple fixed cameras, or an array thereof, may be mounted to cover a wide field of view as needed.

[0059] The backhaul communication module 41 and the local area communication module 42 may use any type of communication technology and / or communication network, including, but not limited to: the term "communication technology" or "communication network" or simply "network" refers to any type of communication medium, including, but not limited to, fixed (wire, cable) networks, wireless networks, and / or satellite networks, fixed or wireless wide area networks (WANs) including various types of cellular networks, fixed or wireless local area networks (LANs) including Wi-Fi, and fixed or wireless personal area networks (PANs) including Bluetooth, ZigBee, and NFC, power line carrier (PLC) communication technologies, etc. The term "communication network" or "network" may refer to any number of networks and any combination of networks and / or communication technologies.

[0060] Optionally, cable device 10 may also include a Global Positioning Service (GPS) module 45 that may be used to measure, monitor, and / or control the position of cable device 10 along electrical cable 11. GPS module 45 may provide, for example, an accurate universal clock to precisely determine the absolute time of a measurement.

[0061] The controller module 38 may include a processor unit, one or more memory units (e.g., random access memory (RAM), non-volatile memory such as flash memory, etc.), and one or more storage units (e.g., including a hard disk drive and / or a removable storage drive, etc.) that may be used to store and / or execute software programs and associated data and communicate with external devices. The controller module 38 may also function as the processor 31 of FIG. 3. Alternatively, the controller module 38 may be electrically coupled to the output 32 of the processor 31 of FIG. 3.

[0062] The propulsion control module 44 may be coupled to one or more actuation devices, such as an electric motor 51, which may be coupled to one or more wheels 52. The wheels 52 may be mounted on the cable 11 such that controlling the electric motor 51 enables the propulsion control module 44 to move the cable device 10 along the cable 11.

[0063] It should be understood that the propulsion system of the cable device 10 (including, but not limited to, the propulsion control module 44, one or more electric motors 51, one or more wheels 52, etc.) may operate to move the cable device 21 along the cable 11 and / or to rotate the cable device 10 around the cable 11.

[0064] It should be understood that electric motor 51, as used herein, represents any type of technology suitable for steering cable device 10 along and / or around cable 11, including, but not limited to, AC motors, DC motors, stepper motors, pneumatic pumps and / or motors, hydraulic pumps and / or motors, or any other type of actuator.

[0065] The cable clamping part 21 may include, for example, a cable holder part 53 that may be pressed against the cable 11 to securely attach the cable device 10 to the cable 11. The cable holder part 53 may be manipulated (e.g., up and down) by electrical means and / or by mechanical means such as a threaded rod 54. The threaded rod 54 may be operated by an electric actuator or by a shaft 55 inserted into a socket of the cable attachment actuator part 20 as shown in FIG. 5. Alternatively, the threaded rod 54 may be operated by a rod inserted into a socket 56. The cable holder part 53 may provide an electrical coupling of the voltage measurement system 13 to the cable 11 as shown and described with reference to FIG. 3.

[0066] Reference is now made to FIG. 6, which is a simplified diagram of a side cutaway of a box 36 showing a pair of downwardly curved plates 15 in the form of a curved PCB 34 according to one exemplary embodiment, and to FIG. 7, which is a simplified diagram of a side cutaway of a box 36 showing a pair of upwardly curved plates 15 according to one exemplary embodiment.

[0067] As an option, the diagrams of Figures 6 and 7 may be viewed in the context of the details of the previous figures. However, it will be appreciated that the diagrams of Figures 6 and 7 may be viewed in the context of any desired environment. Furthermore, the above definitions may be equally applied to the following description.

[0068] As shown in Figures 6 and 7, the bottom side of box 36 may include a plurality of parallel peaks 57 and valleys 58 to reduce the accumulation of precipitation such as rain and dew. Figure 7 additionally shows that the bottom side of box 36 may include a sidewall 59 that surrounds the bottom of box 36 to further reduce the accumulation of precipitation such as rain. It should be understood that the body of Figure 6 may also include such a sidewall.

[0069] Reference is now made to FIG. 8, which is a simplified diagram of a computing device 60 typically included within box 36 according to one exemplary embodiment.

[0070] As an option, the diagram of Figure 8 may be viewed in conjunction with the details of the previous figures. However, it will be appreciated that the diagram of Figure 8 may be viewed in conjunction with any desired environment. Furthermore, the above definitions may be equally applied to the following description.

[0071] Computing device 60 is provided as an example implementation of the processing portion of cable device 10 and / or voltage measurement system 13. As shown in Figure 8, computing device 60 may include at least one processor unit 61, one or more memory units 62 (e.g., random access memory (RAM), non-volatile memory such as flash memory, etc.), and one or more storage units 63 (e.g., including hard disk drives, and / or removable storage drives representing floppy disk drives, magnetic tape drives, compact disk drives, flash memory devices, etc.).

[0072] Computing device 60 may also include one or more communication units 64. Such communication units 64 may use any type of communication technology, in particular RF communication technology, in particular Wi-Fi, Bluetooth, ZigBee, etc., and any remote control communication technology, such as may be used by cable device 10, to communicate with any other cable device 10, or with a remote controller, a remote server, or any other computing device.

[0073] Computing device 60 may also include one or more communication buses 65 connecting the above units. Computing device 60 may also include one or more control circuitry 66 for controlling other devices coupled to or contained within main body 15.

[0074] The computing device 60 may also include circuitry 67 of the voltage measurement system 13 as shown and described with reference to FIG.

[0075] The computing device 60 may also include one or more computer programs 68 or computer control logic algorithms, which may be stored in any of the memory unit 62 and / or the storage unit 63. Such computer programs, when executed, enable the computing system 60 to perform various functions as described herein. The memory unit 62 and / or the storage unit 63, and / or any other storage device are possible examples of tangible computer readable media. In particular, the computer programs 68 may include a software program for calculating the cable voltage relative to the reference point and the collected data.

[0076] As disclosed above, the voltage measurement system 13 may include two or more metal plates 15 connected to the power line 11 and facing a reference point, which may be a reference point 17 below the power line. The plates may have different areas, which may be known. For example, the areas of the two plates may have a 1:2 ratio.

[0077] The plate may be mounted inside the cable device 10 enclosure with a non-conductive cover on the face facing the reference point. The plate may be sealed from the environment by a cover and a seal. The plate may be thin, for example, produced as a thin-walled PCB. Using this PCB allows the plate to be rolled to form an arc in order to receive better measurements when the cable device 10 is clinging to a wire that is swaying due to wind. Two or more plates may be formed on the same single PCB with a space of a few millimeters between the plates (for example).

[0078] The plates may have the voltage potential of the power line 11 when each plate is connected to the power line through a low resistance ammeter. A parasitic impedance may be formed from each plate and a reference point. The voltage across each impedance may be close to the voltage of the power line.

[0079] To calculate the voltage, the voltage measurement system 13 may measure the current flowing through each of the two or more plates to a reference point and the impedance between each of the two or more plates and the reference point. The current and impedance may be measured repeatedly and / or frequently since the impedance may change due to environmental changes such as rain, snow, humidity, air pollution, etc.

[0080] By using two or more plates of different areas and an accurate ammeter, the following equation can be solved to calculate the cable voltage. A simplified version of the equation can be as follows: Equation 1 Vline=I1×Rp+I1×RL Equation 2 Vline=I2×Rp+I2×A×RL Result: Vline=C×I1×Rp×(I1-I2) / (A×I2-I1) During the ceremony, I1 is the large plate current. I2 is the current in the smaller plate. A is the ratio between the areas of the plates after calibration and tilt adjustment. Rp is the resistance of the measuring resistors 25 and 26 in FIG. RL is the impedance of the parasitic capacitor between the plate and the reference point. C is an optional calibration factor to adjust the results during production calibration.

[0081] The A parameter is based on the area ratio between the plates and is calibrated during manufacturing. During actual measurements, it is recommended to adjust the currents I1 and I2 according to the tilt angle of the plates with respect to the reference ground to get better results. When the plates are tilted, the current is a little lower than when the plates are parallel to the ground reference plane. Dividing the current by Cos(α), where α is the tilt angle, may improve the results.

[0082] To measure the current, a smaller resistor (i.e., 5k ohms) may be connected between the power line contact and each of the plates. An operational amplifier may be provided, with two input terminals connected to the two sides of each respective resistor. The output voltage of the operational amplifier may be sampled at a sufficiently high sample rate by two respective analog-to-digital converters (ADCs). The sampling rate may typically be 10 times the frequency of the power line voltage (for AC power lines).

[0083] A microprocessor may be connected to the outputs of the two (or more) ADCs to calculate average values ​​such as the RMS value of the voltage across each of the resistors and the respective current. Alternatively, a hardware component for calculating the RMS may be used. From the formula, it is possible to extract the value of the impedance using the measured current and then calculate the voltage.

[0084] It should be understood that having two or more metal plates may create respective parasitic capacitors between the plates and the body of the device and / or between the plates and the power line itself, and these should be taken into account in the equations. These parasitic capacitors can be measured in a proper laboratory as part of the calibration process of the voltage measurement system 13.

[0085] The manufacturing calibration process of the voltage measurement system 13 may also include calibrating the current measurement system, for example, using a precision signal generator to inject a low voltage (e.g., 200m VAC) into the connectors of the plates. A final calibration can be performed, for example, by attaching the cable device 10 to a power line with a low voltage (e.g., 500v) and calibrating the parasitic capacitor values.

[0086] When the plate is not positioned parallel to the reference point, the projected area of ​​the plate is smaller by the angle of tilt, and therefore the parasitic capacitance to the reference point may change. To solve such problems, the cable device 10 may additionally be equipped with a 3D accelerometer and / or a 3D gyroscope to measure the tilt, roll, and pitch of the cable device 10. The tilt, roll, and pitch measurements of the cable device 10 may be used to correct the current measurements when the device is positioned on a slope of the line, or when the line and cable device 10 are tilted or galloping due to the wind.

[0087] To further reduce misalignment between the two (or more) plates 15 due to tilt, roll, and / or pitch, the plates may be arranged in an interleaved mode, such as device 35 of FIG. 4C.

[0088] The bottom cover of the plate, which may be non-conductive, may be made from a water-repellent (hydrophobic) material or may be coated with a water-repellent (hydrophobic) material such as Teflon or a similar material.

[0089] It should be understood that certain features that are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features that are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable subcombination.

[0090] Although the present invention has been described in conjunction with specific embodiments thereof, it is apparent that many alternatives, modifications, and variations will be apparent to those skilled in the art. It is therefore intended to embrace all such alternatives, modifications, and variations. All publications, patents, and patent applications mentioned herein are incorporated herein by reference in their entirety to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated herein by reference. In addition, citation or identification of any reference in this application shall not be construed as an admission that such reference is available as prior art.

Claims

1. A voltage measuring device for measuring the voltage of an electric cable of an electric grid, said voltage measuring device comprising: a first plate having a first area, the first plate providing a first capacitance between the first plate and a reference point; at least a second plate having a second area, the at least second plate providing a second capacitance between the second plate and the reference point; at least one current measuring device for measuring current through each of the first plate and the second plate, the at least one current measuring device providing respective first and second current measurements; a processor electrically coupled to the at least one current measuring device; Equipped with A voltage measurement device wherein the processor receives the first and second current measurements and calculates the voltage between the electrical cable and the reference point by comparing the first current measurement with the second current measurement.

2. The voltage measurement device according to claim 1 , wherein the voltage measurement device is mounted on an electrical cable of the electrical grid.

3. The voltage measurement device of claim 1 , wherein the voltage measurement device is not electrically connected to the reference point.

4. 2. The voltage measurement device of claim 1, wherein at least one of the first plate and the second plate faces the reference point and is rounded such that the at least one of the first plate and the second plate faces the reference point when the voltage measurement device, the first plate, and the second plate perform at least one of a yaw, a pitch, and a roll.

5. The voltage measurement device of claim 1 , wherein the first plate and the second plate are interleaved with one another.

6. and at least one of an accelerometer and a gyroscope for measuring the at least one of a yaw, pitch, and roll of the voltage measurement device and the at least one of the plates; The voltage measurement device of claim 4 , wherein the processor of the voltage measurement device is operative to calculate the voltage between the electrical cable and the reference point according to the measured yaw, pitch, and / or roll.

7. The voltage measurement device of claim 1 , wherein the processor monitors relationships between current measurements to detect at least one of defects and weather conditions including at least one of humidity, rain, and ice.

8. 2. The voltage measurement device of claim 1, wherein the processor calculates a fast change in the voltage between the electrical cable and the reference point using at least one of the current measurements, the calculated voltage between the electrical cable and the reference point, and the capacitance between the plate and the reference point.

9. measuring the capacitance between each of said plates and said electrical cable in a laboratory to form an internal capacitance value; providing the internal capacitance value to the processor for calculating the voltage between the electrical cable and the reference point; The voltage measurement device of claim 1 further comprising:

10. 1. A computer-implemented method for measuring a voltage between an electrical cable of an electrical grid and a reference point, the method comprising: mounting a voltage measurement device on the electrical cable; The voltage measuring device is a first plate having a first area, the first plate providing a first capacitance between the cable and the reference point; a second plate having a second area, the second plate providing a second capacitance between the cable and the reference point; at least one current measuring device for measuring current through each of the first plate and the second plate, the at least one current measuring device providing respective first and second current measurements; a processor electrically coupled to the at least one current measuring device; Equipped with the processor receives the current measurements and calculates the voltage between the electrical cable and the reference point; the first plate has a first area and provides a first capacitance between the plate and the reference point; the second plate has a second area and provides a second capacitance between the plate and the reference point; The method of claim 1, wherein the processor calculates the voltage between the electrical cable and the reference point by comparing the current measurements.

11. A computer program product embodied on a non-transitory computer readable medium, the computer program product including instructions that, when executed by at least one processor, cause the processor to perform operations including receiving at least two current measurements; The at least two current measurements are measured by at least one current measuring device electrically coupled to at least a first plate and a second plate, the first plate having a first area and providing a first capacitance between the first plate and a reference point, and the second plate having a second area and providing a second capacitance between the second plate and the reference point; The processor calculates a voltage between the electrical cable and the reference point by comparing the at least two current measurements.

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