WO2022185236A1

WO2022185236A1 - Device for measuring voltage and current in power transmission lines

Info

Publication number: WO2022185236A1
Application number: PCT/IB2022/051856
Authority: WO
Inventors: Guillermo León GALLO HERNÁNDEZ; Wilder HERRERA PORTILLA; Diana Marcela URIBE CORREA
Original assignee: Rymel Ingenieria Electrica S.A.S.
Priority date: 2021-03-02
Filing date: 2022-03-02
Publication date: 2022-09-09
Also published as: CO2021002884A1

Abstract

The present invention relates to a device for measuring voltage and current in power transmission lines, which comprises: a primary electrical conductor connected in series to a voltage line, wherein an electric current from the voltage line flows through the electrical conductor, the primary electrical conductor forming a plurality of turns; a coil with at least two terminals, which surrounds the primary electrical conductor, wherein the coil is designed to induce a voltage proportional to the magnitude of the electric current that flows through the electrical conductor; and a grounded voltage divider connected to the electrical conductor. The voltage divider is designed to supply a voltage proportional to the voltage of the electrical conductor relative to ground. In addition, the device for measuring voltage and current also includes an impedance connected to at least one of the at least two terminals of the coil.

Description

DEVICE FOR MEASURING VOLTAGE AND CURRENT IN POWER LINES

POWER TRANSMISSION

FIELD OF THE INVENTION

The present invention is related to devices for measuring voltage and current in electric power transmission lines.

DESCRIPTION OF THE STATE OF THE ART

In power transmission and distribution lines, it is necessary to measure electrical variables such as current levels, voltage levels and phase shifts, among others, for measurement, control or protection purposes. Due to the fact that these measurements are made in the presence of high voltages, such as, for example, greater than 1000 V, the use of devices that allow the voltage and current levels of the line to be transformed into small signals with magnitude levels is required. low, non-hazardous and proportional, which can be easily processed by an electronic device, by an instrument or by an electrical energy analyzer. For years, energy companies have used inductive transformers, which allow reducing the high levels of voltage and current of the electrical network, to low levels that can be managed by measurement equipment. These units are installed in groups of three voltage transformers and three individual current transformers and work using a saturable magnetic core. These devices have certain disadvantages, such as the relative complexity of their installation, due to the fact that they are relatively heavy, which is why they require a special support for their installation. Also, because they use a magnetic core whose behavior is non-linear, they cannot guarantee the same accuracy for the entire measurement range. Additionally, these inductive transformers introduce a phase shift in the secondary with respect to the primary, which must be taken into account for the measurement process. Currently, there are sensors for the non-conventional measurement of electrical variables, which use voltage dividers and air core sensors and therefore are elements that have better linearity compared to conventional inductive transformers. However, the disadvantage of air core sensors is that they deliver a small output signal of the order of millivolts, which is why they are not suitable for measuring small currents (less than 200 Amperes).

On the other hand, the use of voltage dividers and air core sensors, in the presence of high voltages, implies the appearance of high concentrations of electric field, which produces the appearance of partial discharges, which must be adequately controlled, to avoid damage to the insulation system. Additionally, the small signals coming from unconventional sensors must be adequately processed and must be protected from interference generated by electromagnetic noise.

Therefore, such devices on power transmission lines may be non-conventional current and voltage measurement devices, such as those disclosed in US3932810A and US5252913A.

US3932810A discloses a current and voltage measuring device having a resin body, with a conductor inside it. Said device includes current measurement elements comprising: a coreless coil for detecting the current in the conductor; an operational amplifier connected to the coreless coil; and, an iron core that has a winding wound on it. Said winding and the conductor together define a saturation current transformer, which allows a voltage to be supplied to the operational amplifier. The voltage and current measurement device also includes a capacitive voltage divider with an amplifier connected to it.

For its part, document US5252913A discloses a current and voltage sensor that includes an air core coil spaced at a particular distance from a conductor, immersed in a dielectric medium. Patent document US5252913A also discloses a variable compensation resistor connected between the output terminals of the coil and one of the coil terminals is connected to ground, a voltage divider consisting of a primary and secondary resistor is connected by a first terminal of the voltage divider to the coil terminal that is connected to ground.

The above documents disclose devices that incorporate voltage and current measurement in a single body, using air-core sensors. The main disadvantage of these sensors is that the output signals are very small, in the order of 100 millivolts, and therefore the application of these sensors is limited to the measurement of large currents, generally greater than 200 Amperes, since these current levels allow the induction of signals, with magnitudes sufficient to be measured by instruments or electronic circuits.

On the other hand, the previous documents do not disclose a system that allows controlling the concentrations of the electric field, to avoid the appearance of partial discharges, nor do they disclose an adjustment and coupling system for the adequate treatment of the output signals.

BRIEF DESCRIPTION OF THE INVENTION

The present invention relates to a built-in voltage and current measurement device in power transmission lines, which allows small currents of less than 200 amps to be measured. Additionally, said device avoids introducing phase shifts in the output signal.

Therefore, the present invention comprises: a primary electrical conductor that forms a plurality of turns, connected in series with the power line, where an electrical current from the power line circulates through the primary electrical conductor. Said device further comprises a coil with at least two terminals, surrounding the primary electrical conductor, where the coil is configured to induce a voltage proportional to the magnitude of the electrical current flowing through the primary electrical conductor, and a voltage divider connected to the primary electrical conductor and to ground. Said voltage divider is configured to supply a voltage proportional to the voltage of the electrical conductor with respect to ground. Additionally, the voltage and current measurement device also includes an impedance connected to at least one of the at least two terminals of the coil and an impedance connected to the output terminal of the divider.

Additionally, the present invention allows to reduce the electromagnetic node interference in the output signal.

BRIEF DESCRIPTION OF THE FIGURES

The F1G. 1 illustrates a device for measuring voltage and current in power transmission lines that includes a primary electrical conductor that forms a loop, connected in series with the power line, and an air-core coil that surrounds the primary electrical conductor. , where the conductor connects to a voltage divider. Both said voltage divider and the coil are connected to an electronic circuit.

FIG. 2 illustrates the schematic design of a device for measuring voltage and current in power transmission lines that includes a primary electrical conductor that forms a plurality of turns, connected in series with the power line, and a coil magnetically coupled to the electrical conductor. primary that physically surrounds said conductor, where the conductor is connected to a voltage divider and both the voltage divider and the coil are connected to an electronic circuit.

FIG. 3 illustrates a device for measuring voltage and current in power transmission lines that includes a primary electrical conductor that forms a loop, connected in series with the power line, and a coil that surrounds the primary electrical conductor, where the electrical conductor The primary is connected to a voltage divider and both the voltage divider and the coil are connected to an electronic circuit. FIG. 4 illustrates an isometric view of a device for measuring voltage and current in power transmission lines that includes a primary electrical conductor that forms a plurality of turns, and a coil that surrounds the primary electrical conductor, where the conductor also surrounds the coil.

FIG. 5 illustrates three voltage and current measurement devices connected on different power transmission lines, where each of said devices is connected to an electronic circuit.

DETAILED DESCRIPTION

The present invention relates to a voltage and current measurement device (100), which allows measurements to be made on power lines, where said device allows voltages and currents to be measured, obtaining linear measurements in a wide working range and allows very small currents to be measured, such as currents less than 200 amps.

The device of the present invention allows measuring currents with a wide range of values. The current measurement range goes from one Ampere to hundreds or thousands of Ampere. Regarding the voltage sensor, it can operate in low, medium or high voltage.

Particularly, the voltage and current measurement device (100) in power transmission lines, comprising a primary electrical conductor (1) that forms a plurality of turns, connected in series with the voltage line, where by the electrical conductor The primary conductor (1) circulates an electric current from the power line and a coil (2) with at least two terminals, which surrounds the primary electrical conductor (1), where a voltage proportional to the voltage is induced in the coil (2). magnitude of the electrical current flowing through the primary electrical conductor (1). Said device also includes a voltage divider (3) connected to the primary electrical conductor (1) and to ground (9). For the understanding of the present invention, high voltage lines will be understood as lines through which electrical energy with a voltage greater than 52 kV circulates, and medium voltage lines will be understood as lines through which electrical energy with a voltage greater than 52 kV circulates. between 1 kV and 52 kV. Finally, low-voltage lines will be understood as those lines through which electrical energy circulates with a voltage of less than 1 kV.

In particular, the voltage divider (3) is configured to supply a voltage proportional to the voltage of the primary electrical conductor (1) with respect to ground (9). In addition, the voltage and current measurement device also includes a first impedance (5) connected to at least one of the terminals (2a, 2b) of the coil (2).

On the other hand, the voltage and current measurement device (100) can include an electronic circuit (4). Said electronic circuit (4) is connected to the first impedance (5), to the voltage divider (3) and to at least one of the terminals (2a) or (2b) of the coil (2), where the first impedance (5 ) adjusts the voltage that is induced in the coil (2); and the electronic circuit (4) reads said adjusted voltage and also reads the voltage delivered by the voltage divider (3).

The primary electrical conductor (1), can be formed by a conductive material such as copper, which must be covered by a dielectric material and can also be formed by a plurality of turns. For the understanding of the present invention, plurality of turns means more than one turn. On the other hand, the coil (2) for its part can be formed by a wire or a thread of some conductive material such as copper, which can be a conductive thread and be covered by an insulating material (7) for example by means of of a dielectric varnish. Said conductive thread can be wound around an air core, forming the coil (2) which has a center and a guideline. The turns of the primary electrical conductor pass through the guideline of the coil (2).

The current flowing through the primary electrical conductor (1) induces an output voltage proportional to the magnitude of the electrical current at the terminals of the coil (2). In the present invention, the fact that the coil (2) is made of an air core allows the sensor to have a linear response guaranteeing accuracy in a wide working range that goes from 1 to 1000 A. Also, said linearity allows the sensor to be used in both measurement and protection applications. In addition, the use of an air core, together with the electronic circuit (4) guarantees that there are no phase shifts in the output signal with respect to the input.

Additionally, the plurality of turns in the primary electrical conductor (1), in combination with the turns of the coil (2), makes it possible to increase the mutual inductance, which allows that, given the circulation of a small current in the primary electrical conductor (1 ), an output voltage with magnitudes of the order of volts is obtained, facilitating the measurement of small currents less than 200 amps.

Furthermore, given the low power of the output signal, the safety of a user is increased in the event that the terminals of said coil are short-circuited in an installation or maintenance operation. The output terminals of the coil (2) are connected to an impedance, which allows the output voltage to be adjusted to the exact expected value, in order to then send the signal to the electronic circuit.

Additionally, the fact of using an air coil reduces manufacturing costs because it does not require a magnetic core, and furthermore, said air coil can be opened and arranged around the electrical conductor (1), without the need to split the core. driver. Referring to FIG. 1, the voltage measurement is performed using a voltage divider (3), which can be made up of two fixed impedances connected in series and in which one end is connected to the primary electrical conductor (1) and the other end is connected to a ground point.

At the junction point of the two fixed impedances, a voltage is obtained with respect to ground, which is proportional to the voltage present in the primary electrical conductor (1) with respect to ground. The use of a voltage divider (3) with fixed impedances allows the sensor to have a linear response, guaranteeing accuracy over a wide working range that can cover low, medium and high voltage. Also, said linearity allows the sensor of the present invention to be used both in applications of measurement of current and voltage _j e as in protection. In addition, the use of a voltage divider (3) guarantees that there are no phase shifts in the output signal with respect to the input. Additionally, the voltage divider (3) can be designed to deliver a small voltage of the order of ios volts. The low power of the output signal increases the safety of a user in case the splitter output terminals are short-circuited in an installation or maintenance operation.

The impedances that make up the voltage divider (3) can be resistive or capacitive. The fact that the voltage divider (3) is resistive has some technical advantages; a resistive voltage divider has smaller radial dimensions compared to a capacitive one, which allows the measurement device of the present invention to be assembled in places with more difficult accessibility, and also facilitates its assembly.

The output terminals of the voltage divider (3) are connected to an impedance, which allows the output voltage to be adjusted to the exact expected value, in order to then send the signal to the electronic circuit.

When an electrical current circulates through a power line (11), it circulates through the primary electrical conductor (1), and later in the coil (2) a voltage proportional to the magnitude of the electrical current that circulates through the conductor is induced. primary electrical (1). The voltage divider (3) supplies a voltage to the electronic circuit (4), proportional to the voltage of the primary electrical conductor (1) with respect to ground, while, and as mentioned above, the first impedance (5) performs calibration adjustments of the measurement of the current, by means of an adjustment in the voltage induced in the coil (2). Then, the electronic circuit (4) obtains two voltage signals; one proportional to the current flowing through the conductor and the other proportional to the voltage between the primary electrical conductor (1) and ground.

In particular, the electronic circuit (4) receives the voltages sent both by the voltage divider (3) and by the coil (2) and performs a signal treatment on them. For the understanding of the present invention, treatment of a signal, or a voltage, performing operations with said voltage or signal value in order to be able to measure the voltage and/or the current of the power line (11).

The electronic circuit (4) can comprise at least two operational amplifiers that can be of high precision, where said operational amplifiers are used for the impedance coupling of the signals coming from the coil (2) and the voltage divider (3) . The output of each operational amplifier is connected to a low pass filter that can be first order or higher, which allows reducing the noise of a signal coming from the electrical conductor (1), and thus obtaining measurements of voltages and currents with a acceptable noise level according to the desired requirements. Said electronic circuit (4) can also have other filters in later stages, which allow a better measurement to be obtained. Additionally, such filters prevent a phenomenon called aliasing.

Specifically, the first filter is a first order filter that allows the voltage signals coming from the voltage divider (3) to be filtered. The second filter is second order and allows filtering the voltage signals coming from the coil (2). This is due to the fact that air-core coils, such as Rogowski coils, have a response that depends on the frequency, therefore, it is necessary to filter out-of-band signals.

In another embodiment of the invention, the filter configuration can be a set of anti-aliasing filters, which can be connected to a power quality monitoring circuit, which makes measurements of active, reactive and frequency, phase angle, voltage total harmonic distortion (VTHD), current total harmonic distortion (ITHD), power factor, and SWELL monitoring; in polyphase systems, variables can obtained in total, or by phase. Additionally, said electronic circuit (4) can be connected to a microcontroller. The microcontroller allows the data coming from the electronic circuit (4) to be scaled by means of conversion constants. Said conversion constants they are relative to the voltage and current transformation ratios. Referring to FIG. 1, the current and voltage measuring device (100) includes a coil (2) which is an air-core coil having a toroid shape with a center and a directrix. For its part, the primary electrical conductor (1) is introduced through the direction of the coil (2). In said FIG. 1, the primary electrical conductor (1) forms a loop around the coil (2) and has two ends, a first end and a second end, where each of the ends is connected to a power line (11) by where an electric current flows. For the understanding of the present invention, a power transmission line will be understood as a voltage line (11).

In said FIG. 1, a voltage divider (3) is connected to the primary electrical conductor (1) which is made up of two impedances, a first impedance (Z1) connected to the primary electrical conductor (1) and a second impedance (Z2), where the second impedance is connected to ground (9). Said voltage divider (3) is connected to an electronic circuit (4), and supplies a voltage proportional to the voltage of the primary electrical conductor (I) with respect to ground (9), thus taking it to the electronic circuit (4) for its treatment.

Additionally, the coil (2) of the voltage and current measurement device (100) of FIG. 1 has two terminals which are connected to the electronic circuit (4), where, between said terminals, a first impedance Z4 (5) is connected. Where said first impedance Z4 (5) allows adjusting the output voltage of the coil (2).

When the voltage divider (3) is made up of two impedances (Z1 and Z2), the first impedance (Z1) can be a high voltage resistance while the second impedance (Z2) can be a low voltage resistance. The values of Z1 and Z2 are selected in such a way that the output signal has a suitable level for its treatment.

On the other hand, and referring to FIG. 2, a diagram of the voltage and current measurement device (100) is illustrated, which is connected in series to a transmission line, which supplies various loads. In addition, the primary electrical conductor (1) it is a coil with terminals (10). On the other hand, in said FIG. 2 shows three ways in which the voltage divider (3) can be configured: a first configuration (3a), corresponding to two impedances connected in series, a first impedance (Z1) and a second impedance (Z2), as in the voltage and current measurement device (100) of FIG. 1. In said first configuration (3a), preferably the first impedance (Z1) and the second impedance (Z2) have a sufficiently exact relationship.

A second configuration (3b) is a T configuration made up of a first impedance (Z1) connected to a second impedance (Z2) and a third impedance (Z3) connected between the first impedance (Z1) connected to a second impedance (Z2) . In said configuration, the input impedance increases (the third impedance (Z3) is added) of the operational amplifier of the electronic circuit (4) that receives the signal.

On the other hand, the third configuration (3c) is a configuration made up of a first impedance (Z1) connected to a second impedance (Z2) and a third impedance (Z3) connected in parallel with a second impedance (Z2). In this configuration, if the third impedance (Z3) were variable, it would allow an adequate adjustment of the relationship between the first impedance (Z1) and the second impedance (Z2), which would help to adjust the voltage and current measurement device accordingly. power transmission lines after assembly.

For its part, in said FIG. 2 also shows three ways in which the first impedance (5) can be configured by: a first configuration (5a) corresponding to a first impedance (5) corresponding to an impedance (Z4) connected in series between a terminal (2a or 2b) of the coil (2) and the electronic circuit (4). Said configuration (5a) allows measurements of the electrical current flowing through the voltage line (11), where said voltage line (11) is connected to a terminal (10) of the primary electrical conductor (1). Additionally, said configuration can be used in cases where current transformers are used, for example, the impedance (Z4) can be a resistance of a very small value (a shunt resistance). In this case, the electronic circuit (4) perceives a small drop of tension in the impedance (Z4) and from there, it calculates the current. Furthermore, if the coil (2) were an air-core or Rogowski coil, the impedance (Z4) could increase the input impedance of the operational amplifier of the electronic circuit (4) receiving the signal.

A second configuration (5b) of first resistive impedance (5) corresponding to an impedance (Z4) connected in parallel to the coil (2) and connected to the electronic circuit (4). Said configuration (5b) allows measurements to be made of the current flowing through the voltage line (11). Also, if in this configuration the impedance (Z4) is a variable resistor, it can help adjust the voltage induced in the coil (2) when it is an air core coil or a Rogowski coil.

The third configuration (5c) of the first impedance (5), corresponds to an impedance (Z4) connected in parallel to the coil (2) and the electronic circuit (4), and an impedance (Z5) connected to the coil (2) and to the electronic circuit (4). Said configuration allows measurements to be made of the current flowing through the voltage line (11). Additionally, this configuration can be used in cases where current transformers are used, for example, the impedance (Z4) can be a resistance of a very small value (a shunt resistance),

In this case, the electronic circuit (4) perceives a small voltage drop in the impedance (Z4) and from there, calculates the current. Furthermore, if the coil (2) were an air-core or Rogowski coil, the impedance (Z4) can adjust the voltage induced in the coil (2). The role of the impedance (Z5) is to increase the input impedance of the operational amplifier of the electronic circuit (4) that receives the signal.

For the understanding of the present invention, electrical noise will be understood as all those signals of unwanted electrical interference, and which join the main signal, or useful, in such a way that they can alter said main signal producing effects that can be more or less harmful or altering the value of the signal. On the other hand, and in one embodiment of the invention, the coil (2), the primary electrical conductor (1) and the voltage divider (3) may be covered by a dielectric. Said dielectric (6) is an insulating material that makes it possible to electrically insulate both the primary electrical conductor (1), the coil (2) and the voltage divider (3). In addition, said dielectric (6) can be a material that is selected from the group consisting of dielectric liquids, dielectric gases (SF6), dielectric solid materials, equivalent materials known to a person of ordinary skill in the art, or a combination of the above. Additionally, the coil (2) can be covered by an insulating material (7), which allows electrically insulating the primary electrical conductor (1) from the coil (2).

In addition, the insulating material (7) that covers the coil (2) can be covered by a composite material (8), which can be selected from the group made up of conductive or semiconducting materials such as aluminium, gallium, silicon, paper with particles graphite, paper with carbon particles, brass, etc., and/or a combination of the above. Said composite material (8) allows to reduce the electric field concentrations in the device (100), to avoid partial discharges and to reduce the effects of electromagnetic mido. In the event that conductive materials are used, these preferably do not form a closed loop around the coil (2), because currents can be produced that circulate through the conductive material, interfering with the safety and proper functioning of the sensor of the present invention.

Referring to FIG. 3, the current and voltage measuring device (100) includes a coil (2) which is an air-core coil, having a toroid shape with a center and a directrix. For its part, the primary electrical conductor (1) is introduced through the direction of the coil (2). End said FIG. 3, the primary electrical conductor (1) forms a plurality of turns around the coil (2) and has two ends, a first end and a second end, where each of the ends is connected to a voltage line (11). ) through which an electric current circulates. In said FIG. 3, a voltage divider (3) is connected to the primary electrical conductor (1), which is made up of two impedances, a first impedance (Z1) connected to the primary electrical conductor (1) and a second impedance (Z2), in where the second impedance (Z2) is connected to ground (9). Said voltage divider (3) is connected to an electronic circuit (4), and supplies a voltage proportional to the voltage of the primary electrical conductor (1) with respect to ground (9), thus taking it to the electronic circuit (4) for its treatment of voltage signal. Additionally, in said voltage divider (3) the first impedance (Z1) can have a value greater than the second impedance (Z2), which allows the voltage measured in the electronic circuit (4) in the voltage divider (3) is a fraction of the voltage of the power line, which allows obtaining voltage values that allow its treatment.

Additionally, the coil (2) of the voltage and current measurement device (100) of FIG. 3 has two terminals which are connected to the electronic circuit (4), where, between said terminals (2a, 2b) a first impedance (5) is connected, where said first impedance Z4 (5) allows adjusting the output voltage of the coil (2). Said voltage and current measurement device (100) also includes a second impedance connected between the connection of the voltage divider (3) and the electronic circuit (4), where said second impedance (Z6) is connected to ground (9). ). Particularly, said impedance (Zó) can be a variable impedance, which allows a suitable adjustment according to the output voltage requirements of the voltage divider.

Additionally, said voltage and current measurement device (100) of FIG. 3 includes a dielectric (6) which covers the primary electrical conductor (1), the voltage divider (3), and the first impedance (5). Said dielectric (6) is illustrated as a dotted line that encloses the voltage and current measurement device (100).

On the other hand, and according to FIG. 3, the primary electrical conductor (1) is inserted in the guideline of the coil (2), and between the coil (2) and the primary electrical conductor (1) there is a distance (DI) from the surface of the primary electrical conductor ( 1) and an internal surface of the coil (2). The technical effect of the distance (DI) is to guarantee the insulation between the coil (2) and the primary electrical conductor (1). Said distance (Di) is selected, depending on the voltage level under which the equipment will operate.

Referring to FIG. 4, an embodiment of the invention corresponding to the voltage and current measurement device (100) of FIG, 3 is illustrated, with the difference that the electrical conductor (1) passes through the center of the coil (2), and forms a plurality of turns around the directrix of said coil (2). In said FIG. 4, the electrical conductor (1) corresponding to a primary winding, for each turn that a turn of the electrical conductor (1) makes inside the coil (2), the generated magnetic field is amplified and with it a higher voltage is induced in the coil (2).

That is, in the coil (2) a voltage proportional to the magnitude of the electrical current circulating through the electrical conductor (1) is induced, where each turn of the electrical conductor (1) increases the induced voltage; that is, the greater the number of turns: the greater the mutual inductance between the coil (2) and the conductor (1), in turn increasing the induced voltage. This is useful for measuring small currents, particularly currents less than 200 A. Additionally, said FIG. 4 the device includes a support that allows the coil (2) to be kept in a single position.

On the other hand, and referring to FIG. 5 three voltage and current measurement devices (100) are illustrated, a first device (100a), a second device (100b) and a third device (100c), where each of said devices is like the devices of the modality of FIG. 3. Said devices (100a, 100b, 100c) can be connected to three different power lines where each one sends signals to an electronic circuit (4) that allows measuring the voltage, current and other electrical variables of the power lines , over time such as power, energy, power factor, frequency, harmonic distortion in voltage and current, angles between voltages and currents, among others.

Additionally, and referring to said FIG. 5, the electronic circuit (4) can be connected by wireless communication (12) to a user equipment (13), where in said user equipment (13) the signals of voltage, current and other variables of the power lines, remotely, obtained by each of the voltage and current measurement devices (100a, 100b, 100c), where said signals correspond to the signals conditioned by the electronic circuit ( 4),

Said wireless communication (12) can be carried out by means of communication modules that are selected from the group consisting of Bluetooth, WiFi, Radio Frequency RF (for the acronym in English of Radio Frequency), UWB (for the acronym in English of Ultra Wide Band) , GPRS, Konnex or KNX, DMX (Digital Multiple X), WiMax and equivalent wireless communication technologies that are known to a person of ordinary skill in the art and combinations of the above.

Additionally, the user equipment (13) can be a device that processes data, for example, microcontrollers, microprocessors, DSCs (Digital Signa! Controller for its acronym in English), FPGAs (Field Programmable Gate Array for its acronym in English) , CPLDs (Complex Programmable Logic Device), ASICs (Application Specific Integrated Circuit), SoCs (System on Chip), PSoCs (Programmable System on Chip) ), computers, servers, tablets, cell phones, smart phones, signal generators and user equipment (13) known to a person moderately versed in the matter and combinations of these.

In addition, the information sent by the communications module can be sent to a server or to a web server, which allows storing the information coming from at least one voltage and current measurement device (100).

EXAMPLE 1

Referring to FIG. 3, a voltage and current measuring device (100) was made comprising a coil (2) which is an air-core coil, having a toroid shape with a center and a directrix. Said coil (2) had the following specifications: Air core coil formed from copper or aluminum wire.

For its part, a primary copper electrical conductor (1) is inside the guideline of the coil (2) with a plurality of turns.

In said EXAMPLE 1, a voltage divider (3) was connected to the primary electrical conductor (1) which is made up of two resistors, a first resistance (Z1), fixed, high voltage connected to the primary electrical conductor (1) and a second resistance (Z2), fixed, low voltage, where the second resistance is connected to ground (9). Said voltage divider (3) is connected to an electronic circuit (4), with the following characteristics: Impedance coupling, anti-aliasing filters, digital analog converter and a signal analyzer.

Additionally, the coil (2) has two terminals (2a, 2b) which are connected to the electronic circuit (4), where, between said terminals (2a, 2b), a first impedance (5) is connected. Where said first impedance (5) corresponds to a fourth resistance (Z4). Said voltage and current measurement device (100) also includes a second impedance connected between the connection of the voltage divider (3) and the electronic circuit (4), where said second impedance is a resistance (Z6) that is connected to land ( 9).

Additionally, said voltage and current measurement device (100) of FIG. 3 includes a dielectric (6) which covers the primary electrical conductor (1), the voltage divider (3), and the first impedance (5). Said, dielectric (6) is epoxy resin.

With the device it was possible to measure electrical variables such as: voltage, current, power, energy, frequency, power factor, phase angles, harmonic distortion factors, etc. This device served to monitor electrical systems of a wide range of currents and voltages. Including low current systems, that is, between 1 and 5 Amps; and high voltages, that is, more than 1000 volts.

EXAMPLE 2 Referring to FIG. 3, a voltage and current measuring device (100) was made comprising a coil (2) which is an air-core coil, having a toroid shape with a center and a directrix. Said coil (2) had the following specifications: air core coil formed of copper wire forming a total of 1000 turns around the air core.

For its part, im copper primary electrical conductor (1) is inside the guideline of the coil (2) with a plurality of 10 turns. In said example, the coil (2) induces a voltage greater than 0.225 Volts when a current of 20 Amps flows through the primary electrical conductor (1).

In said EXAMPLE 1, a voltage divider (3) was connected to the primary electrical conductor (1) which is made up of two resistors, a first resistor (Z1), with a value of 200 Mega Ohms, high voltage, connected to the primary electrical conductor (1) and a second resistance (Z2), with a value of 100 kilo Ohms, low voltage, where the second resistance is connected to ground (9) and to the first resistance (Z1). A voltage greater than 1.88V with respect to ground (9) falls on the second resistance (Z2), when the voltage of the primary electrical conductor (1) with respect to ground (9) is 7621 V.

Said voltage divider (3) is connected to a filter to eliminate high-frequency noise and to an electronic circuit (4), with the following characteristics: an electronic circuit provided with impedance matching with high-precision operational amplifiers, two anti- aliasing with a cutoff frequency of 7 kHz, a digital analog converter with a sampling rate of 8000 samples per second, a signal analyzer, a microcontroller and a GPRS communication module.

Additionally, the coil (2) has two terminals, which are connected to the electronic circuit (4), where, between said terminals, a first impedance (5) is connected. Said first impedance (5) corresponds to a fourth resistance (Z4 ), said fourth resistance (Z4) can be variable or can be a potentiometer with a value of 500 Ohms. Said fourth resistance (Z4) can be adjusted until the voltage induced in the coil (2) is equal to 0.225 V. Said voltage and current inedition device (100) also includes a second impedance connected between the connection of the voltage divider (3) and the electronic circuit (4), where said second impedance is a resistance (Z6) that is connected to ground (9), The resistance (Z6) can be variable or it can be a potentiometer with a value of one Mega Ohm. The resistance (Zó) must be varied until the voltage that falls on the resistance (Z2) with respect to ground is equal to 1.88 V.

Additionally, referring to FIG. 3, said voltage and current measurement device (100) includes a dielectric (6) which covers the primary electrical conductor (1), the voltage divider (3), and the first impedance (5). Said, dielectric (6) is epoxy resin.

With this device it was possible to measure electrical variables in a medium voltage line such as voltage, current, power, energy, frequency, power factor, etc. Given the linearity of the resistive divider and the air core coil (2), the measurement range is wider compared to those sensors that have embedded magnetic cores. In addition, the plurality of turns of the primary electrical conductor (1) made it possible to increase the mutual inductance of the sensor, which made it possible to measure low currents, for example 20 Amps.

It should be understood that the present invention is not limited to the modalities described and illustrated, since as will be evident to a person versed in the art, there are possible variations and modifications that do not deviate from the spirit of the invention, which is only found defined by the following claims.

Claims

1. A device for measuring voltage and current in power transmission lines, comprising: a primary electrical conductor (1) connected in series with the power transmission line, where a current flows through the primary electrical conductor (1) electricity from the power transmission line, the primary electrical conductor (1) forms a loop; a coil (2) with at least two terminals, surrounding the primary electrical conductor (1), where a voltage proportional to the magnitude of the electrical current flowing through the primary electrical conductor is induced in the coil (2)

(Yo); a voltage divider (3) connected to the primary electrical conductor (1) and to ground (9), said voltage divider (3) supplies a voltage proportional to the voltage of the primary electrical conductor (1) with respect to ground; and a first impedance (5) connected to at least one of the at least two terminals of the coil (2), which adjusts the voltage that is induced in the coil (2).

2. The device of Claim i, wherein the coil (2) is an air-core coil which has a center and a leader.

3. The device of Claim 1, wherein the coil (2) is a Rogowski coil which has a center and a directrix.

4. The device of Claim 1 or Claim 2, wherein the electrical conductor (1) passes through the center of the coil (2), and forms a plurality of turns around the directrix of said coil (2).

5. The device of Claim 1 or Claim 2, wherein between the coil (2) and the primary electrical conductor (1) there is a distance that will depend on the maximum voltage of the device.

6. The device of Claim 1 or Claim 2, wherein the coil (2) is covered by an insulating material (7).

7. The device of Claim 6, wherein the insulating material (7) that covers the coil (2) is covered by a composite material (8).

8. The device of Claim 7, wherein the composite material is selected from the group consisting of aluminum, copper, bronze, gallium, silicon, paper with graphite particles, paper with carbon particles, brass, among others and combinations of the previous.

9. The device of Claim 1 or Claim 2, wherein the voltage divider (3) is a voltage divider made up of at least one first impedance (Z1) connected to the primary electrical conductor (1) and a second impedance ( Z2), where the second impedance is connected to ground (9).

10. The device of Claim 9, wherein an electronic circuit (4) is connected to the first impedance (5), to the voltage divider (3) and to at least one of the at least two terminals of the coil (2) , where the first impedance (5) adjusts the voltage that is induced in the coil (2), and the electronic circuit (4) obtains said adjusted voltage and the voltage delivered by the voltage divider (3).

11. The device of Claim 10, wherein between the connection of the voltage divider (3) and the electronic circuit (4) a second impedance (Z6) that is connected to ground (9) is connected.

12. The device of Claim 1 or Claim 2, wherein a dielectric (6) covers the coil (2), the primary electrical conductor (1) and the voltage divider (3).