CN113176441B - Non-contact voltage measuring device and method - Google Patents

Abstract

The application relates to a non-contact voltage measuring method and device, and relates to the technical field of electric power testing. The non-contact voltage measuring device comprises a probe and a voltage sensing assembly, wherein the probe comprises a first probe and a second probe, the voltage sensing assembly comprises a processing unit, a voltage division capacitor and a reference signal source which are sequentially connected, and the first probe is used for being coupled with a circuit to be measured to form a first coupling capacitor; the second probe is used for being coupled with the zero line circuit to form a second coupling capacitor; the voltage sensing assembly is respectively connected with the first coupling capacitor and the second coupling capacitor to form an electric loop. The non-contact voltage measuring device has the advantages that the insulating layer of the power transmission line is not required to be damaged in the process of measuring voltage by using the non-contact voltage measuring device, and the non-contact voltage measuring device is not required to be powered off for installation, use and detachment, so that a large number of measuring points can be arranged at low labor cost, and the measuring process is not influenced by line insulation.

Description

Non-contact voltage measuring device and method

technical field

The present application relates to the technical field of electric power testing, and in particular, to a non-contact voltage measurement device and method.

Background technique

Voltage measurement is widely used in power systems, and the accuracy, reliability, and convenience of voltage measurement play an important role in fault detection and fault analysis of power systems.

At present, the most commonly used voltage measurement technology is the voltage measurement technology based on electromagnetic voltage transformers. Among them, the electromagnetic transformer includes a primary winding and a secondary winding. The process of measuring the voltage includes: first, power off the high-voltage wire, then connect the primary winding of the electromagnetic transformer to the high-voltage wire, and finally, make The high-voltage wire is energized, so that current appears in the primary winding of the electromagnetic transformer. Based on the principle of electromagnetic induction, the secondary winding also generates current, and the voltage information of the high-voltage wire is obtained based on the current of the secondary winding.

Among them, the primary winding and the secondary winding are both formed by winding copper wire, so they are very heavy. The high-voltage wires are generally set at high altitudes away from the ground. Therefore, special support piers need to be built, and then the electromagnetic transformers are hoisted to the support piers through hoisting equipment, so that the primary windings of the electromagnetic transformers can be connected to on high-voltage wires.

It can be seen that the above-mentioned voltage measurement method based on the electromagnetic voltage transformer is cumbersome in process and difficult in construction.

SUMMARY OF THE INVENTION

Based on this, it is necessary to provide a non-contact voltage measurement device and method for the above technical problems.

first:

A non-contact voltage measurement device includes a probe and a voltage sensing assembly, the probe includes a first probe and a second probe, and the voltage sensing assembly includes a processing unit, a voltage dividing capacitor and a reference signal source connected in sequence, wherein:

The first probe is used for coupling with the circuit to be tested to form a first coupling capacitor; the second probe is used for coupling with the neutral circuit to form a second coupling capacitor; the voltage sensing component is respectively connected with the first coupling capacitor and the second coupling capacitor form an electrical circuit;

a processing unit, connected to the voltage dividing capacitor, for acquiring waveform information of the voltage on the voltage dividing capacitor, and generating a reference signal generation instruction according to the waveform information;

The reference signal source, connected with the processing unit, is used to input the first reference voltage signal with the same frequency and phase as the voltage on the voltage dividing capacitor and the first reference voltage signal with the same frequency and opposite phase as the voltage on the voltage dividing capacitor to the electrical circuit according to the reference signal generation instruction. Two reference voltage signals, the amplitudes of the first reference voltage signal and the second reference voltage signal are equal;

The processing unit is further configured to acquire the first current of the electrical circuit during the process of inputting the first reference voltage signal to the electrical circuit by the reference signal source; after acquiring the first current, input the second reference to the voltage dividing capacitor from the reference signal source During the voltage signal process, the second current of the electrical circuit is obtained, and the voltage of the circuit to be tested is calculated according to the first current and the second current.

In one of the embodiments, the voltage sensing assembly further includes a current detection unit, wherein:

The current detection unit is connected in series in the electrical circuit and is connected with the processing unit, and is used for detecting the current of the electrical circuit in the process of inputting the first reference voltage signal to the voltage dividing capacitor by the reference signal source to obtain the first current, which is obtained in the reference During the process of inputting the second reference voltage signal to the voltage dividing capacitor, the signal source detects the current of the electrical circuit to obtain the second current.

In one of the embodiments, the voltage sensing assembly further includes a voltage detection unit, wherein:

The voltage detection unit is connected with the voltage dividing capacitor and the processing unit, and is used for detecting the voltage on the voltage dividing capacitor and sending the voltage on the voltage dividing capacitor to the processing unit.

In one of the embodiments, the processing unit includes an amplification circuit, an analog-to-digital conversion circuit, a Fourier transform module and a first processing circuit, wherein,

The amplifying circuit is connected with the analog-to-digital conversion circuit, and is connected to both ends of the voltage dividing capacitor, and is used to amplify the voltage on the voltage dividing capacitor;

an analog-to-digital conversion circuit, connected with the Fourier transform module, for converting the amplified voltage into discrete digital signals, and sending the discrete digital signals to the Fourier transform module;

a Fourier transform module, connected to the first processing circuit, for performing spectrum analysis on the discrete digital signal, obtaining waveform information of the voltage on the voltage dividing capacitor, and sending the waveform information to the first processing circuit;

The first processing circuit is used for generating a reference signal generating instruction according to the waveform information.

In one of the embodiments, the processing unit includes a phase lock circuit and a second processing circuit, wherein,

A phase-locked circuit, used to obtain the waveform information of the voltage on the voltage dividing capacitor, the waveform information includes frequency and phase information;

The second processing circuit is configured to generate first reference data corresponding to the first reference voltage signal and second reference data corresponding to the second reference voltage signal according to the waveform information, and generate reference signal generation according to the first reference data and the second reference data instruction.

In one of the embodiments, the phase-locked circuit includes a phase detector, a low-pass filter, a voltage-controlled oscillator, and a feedback circuit, wherein,

The feedback circuit is used to send the feedback signal output by the voltage controlled oscillator to the phase detector;

a phase detector for determining the phase difference between the voltage on the voltage dividing capacitor and the feedback signal, and determining the error voltage signal based on the phase difference;

A filter is used to filter the error voltage signal to obtain the control voltage signal;

The voltage controlled oscillator is used for receiving the control voltage signal, outputting the target signal based on the control voltage signal, and obtaining the waveform information of the voltage on the voltage dividing capacitor according to the waveform information of the target signal.

In one embodiment, the reference signal generation instruction carries first reference data corresponding to the first reference voltage signal and second reference data corresponding to the second reference voltage signal, and the reference signal source includes a waveform generator and a third processing circuit, in,

a third processing circuit, configured to parse the reference signal generation instruction to obtain the first reference data and the second reference data;

The waveform generator is used for generating a first reference voltage signal according to the first reference data, and after acquiring the first current, generating a second reference voltage signal according to the second reference data.

In one embodiment, the probe includes a first surface and a second surface opposite the first surface, the second surface being electrically connected to the voltage sensing assembly.

In one of the embodiments, the second surface is provided with a substrate, metal traces and a sensor array,

a substrate disposed on the second surface;

metal traces, arranged on the substrate, and electrically connected with the voltage sensing component;

Sensor arrays, set on metal traces.

Second aspect:

A non-contact voltage measurement method, applied to the non-contact voltage measurement device according to any one of the above-mentioned first aspects, the method comprising:

Obtain the waveform information of the voltage on the voltage dividing capacitor, and generate a reference signal generation instruction according to the waveform information;

Input a first reference voltage signal of the same frequency and phase as the voltage on the voltage dividing capacitor to the electrical circuit according to the reference signal generation instruction, and obtain the current of the electrical circuit to obtain the first current;

After obtaining the first current, input a second reference voltage signal with the same frequency and opposite phase to the voltage on the voltage dividing capacitor to the voltage dividing capacitor according to the reference signal generation instruction, and obtain the current of the electrical circuit to obtain the second current;

Calculate the voltage of the circuit under test according to the first current and the second current.

The above-mentioned non-contact voltage measurement device includes a probe and a voltage sensing assembly, the probe includes a first probe and a second probe, the voltage sensing assembly includes a processing unit, a voltage divider capacitor and a reference signal source connected in sequence, and the first probe is used for The first coupling capacitor is formed by coupling with the circuit to be tested; the second probe is used for coupling with the zero line circuit to form the second coupling capacitor; the voltage sensing component is respectively connected with the first coupling capacitor and the second coupling capacitor to form an electrical loop. The processing unit, connected to the voltage dividing capacitor, is used to obtain waveform information of the voltage on the voltage dividing capacitor, and generate a reference signal generation instruction according to the waveform information; the reference signal source is connected to the processing unit and used to generate the instruction according to the reference signal Input the first reference voltage signal with the same frequency and phase as the voltage on the voltage dividing capacitor and the second reference voltage signal with the same frequency and opposite phase as the voltage on the voltage dividing capacitor into the electrical circuit, the first reference voltage signal and the second reference voltage signal The amplitudes are equal; the processing unit is further configured to obtain the first current of the electrical circuit in the process of inputting the first reference voltage signal to the voltage dividing capacitor from the reference signal source, and inputting the second reference voltage signal to the voltage dividing capacitor from the reference signal source During the process, the second current of the electrical circuit is obtained, and the voltage of the circuit under test is calculated according to the first current and the second current. In the process of using the non-contact voltage measuring device to measure the voltage, there is no need to destroy the insulating layer of the power transmission line, and the installation, use and removal of the non-contact voltage measuring device do not require power outage operations, so a large number of measurement points can be arranged at a lower labor cost, And the measurement process is not affected by the line insulation. The non-contact voltage measuring device has many advantages, such as economy, safety, and full electrified operation, and has great practical significance.

Description of drawings

Fig. 1 shows the module schematic diagram of the non-contact voltage measurement device;

Figure 2 shows a schematic diagram of the electrical connection of the non-contact voltage measurement device;

Figure 3 shows a schematic diagram of the electrical circuit of the non-contact voltage measuring device during measurement;

FIG. 4 shows an equivalent circuit diagram corresponding to an embodiment of the present application;

FIG. 5 is an equivalent circuit diagram of a detection loop provided by an embodiment of the present application;

FIG. 6 is an equivalent circuit diagram of another detection loop provided by an embodiment of the present application;

FIG. 7 is a schematic structural diagram of a phase-locked circuit according to an embodiment of the present application.

Component label description:

Processing unit: 201; second coupling capacitor: C2; second probe: 102; first coupling capacitor: C1; first probe: 101; voltage sensing component: 20; probe: 10; reference signal source: 203, voltage divider Capacitance: C.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present application more clearly understood, the present application will be described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application, but not to limit the present application.

In the prior art, for the voltage detection of power system transmission lines, a contact-type voltage measurement method is usually used, wherein the contact-type voltage measurement method refers to connecting the probe of the electromagnetic transformer with the metal wire inside the transmission line, The voltage on the transmission line is then measured based on the principle of electromagnetic induction. Among them, when connecting the probe of the electromagnetic transformer to the metal wire inside the transmission line, it is necessary to control the transmission line to stop the power supply first, and then the staff cut the insulating sheet of the measurement point reserved on the transmission line, so as to separate the electromagnetic mutual inductance. The probe of the detector is connected to the power line.

Among them, when erecting a transmission line, it is necessary to reserve a measurement point on the transmission line, and the insulating layer of the measurement point should be removed, so as to facilitate the connection of various measurement equipment for power measurement in the later stage. The above-mentioned contact-type voltage measurement method also relies on the reserved measurement points during measurement, so the above-mentioned measurement method is limited by the measurement points, resulting in poor flexibility.

At the same time, since the electromagnetic transformer is made of copper wire and electromagnet, it is bulky and heavy. At the same time, transmission lines are generally erected at high altitudes away from the ground, so special support piers need to be built, and then the electromagnetic transformers can be connected to the transmission lines after the electromagnetic transformers are installed on the support piers through hoisting equipment. . This process requires the cooperation of multiple manpower and multiple equipment, which is cumbersome and difficult to construct.

In practical applications, due to repeated damage to the insulating sheet of the reserved measurement point, the insulation of the transmission line will be damaged, which is prone to unsafe accidents and reduces the safety of the transmission line.

In view of the above-mentioned problems in the prior art, the embodiments of the present application provide a non-contact voltage measurement device, which can measure the voltage of the transmission line without destroying the insulating layer of the transmission line.

The non-contact voltage measurement device includes a probe and a voltage sensing assembly, the probe includes a first probe and a second probe, the voltage sensing assembly includes a processing unit, a voltage dividing capacitor and a reference signal source connected in sequence, the first probe is used for connecting with The circuit to be tested is coupled to form a first coupling capacitor; the second probe is used for coupling with the neutral circuit to form a second coupling capacitor; the voltage sensing component is respectively connected with the first coupling capacitor and the second coupling capacitor to form an electrical loop. The processing unit, connected to the voltage dividing capacitor, is used to obtain waveform information of the voltage on the voltage dividing capacitor, and generate a reference signal generation instruction according to the waveform information; the reference signal source is connected to the processing unit and used to generate the instruction according to the reference signal Input the first reference voltage signal with the same frequency and phase as the voltage on the voltage dividing capacitor and the second reference voltage signal with the same frequency and opposite phase as the voltage on the voltage dividing capacitor into the electrical circuit, the first reference voltage signal and the second reference voltage signal The amplitudes are equal; the processing unit is further configured to obtain the first current of the electrical circuit in the process of inputting the first reference voltage signal to the voltage dividing capacitor from the reference signal source, and inputting the second reference voltage signal to the voltage dividing capacitor from the reference signal source During the process, the second current of the electrical circuit is obtained, and the voltage of the circuit under test is calculated according to the first current and the second current. In the process of using the non-contact voltage measuring device to measure the voltage, there is no need to destroy the insulating layer of the power transmission line, and the installation, use and removal of the non-contact voltage measuring device do not require power outage operations, so a large number of measurement points can be arranged at a lower labor cost, And the measurement process is not affected by the line insulation. The non-contact voltage measuring device has many advantages, such as economy, safety, and full electrified operation, and has great practical significance.

The technical solutions of the present application and how the technical solutions of the present application solve the above-mentioned technical problems will be described in detail below with specific embodiments. The following specific embodiments may be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of the present application will be described below with reference to the accompanying drawings.

As shown in FIG. 1, FIG. 1 shows a schematic diagram of a module of a non-contact voltage measurement device, wherein the non-contact voltage measurement includes a probe 10 and a voltage sensing assembly 20, and the voltage sensing assembly 20 includes a processing unit 201 and sequentially connected The voltage dividing capacitor C and the reference signal source 203, and the processing unit 201 is respectively connected to the voltage dividing capacitor C and the reference signal source 203.

As shown in FIG. 2, FIG. 2 shows a schematic diagram of the electrical connection of the non-contact voltage measurement device, wherein the probe 10 includes a first probe 101 and a second probe 102, the first probe is connected to the circuit to be measured, and the second probe is connected to on the neutral circuit.

As shown in FIG. 3, FIG. 3 shows a schematic diagram of the electrical circuit of the non-contact voltage measurement device during measurement, wherein the first probe 101 is coupled with the circuit to be measured to form a first coupling capacitor C1, and the second probe 102 is connected to the neutral circuit The coupling forms a second coupling capacitor C2, and the voltage sensing component 20 is connected with the first coupling capacitor C1 and the second coupling capacitor C2 to form an electrical loop. The reference signal source 203 is connected to the first probe 101, and the voltage dividing capacitor is connected to the second probe.

In the embodiment of the present application, for the first coupling capacitor C1, the metal electrode plate in the first probe 101 is one electrode plate of the first coupling capacitor C1, and the circuit to be tested is the other electrode plate of the first coupling capacitor C1. For the second coupling capacitor C2, the metal electrode plate in the second probe 102 is one electrode plate of the second coupling capacitor C2, and the neutral circuit is the other electrode plate of the second coupling capacitor C2. Starting from the circuit principle, an electrical connection is established with the circuit under test through the first coupling capacitor C1 , the voltage sensing component 20 and the second coupling capacitor C2 , as shown in FIG. 3 . Among them, the voltage of the circuit to be tested is represented by Us, and the frequency is the power frequency, which is represented by fs. In this embodiment of the present application, the first coupling capacitor C1 is connected to the voltage sensing component 20 . On the other hand, the voltage sensing component 20 is connected to the ground (neutral line/ground line) through the second coupling capacitor C2, thereby forming an electrical circuit as shown in FIG. 3 .

The structure of the probe 10 will be described in detail below.

In this embodiment of the present application, the structures of the first probe 101 and the second probe 102 are the same, and the structure of the first probe 101 is described below by taking the first probe 101 as an example.

The first probe 101 includes a first surface and a second surface, wherein the first surface can be movably sleeved on the insulating layer of the circuit to be tested, and the second surface is opposite to the first surface and electrically connected to the voltage sensing component 20 . connected to form a first coupling capacitor C1 with the first surface.

Optionally, in the embodiment of the present application, a substrate, metal traces and a sensor array are provided on the second surface, wherein the substrate is provided on the second surface; the metal traces are provided on the substrate and are connected with the voltage sensing component. Electrical connections; sensor arrays, disposed on metal traces.

Optionally, the first probe 101 may be a cylindrical structure composed of two nested rings. The inner side of the cylindrical probe 10 (ie, the surface opposite to the circuit to be tested) is provided with a conductive electrode plate, that is, a metal electrode. The metal electrode is connected with the voltage sensing assembly 20; the outer side of the cylindrical probe 10 can be made of insulating material;

For the way in which the first probe 101 is sleeved on the insulating layer of the circuit to be tested, optionally, the first probe 101 can adopt a clamp structure to clamp the first probe 101 on the insulating layer of the circuit to be tested; Other structures are adopted, such as a buckle structure, etc. It should be noted that this embodiment does not limit the connection mode between the first probe 101 and the circuit to be tested.

The structure of the voltage sensing assembly 20 will be described in detail below.

As shown in FIG. 3, in the embodiment of the present application, the first coupling capacitor C1 is connected to the reference signal source 203, the reference signal source 203 is connected to the voltage dividing capacitor C, and the voltage dividing capacitor C is connected to the second coupling capacitor C2, wherein, The processing unit 201 is disposed between the reference signal source 203 and the voltage dividing capacitor C.

Optionally, the voltage dividing capacitor may be one capacitor, or may be a plurality of capacitors connected in series and parallel. In this embodiment of the present application, the form of the capacitor in the voltage dividing capacitor C is not limited.

The reference signal source 203 may be a voltage signal source with adjustable frequency or a voltage signal source with a fixed output, and the form of the reference signal source 203 is not limited in this embodiment;

The processing unit 201 may be a microprocessor, an embedded processor, a dedicated digital signal processor, etc., and the type of the processing unit 201 is not limited in this embodiment;

Optionally, the voltage sensing assembly 20 in this embodiment further includes a power supply unit, which provides a working voltage for the processing unit 201 . The power supply unit may be a lithium battery or other hardware structures capable of providing power.

Optionally, in this embodiment of the present application, the voltage sensing component 20 may further include a voltage detection unit 202, wherein, as shown in FIG. 201 is connected to detect the voltage on the voltage dividing capacitor C, and send the voltage on the voltage dividing capacitor C to the processing unit.

Optionally, in this embodiment of the present application, the voltage sensing assembly 20 further includes a current detection unit 204, the current detection unit 204 is connected in series in the electrical circuit and connected to the processing unit 201, and is used for transmitting the reference signal source to the distribution unit. In the process of inputting the first reference voltage signal to the voltage capacitor, the current of the electrical circuit is detected to obtain the first current, and in the process of inputting the second reference voltage signal to the voltage dividing capacitor by the reference signal source, the current of the electrical circuit is detected to obtain the first current. Second current.

As shown in Figure 1, the circuit to be tested and the neutral circuit are part of the power system. The power system is grounded as a whole, which is equivalent to grounding one end of the circuit to be tested. The neutral circuit is also called the ground circuit, which has the function of grounding protection. It can be seen that FIG. 3 can be equivalent to the circuit diagram shown in FIG. 4 . Among them, the voltage to be tested of the circuit to be tested is U _s , the frequency is the power frequency f _s , the first coupling capacitor C1, the voltage dividing capacitor C, the second coupling capacitor C2, the voltage output by the reference signal source 203 is _Ur , and the frequency is Power frequency f _s .

In the embodiment of the present application, the processing unit is configured to acquire waveform information of the voltage on the voltage dividing capacitor, and generate a reference signal generation instruction according to the waveform information.

The voltage dividing capacitor C is connected in parallel with the first coupling capacitor C1. In the case where the reference signal source 203 does not output a reference signal, the reference signal source 203 is equivalent to a wire. In this case, the voltage on the voltage dividing capacitor C is equal to The voltages of the circuit under test are of the same frequency and same phase. Therefore, it can be known that the waveform information of the voltage on the voltage dividing capacitor C can be used to reflect the waveform information of the voltage of the circuit under test. Based on this, the processing unit 201 obtains the waveform information of the voltage on the voltage dividing capacitor C, that is, obtains the waveform information of the voltage of the circuit under test.

Optionally, the waveform information of the voltage on the voltage dividing capacitor C includes the frequency and phase of the voltage on the voltage dividing capacitor C. Among them, the frequency of the voltage on the voltage dividing capacitor is generally the power frequency frequency.

The process of acquiring the waveform information of the voltage on the voltage dividing capacitor C by the processing unit 201 will be described below:

In a first optional implementation manner, the processing unit 201 may acquire the voltage on the voltage dividing capacitor C under the condition that the reference signal source 203 does not output the reference signal, and based on the processing software preset by the processing unit 201, the voltage dividing capacitor C may be The voltage on C is analyzed, so as to obtain the waveform information of the voltage on the voltage dividing capacitor C.

The process of analyzing the voltage on the voltage dividing capacitor C includes: performing amplification processing and analog-to-digital conversion processing on the voltage on the voltage dividing capacitor C to obtain a converted digital signal, and then performing Fourier transform processing on the digital signal The frequency and phase information of the digital signal is obtained, and the waveform information of the voltage on the voltage dividing capacitor C is determined according to the frequency and phase information of the digital signal.

Optionally, in this embodiment of the present application, the processing unit 201 may include an amplifier circuit, an analog-to-digital conversion circuit, a Fourier transform module, and a first processing circuit that are connected in sequence, wherein the amplifier circuit is connected to both ends of the voltage dividing capacitor C. , the voltage on the voltage dividing capacitor C can be amplified, and the amplification processing is only embodied in amplifying the amplitude of the voltage on the voltage dividing capacitor, without changing the frequency and phase. After amplification, the amplified voltage may be converted from an analog signal to a discrete digital signal via an analog-to-digital conversion circuit, and the discrete digital signal may be sent to a Fourier transform module. The Fourier transform module can perform spectrum analysis on the discrete digital signal, obtain waveform information of the voltage on the voltage dividing capacitor, and send the waveform information of the voltage on the voltage dividing capacitor to the first processing circuit, wherein the first processing circuit can The reference signal generation instruction is generated according to the waveform information of the voltage on the voltage dividing capacitor.

In a second optional implementation manner, the processing unit 201 may send preset reference data to the reference signal source 203, and optionally, the reference data is a duty cycle array. After receiving the reference data, the reference signal source 203 can generate a target reference voltage signal according to the reference data, and input the target reference voltage signal into the electrical circuit. Wherein, the target reference voltage signal and the voltage on the voltage dividing capacitor C are different in frequency and out of phase. Then the processing unit 201 can detect the voltage on the voltage dividing capacitor C in this case to obtain the third voltage. Finally, the processing unit 201 can obtain the waveform information of the voltage on the voltage dividing capacitor C by performing signal analysis on the third voltage.

Optionally, in this embodiment of the present application, the processing unit 201 includes a phase-lock circuit and a second processing circuit, wherein the phase-lock circuit is used to track the frequency and phase of the voltage on the voltage dividing capacitor C to obtain the voltage dividing capacitor C. The waveform information of the voltage on the second processing circuit is used for generating a reference signal generating instruction according to the waveform information.

Optionally, the second processing circuit is configured to generate first reference data corresponding to the first reference voltage signal and second reference data corresponding to the second reference voltage signal according to the waveform information, and generate according to the first reference data and the second reference data. Reference signal generation command.

The process of generating the reference signal generation instruction by the processing unit 201 according to the waveform information will be described below:

The reference signal generation instruction is used to instruct the reference signal source 203 to generate the first reference voltage signal and the second reference voltage signal. The reference signal generation instruction also carries the frequency and phase information of the voltage on the voltage dividing capacitor C.

Optionally, in this embodiment of the present application, the processing unit 201 may determine the duty cycle parameters of the square waves corresponding to the first reference voltage signal and the second reference voltage signal according to the frequency and phase information of the voltage on the voltage dividing capacitor C, and then The duty cycle parameter is carried in the reference signal generation instruction.

After obtaining the reference signal generation instruction, the processing unit may send the reference signal generation instruction to the reference signal source.

The reference signal source is used to input a first reference voltage signal with the same frequency and phase as the voltage on the voltage dividing capacitor and a second reference voltage signal with the same frequency and opposite phase as the voltage on the voltage dividing capacitor to the electrical circuit according to the reference signal generating instruction.

Wherein, the amplitudes of the first reference voltage signal and the second reference voltage signal are equal.

In the embodiment of the present application, the amplitudes of the first reference voltage signal and the second reference voltage signal are smaller than the amplitudes of the voltage of the circuit to be tested.

In this embodiment of the present application, the equivalent circuit when the reference signal source 203 inputs the first reference voltage signal into the electrical circuit is shown in FIG. 5 (the processing unit and the voltage detection unit are not shown), which is obtained based on the circuit diagram in FIG. 5 After reaching the first current, the equivalent circuit when the reference signal source 203 inputs the second reference voltage signal into the electrical circuit is shown in FIG. 6 (the processing unit and the voltage detection unit are not shown).

Wherein, the first reference voltage signal Ur in FIG. 5 is in the same phase and the same frequency as the voltage to be measured Us, and the amplitudes are not equal. The second reference voltage signal Ur in FIG. 6 is opposite to the voltage to be measured and has the same frequency and unequal amplitude. The opposite phase means that the phase difference is 180°.

Optionally, the amplitude of the first reference voltage signal Ur is greater than 20 volts and less than or equal to 40 volts. In the present application, a lower reference voltage signal can be used to measure a higher voltage to be measured, wherein the amplitude of the voltage to be measured can be, for example, 400V-10kV.

In the embodiment of the present application, when the voltage on the voltage dividing capacitor C crosses the zero point, the reference signal source 203 inputs the first reference voltage signal into the electrical circuit, so as to ensure that the first reference voltage signal is in phase with the voltage of the circuit to be tested, and the second reference voltage signal is inverse to the voltage of the circuit under test.

Optionally, after receiving the reference signal generating instruction, the reference signal source 203 may first generate the first reference voltage signal according to a preset sequence, and keep the first reference voltage signal for a preset duration. Then, the second reference voltage signal is generated and maintained for a preset time period.

Optionally, in this embodiment of the present application, the first reference voltage signal may include multiple signal waves, so that a first reference voltage signal that lasts in time can be generated, so that the voltage on the voltage dividing capacitor C can be detected, and Get the first current.

Optionally, in this embodiment of the present application, the reference signal generation instruction carries first reference data corresponding to the first reference voltage signal and second reference data corresponding to the second reference voltage signal. The reference signal source 203 includes a waveform generator and a third processing circuit, wherein the third processing circuit is used to parse the reference signal generation instruction to obtain the first reference data and the second reference data; The reference data generates a first reference voltage signal, and after acquiring the first current, a second reference voltage signal is generated according to the second reference data.

The processing unit acquires the first current of the electrical circuit in the process of inputting the first reference voltage signal to the electrical circuit by the reference signal source, and after acquiring the first current, the process of inputting the second reference voltage signal to the voltage dividing capacitor by the reference signal source , obtain the second current of the electrical circuit, and calculate the voltage of the circuit under test according to the first current and the second current.

In the embodiment of the present application, in the process of inputting the first reference voltage signal to the electrical circuit by the reference signal source, the current in the electrical circuit is detected by the current detection unit, the first current is obtained, and the first current is sent to the processing unit. During the process of inputting the second reference voltage signal into the electrical circuit by the reference signal source, the current in the electrical circuit is detected by the current detection unit, the second current is obtained, and the second current is sent to the processing unit.

In an optional implementation manner, a mathematical model may be preset in the processing unit 201, and the first current and the second current are input to the mathematical model, and the voltage of the circuit under test output by the mathematical model can be obtained.

In another optional implementation manner, the ratio of the first current to the second current may be determined as the voltage coefficient. Then, the voltage of the circuit under test is calculated according to the product of the voltage coefficient and the amplitude of the first reference voltage signal (or the second reference voltage signal).

In another optional implementation manner, the ratio of the sum of the first current and the second current to the difference between the first current and the second current may be determined as the voltage coefficient. The voltage of the circuit under test is calculated according to the voltage coefficient and the amplitude of the first reference voltage signal (or the second reference voltage signal).

In another optional implementation manner, as shown in FIG. 5 , when the measured voltage Us and the first reference voltage signal Ur are in phase, the current ( _ie , the first current) I ₁ of the electrical circuit can be expressed as:

Wherein, C1 is the capacitance parameter of the first coupling capacitor C1, C2 is the capacitance parameter of the second coupling capacitor C2, fs is the common frequency, and C is the coupling parameter of the voltage dividing capacitor C.

As shown in Figure 6, when the measured voltage Us and the second reference voltage signal Ur are in opposite phases, the current (ie, the second current) I2 of the current in the electrical loop can be expressed as:

Combining Equation (1) and Equation (2), we can get:

Among them, the first current I1 and the second current I2 are the currents in the electrical loop, the capacitances C, C1, and C2 are all unknown quantities, and the measured voltage Us is the quantity to be determined.

The simultaneous equations can be further simplified as:

By solving equation (3), the voltage of the circuit to be tested can be calculated.

In this embodiment of the present application, the phase difference between _Ur and _Us is controlled by generating a first reference voltage signal that is in phase with the voltage on the voltage dividing capacitor and a second reference voltage signal that is opposite to the voltage on the voltage dividing capacitor. It is 0 degrees and 180 degrees, that is to say, two states of _Ur and Us in _phase and _Ur and Us in _opposite phase can be constructed. Then, the voltage of the circuit under test is calculated based on the currents in the electrical circuit measured in the two states. When measuring the voltage of the circuit under test, the device does not need to destroy the insulating layer of the circuit under test, and has the advantages of simple structure and low cost. Inexpensive features, thus reducing the cost of making voltage measurements.

In the embodiment of the present application, by sequentially inputting the first reference voltage signal and the second reference voltage signal with the same frequency and opposite phase amplitude into the electrical circuit, the corresponding first current and second current are obtained, and then the first current is passed through. and the second current to calculate the voltage of the circuit under test. The purpose of detecting the voltage of the high-voltage transmission line through a reference signal with a smaller amplitude can be achieved.

Further, since the amplitudes of the first reference voltage signal and the second reference voltage signal are small, the difficulty in implementing the non-contact voltage measurement method is reduced.

Finally, in the embodiment of the present application, the voltage at any position in the power line can be measured, so it is more flexible and convenient.

In an embodiment of the present application, as shown in FIG. 7 , which shows a schematic diagram of a phase-locked circuit, the phase-locked circuit includes a phase detector, a low-pass filter, a voltage-controlled oscillator, and a feedback circuit, wherein, The feedback circuit is used to send the feedback signal output by the voltage controlled oscillator to the phase detector; the phase detector is used to determine the phase difference between the voltage on the voltage dividing capacitor C and the feedback signal, and determine the error voltage signal based on the phase difference; The filter is used to filter the error voltage signal to obtain the control voltage signal; the voltage controlled oscillator is used to receive the control voltage signal and output the target signal based on the control voltage signal. Based on the phase-locked characteristics of the phase-locked circuit, it can be known that the target signal can be used to reflect the frequency and phase information of the voltage on the voltage dividing capacitor C, so the waveform information of the voltage on the voltage dividing capacitor C can be obtained according to the waveform information of the target signal.

Among them, the basic working process of the phase-locked circuit is: the phase detector is used to compare the phase deviation of the input signal and the feedback signal, and generate an error voltage Vc(t). The high-frequency components in the error voltage (including the high-frequency components in the noise) are filtered out by the low-pass filter to form the control voltage Vd(t). Under the action of the control voltage, the frequency and phase of the VCO gradually approach the frequency and phase of the loop input signal. If the frequency of the voltage-controlled oscillator can be changed to the same frequency as the input signal, it will stabilize at this frequency under the condition of stability. After reaching stability, the frequency difference between the input signal and the output signal of the VCO is zero, the difference does not change with time, the error voltage is a fixed value, and the circuit enters the "locked" state. When locked, the VCO can make the frequency of the output signal change with the frequency of the input signal, and the input and output signals remain synchronized. This is how the signal synchronization circuit works.

At present, generally speaking, the frequency of the voltage in the transmission line is generally 50Hz power frequency, but it also fluctuates up and down. In order to generate a trigger pulse that is strictly synchronized with the grid frequency, grid frequency tracking is necessary. For this purpose, the grid frequency also needs to be tracked.

In an embodiment of the present application, a non-contact voltage measurement method is provided based on the above non-contact voltage measurement device, the method comprising:

The waveform information of the voltage on the voltage dividing capacitor is acquired, and a reference signal generation instruction is generated according to the waveform information. According to the reference signal generation instruction, a first reference voltage signal having the same frequency and phase as the voltage on the voltage dividing capacitor and a second reference voltage signal having the same frequency and opposite phase as the voltage on the voltage dividing capacitor are input to the electrical circuit. Wherein, the amplitudes of the first reference voltage signal and the second reference voltage signal are equal. During the process that the reference signal source inputs the first reference voltage signal to the electrical circuit, the first current of the electrical circuit is obtained, and during the process that the reference signal source inputs the second reference voltage signal to the voltage dividing capacitor, the processing unit obtains the first current of the electrical circuit. Two currents, and calculate the voltage of the circuit under test according to the first current and the second current.

In this embodiment of the present application, the processing unit may control the reference signal source to input a third reference signal into the electrical circuit. Optionally, the third reference signal is a null signal. The amplitude of the third reference signal is 0, and it can be considered that the reference signal source is short-circuited. In this case, the voltage on the voltage dividing capacitor can be measured by the voltage detection unit. Then, the waveform information of the voltage on the voltage dividing capacitor is obtained by performing signal analysis on the voltage on the voltage dividing capacitor. Then, when the phase of the voltage on the voltage dividing capacitor crosses the zero point, the first reference voltage signal can be turned on, and the first reference voltage signal and the voltage of the circuit under test are not equal to the same frequency and same phase amplitude. Wherein, the first reference voltage signal is input into the electrical circuit and maintained for a preset period of time. During this process, the current of the electrical circuit can be obtained to obtain the first current. After the first current is obtained, the reference voltage source can then generate a second reference voltage signal, and input the second reference voltage signal into the electrical circuit for a preset period of time. During this process, the current in the electrical circuit can be obtained , so as to obtain the second current. Finally, the voltage of the circuit to be tested is calculated according to the first current and the second current.

Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be implemented by instructing relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage In the medium, when the computer program is executed, it may include the processes of the above-mentioned method embodiments. Wherein, any reference to memory, storage, database or other media used in the various embodiments provided in this application may include at least one of non-volatile and volatile memory. The non-volatile memory may include Read-Only Memory (ROM), magnetic tape, floppy disk, flash memory or optical memory, and the like. Volatile memory may include random access memory (Random Access Memory, RAM) or external cache memory. By way of illustration and not limitation, the RAM may be in various forms, such as static random access memory (Static Random ACess Memory, SRAM) or dynamic random access memory (Dynamic Random ACess Memory, DRAM).

The technical features of the above embodiments can be combined arbitrarily. In order to make the description simple, all possible combinations of the technical features in the above embodiments are not described. However, as long as there is no contradiction in the combination of these technical features It is considered to be the range described in this specification.

The above-mentioned embodiments only represent several embodiments of the present application, and the descriptions thereof are specific and detailed, but should not be construed as a limitation on the scope of the invention patent. It should be pointed out that for those skilled in the art, without departing from the concept of the present application, several modifications and improvements can be made, which all belong to the protection scope of the present application. Therefore, the scope of protection of the patent of the present application shall be subject to the appended claims.

Claims (10)

1. The utility model provides a non-contact voltage measuring device, its characterized in that includes probe and voltage sensing subassembly, the probe includes first probe and second probe, the voltage sensing subassembly includes processing unit and the partial pressure electric capacity and the reference signal source that connect gradually, wherein:

the first probe is used for being coupled with a circuit to be tested to form a first coupling capacitor; the second probe is used for being coupled with the zero line circuit to form a second coupling capacitor; the voltage sensing assembly is respectively connected with the first coupling capacitor and the second coupling capacitor to form an electric loop; the first coupling capacitor is connected with a reference signal source in the voltage sensor assembly, and the second coupling capacitor is connected with a voltage dividing capacitor in the voltage sensor assembly;

the processing unit is connected with the voltage division capacitor and used for acquiring waveform information of voltage on the voltage division capacitor and generating a reference signal generation instruction according to the waveform information;

the reference signal source is connected with the processing unit and used for inputting a first reference voltage signal with the same frequency and phase as the voltage on the voltage division capacitor and a second reference voltage signal with the same frequency and phase opposite to the voltage on the voltage division capacitor to the electric loop according to the reference signal generation instruction, and the amplitude of the first reference voltage signal is equal to that of the second reference voltage signal;

the processing unit is further configured to obtain a first current of the electrical loop in a process that the reference signal source inputs the first reference voltage signal to the electrical loop; after the first current is obtained, in the process that the reference signal source inputs the second reference voltage signal to the voltage division capacitor, the second current of the electric loop is obtained, and the voltage of the circuit to be tested is calculated according to the first current and the second current.

2. The apparatus of claim 1, wherein the voltage sensing assembly further comprises a current detection unit, wherein:

the current detection unit is connected in series in the electrical loop, is connected with the processing unit, and is configured to detect a current of the electrical loop to obtain the first current in a process that the reference signal source inputs the first reference voltage signal to the voltage division capacitor, and detect a current of the electrical loop to obtain the second current in a process that the reference signal source inputs the second reference voltage signal to the voltage division capacitor.

3. The apparatus of claim 1, wherein the voltage sensing component further comprises a voltage detection unit, wherein:

the voltage detection unit is connected with the voltage division capacitor and the processing unit and used for detecting the voltage on the voltage division capacitor and sending the voltage on the voltage division capacitor to the processing unit.

4. The apparatus of claim 1, wherein the processing unit comprises an amplification circuit, an analog-to-digital conversion circuit, a Fourier transform module, and a first processing circuit, wherein,

the amplifying circuit is connected with the analog-to-digital conversion circuit, connected to two ends of the voltage dividing capacitor and used for amplifying the voltage on the voltage dividing capacitor;

the analog-to-digital conversion circuit is connected with the Fourier transform module and is used for converting the amplified voltage on the voltage division capacitor into a discrete digital signal and sending the discrete digital signal to the Fourier transform module;

the Fourier transform module is connected with the first processing circuit and used for carrying out frequency spectrum analysis on the discrete digital signal to obtain waveform information of voltage on the voltage-dividing capacitor and sending the waveform information to the first processing circuit;

the first processing circuit is used for generating a reference signal generation instruction according to the waveform information.

5. The apparatus of claim 1, wherein the processing unit comprises a phase lock circuit and a second processing circuit, wherein,

the phase-locked circuit is used for acquiring waveform information of the voltage on the voltage-dividing capacitor, wherein the waveform information comprises frequency and phase information;

the second processing circuit is configured to generate first reference data corresponding to the first reference voltage signal and second reference data corresponding to the second reference voltage signal according to the waveform information, and generate the reference signal generation instruction according to the first reference data and the second reference data.

6. The apparatus of claim 5, wherein the phase-lock circuit comprises a phase detector, a low-pass filter, a voltage-controlled oscillator, and a feedback circuit, wherein,

the feedback circuit is used for sending a feedback signal output by the voltage-controlled oscillator to the phase detector;

the phase detector is used for determining the phase difference between the voltage on the voltage-dividing capacitor and the feedback signal and determining an error voltage signal based on the phase difference;

the filter is used for filtering the error voltage signal to obtain a control voltage signal;

the voltage-controlled oscillator is used for receiving the control voltage signal, outputting a target signal based on the control voltage signal, and acquiring waveform information of the voltage on the voltage-dividing capacitor according to the waveform information of the target signal.

7. The apparatus of claim 1, wherein the reference signal generation instruction carries first reference data corresponding to the first reference voltage signal and second reference data corresponding to the second reference voltage signal, the reference signal source comprises a waveform generator and a third processing circuit, wherein,

the third processing circuit is configured to parse the reference signal generation instruction to obtain the first reference data and the second reference data;

the waveform generator is configured to generate the first reference voltage signal according to the first reference data, and generate the second reference voltage signal according to the second reference data after acquiring the first current.

8. The apparatus of claim 1, wherein the probe comprises a first surface and a second surface opposite the first surface, the second surface being electrically connected to the voltage sensing component.

9. The device of claim 8, wherein the second surface has disposed thereon a substrate, metal traces, and a sensor array,

the substrate is arranged on the second surface;

the metal wire is arranged on the substrate and is electrically connected with the voltage sensing assembly;

the sensor array is arranged on the metal wiring.

10. A non-contact voltage measuring method applied to the non-contact voltage measuring apparatus according to any one of claims 1 to 9, the method comprising:

acquiring waveform information of the voltage on the voltage-dividing capacitor, and generating a reference signal generation instruction according to the waveform information;

inputting a first reference voltage signal with the same frequency and phase as the voltage on the voltage-dividing capacitor to the electric loop according to the reference signal generation instruction, and acquiring the current of the electric loop to obtain a first current;

after the first current is obtained, inputting a second reference voltage signal which is in the same frequency and opposite phase with the voltage on the voltage-dividing capacitor to the voltage-dividing capacitor according to the reference signal generation instruction, and obtaining the current of the electric loop to obtain a second current;

and calculating the voltage of the circuit to be tested according to the first current and the second current.

Images