Humidity-compensated ac high-voltage and extra-high-voltage line voltage on-line measuring method

Abstract

The application discloses a humidity compensation AC high-voltage and super-high-voltage line voltage on-line measuring method, which comprises the following steps: building a voltage measuring calibration circuit; using a controller in the calibration circuit to obtain sample data under different humidity in different environments; obtaining a relationship formula of the circuit gain changing with humidity through a fitting algorithm and an expected conditioning circuit gain; dynamically controlling the parameters of element R f in a negative feedback loop through the controller, so that the output voltage of the signal conditioning circuit and the line voltage have a linear relationship, real-time measurement of humidity information is obtained, and the deviation of the humidity information to the voltage measurement is compensated, thereby realizing reliable and accurate on-line measurement of the high-voltage and super-high-voltage AC line. For application scenarios with low voltage measurement accuracy, the relationship of the sensor output voltage changing with humidity can be obtained through the voltage sensor parameters ε1 and d1, the sensor installation position d2 and the environmental humidity change range parameter ε2, and the relationship formula of the gain changing with humidity can be inversely deduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electric energy metering, in particular to a humidity-compensated AC high-voltage and ultra-high-voltage line voltage on-line measurement method. BACKGROUND

[0002] With the development of digitalization, intelligentization and networking of power grids, power grid intelligent monitoring devices have been widely promoted and applied. The on-line measurement of the voltage of high-voltage and ultra-high-voltage lines of power grids has become an important supporting technology for the digitalization and intelligentization of power grids, and on-line measurement is a key link in the operation and maintenance of power systems, which is crucial for ensuring the safe, stable and efficient operation of power grids. Today, more advanced means such as non-contact optical sensors, electromagnetic field induction technology and wireless communication-based data acquisition systems are mainly used, which provide higher safety and accuracy. However, temperature, humidity, electromagnetic interference, air pollution and other adverse environmental conditions will affect the accuracy of the measuring equipment. The present application provides a humidity-compensated AC high-voltage and ultra-high-voltage line voltage on-line measurement method. Compared with the traditional method, the method can effectively overcome the measurement drift of the voltage caused by the humidity in the operating environment of the equipment, thereby improving the voltage measurement accuracy. SUMMARY

[0003] The humidity-compensated AC high-voltage and ultra-high-voltage line voltage on-line measurement method provided by the present application can at least solve one of the technical problems in the background art.

[0004] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0005] A humidity-compensated AC high-voltage and ultra-high-voltage line voltage on-line measurement method, the method comprising:

[0006] A simplest humidity voltage calibration measurement circuit is built, the humidity sensor and the voltage sensor of the simplest humidity voltage calibration measurement circuit are used to convert the AC high-voltage and ultra-high-voltage line voltage to be measured and the environmental humidity into corresponding electrical signals, the humidity information of the high-voltage line is obtained through the preprocessing of the electrical signals, the humidity information is used as the basic information for compensating the measured voltage value, and the deviation caused by the humidity to the measurement circuit is compensated by adjusting the gain of the conditioning circuit, and then the voltage signal of the voltage sensor is calibrated.

[0007] Further, the simplest humidity voltage calibration measurement circuit comprises a voltage sensor, a humidity sensor, a capacitor CP, a filter circuit, a conditioning circuit and a controller.

[0008] The voltage sensor output end is connected with the filter circuit input end, the filter circuit output end is connected with the conditioning circuit input end, and the conditioning circuit output end is connected with the controller; the humidity sensor is connected with the controller input end, and the controller output end is connected with the conditioning circuit feedback input end; the capacitor CP is connected at the voltage sensor output end;

[0009] The voltage sensor and the humidity sensor convert the to-be-measured voltage and the ambient humidity into corresponding electric signals, and the humidity sensor output signal is not limited to an analog signal or a digital signal.

[0010] The filter circuit is mainly used for filtering the electric signal output by the voltage sensor and inputting the processed voltage signal into the conditioning circuit, and is only a unit gain, that is, does not amplify or attenuate the signal.

[0011] The conditioning circuit is mainly used for conditioning the voltage signal processed by the filter circuit into a signal suitable for the controller to collect, and simultaneously serving as a feedback node for compensating the voltage measurement deviation caused by humidity, wherein the conditioning circuit gain adjustment mode includes but is not limited to voltage feedback of a negative feedback loop or a programmed digital device.

[0012] The controller further comprises a controllable negative feedback element, which is mainly used for completing digital-to-analog conversion of the voltage signal to obtain humidity information.

[0013] Further, the filter circuit structure of the present application further comprises a passive and active filter realized by a capacitor, an inductor, a resistor and an amplifier.

[0014] The parallel capacitor is used to reduce the to-be-measured signal amplitude to a range meeting the measurement signal requirement.

[0015] Further, the humidity information is used as basic information for compensating the measured voltage value in the present application, and the gain of the conditioning circuit is adjusted to compensate the deviation caused by humidity to the measurement circuit, and then the voltage signal method of the voltage sensor is calibrated.

[0016] The dielectric constant between the upper metal plate and the lower metal plate is ε1, the vertical distance between the two is d1, the relative dielectric constant between the lower metal plate and the ground at a certain humidity is ε2, the distance between the lower metal plate and the ground is d2, the equivalent capacitance between the upper metal plate and the lower metal plate is C S , the equivalent capacitance between the lower metal plate and the ground at a reference humidity is C G , the effective area between the upper plate and the lower plate of the capacitor is S, the line voltage V L and the voltage sensor output voltage V S have the following relationship:

[0017]

[0018] From (1) (2) and (3), we can know that

[0019]

[0020] From (4), we can know that the greater the vertical distance between the sensor and the ground, the smaller the sensor output voltage. In a specific installation position, ε1, d1 and d2 are constants, and k is the electrostatic force constant, with a value of 8.987551 x 10 9 Nm 2 / C 2 Let the ratio of the sensor output voltage and the line voltage be γ:

[0021]

[0022] We have

[0023]

[0024] However, since the medium between the sensor and the ground is air, its dielectric constant ε2 is greatly affected by the environmental humidity. If the gain of the signal conditioning circuit is β, then the output signal of the signal conditioning circuit is:

[0025] V A = β · V S (7)

[0026] Let where δ is a constant, which is the constant amplification gain of the signal conditioning signal to the sensor output signal. For example, within the dielectric constant fluctuation range, the maximum value of the sensor output is V SMAX , the controller AD conversion reference is V REF , and V SMAX <V REF . In order to obtain a better dynamic range, a constant amplification multiple δ is compensated in the gain link, so that δ · V SMAX = V REF , we have

[0027] V A = β · γ · V S = δ · V L (9)

[0028] That is, when the gain β of the signal conditioning circuit obeys the distribution formula (8), the signal conditioning circuit output voltage collected by the controller has a linear relationship with the line voltage (9), and δ is the variable ratio of the signal conditioning circuit output voltage to the line voltage. Moreover, β, δ, and γ have the following relationship:

[0029]

[0030] Further, the line voltage calculation method of the present application is:

[0031] Set R1=0Ω, R2=10KΩ, controllable negative feedback element R f is a digital potentiometer, and the maximum resistance is 20KΩ, the resolution is 1024, and the reachable gain adjustment range is 0.0-2.0;

[0032] In the test environment, keep R f =10KΩ unchanged, record the line voltage as x, and the signal conditioning circuit measures the voltage value y when the humidity is h i , the relationship y=f(h) between the signal conditioning circuit measurement voltage value y and the environmental humidity h is obtained by mathematical fitting, and then

[0033]

[0034] That is, after obtaining the above data and the relationship, by controlling R f , the gain β of the conditioning circuit and the humidity h satisfy the following formula, so that the influence of humidity on the measurement voltage can be compensated.

[0035]

[0036] The voltage calculation line voltage is:

[0037]

[0038] Wherein, γ0 is the ratio of the sensor output voltage and the line voltage in the standard humidity environment.

[0039] From the above technical solution, the humidity compensation AC high voltage and super high voltage line voltage on-line measurement method of the present application obtains sample data under different humidity in different environments through the controller, obtains the relationship formula of the circuit gain changing with humidity through the fitting algorithm and the expected conditioning circuit gain; by dynamically controlling the parameter of the element R f in the negative feedback loop through the controller, the output voltage of the signal conditioning circuit and the line voltage are in a linear relationship, the real-time measurement of the humidity information is obtained, and the deviation of the humidity information on the voltage measurement is compensated, which realizes the reliable and accurate measurement of the high voltage and super high voltage AC line. For the application scene with low voltage measurement accuracy, the relationship of the sensor output voltage changing with humidity can be obtained through the sensor parameters ε1, d1, the sensor installation position d2 and the environmental humidity change range parameter ε2, and the relationship formula of the gain changing with humidity can be deduced inversely. Then, according to the environmental humidity, the gain of the conditioner is adjusted through the controller to achieve more accurate voltage measurement. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1 is the schematic diagram of the simplest humidity voltage calibration measurement circuit of the present application;

[0041] Figure 2 Schematic diagram of technical principle for voltage sensor

[0042] Figure 3 Schematic diagram of voltage V output by voltage sensor S Calculation schematic diagram

[0043] Figure 4 Schematic diagram of 110KV humidity voltage calibration measurement circuit

[0044] Figure 5 Schematic diagram of 110KV humidity voltage calibration simulation data

[0045] Figure 6 Schematic diagram of 220KV humidity voltage calibration measurement circuit

[0046] Figure 7 Schematic diagram of 220KV humidity voltage calibration simulation data DETAILED DESCRIPTION

[0047] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described below in connection with the drawings of the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application.

[0048] As shown in Figure 1 The present embodiment realizes the online measurement method of the humidity-compensated AC high-voltage and extra-high-voltage line voltage by building the simplest humidity voltage calibration measurement circuit, which comprises the following steps:

[0049] S100, building the simplest humidity voltage calibration measurement circuit, converting the circuit voltage to be measured and the environmental humidity into corresponding electrical signals through the humidity sensor and the voltage sensor of the calibration measurement circuit;

[0050] S200, filtering the electrical signals output by the humidity sensor and the voltage sensor through the filtering circuit, and inputting the filtered electrical signals into the conditioning circuit;

[0051] S300, pre-processing the filtered electrical signals through the conditioning circuit, and inputting the pre-processed electrical signals into the controller;

[0052] S400, the controller performs digital-to-analog conversion on the humidity sensor output signal to obtain humidity information as basic information for compensating the measured voltage value, and compensates the deviation of the humidity on the measurement circuit through the gain adjustment of the conditioning circuit, and then calibrates the voltage signal of the voltage sensor.

[0053] The following describes each step in detail:

[0054] S100, build the simplest humidity voltage calibration measurement circuit, through the humidity sensor and voltage sensor of the calibration measurement circuit, the voltage of the to-be-measured circuit and the environmental humidity are converted into corresponding electrical signals;

[0055] The simplest humidity voltage calibration measurement circuit comprises a voltage sensor, a humidity sensor, a capacitor CP, a filter circuit, a conditioning circuit and a controller.

[0056] The output end of the voltage sensor is connected with the input end of the filter circuit, the output end of the filter circuit is connected with the input end of the conditioning circuit, and the output end of the conditioning circuit is connected with the controller; the humidity sensor is connected with the input end of the controller, and the output end of the controller is connected with the feedback input end of the conditioning circuit; the capacitor CP is connected at the output end of the voltage sensor.

[0057] The voltage sensor and the humidity sensor convert the to-be-measured voltage and the environmental humidity into corresponding electrical signals, and the output signal of the humidity sensor is not limited to an analog signal or a digital signal.

[0058] The filter circuit is mainly used for filtering the electrical signal output by the voltage sensor and inputting the processed voltage signal into the conditioning circuit, and is only a unit gain, that is, does not amplify or attenuate the signal, and the structure can also be realized by a passive and active filter of a capacitor, an inductor, a resistor and an amplifier.

[0059] The conditioning circuit is mainly used for conditioning the voltage signal processed by the filter circuit into a signal suitable for the controller to collect, and simultaneously serving as a feedback node for compensating the voltage measurement deviation caused by humidity, wherein the adjustment mode of the gain of the conditioning circuit includes but is not limited to voltage feedback of a negative feedback loop or a programmed digital device.

[0060] The controller further comprises a controllable negative feedback element, which is mainly used for completing digital-to-analog conversion of the voltage signal to obtain humidity information.

[0061] S200, filtering the electrical signal output by the humidity sensor and the voltage sensor through the filter circuit, and inputting the filtered electrical signal into the conditioning circuit.

[0062] S300, pre-processing the filtered electrical signal through the conditioning circuit and inputting the same into the controller.

[0063] According to the change of the environmental humidity, the conditioning circuit processes the filtered electrical signal, which is the key to realize humidity compensation, and cooperates with the controller to control the controllable negative feedback element R f , so that the gain of the conditioning circuit is subject to the formula:

[0064]

[0065] S400, the controller carries out digital-analog conversion to the humidity sensor output signal to obtain humidity information as basic information for compensating the measured voltage value, and calibrates the information collected by the voltage sensor;

[0066] As Figure 2 shown, the technical principle diagram of the voltage sensor is composed of an upper metal plate and a lower metal plate which are equal in potential to an alternating current high-voltage or super-high-voltage line, wherein the metal plate ② is the upper metal plate and the metal plate ③ is the lower metal plate, and the areas of the upper metal plate and the lower metal plate are both S, the upper metal plate and the lower metal plate are parallel to the ground, and the upper metal plate and the lower metal plate are insulated.

[0067] As Figure 3 shown, the dielectric constant between the upper metal plate and the lower metal plate is set as ε1, and the vertical distance between the upper metal plate and the lower metal plate is d1; the relative dielectric constant between the lower metal plate and the ground at a certain humidity is ε2, and the distance between the lower metal plate and the ground is d2; the equivalent capacitance between the upper metal plate and the lower metal plate is C S , the equivalent capacitance between the lower metal plate and the ground at a reference humidity is C G , the line voltage V L and the output voltage V S of the voltage sensor exist the following relationship:

[0068]

[0069] Under the condition that the sensor parameters are unchanged, it can be known from (1), (2) and (3) that

[0070]

[0071] It can be known from (4) that the greater the vertical distance of the sensor to the ground, the smaller the output voltage of the sensor. In a specific installation position, ε1, d1 and d2 are constants, k is the electrostatic force constant, and the value is 8.987551×10 9 Nm 2 / C 2 , the ratio γ of the output voltage of the sensor to the line voltage is:

[0072]

[0073]

[0074]

[0075] However, since the medium between the sensor and the ground is air, the dielectric constant ε2 is greatly affected by the environmental humidity. If the gain of the signal conditioning circuit is β, then the output signal of the signal conditioning circuit is:

[0076] V A = β·V​S (7)

[0077] If let Where δ is a constant, representing the constant amplification gain of the signal conditioning signal on the sensor output signal. For example, within the dielectric constant fluctuation range, the maximum value of the sensor output is V. SMaX The controller's AD conversion reference is V. REF And V SMAX <V REF To obtain a better dynamic range, a constant amplification factor δ is compensated in the gain stage, such that δ·V SMAX =V REF ,have to

[0078] V A =β·γ·V S =δ·V L (9)

[0079] That is, when the gain β of the signal conditioning circuit follows the distributed formula (8), the output voltage of the signal conditioning circuit acquired by the controller is linearly related to the line voltage (9), overcoming the voltage measurement deviation caused by ambient humidity. δ is the ratio of the output voltage of the signal conditioning circuit to the line voltage, and β, δ, γ have the following relationship:

[0080]

[0081] The controller can obtain sample data under different humidity conditions in the test environment or the actual operating environment, and obtain equation (8) through the fitting algorithm and the desired conditioning circuit gain, and then dynamically adjust the feedback element R. f The parameters ensure that the output voltage of the signal conditioning circuit is linearly related to the line voltage.

[0082] Among them, R f It is a controllable negative feedback element in signal conditioning circuits, not limited to specific implementation schemes, such as digital potentiometers, transistors, field-effect transistors, etc., used to compensate for the deviation of the measured voltage when the humidity deviates from the reference. Figure 1 The signal conditioning circuit described is a non-inverting amplifier circuit, used only to illustrate the implementation principle of the invention and not limited to specific circuit implementations. The filter circuit is used to filter out signals outside the bandwidth of the signal under test, thereby improving the signal-to-noise ratio of the signal under test.

[0083] The following examples illustrate this point:

[0084] Example 1

[0085] like Figure 4 The diagram shows a 110KV voltage calibration circuit.

[0086] Assuming we are measuring the voltage of a 110kV line, with a peak-to-peak voltage of 179.6kV to ground, and a vertical distance of 10 meters from the ground surface, and the required output voltage of the sensor is a peak-to-peak value of 1.796V, with a distance of 10mm between the two electrodes and an electrode area of ​​0.04m², we require a sensor output voltage peak-to-peak value of 1.796V. 2 Its dielectric constant is 2.1, from which the equivalent capacitance of the sensor, the equivalent capacitance between the plate and the ground, and C can be calculated. P The value can be obtained from the formula:

[0087]

[0088] At this time, the equivalent capacitance of the voltage sensor is 885.41pF. According to the literature "Research on the Influence of Ambient Humidity on the Dielectric Constant of Air", when the ambient humidity is less than 75%, the dielectric constant changes relatively much with humidity. When the ambient humidity increases from 68% to 75%, the dielectric constant increases by 20.7%; when the ambient humidity changes from 75% to 90%, the dielectric constant changes relatively slowly, with an increase of 1.17%. Assuming that the range of ambient humidity changes leads to a range of change in the relative dielectric constant of air of 1.0 to 1.8, the range of sensor output voltage change is obtained by equations (1) to (4) as (1.798V, 3.236V), and the reference voltage of the acquisition circuit is 3.3V. If the output voltage remains constant under different humidity levels through compensation measures, the corresponding gain change range is required to be (0.556, 1.000). Among them, the sensor output voltage is 1.798V in dry air without carbon dioxide under standard atmospheric pressure. Therefore, under the condition that the line voltage remains constant, the same acquisition voltage value under standard conditions can be obtained by gain compensation of the conditioning circuit.

[0089] With R1 = 0Ω and R2 = 10KΩ, the controllable negative feedback element R f It is a digital potentiometer with a maximum resistance of 20KΩ, 1024 resolution, and an adjustable gain range of 0.0 to 2.0.

[0090] In the test environment, keep R f =10KΩ remains constant, record the line voltage as x, and the different humidity levels as h. i The signal conditioning circuit measures the voltage value y. Therefore, the relationship between the measured voltage value y and the ambient humidity h can be obtained using mathematical fitting: y = f(h).

[0091]

[0092] That is, after obtaining the above data and relationships, by controlling R f The effect of humidity on the measurement voltage can be compensated by ensuring that the gain β of the conditioning circuit and the humidity h satisfy the following formula.

[0093]

[0094] At this point, the method for calculating the line voltage based on the controller's measured voltage is as follows:

[0095]

[0096] Wherein, γ0 is the ratio of the sensor output voltage to the line voltage under standard humidity conditions; specific experimental results are as follows: Figure 5 As shown.

[0097] Example 2

[0098] like Figure 6 The image shows a dummy 220KV voltage calibration circuit.

[0099] Suppose we are measuring the voltage of a 220kV line, whose peak-to-peak voltage to ground is 359kV, and its vertical distance from the ground is 20 meters. If the required output voltage of the sensor is 2.0V peak-to-peak, the distance between the two electrodes is 1.6mm, and the electrode area is 0.01m², then... 2 Its dielectric constant is 4.6, from which the equivalent capacitance CG of the sensor, the equivalent capacitance CS between the plate and the ground, and C can be calculated. P value.

[0100]

[0101] At this time, the equivalent capacitance of the voltage sensor is 794.659pF. According to the "Study on the Influence of Ambient Humidity on the Dielectric Constant of Air", when the ambient humidity is less than 75%, the dielectric constant changes relatively much with humidity. When the ambient humidity increases from 68% to 75%, the dielectric constant increases by 20.7%; when the ambient humidity changes from 75% to 90%, the dielectric constant changes relatively slowly, with an increase of 1.17%. Assuming that the range of ambient humidity changes leads to a range of change in the relative dielectric constant of air of 1.0 to 1.8, the range of sensor output voltage change is (2.0V, 3.6V) obtained by equations (1) to (4). If the output voltage remains constant under different humidity levels through compensation measures, the corresponding gain change range is required to be (0.555, 1.000). Among them, the sensor output voltage is 1.798V in dry air without carbon dioxide under standard atmospheric pressure. Therefore, under the condition that the line voltage remains constant, the same acquisition voltage value under standard conditions can be obtained through gain compensation of the conditioning circuit.

[0102] With R1 = 0Ω and R2 = 10KΩ, the controllable negative feedback element R f It is a digital potentiometer with a maximum resistance of 20KΩ, 1024 resolution, and an adjustable gain range of 0.0 to 2.0.

[0103] In the test environment, keep R f =10KΩ remains constant, record the line voltage as x, and the different humidity levels as h. i The signal conditioning circuit measures the voltage value y. Therefore, the relationship between the measured voltage value y and the ambient humidity h can be obtained using mathematical fitting: y = f(h).

[0104]

[0105] That is, after obtaining the above data and relationships, by controlling R f The effect of humidity on the measured voltage can be compensated by ensuring that the gain β of the conditioning circuit is related to humidity in the following way.

[0106]

[0107] At this point, the method for calculating the line voltage based on the controller's measured voltage is as follows:

[0108]

[0109] Specific experimental results are as follows: Figure 7 As shown.

[0110] In summary, the humidity-compensated online voltage measurement method for AC high-voltage and ultra-high-voltage lines of the present invention, by constructing a voltage measurement calibration circuit, using a controller to obtain sample data under different humidity conditions in different environments, and obtaining the relationship between circuit gain and humidity through a fitting algorithm and the desired conditioning circuit gain; and by dynamically controlling the component R in the negative feedback loop through the controller. f The parameters ensure a linear relationship between the signal conditioning circuit output voltage and the line voltage, enabling real-time measurement of humidity information and compensating for any deviations in voltage measurement. This provides reliable and accurate online measurement for high-voltage and ultra-high-voltage AC lines. For applications requiring lower voltage measurement accuracy, the relationship between the sensor output voltage and humidity can be obtained using the voltage sensor parameters ε1 and d1, the sensor installation position d2, and the ambient humidity range parameter ε2. From this, the gain-humidity relationship can be derived. Furthermore, based on the ambient humidity, the gain of the conditioner can be adjusted by the controller to achieve more accurate voltage measurement.

[0111] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0112] The various embodiments in this specification are described in a related manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions of the method embodiments.

[0113] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A humidity-compensated online voltage measurement method for AC high-voltage and ultra-high-voltage lines, characterized in that, The methods include: A simplified humidity-voltage calibration measurement circuit was constructed. The humidity sensor and voltage sensor of the simplified humidity-voltage calibration measurement circuit converted the AC high voltage and ultra-high voltage line voltage and the ambient humidity into corresponding electrical signals. The humidity information of the high voltage line was obtained by preprocessing the electrical signals. The humidity information was used as the basis for compensating the measured voltage value. The deviation caused by humidity to the measurement circuit was compensated by adjusting the gain of the conditioning circuit, thereby calibrating the voltage signal of the voltage sensor. The method for calibrating the voltage sensor's signal involves using humidity information as the basis for compensating the measured voltage value, and adjusting the gain of the conditioning circuit to compensate for the deviation caused by humidity in the measurement circuit. The dielectric constant between the upper and lower metal plates is set to be... The vertical distance between the two is The relative permittivity between the lower metal plate and the ground at a certain humidity level is: The distance between the lower metal plate and the ground is... The equivalent capacitance between the upper and lower metal plates is: The equivalent capacitance between the lower metal plate and the ground at the reference humidity is: If the effective area S between the upper and lower plates of the capacitor is given by the line voltage... and voltage sensor output voltage The following relationship exists: （1） （2） （3） Assuming the sensor parameters remain constant, it can be seen from (1), (2), and (3) that... （4） As shown in equation (4), the greater the vertical distance from the sensor to the ground, the smaller the sensor output voltage. Under a specific installation location, All are constants, with k being the electrostatic constant, valued at 8.987551 × 10⁻⁶. 9 Nm 2 / C 2 Let the ratio of the sensor output voltage to the line voltage be... for: （5） have to （6） However, since the medium between the sensor and the ground is air, its dielectric constant... Significantly affected by ambient humidity, if the gain of the signal conditioning circuit is... The output signal of the signal conditioning circuit is: （7） If let (8) in, The constant is the constant amplification gain of the signal conditioning signal on the sensor output signal. For example, within the range of dielectric constant fluctuations, the maximum value of the sensor output is... The controller's AD conversion reference is ,and To achieve a better dynamic range, a constant amplification factor is used to compensate in the gain stage. , making ,have to （9） That is, when the gain of the signal conditioning circuit When the signal is distributed according to formula (8), the output voltage of the signal conditioning circuit collected by the controller is linearly related to the line voltage (9). This refers to the ratio of the output voltage of the signal conditioning circuit to the line voltage, and The following relationship exists: ； The method for calculating line voltage is as follows: With R1=0Ω and R2=10KΩ, a controllable negative feedback element is used. It is a digital potentiometer with a maximum resistance of 20KΩ, 1024 resolution, and an adjustable gain range of 0.0~2.

0. In the test environment, maintain The line voltage remains unchanged and is recorded as follows. Different humidity levels are Time signal conditioning circuit measures voltage value The measured voltage value of the signal conditioning circuit is obtained by mathematical fitting. With ambient humidity Relationship ,but That is, after obtaining the above data and relationships, by controlling... This increases the gain of the conditioning circuit. With humidity The following relationship can compensate for the effect of humidity on the measurement voltage; Calculate the line voltage using the obtained voltage: in, This is the ratio of the sensor output voltage to the line voltage under standard humidity conditions.

2. The humidity-compensated online voltage measurement method for AC high-voltage and ultra-high-voltage lines according to claim 1, characterized in that, The simplified humidity voltage calibration measurement circuit includes: a voltage sensor, a humidity sensor, a capacitor CP, a filter circuit, a conditioning circuit, and a controller; The output of the voltage sensor is connected to the input of the filter circuit, the output of the filter circuit is connected to the input of the conditioning circuit, and the output of the conditioning circuit is connected to the controller; the humidity sensor is connected to the input of the controller, and the output of the controller is connected to the feedback input of the conditioning circuit; capacitor CP is connected to the output of the voltage sensor. Among them, the voltage sensor and humidity sensor convert the voltage to be measured and the ambient humidity into corresponding electrical signals. The output signal of the humidity sensor is not limited to analog signals or digital signals. The filtering circuit is mainly used to filter the electrical signal output by the voltage sensor and input the processed voltage signal into the conditioning circuit. It is only unity gain, that is, it does not amplify or attenuate the signal. The conditioning circuit is mainly used to condition the voltage signal processed by the filter circuit into a signal suitable for the controller to collect. It also serves as a feedback node to compensate for voltage measurement deviations caused by humidity. The adjustment methods of the conditioning circuit gain include, but are not limited to, voltage feedback of the negative feedback loop or programmable digital devices. The controller also includes a controllable negative feedback element, which is mainly used to complete the digital-to-analog conversion of voltage signals to obtain humidity information.

3. The humidity-compensated online voltage measurement method for AC high-voltage and ultra-high-voltage lines according to claim 2, characterized in that, The structure of the filter circuit also includes passive and active filters implemented using parallel capacitors, inductors, resistors and amplifiers; The parallel capacitor is used to reduce the amplitude of the signal under test to a range that meets the requirements of the measurement signal.

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