Humidity-compensated alternating-current high-voltage and ultrahigh-voltage line voltage online measurement method

Abstract

According to the humidity-compensated alternating-current high-voltage and ultrahigh-voltage line voltage on-line measurement method, a voltage measurement calibration circuit is built, a controller in the calibration circuit is used for obtaining sample data under different humidity in different environments, and a relational expression that circuit gain changes along with humidity is obtained through a fitting algorithm and expected conditioning circuit gain; parameters of an element Rf in a negative feedback loop are dynamically controlled through a controller, so that output voltage of the signal conditioning circuit and line voltage are in a linear relation, humidity information is measured in real time, deviation generated by voltage measurement is compensated, and online reliable and accurate measurement of high-voltage and ultrahigh-voltage alternating-current lines is achieved. For an application scene with low voltage measurement precision, a relationship between the output voltage of the sensor and the change of the humidity can be obtained through voltage sensor parameters epsilon 1 and d1, a sensor mounting position d2 and an environment humidity change range parameter epsilon 2, so that a relationship between the gain and the change of the humidity can be deduced reversely.

Description

Technical Field

[0001] The invention relates to the technical field of electric energy metering, and in particular to an online measurement method for voltage of an alternating current high voltage and ultra-high voltage line with humidity compensation. Background Art

[0002] With the development of digitalization, intelligence and networking of power grids, intelligent monitoring equipment for power grids has been widely promoted and applied. Online measurement of voltage of high-voltage and ultra-high-voltage lines of power grids has become an important supporting technology for digitalization and intelligence of power grids. Online measurement is a key link in the operation and maintenance of power systems, and is crucial to ensuring the safe, stable and efficient operation of power grids. Nowadays, more advanced means such as non-contact optical sensors, electromagnetic field induction technology and data acquisition systems based on wireless communication are mainly used. These technologies provide higher safety and accuracy. However, under adverse environmental conditions such as temperature, humidity, electromagnetic interference, and air pollution, the accuracy of the measuring equipment will be affected. The present invention proposes a humidity-compensated online measurement method for AC high-voltage and ultra-high-voltage line voltage. Compared with traditional methods, it can effectively overcome the measurement drift caused by humidity in the equipment operating environment on the measured voltage, thereby improving the voltage measurement accuracy. Summary of the invention

[0003] The humidity-compensated online measurement method for AC high-voltage and ultra-high-voltage line voltage proposed in the present invention can at least solve one of the technical problems in the background technology.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

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

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

[0007] Furthermore, the simplest humidity voltage calibration measurement circuit of the present invention comprises: a voltage sensor, a humidity sensor, a capacitor CP, a filter circuit, a conditioning circuit and a controller;

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

[0009] Among them, the voltage sensor and the humidity sensor convert the voltage to be measured and the ambient humidity into corresponding electrical signals, and the output signal of the humidity sensor is not limited to analog signals or digital signals;

[0010] The filter 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 a unit gain, that is, no amplification or attenuation is performed on the signal;

[0011] The conditioning circuit is mainly used to condition the voltage signal processed by the filter circuit into a signal suitable for acquisition by the controller, and at the same time serves as a feedback node for compensating for the voltage measurement deviation caused by humidity, wherein the adjustment method of the conditioning circuit gain includes but is not limited to the voltage feedback of the negative feedback loop or the programmable digital device;

[0012] The controller also includes a controllable negative feedback element which is mainly used to complete the digital-to-analog conversion of the voltage signal to obtain humidity information.

[0013] Furthermore, the filter circuit structure of the present invention also includes passive and active filters implemented using capacitors, inductors, resistors and amplifiers;

[0014] The parallel capacitor is used to reduce the amplitude of the signal to be measured to a range that meets the measurement signal requirements.

[0015] Furthermore, the method of using humidity information as basic information for compensating the measured voltage value and compensating for the deviation of the measurement circuit caused by humidity by adjusting the gain of the conditioning circuit, thereby calibrating the voltage signal of the voltage sensor is as follows:

[0016] The dielectric constant between the upper metal plate and the lower metal plate is set to ε1, and the vertical distance between the two is d1; the relative dielectric constant between the lower metal plate and the earth at a certain humidity is ε2, and the distance between the lower metal plate and the earth 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 the reference humidity is C G , the effective area between the upper and lower plates of the capacitor is S, then the line voltage V L and the voltage sensor output voltage V S The following relationship exists:

[0017]

[0018] When the sensor parameters remain unchanged, it can be known from (1), (2) and (3) that

[0019]

[0020] From formula (4), we can see 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 all constants, and k is the electrostatic force constant, which is 8.987551×10 9 Nm 2 / C 2 , let the ratio of the sensor output voltage to the line voltage be γ:

[0021]

[0022] have to

[0023]

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

[0025] V A =β·V S (7)

[0026] If you Among them, 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 , and the controller AD conversion reference is V REF , and V SMAX <V REF In order to obtain a better dynamic range, a constant amplification factor δ is compensated in the gain link, so that δ·V SMAX =V REF ,have to

[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 of formula (8), the output voltage of the signal conditioning circuit collected by the controller is linearly related to the line voltage (9), 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:

[0029]

[0030] Furthermore, the calculation method of the line voltage of the present invention is:

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

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

[0033]

[0034] That is, after obtaining the above data and relationship, by controlling R f The relationship between the gain β of the conditioning circuit and the humidity h satisfies the following equation to compensate for the effect of humidity on the measured voltage:

[0035]

[0036] The voltage is calculated by:

[0037]

[0038] Where γ0 is the ratio of the sensor output voltage to the line voltage under standard humidity environment.

[0039] It can be seen from the above technical solution that the humidity-compensated AC high-voltage and ultra-high-voltage line voltage online measurement method of the present invention obtains sample data under different humidity in different environments through a controller, obtains the relationship between the circuit gain and the humidity through a fitting algorithm and the expected conditioning circuit gain; and dynamically controls the element R in the negative feedback loop through the controller. f The parameters make the output voltage of the signal conditioning circuit linearly related to the line voltage, obtain real-time measurement of humidity information, and compensate for the deviation caused by voltage measurement, so as to provide reliable and accurate online measurement of high-voltage and ultra-high-voltage AC lines. For application scenarios with low voltage measurement accuracy, the relationship between the sensor output voltage and humidity can be obtained through the voltage sensor parameters ε1 and d1, the sensor installation position d2 and the ambient humidity range parameter ε2, from which the relationship between the gain and humidity can be inferred. Then, according to the ambient humidity, the controller adjusts the gain of the conditioner to achieve more accurate voltage measurement. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0041] Figure 2 It is a technical principle diagram of the voltage sensor;

[0042] Figure 3 The voltage sensor output voltage V S Calculation principle diagram;

[0043] Figure 4 This is the schematic diagram of the 110KV humidity voltage calibration measurement circuit;

[0044] Figure 5 This is a schematic diagram of 110KV humidity voltage calibration simulation data;

[0045] Figure 6 This is the schematic diagram of the 220KV humidity voltage calibration measurement circuit;

[0046] Figure 7 This is a schematic diagram of 220KV humidity voltage calibration simulation data. DETAILED DESCRIPTION

[0047] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments.

[0048] like Figure 1 As shown, this embodiment implements the humidity-compensated AC high-voltage and ultra-high-voltage line voltage online measurement method by building a simplest humidity voltage calibration measurement circuit, including the following steps:

[0049] S100, building a simplest humidity voltage calibration measurement circuit, and converting the voltage of the circuit to be tested and the ambient humidity into corresponding electrical signals by calibrating the humidity sensor and the voltage sensor of the measurement circuit;

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

[0051] S300, pre-processing the filtered electrical signal through a conditioning circuit and inputting it into a controller;

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

[0053] The following is a detailed description of each step:

[0054] S100, building a simplest humidity voltage calibration measurement circuit, and converting the voltage of the circuit to be tested and the ambient humidity into corresponding electrical signals by calibrating the humidity sensor and the voltage sensor of the measurement circuit;

[0055] The simplest humidity voltage calibration measurement circuit includes 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 to the input end of the filter circuit, the output end of the filter circuit is connected to the input end of the conditioning circuit, and the output end of the conditioning circuit is connected to the controller; the humidity sensor is connected to the input end of the controller, and the output end of the controller is connected to the feedback input end of the conditioning circuit; the capacitor CP is connected to the output end of the voltage sensor.

[0057] Among them, the voltage sensor and the humidity sensor convert the voltage to be measured and the ambient humidity into corresponding electrical signals, and the output signal of the humidity sensor is not limited to analog signals or digital signals;

[0058] The filter 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 a unit gain, that is, no amplification or attenuation is performed on the signal. Its structure can also adopt passive and active filters realized by capacitors, inductors, resistors and amplifiers;

[0059] The conditioning circuit is mainly used to condition the voltage signal processed by the filter circuit into a signal suitable for acquisition by the controller, and at the same time serves as a feedback node for compensating for the voltage measurement deviation caused by humidity, wherein the adjustment method of the conditioning circuit gain includes but is not limited to the voltage feedback of the negative feedback loop or the programmable digital device;

[0060] The controller also includes a controllable negative feedback element which is mainly used to complete the digital-to-analog conversion of the voltage signal to obtain humidity information.

[0061] S200, filtering the electrical signals output by the humidity sensor and the voltage sensor through a filtering circuit, and inputting the filtered electrical signals into a conditioning circuit;

[0062] S300, pre-processing the filtered electrical signal through a conditioning circuit and inputting it into a controller;

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

[0064]

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

[0066] like Figure 2 As shown, it is a diagram of the technical principle of the voltage sensor, which consists of an upper metal plate and a lower metal plate with the same potential as the AC high voltage or ultra-high voltage line, wherein metal plate ② is the upper metal plate and metal plate ③ is the lower metal plate, both of which have an area of ​​S, and both 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] like Figure 3 As shown, the dielectric constant between the upper metal plate and the lower metal plate is set to ε1, and the vertical distance between the two is d1; the relative dielectric constant between the lower metal plate and the earth at a certain humidity is ε2, and the distance between the lower metal plate and the earth 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 the reference humidity is C G , then the line voltage V L and the voltage sensor output voltage V S The following relationship exists:

[0068]

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

[0070]

[0071] From formula (4), we can see 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 all constants, and k is the electrostatic force constant, which is 8.987551×10 9 Nm 2 / C 2 , let the ratio of the sensor output voltage to the line voltage be γ:

[0072]

[0073] have to

[0074]

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

[0076] V A =β·VS (7)

[0077] If you Among them, 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 , and the controller AD conversion reference is V REF , and V SMAX <V REF In order to obtain a better dynamic range, a constant amplification factor δ is compensated in the gain link, so 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 obeys the distribution of formula (8), the output voltage of the signal conditioning circuit collected 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, and 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 expected conditioning circuit gain, and then dynamically adjust the feedback element R f The parameters make the output voltage of the signal conditioning circuit linearly related to the line voltage;

[0082] Among them, R f It is a controllable negative feedback element in the signal conditioning circuit, not limited to a specific implementation scheme, such as a digital potentiometer, a transistor, a field effect transistor device, etc., and is used to compensate for the deviation of the measured voltage when the humidity deviates from the reference. Figure 1 The signal conditioning circuit in the embodiment is a common-phase proportional amplifier circuit, which is only used to illustrate the implementation principle of the present invention and is not limited to the specific circuit implementation. The filter circuit is used to filter out other signals outside the bandwidth of the signal to be measured and improve the signal-to-noise ratio of the signal to be measured.

[0083] Specifically described by the following examples:

[0084] Embodiment 1

[0085] like Figure 4 As shown, it is a 110KV voltage calibration circuit;

[0086] Assume that the line voltage of 110kV is measured, and its peak-to-peak voltage to ground is 179.6kV. Its vertical distance from the bottom surface is 10 meters. If the requirement is that the peak-to-peak output voltage of the sensor is 1.796V, the distance between the two plates of the sensor is 10mm, and the plate area is 0.04m 2 , whose dielectric constant is 2.1, from which the equivalent capacitance of the sensor, the equivalent capacitance between the plate and the ground, and C P Value, according to the formula:

[0087]

[0088] At this time, the equivalent capacitance value of the voltage sensor is 885.41pF. According to the literature "Study on the Influence of Environmental Humidity on the Dielectric Constant of Air", when the environmental humidity is less than 75%, the dielectric constant changes relatively greatly with humidity. When the environmental humidity rises from 68% to 75%, the dielectric constant growth rate is 20.7%; when the environmental humidity changes from 75% to 90%, the dielectric constant changes relatively slowly, with a growth rate of 1.17%. Assuming that the environmental humidity change range causes the relative dielectric constant of air to change in the range of 1.0 to 1.8, the sensor output voltage change range is (1.798V, 3.236V) obtained by equations (1) to (4), and the acquisition circuit reference voltage is 3.3V. If the output voltage remains unchanged at different humidity levels through compensation measures, the corresponding gain change range is required to be (0.556, 1.000). Among them, under standard atmospheric pressure, the sensor output voltage value is 1.798V when the air is dry and does not contain carbon dioxide. Therefore, when the line voltage remains unchanged, the gain compensation of the conditioning circuit is used to obtain the same acquisition voltage value under standard conditions.

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

[0090] In the test environment, keep R f =10KΩ unchanged, record the line voltage as x, different humidity as h i When the signal conditioning circuit measures the voltage value y, the relationship between the voltage value y measured by the signal conditioning circuit and the ambient humidity h can be obtained by mathematical fitting method: y = f(h), then

[0091]

[0092] That is, after obtaining the above data and relationship, by controlling R f The influence of humidity on the measured voltage can be compensated by making the relationship between the gain β of the conditioning circuit and the humidity h satisfy the following equation.

[0093]

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

[0095]

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

[0097] Embodiment 2

[0098] like Figure 6 As shown, the 220KV voltage calibration circuit is false;

[0099] Suppose the measured line voltage is 220kV, the peak-to-peak voltage to ground is 359kV, and the vertical distance from the bottom is 20 meters. If the requirement is that the output voltage peak-to-peak of the sensor is 2.0V, the distance between the two plates of the sensor is 1.6mm, and the plate area is 0.01m 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 P value.

[0100]

[0101] At this time, the equivalent capacitance value 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 greatly with humidity. When the ambient humidity rises 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 a growth rate of 1.17%. Assuming that the ambient humidity change range causes the relative dielectric constant of air to change in the range of 1.0 to 1.8, the sensor output voltage change range is (2.0V, 3.6V) obtained by equations (1) to (4). If the output voltage remains unchanged at different humidity levels through compensation measures, the corresponding gain change range is required to be (0.555, 1.000). Under standard atmospheric pressure, the sensor output voltage value is 1.798V when the air is dry and does not contain carbon dioxide. Therefore, when the line voltage remains unchanged, the gain compensation of the conditioning circuit is used to obtain the same acquisition voltage value under standard conditions.

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

[0103] In the test environment, keep R f =10KΩ unchanged, record the line voltage as x, different humidity as h i When the signal conditioning circuit measures the voltage value y, the relationship between the voltage value y measured by the signal conditioning circuit and the ambient humidity h can be obtained by mathematical fitting method: y = f(h), then

[0104]

[0105] That is, after obtaining the above data and relationship, by controlling R f The influence of humidity on the measured voltage can be compensated by making the relationship between the gain β of the conditioning circuit and the humidity satisfy the following equation.

[0106]

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

[0108]

[0109] The specific experimental results are as follows Figure 7 shown.

[0110] In summary, the humidity-compensated AC high-voltage and ultra-high-voltage line voltage online measurement method of the present invention builds a voltage measurement calibration circuit, uses a controller to obtain sample data under different humidity in different environments, and obtains the relationship between the circuit gain and the humidity through a fitting algorithm and the expected conditioning circuit gain; dynamically controls the element R in the negative feedback loop through the controller f The parameters make the output voltage of the signal conditioning circuit linearly related to the line voltage, obtain real-time measurement of humidity information, and compensate for the deviation caused by voltage measurement, so as to provide reliable and accurate online measurement of high-voltage and ultra-high-voltage AC lines. For application scenarios with low voltage measurement accuracy, the relationship between the sensor output voltage and humidity can be obtained through the voltage sensor parameters ε1 and d1, the sensor installation position d2 and the ambient humidity range parameter ε2, from which the relationship between the gain and humidity can be inferred. Then, according to the ambient humidity, the controller adjusts the gain of the conditioner to achieve more accurate voltage measurement.

[0111] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0112] Each embodiment in this specification is described in a related manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0113] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A humidity-compensated AC high-voltage and ultra-high-voltage line voltage online measurement method, characterized in that: Methods include: Build a simplest humidity voltage calibration measurement circuit. Through the humidity sensor and voltage sensor of the simplest humidity voltage calibration measurement circuit, convert the AC high-voltage and ultra-high-voltage line voltage and ambient humidity to be measured into corresponding electrical signals. By preprocessing the electrical signal, the humidity information of the high-voltage line is obtained. The humidity information is used as the basic information for compensating the measured voltage value. By adjusting the gain of the conditioning circuit, the deviation caused by humidity on the measurement circuit is compensated, and then the voltage signal of the voltage sensor is calibrated.

2. The humidity-compensated AC high-voltage and ultra-high-voltage line voltage online measurement method according to claim 1 is characterized in that: 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; The output end of the voltage sensor is connected to the input end of the filter circuit, the output end of the filter circuit is connected to the input end of the conditioning circuit, and the output end of the conditioning circuit is connected to the controller; the humidity sensor is connected to the input end of the controller, and the output end of the controller is connected to the feedback input end of the conditioning circuit; the capacitor CP is connected to the output end of the voltage sensor; Among them, the voltage sensor and the humidity sensor convert the voltage to be measured and the ambient humidity into corresponding electrical signals, and the output signal of the humidity sensor is not limited to analog signals or digital signals; The filter 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 a unit gain, that is, no amplification or attenuation is performed on the signal; The conditioning circuit is mainly used to condition the voltage signal processed by the filter circuit into a signal suitable for acquisition by the controller, and at the same time serves as a feedback node for compensating for the voltage measurement deviation caused by humidity, wherein the adjustment method of the conditioning circuit gain includes but is not limited to the voltage feedback of the negative feedback loop or the programmable digital device; The controller also includes a controllable negative feedback element which is mainly used to complete the digital-to-analog conversion of the voltage signal to obtain humidity information.

3. The humidity-compensated AC high-voltage and ultra-high-voltage line voltage online measurement method according to claim 2 is characterized in that: Structural filter circuit structures also include passive and active filters implemented using parallel capacitors, inductors, resistors and amplifiers; The parallel capacitor is used to reduce the amplitude of the signal to be measured to a range that meets the measurement signal requirements.

4. The humidity-compensated AC high-voltage and ultra-high-voltage line voltage online measurement method according to claim 1 is characterized in that: The humidity information is used as the basic information for compensating the measured voltage value, and the deviation caused by humidity on the measurement circuit is compensated by adjusting the gain of the conditioning circuit, and then the voltage signal of the voltage sensor is calibrated as follows: The dielectric constant between the upper metal plate and the lower metal plate is set to ε1, and the vertical distance between the two is d1; the relative dielectric constant between the lower metal plate and the earth at a certain humidity is ε2, and the distance between the lower metal plate and the earth 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 the reference humidity is C G , the effective area between the upper and lower plates of the capacitor is S, then the line voltage V L and the voltage sensor output voltage V S The following relationship exists: When the sensor parameters remain unchanged, it can be known from (1), (2) and (3) that From formula (4), we can see 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 all constants, and k is the electrostatic force constant, which is 8.987551×10 9 Nm 2 / C 2 , let the ratio of the sensor output voltage to the line voltage γ be: have to However, since the medium between the sensor and the ground is air, its dielectric constant ε2 is greatly affected by the ambient humidity. If the gain of the signal conditioning circuit is β, the output signal of the signal conditioning circuit is: V A =β·V S (7) If you Among them, 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 , and the controller AD conversion reference is V REF , and V SMAX <V REF In order to obtain a better dynamic range, a constant amplification factor δ is compensated in the gain link, so that δ·V SMAX =V REF ,have to V A =βγ·V S =δ·V L (9) That is, when the gain β of the signal conditioning circuit obeys the distribution of formula (8), the output voltage of the signal conditioning circuit collected by the controller is linearly related to the line voltage (9), 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:

5. The humidity-compensated AC high-voltage and ultra-high-voltage line voltage online measurement method according to claim 4 is characterized in that: The line voltage is calculated as: Set R1 = 0Ω, R2 = 10KΩ, and the controllable negative feedback element R f It is a digital potentiometer with a maximum resistance of 20KΩ, a resolution of 1024, and a gain adjustment range of 0.0 to 2.0; In the test environment, keep R f =10K Ω unchanged, record the line voltage as x, and the different humidity as h i When the signal conditioning circuit measures the voltage value y, the relationship between the voltage value y measured by the signal conditioning circuit and the ambient humidity h is obtained by mathematical fitting method: y = f(h), then That is, after obtaining the above data and relationship, by controlling R f The relationship between the gain β of the conditioning circuit and the humidity h satisfies the following equation to compensate for the effect of humidity on the measured voltage: The voltage is calculated by: Where γ0 is the ratio of the sensor output voltage to the line voltage under standard humidity environment.

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