Calibration system and calibration method of electro-optical crystal electric field measuring device

Abstract

The invention provides a calibration system and a calibration method for an electro-optical crystal electric field measuring device, and belongs to the technical field of power grid environment protection, and the calibration system comprises a temperature and humidity box which is used for controlling the temperature and humidity of a calibration area; the electrostatic field generation unit is used for generating an electrostatic field E0; the ion current generation unit is used for generating ion current; the ion mobility measuring device is used for measuring the ion density in the calibration area; the electro-optical crystal measuring device is used for acquiring the electric field of the photoelectric crystal in the electrostatic field; the voltage measuring unit is used for respectively measuring voltages on the ion current electrode and the high-voltage electrode; and the ion flow measuring unit is used for measuring the size of the ion flow and collecting the measured ion flow. The device has the advantages that the ion flow generation unit and the temperature and humidity cooperative control module are introduced, the ion migration effect and the temperature fluctuation scene under the actual working condition are reproduced in the calibration process, the calibration environment is made to fit the ionization, temperature and humidity conditions of a power transmission and transformation project site, and the applicability of the measuring device in the real environment is remarkably improved.

Description

Technical Field

[0001] The invention belongs to the technical field of power grid environmental protection, and in particular relates to a calibration system and a calibration method for an electro-optical crystal electric field measuring device. Background Art

[0002] With the rapid development of my country's social economy, the demand for electricity has increased rapidly. In order to meet the growing national economic and social electricity demand, the scale of the power grid has become larger and larger, and the transmission lines and substations are getting closer and closer to the public activity areas. The electromagnetic environment problems, disputes and complaints caused by the transmission and transformation projects have also increased. Among them, the impact of the DC electric field of the DC transmission and transformation project on the surrounding environment is an important topic in the field of environmental protection. At the same time, the DC electric field has an important impact on the insulation safety of the equipment in the substation. In view of the complexity of DC electric field measurement, accurately measuring the DC electric field around the transmission lines and converter stations is the main technical means to resolve environmental disputes and ensure equipment safety.

[0003] In the prior art, the calibration of electro-optical crystal DC electric field measurement devices is usually based on the electrostatic field environment, without considering the interference of spatial charge distribution and temperature changes on the measurement in actual applications, resulting in deviations between the calibration results and the actual working conditions, making it difficult to ensure the accuracy of the measurement. Therefore, there is an urgent need for a calibration system and method that can comprehensively simulate complex environmental conditions (such as ion migration and temperature fluctuations) to improve the applicability and reliability of electro-optical crystal measurement devices. Summary of the invention

[0004] The technical problem to be solved by the present invention is that the calibration of an electro-optical crystal DC electric field measuring device is usually based on an electrostatic field environment, and the interference of spatial charge distribution and temperature changes on the measurement in actual applications is not considered, resulting in a deviation between the calibration result and the actual working condition. In view of the shortcomings of the prior art, a calibration system and a calibration method for an electro-optical crystal electric field measuring device are provided to solve the defect that the prior art cannot truly reflect the actual working condition, thereby improving the calibration accuracy of the measuring device and the reliability of practical application. In order to solve the above technical problems, the technical solution adopted by the present invention is as follows: comprising: a temperature and humidity chamber: used to control the temperature and humidity of the calibration area and adjust it to a preset temperature point T i; Electrostatic field generating unit: including a high-voltage electrode and a grounding electrode plate, which are arranged inside the temperature and humidity chamber with a spacing of d, and are used to apply voltage to generate an electrostatic field E; ion flow generating unit: including an ion flow electrode, which is arranged inside the temperature and humidity chamber and is used to generate charged ions with the same polarity as the electrostatic field when the system is running, and is driven into an ion flow by the electrostatic field; ion mobility measuring device: used to measure the ion density in the calibration area; electro-optical crystal measuring device: used to obtain the electric field of the photoelectric crystal in the electrostatic field; fixed platform: used to switch and install the calibrated electro-optical crystal measuring device and the ion mobility measuring device, which is arranged in the electrostatic field and is at a distance of z from the high-voltage electrode; voltage measuring unit: including a first high-voltage voltage divider and a second high-voltage voltage divider, which are used to measure the voltage on the ion flow electrode and the high-voltage electrode respectively; ion flow measuring unit: including a picoammeter and a Wilson plate, the picoammeter is used to measure the size of the ion flow; the Wilson plate is used to collect and measure the ion flow; a DC electric field measuring device fixing device, installed on the temperature and humidity chamber, is used to fix the DC electric field measuring device.

[0005] Furthermore, the height of the fixed platform is set to be d / 2 from the high voltage electrode and the grounding electrode.

[0006] Furthermore, it also includes a DC power supply: the DC power supply includes a first DC power supply and a second DC power supply, and the discharge ends of the first DC power supply and the second DC power supply are both arranged inside the temperature and humidity chamber, for applying voltage to the ion flow electrode and the high voltage electrode respectively.

[0007] Furthermore, it also includes an insulating layer for isolating the temperature and humidity chamber from the high-voltage electrode, and for preventing the high-voltage electrode from discharging to the temperature and humidity chamber.

[0008] A calibration method for an electro-optical crystal electric field measuring device is implemented based on a calibration system for the electro-optical crystal electric field measuring device, and includes the following steps:

[0009] Adjust the temperature and humidity Ti and the voltage of the ion current electrode and the high-voltage electrode plate;

[0010] The ion density K is obtained by the ion mobility measuring device, and the ion current density J is measured by the picoammeter and the Wilson plate;

[0011] Replacing the ion mobility measurement device with a calibrated electro-optical crystal measurement device;

[0012] Measure the electric field reading E of the photoelectric crystal corresponding to the ion current density J at the corresponding temperature;

[0013] Obtain the electric field strength E0 of the high voltage plate and the spatial electric field E1 at different temperatures Ti in the calibration area ion density K;

[0014] Obtain the calibration coefficient m corresponding to the adjusted temperature value, and obtain the calibration coefficient m of the electro-optical crystal measurement device at any temperature through linear interpolation i .

[0015] Further, the method for adjusting the temperature and humidity Ti includes:

[0016] Set the temperature in the temperature and humidity chamber to a certain temperature T i , where i = 1, 2, 3, 4, 5; the value range of Ti is -20℃~40℃;

[0017] Methods for adjusting the voltage of the ion current electrode and the high voltage plate include:

[0018] Voltages U1 and U are applied to the ion current electrode and the high voltage electrode respectively to generate an initial electrostatic field and charged ions of the same polarity.

[0019] Furthermore, the method for obtaining the electric field strength E0 of the high voltage plate and the spatial electric field E1 at different temperatures Ti in the calibration area ion density K includes:

[0020]

[0021] Among them, U is the voltage on the high-voltage plate, J is the current density between the high-voltage plate and the ground plate; K is the ion mobility; ε 0 is the vacuum dielectric constant; z is the distance between the point where the DC electric field measurement device is located and the high-voltage plate, which is taken as d / 2; d is the gap distance between the high-voltage plate and the grounding plate.

[0022] Furthermore, the method for obtaining the calibration coefficient m corresponding to the adjusted temperature value includes:

[0023]

[0024] Where E is the display value of the DC electric field measuring device.

[0025] Further, the method of obtaining the calibration coefficient m corresponding to the adjusted temperature value and obtaining the calibration coefficient of the electro-optical crystal measuring device at any temperature by linear interpolation includes:

[0026] A set number of voltage point values ​​are selected at equal intervals according to the measuring range of the DC electric field measuring device, and the voltage U of the high-voltage plate is adjusted to the selected voltage point value to calibrate the DC electric field;

[0027] Change the temperature Ti in the temperature and humidity chamber to obtain the electric field calibration coefficient m at the corresponding temperature i ;

[0028] According to the calibration coefficients of the electro-optical crystal at different temperatures Ti, linear interpolation is used to obtain the calibration coefficients of the electro-optical crystal measuring device at any temperature.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] 1. By introducing the ion flow generation unit and the temperature and humidity coordinated control module, the ion migration effect and temperature fluctuation scenario under actual working conditions are reproduced for the first time in the calibration process, so that the calibration environment is highly consistent with the ionization, temperature and humidity conditions of the power transmission and transformation project site, and the applicability of the measuring device in the real environment is significantly improved. The present invention fundamentally overcomes the theoretical defects of traditional calibration technology, and provides a calibration scheme for DC electric field measurement that combines environmental simulation and measurement reliability, which has important practical value for promoting environmental protection compliance of power transmission and transformation projects and intelligent equipment safety management;

[0031] 2. By dynamically correlating the coupling relationship between ion mobility, temperature parameters and electric field strength, a multi-physical field coupling calibration model was established, which can compensate the temperature and ion density of the electro-optical crystal measurement values, reducing the comprehensive error of DC electric field measurement to less than 1%, solving the technical bottleneck of the disconnection between the traditional electrostatic field calibration results and the actual measured values ​​in complex environments;

[0032] 3. Through high-precision calibration methods, reliable data support is provided for the compliance assessment of DC electric field strength around power transmission and transformation projects, effectively reducing public complaints caused by electric field measurement disputes; at the same time, accurate electric field monitoring capabilities can provide early warning of insulation risks of substation equipment, avoid equipment breakdown accidents caused by electric field distortion, and ensure the safe operation of the power grid;

[0033] 4. It supports calibration over a wide temperature range (-20°C to 40°C) and dynamic correction of ion flow, which can adapt to the needs of power transmission and transformation projects in different geographical and climatic regions. It solves the limitation of existing technologies that only calibrate for laboratory steady-state environments, and significantly expands the deployment range and long-term stability of electro-optical crystal measurement devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The present invention is further described in detail below in conjunction with the accompanying drawings.

[0035] Figure 1 : A schematic diagram of the structure inside the temperature and humidity chamber in Example 1 of the present invention;

[0036] Figure 2 : Schematic diagram of the method flow in Example 2 of the present invention;

[0037] Among them, 1-temperature and humidity chamber, 2-insulating layer, 3-fixed platform, 4-first DC power supply, 5-second DC power supply, 6-first high-voltage voltage divider, 7-second high-voltage voltage divider, 8-picoammeter, 9-Wilson plate, 10-DC electric field measuring device fixing device, 11-ion flow electrode, 12-high-voltage electrode, 13-grounding plate, 14-support frame. DETAILED DESCRIPTION

[0038] In order to better understand the present invention, the content of the present invention is further clearly described below in conjunction with the embodiments and the accompanying drawings, but the protection content of the present invention is not limited to the following embodiments. In the following description, a large number of specific details are provided to provide a more thorough understanding of the present invention. However, it is obvious to those skilled in the art that the present invention can be implemented without one or more of these details.

[0039] Example 1: See Figure 1 The present embodiment provides a calibration system for an electro-optical crystal electric field measurement device, which comprises

[0040] 1. The temperature and humidity chamber 1 is made of double-layer insulation material, with a built-in temperature and humidity sensor and an automatic adjustment module. The temperature adjustment range is -20°C to 40°C, with an accuracy of ±0.5°C; the temperature in the chamber is stabilized at a preset temperature point Ti (such as Ti = -10°C, 0°C, 20°C, 30°C, 40°C).

[0041] 2. Electrostatic field generating unit: The high-voltage electrode 12 is a copper plate with a size of 300mm×300mm, fixed to the top of the temperature and humidity chamber by an insulating ceramic support; the grounding plate 13 is an aluminum plate of the same size, installed parallel to the bottom of the chamber, with a distance d=100mm between the two. The second DC power supply 5 applies an adjustable voltage U=0~50kV to the high-voltage electrode to generate an electrostatic field E 0 =U / d.

[0042] 3. Ion flow generating unit: the ion flow electrode 11 is a needle-shaped electrode, installed 20 mm below the high voltage electrode 12, and a voltage U of the same polarity is applied by the first DC power supply 4. 1 = 5~20kV, ionizing the air to produce charged ions with the same polarity as the electrostatic field. The ion flow is driven by the electrostatic field to form a stable flow, and the flow rate is monitored by a picoammeter 8.

[0043] 4. The fixed platform 3 adopts a liftable mechanical structure. The vertical distance between the platform surface and the high voltage electrode 12 and the grounding electrode 13 is d / 2=50mm. The platform is equipped with a quick disassembly interface for alternately fixing the ion mobility measurement device and the electro-optical crystal measurement device.

[0044] 5. Measurement unit, voltage measurement: the first high voltage divider 6 is connected to the ion current electrode 11, the voltage divider ratio is 1000:1; the second high voltage divider 7 is connected to the high voltage electrode 12, the measurement error is ≤0.5%. Ion current measurement: the area of ​​the Wilson plate 9 is 100cm 2 The collected ion current is recorded by a picoammeter 8 with a current resolution of 0.1 pA.

[0045] 6. The insulating layer 2 covers the inner wall of the temperature and humidity chamber 1 and is made of polytetrafluoroethylene material with a thickness of 5 mm and a withstand voltage level of ≥50 kV to prevent the high-voltage electrode from discharging to the chamber. The withstand voltage design of the insulating layer and the temperature and humidity chamber can withstand high voltage above 50 kV, avoiding the risk of discharge during the calibration process and ensuring safe operation.

[0046] 7. A DC electric field measuring device fixing device 10 is installed on the temperature and humidity chamber 1 and is used to fix the DC electric field measuring device and also plays the role of fixing the optical fiber transmission line;

[0047] 8. A support frame 14 is arranged inside the temperature and humidity chamber 1 and is used to fix and support the ion current electrode 11, the high voltage electrode 12 and the grounding electrode plate 13.

[0048] Beneficial effects:

[0049] 1. Through the coordinated design of the temperature and humidity chamber, electrostatic field generation unit and ion flow generation unit, the system reproduces the complex conditions of the actual power transmission and transformation project site (such as temperature fluctuations and ion migration effects) in the calibration environment, solving the defects of the traditional electrostatic field calibration environment being single and out of touch with the actual working conditions; the system integrates high-voltage electrodes, ion flow electrodes and a fixed platform to simultaneously simulate the dynamic interaction scenes of high-voltage electrostatic fields and spatial ion flows, providing a multi-dimensional calibration benchmark for electro-optical crystal measurement devices.

[0050] 2. Through the linkage configuration of voltage measurement unit, ion flow measurement unit (picoammeter, Wilson plate) and ion mobility measurement device, the synchronous high-precision acquisition of electrostatic field intensity, ion flow density and ion mobility is achieved, supporting multi-physical field coupling analysis.

[0051] 3. The fixed platform adopts a quick disassembly and assembly structure, which supports seamless switching between the electro-optical crystal measurement device and the ion mobility measurement device, and can improve the calibration efficiency.

[0052] Embodiment 2: A calibration method for an electro-optical crystal electric field measuring device is implemented based on the calibration system of the electro-optical crystal electric field measuring device of Embodiment 1, see Figure 2 , which includes:

[0053] a) Adjust the temperature in the temperature and humidity chamber to keep it fixed at a certain temperature T i , where i = 1, 2, 3, 4, 5; the value range of T is -20℃~40℃;

[0054] b) Apply voltage U to the ion current electrode 11 and the high voltage electrode 12 respectively 1 and U, which generate the initial electric field and charged ions of the same polarity;

[0055] c) using an ion mobility measuring device to measure the ion density K in the calibration area;

[0056] d) 8 and 9 are used simultaneously to measure the ion current density J in the space;

[0057] e) then replacing the ion mobility measuring device with a calibrated photoelectric crystal electric field measuring device, and then repeating steps a) and b) to read the electric field reading E of the photoelectric crystal;

[0058] f) Based on the measurement results of the previous step, the electric field strength E at the high voltage plate is calculated using formula (1): 0

[0059]

[0060] Where U is the voltage on the high voltage plate, J is the current density between the high voltage plate and the ground plate; K is the ion mobility; ε 0 is the dielectric constant of vacuum; z is the distance between the point where the DC electric field measuring device is located and the high voltage plate, generally taken as d / 2, and d is the gap distance between the plates.

[0061] g) Based on the electric field strength E calculated in the previous step 0 , and further calculate the electric field E in the space electric field according to formula (2): 1 ;

[0062]

[0063] h) Then, the DC electric field measurement device at temperature T is calculated by formula (3). 1 Calibration coefficient m 1 , where E is the display value of the DC electric field measuring device;

[0064]

[0065] i) changing the voltage U of the high voltage plate, the value of U needs to be determined according to the measuring range of the DC electric field measuring device of the electro-optical crystal, generally at least 5 points are evenly taken, and then b) to h) are repeated to realize accurate calibration within the measuring range of the DC electric field;

[0066] j) Changing the temperature Ti in the temperature and humidity chamber, repeating steps b) to i), thereby obtaining the electric field calibration coefficient m of the electro-optical crystal at different temperatures i ;

[0067] k) The calibration coefficient of the electro-optical crystal at the temperature Ti is obtained, and then the calibration coefficient of the electro-optical crystal measuring device at any temperature can be obtained by linear interpolation.

[0068] Beneficial Effects

[0069] 1. Through the phased calibration process (first measuring the ion mobility, then calibrating the electro-optical device), the interference of temperature and ion flow on the electric field measurement can be dynamically eliminated, reducing the calibration error.

[0070] 2. A temperature-coefficient mapping table is constructed based on the calibration coefficient mi of the temperature point Ti, and a linear interpolation algorithm is used to achieve fast compensation of any temperature, solving the measurement deviation problem caused by temperature drift of the electro-optical crystal.

[0071] 3. The method supports the coverage of equally spaced calibration points of electric field strength by adjusting the high-voltage electrode voltage U. Combined with the calibration data of multiple temperature points, the calibration curve under the whole working condition can be generated. Through high-precision calibration data, it provides an authoritative basis for the compliance of the electric field around the power transmission and transformation project. Combined with the calibrated electric field measurement device, it can provide real-time warning of insulation abnormalities of substation equipment (such as electric field distortion), avoid equipment breakdown accidents caused by excessive electric field, and improve safety management and control capabilities.

[0072] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Other modifications or equivalent substitutions made to the technical solution of the present invention by ordinary technicians in the field should be included in the scope of the claims of the present invention as long as they do not depart from the spirit and scope of the technical solution of the present invention.

Claims

1. A calibration system for an electro-optical crystal electric field measurement device, characterized in that: include: Temperature and humidity chamber (1): used to control the temperature and humidity of the calibration area and adjust it to the preset temperature point T i ; The electrostatic field generating unit comprises a high voltage electrode (12) and a grounding electrode plate (13), which are arranged inside the temperature and humidity chamber (1) with a spacing of d, and are used to apply voltage to generate an electrostatic field E (0); An ion flow generating unit comprises an ion flow electrode (11), which is arranged inside the temperature and humidity chamber (1) and is used to generate charged ions with the same polarity as the electrostatic field when the system is running, and is driven into ion flow by the electrostatic field; Ion mobility measurement device: used to measure the ion density in the calibration area; Electro-optical crystal measurement device: used to obtain the electric field of the photoelectric crystal in the electrostatic field; A fixed platform (3): used for switching and installing the calibrated electro-optical crystal measuring device and the ion mobility measuring device, arranged in the electrostatic field and at a distance z from the high voltage electrode (12); A voltage measuring unit: comprising a first high-voltage voltage divider (6) and a second high-voltage voltage divider (7), used to measure the voltage on the ion current electrode (11) and the high-voltage electrode (12) respectively; The ion flow measurement unit comprises a picoammeter (8) and a Wilson plate (9), wherein the picoammeter (8) is used to measure the ion flow size; The Wilson plate (9) is used to collect and measure the ion flow; The DC electric field measuring device fixing device (10) is installed on the temperature and humidity chamber (1) and is used to fix the DC electric field measuring device.

2. The calibration system of the electro-optical crystal electric field measurement device according to claim 1, characterized in that: The height of the fixed platform (3) is set such that the distance from the high voltage electrode (12) and the grounding electrode plate (13) is d / 2.

3. The calibration system of the electro-optical crystal electric field measurement device according to claim 1, characterized in that: It also includes a DC power supply: the DC power supply includes a first DC power supply (4) and a second DC power supply (5), and the discharge ends of the first DC power supply (4) and the second DC power supply (5) are both arranged inside the temperature and humidity chamber (1) and are used to apply voltage to the ion flow electrode (11) and the high-voltage electrode (12) respectively.

4. The calibration system of the electro-optical crystal electric field measurement device according to claim 1, characterized in that: It also includes an insulating layer (2) for isolating the temperature and humidity chamber from the high-voltage electrode (12) and for preventing the high-voltage electrode from discharging to the temperature and humidity chamber (1).

5. A calibration method for an electro-optical crystal electric field measuring device, based on the calibration system for an electro-optical crystal electric field measuring device according to any one of claims 1 to 4, characterized in that: The following steps are involved: Regulating the temperature and humidity Ti and the voltage of the ion current electrode (11) and the high voltage electrode (12); The ion density K is obtained by an ion mobility measuring device, and the ion current density J is measured by a picoammeter (8) and a Wilson plate (9); Replacing the ion mobility measurement device with a calibrated electro-optical crystal measurement device; Measure the electric field reading E of the photoelectric crystal corresponding to the ion current density J at the corresponding temperature; Obtaining the electric field intensity E0 and the spatial electric field E1 of the high voltage plate (12) at different temperatures Ti in the calibration area ion density K; Obtain the calibration coefficient m corresponding to the adjusted temperature value, and obtain the calibration coefficient m of the electro-optical crystal measurement device at any temperature through linear interpolation i .

6. The calibration method of the electro-optical crystal electric field measurement device according to claim 5, characterized in that: The method of adjusting the temperature and humidity Ti includes: Set the temperature in the temperature and humidity chamber (1) to a certain temperature T i , where i = 1, 2, 3, 4, 5; the value range of Ti is -20℃~40℃; The method for adjusting the voltage of the ion current electrode (11) and the high voltage electrode plate (12) comprises: Voltages U1 and U are applied to the ion current electrode (11) and the high voltage electrode plate (12) respectively, so as to generate an initial electrostatic field and charged ions of the same polarity.

7. The calibration method of the electro-optical crystal electric field measurement device according to claim 5, characterized in that: The method for obtaining the electric field intensity E0 and the spatial electric field E1 of the high voltage plate (12) at different temperatures Ti in the calibration area ion density K comprises: Among them, U is the voltage on the high-voltage plate, J is the current density between the high-voltage plate and the grounding plate; K is the ion mobility; ε0 is the vacuum dielectric constant; z is the distance between the point where the DC electric field measurement device is located and the high-voltage plate, which is taken as d / 2; d is the gap distance between the high-voltage plate and the grounding plate.

8. The calibration method of the electro-optical crystal electric field measurement device according to claim 5, characterized in that: The method for obtaining the calibration coefficient m corresponding to the adjustment temperature value includes: Where E is the display value of the DC electric field measuring device.

9. The calibration method of the electro-optical crystal electric field measurement device according to claim 5, characterized in that: The method of obtaining the calibration coefficient m corresponding to the adjusted temperature value and obtaining the calibration coefficient of the electro-optical crystal measuring device at any temperature by linear interpolation includes: A set number of voltage point values ​​are selected at equal intervals according to the measuring range of the DC electric field measuring device, and the voltage U of the high voltage plate (12) is respectively adjusted to the selected voltage point value to calibrate the DC electric field; Change the temperature Ti in the temperature and humidity chamber (1) to obtain the electric field calibration coefficient m at the corresponding temperature. i ; According to the calibration coefficients of the electro-optical crystal at different temperatures Ti, linear interpolation is used to obtain the calibration coefficients of the electro-optical crystal measuring device at any temperature.

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