Temperature measuring and controlling device for space charge detection in extreme temperature environment

Abstract

A kind of temperature measurement and control device for detecting space charge in extreme temperature environment pilot sample, comprising: original voltage signal measurement loop and sample temperature detection control loop characterized by space charge.This application only uses the original voltage signal characterized by space charge obtained by space charge-acoustic wave-voltage transformation under the excitation of polarization electric field and electric pulse superposition, based on the time delay of peak value in original voltage signal caused by the change of propagation speed of corresponding acoustic wave in different temperature ground electrode after the interface charge of sample / ground electrode, directly determines the actual temperature of sample, so as to realize the direct and accurate measurement of sample temperature without setting temperature sensor of electric signal and optical signal, finally, according to the comparison between actual temperature and set temperature, control the output of cold and hot output source, realize the accurate temperature control of sample.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electrical equipment insulation performance measurement, and particularly relates to a sample temperature measurement and control device in extreme temperature environment space charge detection. BACKGROUND

[0002] The space charge distribution in the electrical equipment insulation material directly determines the electric field distribution at different positions in space. Therefore, detecting the space charge distribution of the insulation material under the running condition is of great significance for the selection of the electrical equipment insulation material and the design of the insulation structure. Temperature is one of the core index parameters of the running condition. With the diversification of the electrical equipment running scene, the temperature range of the insulation material ranges from the extreme low temperature in aerospace to the extreme high temperature in power equipment, covering an extreme temperature range of about -196.56-200 DEG C. In order to analyze the space charge characteristics of the electrical equipment insulation under the actual running condition, the charge detection of the insulation sample to be detected needs to be carried out under different extreme temperature environments.

[0003] At present, the most commonly used detection principle of the commercial space charge detection instrument is the electro-acoustic pulse method. The temperature control of the insulation sample to be detected is mainly realized through the heat conduction of the metal electrode in close contact with the sample in the detection system. Therefore, in order to realize the accurate temperature measurement and control of the insulation sample to be detected, a traditional electric signal temperature sensor such as a thermocouple or a thermal resistor is usually arranged in the metal electrode of the electro-acoustic pulse method detection. The electric signal temperature sensor has the advantages of mature technology. The electric signal temperature sensor, the heater and the PID temperature controller are combined, and the insulation sample to be detected can be effectively heated through the accurate temperature control of the metal electrode. However, the electric signal temperature sensor has three problems in the temperature measurement process.

[0004] Firstly, the surface of the electric signal temperature sensor must be in close contact with the metal electrode. In order to apply the space charge and temperature synchronous detection in the extreme temperature environment of liquid nitrogen ultra-low temperature and more than 100 DEG C wide temperature range, the design and processing cost of the electrode structure is high, and the contact is easy to loosen and the sensor is easy to age in the long-term use process, resulting in temperature fluctuation and error increase in the temperature measurement process. Secondly, after the electric signal temperature sensor is in contact with the metal electrode, the strong electromagnetic interference of the temperature detection loop is easy to enter the electrode loop of the space charge detection, which causes interference to the original signal of the space charge detection. The infrared temperature sensor can effectively solve the problems existing in the application of the traditional electric signal temperature sensor, but it is difficult to install in the compact electrode system of the electro-acoustic pulse method and the technical cost is high. Thirdly, the electrode temperature needs to be stably and uniformly distributed after a period of heat conduction, and the temperature detected by the electric signal temperature sensor is the temperature of the contact surface between the temperature sensor and the electrode. Therefore, there is a time lag between the actual temperature of the sample and the temperature detected by the temperature sensor / electrode contact surface, and the temperature of the electrode and the sample needs to be balanced after a period of temperature stabilization.

[0005] Therefore, there is a need for a temperature detection and control method which is low in technical implementation difficulty and cost, and directly reflects the temperature of a sample, according to the application characteristics of the space charge of the electro-acoustic pulse method. SUMMARY

[0006] The present application is directed to the above-mentioned deficiencies in the prior art, and proposes a temperature measurement and control device for sample temperature in space charge detection in an extreme temperature environment, which directly determines the actual temperature of the sample by only using the original voltage signal representing the space charge obtained after the space charge-sound wave-voltage transformation under the superimposed excitation of the polarization electric field and the electric pulse, and based on the time delay of the peak in the original voltage signal caused by the change in the propagation speed of the sound wave corresponding to the interface charge of the sample / ground electrode at different temperatures in the ground electrode, so as to realize the direct and accurate measurement of the sample temperature without the need to set a temperature sensor for electric signals and optical signals, and finally control the output of the cold and hot output sources according to the comparison between the actual temperature and the set temperature, so as to realize the accurate temperature control of the sample.

[0007] The present application is realized by the following technical solutions:

[0008] The present application relates to a temperature measurement and control device for sample temperature in space charge detection in an extreme temperature environment, which comprises: an original voltage signal measurement circuit for representing the space charge, and a sample temperature detection and control circuit, wherein: the original voltage signal measurement circuit detects the space charge representation signal V(t), and the sample temperature detection and control circuit calculates the sample temperature T by testing the system temperature time delay curve and the formal test temperature control process, according to the time delay t of the peak V in the space charge representation signal V(t) corresponding to the interface charge of the sample / ground electrode, and controls the output of the cold and hot output sources according to the comparison between the actual temperature T and the set temperature T, so as to realize the accurate temperature control of the sample. peak 地延 测 测 设

[0009] The original voltage signal measurement circuit comprises: a high-voltage polarization power supply, an electric pulse source, an excitation coupler, a semi-conductive electrode, a sample, a low-voltage pole, a sensor, an amplifier and an oscilloscope, wherein: the high-voltage polarization power supply and the electric pulse source are respectively connected to the two output ends of the excitation coupler, one output end of the excitation coupler is connected to the semi-conductive electrode, the sample is placed between the semi-conductive electrode and the low-voltage pole, the internal space charge of the sample forms a sound wave signal under the superimposed excitation of the high-voltage polarization and the electric pulse, the sensor is placed on the other side of the low-voltage pole for detecting the sound wave signal and transforming the output corresponding voltage signal, the voltage signal is amplified by the amplifier and then collected by the oscilloscope to form the original voltage signal V(t) representing the space charge.

[0010] ​​​​​The sample temperature detection and regulation loop comprises a temperature extraction module, a cold and hot output source, a temperature regulator and a sample constant temperature cavity, wherein the input end of the temperature extraction module receives the peak value V peak of the interface charge between the sample and the ground electrode in the original voltage signal V(t) output by the oscilloscope 地延 , the time delay t 地延 of the peak value is determined by the system temperature time delay curve test, the sample temperature T is calculated and input to the temperature regulator, the temperature regulator controls the output of the cold and hot output source according to the comparison between the actual temperature T 测 and the set temperature T 设 , cools / heats the sample constant temperature cavity, and synchronously cools / heats the semiconductive electrode, the sample, the low-voltage electrode and the sensor in the sample constant temperature cavity, so as to realize accurate temperature control of the sample.

[0011] The system temperature time delay curve test refers to that the original voltage signal measurement loop for characterizing space charge is used to apply a reference polarization electric field and an electric pulse excitation electric field to a standard sample, the sample temperature T is measured during the heating of the ground electrode, and the original voltage signal V(t) after the space charge-acoustic wave-voltage conversion is measured at the same time, the time delay t 地延 of the charge peak of the interface between the ground electrode and the sample is extracted from the voltage signal, the function T(t 地延 of the sample temperature and the interface charge peak time delay is obtained by data fitting of the sample temperature T 标 and the interface charge peak time delay t 地延 . The function T(t 地延 ) of the time delay t 地延 of the detection device and the sample temperature T is the inherent characteristic of the device and will not change with the change of the detection sample, so the test only needs to be performed once.

[0012] The formal test temperature control refers to that the original voltage signal measurement loop for characterizing space charge is used to apply a reference polarization electric field and an electric pulse excitation electric field to a sample to be tested, the original voltage signal V(t) after the space charge-acoustic wave-voltage conversion is measured during the heating of the low-voltage electrode, the time delay t 地延 of the charge peak of the interface between the ground electrode and the sample is extracted, the sample temperature T 测 is calculated according to the function T(t 地延 ) of the sample temperature and the interface charge peak time delay obtained by the system temperature time delay curve test, the temperature difference ΔT is compared with the set temperature T 设 of the sample test, the temperature difference ΔT is fed back to the temperature regulator, the output of the cold and hot output source is regulated by the temperature regulator, the sample temperature is regulated, the temperature difference ΔT exceeds 0℃ after multiple cycles, so that the electrode temperature is stabilized at the set measurement temperature T 设 .

[0013] Technical effect

[0014] This invention determines the time delay t of the detection device. 地延 The function of sample temperature T, T(t) 地延 Afterwards, without the need for temperature sensors for electrical and optical signals, direct and accurate measurement of sample temperature is achieved without introducing additional electromagnetic interference during the measurement process. Compared with existing technologies, this invention achieves dual information extraction of the original voltage signal V(t) characterizing space charge in the electroacoustic pulse method, namely, the simultaneous extraction of space charge distribution information and real-time temperature in the sample. It only utilizes the original voltage signal V(t) characterizing space charge obtained after the space charge-sound wave-voltage transformation in the sample under the superposition of polarization electric field and electric pulse excitation in the electroacoustic pulse method detection, based on the peak value V(t) in the original voltage signal V(t) caused by the change in the propagation speed of the sound wave corresponding to the sample / ground electrode interface charge in the ground electrode at different temperatures. peak The delay t 地延 Directly determine the actual temperature T of the sample 测 . Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of the present invention;

[0016] Figure 2 This is a flowchart of the temperature delay curve test and formal test temperature control of the system of the present invention;

[0017] Figure 3 The original voltage signal diagrams for space charge detection at different temperatures under the reference electric field are shown.

[0018] Figure 4 The graph shows the variation of the sample temperature T and the peak time t at the grounding electrode interface under the reference electric field as a function of the measurement time.

[0019] Figure 5 The system temperature-time delay function T(t) of the electroacoustic pulse method detection device. 地延 )picture;

[0020] Figure 6 The above are comparison charts showing the effects of the examples. Detailed Implementation

[0021] like Figure 1As shown in this embodiment, a device for measuring and controlling the sample temperature in space charge detection under extreme temperature conditions includes: a raw voltage signal measurement circuit characterizing space charge and a sample temperature detection and control circuit. The raw voltage signal measurement circuit characterizing space charge is used to detect the space charge characterization signal V(t). The sample temperature detection and control circuit, through system temperature delay curve testing and formal test temperature control processing, is based on the peak value V corresponding to the sample / ground electrode interface charge in the space charge characterization signal V(t). peak The delay t 地延 The sample temperature T was calculated. 测 And based on the actual temperature T 测 and setting temperature T 设 By comparing the results, the output of the hot and cold output sources is controlled to achieve precise temperature control of the sample.

[0022] The original voltage signal measurement circuit characterizing space charge includes: a high-voltage polarization power supply 1, an electrical pulse source 2, an excitation coupler 3, a semiconducting electrode 4, a sample 5, a low-voltage electrode 6, a sensor 7, an amplifier 8, and an oscilloscope 9. The high-voltage polarization power supply 1 and the electrical pulse source 2 are respectively connected to the two output terminals of the excitation coupler 3. One output terminal of the excitation coupler 3 is connected to the semiconducting electrode 4. The sample 5 is placed between the semiconducting electrode 5 and the low-voltage electrode 6. The space charge inside the sample forms an acoustic signal under the superimposed excitation of high-voltage polarization and electrical pulse. The sensor 7 is placed on the other side of the low-voltage electrode 6 to detect the acoustic signal and convert it into a corresponding voltage signal. This voltage signal is amplified by the amplifier 8 and acquired by the oscilloscope 9 to form the original voltage signal V(t) characterizing the space charge.

[0023] The sample temperature detection and control circuit includes: a temperature extraction module 10, a cold / hot output source 11, a temperature regulator 12, and a sample constant temperature chamber 13, wherein: the input terminal of the temperature extraction module 10 receives the peak value V corresponding to the sample / ground electrode interface charge in the raw voltage signal V(t) output by the oscilloscope 9. peak The delay t 地延 T(t) was determined by testing the system temperature delay curve. 地延 The function calculates the sample temperature T and inputs it into the temperature controller 12. The temperature controller 12 then adjusts the temperature according to the actual temperature T. 测 and setting temperature T 设 The comparison controls the output of the cold and heat output source 11 to cool / heat the sample constant temperature chamber 13. The sample constant temperature chamber 13 contains a semiconducting electrode 4, a sample 5, a low-voltage electrode 6, and a sensor 7, which are simultaneously cooled / heated to achieve precise temperature control of the sample 5.

[0024] The temperature extraction module 10 includes an interface peak delay extraction unit and a temperature calculation unit, wherein the interface peak delay extraction unit extracts the peak value V corresponding to the sample / ground electrode interface charge based on the original voltage signal V(t). peak The delay t 地延 The temperature calculation unit determines T(t) based on the system temperature delay curve test. 地延 The function is used to calculate the corresponding temperature.

[0025] like Figure 2 The diagram shows a flowchart of the system temperature delay curve test and formal test temperature control of this invention. During the testing process, the system temperature delay curve test and formal test temperature control are performed sequentially.

[0026] Through specific practical experiments, XLPE with a thickness of 220μm was used as the standard sample to test the system temperature delay curve: the reference electric field was set to a DC polarization electric field of 5kV / mm, the electric pulse excitation electric field was 0.2kV / mm, and the grounding electrode was made of aluminum. Figure 3 The diagram shows a measurement circuit using the original voltage signal characterizing space charge. A reference polarization electric field and an electric pulse excitation electric field are applied to the standard sample. During the heating process at the ground electrode, the original voltage signal V(t) after space charge-sound-voltage transformation is measured. The sample temperature T is measured using thermocouple sensor technology. Figure 3 The charge peak delay t at the ground electrode / sample interface is extracted from the original voltage signal V(t). 地延 The curves showing the changes of the two parameters with polarization time t are as follows: Figure 4 As shown, the two parameters exhibit the same trend during the electrode temperature rise. Finally, the sample temperature T and the interface charge peak delay t are used to determine the optimal parameters. 地延 Data fitting to obtain, for example Figure 5 The sample temperature and the time delay of the interface charge peak are shown as a function T(t) 地延 Linear fitting was employed, and the coefficient of determination for the linear fit reached 0.99211, indicating that this method has good linearity within the sample testing temperature range of 20-90℃. T(t) 地延 ) = 2.62845t 地延 -257.95169.

[0027] Formal testing temperature control was performed using 236μm thick XLPE as the test sample: the reference electric field was set to a 5kV / mm DC polarization electric field, the electric pulse excitation electric field was set to 0.2kV / mm, the grounding electrode was made of aluminum, and the test temperature T of the test sample was... 设 Set to 50℃, based on the system temperature-time delay function obtained from the system temperature-time delay curve test, the ground electrode charge peak delay t 地延 It should be 117.16095ns.

[0028] The original voltage signal measurement circuit for characterizing space charge is adopted, the reference polarization electric field and the electric pulse excitation electric field are applied to the sample to be measured, the original voltage signal V(t) after space charge-acoustic wave-voltage conversion is obtained by measurement during the grounding electrode heating process, the charge peak time delay t 地延 is extracted at the interface between the grounding electrode and the sample 地延 , and the sample temperature T is calculated according to the function T(t 设 ) of the sample temperature and the interface charge peak time delay, the value of which is consistent with the set temperature T 设 of the sample test. Figure 5 After comparison, the temperature difference ΔT is fed back to the temperature regulator 12, the output of the cold and hot output source 11 is regulated by the temperature regulator 12, the sample constant temperature cavity 13 is cooled / heated, and after multiple cycles, the temperature difference ΔT exceeds 0℃, thereby the sample temperature is stabilized at the set measurement temperature T 设 .

[0029] Compared with the prior art, the original voltage signal V(t) for characterizing space charge in the electroacoustic pulse method is extracted twice, that is, the synchronous extraction of the space charge distribution information in the sample and the real-time temperature, after the time delay t 地延 of the detection device and the function T(t 地延 ) of the sample temperature T are determined, the direct and accurate measurement of the sample temperature can be realized without setting the temperature sensors of the electric signal and the optical signal, the structure design of the electrode of the detection system in the extreme temperature environment can be simplified, the corresponding lead and joint of the temperature detection can be reduced, and the reliability of the temperature detection can be improved.

[0030] The above specific embodiments can be adjusted in different ways by those skilled in the art without departing from the principles and purposes of the present application, the protection scope of the present application is subject to the claims and is not limited by the above specific embodiments, and each implementation scheme within the scope is subject to the constraints of the present application.

Claims

1. A device for measuring and controlling the temperature of a sample in space charge detection under extreme temperature environments, characterized in that, include: The system comprises a raw voltage signal measurement loop for characterizing space charge and a sample temperature detection and control loop. The raw voltage signal measurement loop detects the space charge characterization signal V(t). The sample temperature detection and control loop, through system temperature delay curve testing and formal test temperature control processing, determines the temperature based on the peak value Vt corresponding to the sample / ground electrode interface charge in the space charge characterization signal V(t). peak The delay t 地延 The sample temperature T was calculated. 测 And based on the actual temperature T 测 and setting temperature T 设 By comparing the results, the output of the hot and cold output sources is controlled to achieve precise temperature control of the sample; The original voltage signal measurement circuit includes: a high-voltage polarization power supply, an electrical pulse source, an excitation coupler, a semiconducting electrode, a sample, a ground electrode, a sensor, an amplifier, and an oscilloscope. The high-voltage polarization power supply and the electrical pulse source are connected to the two output terminals of the excitation coupler, respectively. One output terminal of the excitation coupler is connected to the semiconducting electrode. The sample is placed between the semiconducting electrode and the ground electrode. Under the superimposed excitation of the high-voltage polarization and the electrical pulse, the internal space charge generates an acoustic signal. The sensor is placed on the other side of the ground electrode to detect the acoustic signal and convert it into a corresponding voltage signal. This voltage signal is amplified by the amplifier and acquired by the oscilloscope to form the original voltage signal V(t) characterizing the space charge.

2. The device for measuring and controlling the sample temperature in space charge detection under extreme temperature environments according to claim 1, characterized in that, The aforementioned system temperature delay curve test refers to: applying a reference polarization electric field and an electric pulse excitation electric field to a standard sample using a raw voltage signal measurement circuit characterizing space charge; measuring the sample temperature T during the heating process of the ground electrode; and simultaneously measuring the raw voltage signal V(t) after space charge-acoustic-voltage transformation; and extracting the charge peak delay t at the sample / ground electrode interface from the voltage signal. 地延 Then, the sample temperature T was measured. 标 and interface charge peak delay t 地延 Data fitting yields a function T(t) that represents the delay of the sample temperature and the interfacial charge peak. 地延 The time delay t of the detection device 地延 The function of sample temperature T, T(t) 地延 This is an inherent characteristic of the device and will not change with changes in the sample being tested; therefore, the test only needs to be performed once.

3. The device for measuring and controlling the sample temperature in space charge detection under extreme temperature environments according to claim 1, characterized in that, The formal test temperature control refers to: applying a reference polarization electric field and an electric pulse excitation electric field to the sample under test using a raw voltage signal measurement circuit characterizing space charge; measuring the raw voltage signal V(t) after space charge-sound-voltage transformation during the heating process of the low-voltage electrode; and then extracting the charge peak delay t at the sample / ground electrode interface. 地延 The function T(t) of the sample temperature and the interface charge peak delay obtained from the temperature delay curve test is... 地延 Calculate the sample temperature T 测 Its value is related to the set temperature T of the sample test. 设 After comparison, the temperature difference ΔT is fed back to the temperature regulator, which adjusts the output of the hot and cold output sources to control the sample temperature. After multiple cycles, the temperature difference ΔT exceeds 0℃, thus stabilizing the electrode temperature at the set measurement temperature T. 设 value.

4. The device for measuring and controlling the sample temperature in space charge detection under extreme temperature environments according to any one of claims 1-3, characterized in that, The sample temperature detection and control circuit includes: a temperature extraction module, a cold / hot output source, a temperature regulator, and a sample constant temperature chamber, wherein: the input terminal of the temperature extraction module receives the peak value V corresponding to the sample / ground electrode interface charge in the raw voltage signal V(t) output by the oscilloscope. peak The delay t 地延 T(t) was determined by testing the system temperature delay curve. 地延 The function calculates the sample temperature T and inputs it into the temperature controller, which then adjusts the temperature based on the actual temperature T. 测 and setting temperature T 设 The comparison controls the output of the cold and hot output sources to cool / heat the sample constant temperature cavity. The sample constant temperature cavity contains a semiconducting electrode, the sample, a grounding electrode, and a sensor, which are simultaneously cooled / heated to achieve precise temperature control of the sample.

5. The device for measuring and controlling the sample temperature in extreme temperature environment space charge detection according to claim 4, characterized in that, The temperature extraction module includes an interface peak delay extraction unit and a temperature calculation unit, wherein the interface peak delay extraction unit extracts the peak value V corresponding to the sample / ground electrode interface charge based on the original voltage signal V(t). peak The delay t 地延 The temperature calculation unit determines T(t) based on the system temperature delay curve test. 地延 The function is used to calculate the corresponding temperature.

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