A warning sensing device for detecting partial discharge signals in power equipment

Abstract

This invention discloses a warning and sensing device for detecting partial discharge signals in power equipment. The device comprises a flexible ultrasonic sensor array for detecting partial discharge in power facilities and a data processing system for processing data from the detection of partial discharge in power facilities by the flexible ultrasonic sensor array. The invention utilizes flexible composite materials suitable for various operating scenarios to construct a flexible sensing-based partial discharge warning and sensing device, enhancing its ability to detect insulation faults and provide early warnings for partial discharge.

Description

Technical Field

[0001] The present invention relates to the technical field of power equipment, and in particular to an early warning sensing device for detecting partial discharge signals in power equipment. Background Art

[0002] With the continuous development of my country's "Smart Grid" initiative, a large number of power facilities have been put into operation. However, power facilities operate under load for long periods of time, and once a failure occurs, it often causes widespread power outages or even major safety incidents such as explosions. To ensure the safe operation of power facilities and reduce the safety risks of equipment failures, early fault warning for power facilities is particularly important. Existing power facilities in my country often have irregular and complex curved surfaces. Flexible electronic devices have strong adaptability to various substrates, exhibit excellent flexibility and ductility, and can even bend and fold freely. Their flexible and diverse structural forms can be arranged arbitrarily according to measurement conditions, making it very convenient to inspect complex curved surfaces. Furthermore, when traditional ultrasonic flaw detection is applied to multi-layer dielectric composite devices with large density differences in power systems, defects such as air gaps, carbonization channels, cracks, and impurities in the composite materials can lead to extremely complex reflection and scattered waves, significantly reducing defect detection accuracy. This results in insufficient ability to detect early insulation faults, making it difficult to detect small cracks and providing early warnings. Furthermore, the scanning (response) angle range of the transmitting (receiving) probes used in traditional ultrasonic flaw detection is relatively small, resulting in low inspection efficiency for devices with multiple curved surfaces. Considering that power equipment is often installed in remote places such as deep mountains, the use of wireless sensor networks to measure and monitor environmental information can, on the one hand, reduce the waste of staff manpower and reduce the safety risks of staff caused by field operations. On the other hand, it can also greatly improve the accuracy and real-time performance of the measurement of local power generation data of power equipment, provide more timely warnings of potential faults, and facilitate the measurement and monitoring of the working status of power equipment. Summary of the Invention

[0003] In view of this, the present invention provides an early warning sensing device based on flexible sensing technology for detecting partial discharge signals in power equipment, comprising: a flexible ultrasonic sensor array and a detection system;

[0004] The flexible ultrasonic sensor array is used to detect partial discharge phenomena in power facilities;

[0005] The detection system is used to transmit, process and issue early warning data on partial discharge phenomena in power facilities detected by the flexible ultrasonic sensor array;

[0006] The flexible ultrasonic sensor array is made of a flexible piezoelectric composite material formed by a flexible substrate material and a piezoelectric material.

[0007] The preparation method of the flexible ultrasonic sensor array comprises:

[0008] The flexible substrate material and the piezoelectric material are prepared in a molar ratio of 3:2;

[0009] The preparation method adopts conventional solid phase sintering technology;

[0010] forming the flexible substrate material into a flexible film substrate;

[0011] Flexible substrates are an essential component of flexible sensors and are primarily categorized into five types: plastic, metal foil, ultra-thin glass, paper, and biocomposite film. Plastic film, due to its ultra-thinness, flexibility, and roll-to-roll production capabilities, is the preferred choice for large-scale flexible substrate manufacturing.

[0012] Preferably, the flexible substrate material is an aromatic polyimide containing 4,5-diazafluorene.

[0013] The present invention uses a novel dianhydride monomer 9,9-bis[4-(3,4-dicarboxyphenoxy)phenyl]-4,5-diazafluorene dianhydride as a raw material to synthesize a series of organically soluble aromatic polyimides containing 4,5-diazafluorene in the polymer chain, which have high glass transition temperature and low dielectric constant.

[0014] The introduction of the 4,5-diazafluorene unit improves the solubility of the aromatic polyimide in common organic solvents (such as dichloromethane, 1,4-dioxane, and tetrahydrofuran). The resulting polyimide film has excellent thermal stability, with a Tg between 270 and 311°C and a Td10% between 493 and 552°C.

[0015] The step of forming the flexible substrate material into a flexible film substrate comprises:

[0016] 12.36 g of potassium hydroxide was added to 100 ml of a water-ethanol solution to obtain a first mixed solution, wherein the volume ratio of water to ethanol was 1:1;

[0017] 1.35 g of a tetracyano compound was added to the first mixed solution, and the mixture was stirred at 80° C. to react until ammonia gas was released, thereby obtaining a second mixed solution;

[0018] The pH value of the first filtrate after filtering the second mixed liquid is adjusted to 2-3 with 20% dilute hydrochloric acid to obtain a precipitate;

[0019] The precipitate was washed with distilled water and then recrystallized from glacial acetic acid / water to obtain 1.21 g of solid 9,9-bis[4-(3,4-dicarboxyphenoxy)phenyl]-4,5-diazafluorene, wherein the volume ratio of glacial acetic acid to water was 1:1;

[0020] 1 g of solid 9,9-bis[4-(3,4-dicarboxyphenoxy)phenyl]-4,5-diazafluorene was added to 7 ml of acetic anhydride to obtain a third mixed solution;

[0021] The third mixed solution was redissolved under nitrogen for 24 hours and then filtered to obtain a second filtrate;

[0022] 14 ml of glacial acetic acid was added to the second filtrate, and after cooling, the second filter residue was filtered to obtain a second filter residue, and the second filter residue was dried under vacuum at 150° C. to obtain 0.47 g of 9,9-bis[4-(3,4-dicarboxyphenoxy)phenyl]-4,5-diazafluorene dicarboxylic anhydride;

[0023] A mixture of 1 mol of diamine, 1 mol of 9,9-bis[4-(3,4-dicarboxyphenoxy)phenyl]-4,5-diazofluorene anhydride and N-methylpyrrolidone was reacted at room temperature for 24 hours to obtain a fourth mixed solution;

[0024] Add 2 mL of toluene to the uniform fourth mixed solution, and react at 180° C. for 4 hours to obtain a fifth mixed solution;

[0025] adding the fifth mixed solution into methanol to obtain fibrous polyimide, and then filtering to obtain a polyimide solid;

[0026] After drying the polyimide solid at 80° C., 1 g of the dried polyimide solid was dissolved in 20.2 ml of DMF at 80° C. to obtain a sixth mixed solution;

[0027] The third filtrate obtained by filtering the sixth mixed liquid was evenly coated on glass, and dried at 90° C. for 6 hours to obtain a flexible film substrate.

[0028] The piezoelectric material is filled into the flexible film substrate, so that the piezoelectric material forms a conductive model with geometric connections between points through seepage, so as to form the flexible ultrasonic sensor array.

[0029] Preferably, the piezoelectric material is (K, Na)NbO3-based lead-free piezoelectric ceramic.

[0030] In the selection of piezoelectric functional materials, the most commonly used piezoelectric materials in piezoelectric devices are lead-based piezoelectric materials represented by lead zirconate titanate (Pb(Zr, Ti)O3, PZT) and its modified multi-element ceramics.

[0031] However, the loss and emission of lead from lead-based piezoelectric devices during their lifecycle poses a serious threat to the ecological environment and human health. Therefore, (K,Na)NbO3 (KNN)-based lead-free piezoelectric ceramics, with their high Curie temperature (TC) and tunable phase boundary structure, are the preferred piezoelectric material for the sensor presented in this invention. The piezoelectric constant (d33) of pure KNN is only 80 pC / N, which does not meet the requirements of conventional piezoelectric devices. Therefore, this invention utilizes a coordinated approach to improve the overall performance of KNN by controlling aspects such as the preparation process and system design.

[0032] The preparation method of the piezoelectric material comprises:

[0033] In (Li x Na 0.53 K 0.47-x )NbO3 system by adding BaZrO3 and (Bi 0.5 Na 0.5 ) ZrO3, mixing uniformly and drying to obtain a first mixed material;

[0034] pre-calcining the first mixed material to obtain a second mixed material;

[0035] granulating the second mixed material to obtain a green billet;

[0036] The green blanks were divided into four groups, all of which were heated from room temperature to 600°C, kept warm for 30 minutes to remove binder, and then continued to be heated to 1200°C, 1250°C, 1300°C, and 1350°C, respectively. They were sintered at the four temperatures for two hours to form porcelain, thereby obtaining piezoelectric materials. The heating rate was 4°C / min.

[0037] The performance of the porcelain-formed samples was characterized in many aspects. The electrical properties were measured after silver electrodes were applied. The obtained piezoelectric material was filled into a flexible substrate. The flexible substrate played the role of supporting and fixing the conductive filler. The piezoelectric material formed a conductive model with geometric connections between points through seepage, and finally connected into a sensor array.

[0038] The detection system includes: a transmission module, a data processing module and an early warning module;

[0039] The transmission module is connected to the data processing module and the flexible ultrasonic sensor array respectively, and the early warning module is connected to the data processing module.

[0040] The transmission module adopts a wireless sensor network based on wifi; the wireless sensor network adopts an integrated wireless module USR-WIFI232-A2 based on the 802.11 wireless standard protocol family.

[0041] The main control microcontroller can be connected to the wireless module through the corresponding GPIO port, and further connected to the wireless local area network.

[0042] The data processing module is also used to perform graded warnings on faults corresponding to the data of the partial discharge phenomenon of the power facility based on the comparison results of the data with the discharge threshold, and send the results of the graded warnings to the warning module so that the warning module can issue an warning.

[0043] The data processing module is further configured to determine the location of a fault corresponding to the data on the partial discharge phenomenon of the power facility by identifying an IP address carried by the data on the partial discharge phenomenon of the power facility.

[0044] After measuring the partial discharge situation, the data processing module can more quickly transmit the detection data back to the data center for analysis, and if there are any hidden dangers of faults, the hidden dangers can be checked in time.

[0045] The detection system further includes: a data visualization module, which is connected to the data processing module and is used to display information sent by the data processing module. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0047] Figure 1 It is the pin interface of the wifi module of the present invention;

[0048] Figure 2 This is the connection method between the main control microcontroller and the wifi module of the present invention;

[0049] Figure 3 This is a structural diagram of the flexible array sensor;

[0050] Figure 4 It is the structural diagram of the detection system;

[0051] Figure 5 It is the system block diagram. DETAILED DESCRIPTION

[0052] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments derived by ordinary technicians in this field based on the embodiments of the present invention without creative work are within the scope of protection of the present invention.

[0053] An embodiment of the present invention discloses a warning sensing device for detecting partial discharge signals in power equipment. This embodiment of the present invention includes: a flexible ultrasonic sensor array for detecting partial discharge in power facilities; and a data processing system for processing data from partial discharge detected by the flexible ultrasonic sensor array. The flexible ultrasonic sensor array is made of a flexible piezoelectric composite material formed of a flexible substrate material and a piezoelectric material.

[0054] The device in the embodiment of the present invention may also adopt a partial discharge tester in the prior art to implement the process of all the method steps in the embodiment, and a single chip microcomputer is provided inside the device.

[0055] See also Figure 4 The data processing system in the device of the embodiment includes the following modules:

[0056] The data processing system includes: a transmission module, a data processing module, a detection module and an early warning module. The transmission module is respectively connected to the data processing module and the flexible ultrasonic sensor array, and the early warning module is connected to the data processing module.

[0057] The data processing module is also used to perform graded warnings on faults corresponding to the data of the partial discharge phenomenon of the power facility based on the comparison results of the data with the discharge threshold, and send the results of the graded warnings to the warning module so that the warning module can issue an warning.

[0058] The data processing module is further configured to determine the location of a fault corresponding to the data on the partial discharge phenomenon of the power facility by identifying an IP address carried by the data on the partial discharge phenomenon of the power facility.

[0059] The detection system further includes: a data visualization module, which is connected to the data processing module and is used to display information sent by the data processing module.

[0060] The detection system in the above embodiment can monitor partial discharge phenomena in power facilities by processing the signals of the flexible ultrasonic sensor array, thereby achieving early warning.

[0061] Detection system in the embodiment

[0062] The embodiment of the present invention also provides a detection system, see Figure 5The reliable and effective implementation of the functions of a single acquisition node in the present invention relies on a suitably performing STM32F103ZET6 master microcontroller. Its central processing unit can process 32 bits of data at a time and operates at a frequency of up to 72 MHz. By adding external interface circuits to the master microcontroller's existing resources through a specific connection method, a minimal microcontroller system can be implemented to ensure the microcontroller's normal operation.

[0063] MCU includes Figure 5 The adaptive sampling rate module in the flexible sensor array is used to collect signals. When no fault signal above the threshold is detected, the system collects data at a low speed and low power consumption. When a signal above the threshold is detected, the system uses a high sampling rate to locate the defect. Alternatively, the system can collect data at a set constant speed.

[0064] The collected signal is detected by the partial discharge detection module. If it is higher than the threshold, it is displayed by the discharge threshold warning module, such as through sound and light display, or transmitted to the user through the network.

[0065] Furthermore, the flexible sensor array can also transmit the collected signals to the data center through a data transmission system.

[0066] The data transmission system uses the integrated wireless module USR-WIFI232-A2 based on the 802.11 wireless standard protocol family. The main control microcontroller can connect to the wireless module through the corresponding GPIO port, such as Figure 1 、 Figure 2 The data transmission system has a data communication module that can realize radio frequency transmission, such as WiFi transmission, or transfer to 4G transmission.

[0067] The data center analyzes the signals collected by the flexible sensor array through the data processing module. If there is a possibility of a fault, the fault feedback module outputs the information and stores it in the data storage module. The analysis results are also output through the data visualization module, and the fault warning grading module displays the warning level.

[0068] The data processing implementation steps of this embodiment are:

[0069] Step 1: Use the flexible array sensors to detect partial discharge phenomena in power facilities, and quickly transmit the detection data back to the data center via Wi-Fi wireless transmission;

[0070] After the flexible sensor array collects potential defect information, it connects to the AP module through the serial port and transmits the collected information transparently to the data center through independent TCP connections for processing, storage and display of specific data.

[0071] In step 2, the data center stores, analyzes, and processes the collected data, further visualizes the data, and classifies the warnings.

[0072] In step three, the data processing results are fed back to the flexible sensor array again via Wi-Fi wireless transmission. Based on the comparison of the results with data such as the discharge threshold, it is determined whether the sensor needs high-power acquisition to further locate specific parameters such as the defect position, depth, and shape; or if the detection parameters are normal, some channels are closed to implement low-power, long-lasting acquisition.

[0073] In embodiments of the present invention, the flexible ultrasonic sensor array can be fabricated as follows: The flexible ultrasonic sensor array is fabricated by filling a flexible substrate with piezoelectric material. The flexible substrate supports and secures the conductive filler, while the piezoelectric material percolates to form a geometrically connected conductive pattern, ultimately forming a sensor array.

[0074] The preparation method comprises the following steps:

[0075] Step 1, preparing the flexible substrate material and the piezoelectric material in a molar ratio of 3:2;

[0076] Step 2: forming the flexible substrate material into a flexible film substrate;

[0077] Step three: filling the piezoelectric material into the flexible film substrate, so that the piezoelectric material forms a conductive model with geometric connections between points through seepage, so as to form the flexible ultrasonic sensor array.

[0078] 1) Implementation plan for preparing flexible film substrates:

[0079] Flexible substrates are an essential component of flexible sensors and are primarily categorized into five types: plastic, metal foil, ultra-thin glass, paper, and biocomposite film. Plastic film, due to its ultra-thinness, flexibility, and roll-to-roll production capabilities, is the preferred choice for large-scale flexible substrate manufacturing.

[0080] Polymer materials used to manufacture flexible substrates must possess excellent properties such as high heat resistance, high dimensional stability, good water vapor transmission rate, and chemical resistance. Plastic substrates can improve water vapor transmission rate and chemical resistance by creating an external permeation barrier. However, the thermal properties of polymers, including glass transition temperature (Tg) and coefficient of thermal expansion (CTE), must be improved to enhance their overall performance.

[0081] Therefore, the design of polyimide with high glass transition temperature and low thermal expansion coefficient becomes the focus of the present invention. For example, bulky side groups or heterocyclic polyimide structures are introduced, among which common heterocyclic structures include imidazole, pyrrole, pyrimidine, thiazole, etc.

[0082] This invention uses a novel dianhydride monomer, 9,9-bis[4-(3,4-dicarboxyphenoxy)phenyl]-4,5-diazafluorene dianhydride, as a raw material to synthesize a series of organically soluble aromatic polyimides containing 4,5-diazafluorene in the polymer chain. The introduction of the 4,5-diazafluorene unit improves the solubility of the aromatic polyimides in common organic solvents (such as dichloromethane, 1,4-dioxane, and tetrahydrofuran). The resulting polyimide films exhibit excellent thermal stability, with a Tg between 270 and 311°C and a Td10% between 493 and 552°C. In addition, polyimide containing 4,5-diazafluorene has a low dielectric constant between 2.78 and 3.38, and has good mechanical properties, with a tensile strength between 92 and 105 MPa and an elongation at break of 4.49% to 24.8%, making it an excellent flexible sensor substrate material.

[0083] In the above embodiment, the steps of preparing the above flexible sensor substrate material into a flexible film substrate are:

[0084] Step 1: Add 12.36 g of potassium hydroxide to 100 ml of a water-ethanol solution to obtain a first mixed solution, wherein the volume ratio of water to ethanol is 1:1;

[0085] Step 2: adding 1.35 g of a tetracyano compound to the first mixed solution and stirring the mixture at 80° C. until ammonia gas is released to obtain a second mixed solution;

[0086] Step 3: adjusting the pH value of the first filtrate obtained by filtering the second mixed solution to 2-3 with 20% dilute hydrochloric acid to obtain a precipitate;

[0087] Step 4: After washing the precipitate with distilled water, recrystallize it from glacial acetic acid / water to obtain 1.21 g

[0088] Solid 9,9-bis[4-(3,4-dicarboxyphenoxy)phenyl]-4,5-diazafluorene, wherein the volume ratio of glacial acetic acid and water is 1:1;

[0089] Step 5: Add 1 g of solid 9,9-bis[4-(3,4-dicarboxyphenoxy)phenyl]-4,5-diazafluorene to 7 ml of acetic anhydride to obtain a third mixed solution;

[0090] Step 6: Redissolve the third mixed solution under nitrogen for 24 hours and then filter to obtain a second filtrate;

[0091] Step 7: Add 14 ml of glacial acetic acid to the second filtrate, cool it, and filter it to obtain the second filter residue.

[0092] The second filter residue was dried under vacuum at 150° C. to obtain 0.47 g of 9,9-bis[4-(3,4-dicarboxyphenoxy)phenyl]-4,5-diazofluorene anhydride;

[0093] Step eight, 1 mol of diamine, 1 mol of 9,9-bis[4-(3,4-dicarboxyphenoxy)phenyl]-4,5-diazolyl

[0094] The mixture of fluorene anhydride and N-methylpyrrolidone was reacted at room temperature for 24 hours to obtain a fourth mixed solution; 5 Step nine, 2 mL of toluene was added to the uniform fourth mixed solution, and the mixture was reacted at 180° C. for 4 hours.

[0095] A fifth mixed solution is obtained;

[0096] Step 10, adding the fifth mixed solution into methanol to obtain fibrous polyimide, and then filtering to obtain a polyimide solid;

[0097] Step 11: After drying the polyimide solid at 80° C., 1 g of the dried polyimide solid was dissolved in 20.2 ml of DMF at 80° C. to obtain a sixth mixed solution;

[0098] Step 12: evenly apply the third filtrate obtained by filtering the sixth mixed liquid on the glass, and dry it at 90° C. for 6 hours to obtain a flexible film substrate.

[0099] 2) In the above embodiment, the piezoelectric functional material preparation implementation plan is:

[0100] At present, the most commonly used piezoelectric material in piezoelectric devices is lead-based piezoelectric material represented by lead zirconate titanate ((Pb(Zr, Ti)O3, 5PZT)) and its modified multi-component ceramics. However, during the use cycle of piezoelectric devices based on lead-based materials, the loss and emission of lead will cause serious harm to the ecological environment and human health. Therefore, in the selection of piezoelectric functional materials, KNN-based lead-free piezoelectric ceramics with a higher Curie temperature (TC) and an adjustable phase boundary structure have become the choice of piezoelectric materials for the sensor of the present invention. The piezoelectric constant (d33) of pure KNN is only 80Pc / N, which cannot meet the use requirements of conventional piezoelectric devices. Therefore, we coordinate and control the preparation process, system design and other aspects to improve the comprehensive performance of KNN. KNN has a rich phase structure, and constructing a quasi-isotropic phase boundary or polymorphic phase coexistence structure similar to PZT in KNN is particularly important for improving its piezoelectric performance.

[0101] Experiments have shown that controlling the RO and OT phase transition behaviors to adjust the phase transition temperature range is an effective method for achieving high piezoelectric properties and good temperature stability in KNN-based ceramics. This paper adopts a strategy of constructing a diffuse phase transition, adding BaZrO3 and (Bi0.5Na0.5)ZrO3 to the 0.925(LixNa0.53K0.47-x)NbO3 system to achieve a diffuse phase transition over a wide temperature range. This system exhibits a high piezoelectric constant (approximately 330Pc / N) while maintaining a piezoelectric constant variation rate of only 10% within the typical application temperature range (25-100°C).

[0102] In the selection of composite methods for flexible piezoelectric sensing materials, although the use of special sintering technologies such as laser sintering technology, spark plasma sintering technology, hot pressing sintering technology, and template grain growth technology can effectively reduce the volatilization of alkali metals and improve the density of ceramics, these preparation methods have problems such as high production costs and complex processes. If they are put into mass production of piezoelectric devices, there are still difficulties.

[0103] Therefore, the present invention adopts conventional solid phase sintering technology to synthesize the raw materials according to a certain molar ratio. The preparation steps are as follows:

[0104] Step 1: Add BaZrO3 and (Bi0.5Na0.5)ZrO3 to the (LixNa0.53K0.47-x)NbO3 system, mix well, and dry to obtain a first mixture;

[0105] Step 2: pre-calcining the first mixed material to obtain a second mixed material;

[0106] Step 3, granulating the second mixed material to obtain a green billet;

[0107] Step 4: Divide the green blank into four groups, heat them from room temperature to 600℃, keep them warm for 30 minutes to remove the binder, then continue to heat them to 1200℃, 1250℃, 1300℃, and 1350℃ respectively, and sinter them at four temperatures for two hours to form porcelain, thereby obtaining piezoelectric materials. The heating rate is 4℃ / min.

[0108] The performance of the porcelain-formed samples was characterized in many aspects. The electrical properties were measured after silver electrodes were applied. The obtained piezoelectric material was filled into a flexible substrate. The flexible substrate played the role of supporting and fixing the conductive filler. The piezoelectric material formed a conductive model with geometric connections between points through seepage, and finally connected into a sensor array.

[0109] 3) Selection of flexible electrodes

[0110] Flexible electrodes must be lightweight and durable while ensuring excellent electrical conductivity and mechanical flexibility. Currently, the most widely used new flexible electrode materials are carbon-based materials, metal nanowires, transition metal oxides, and conductive polymers. However, achieving both excellent optoelectronic properties and high mechanical flexibility in these various electrode materials is extremely challenging. For example, carbon-based materials typically experience reduced electrical conductivity when bent and transparent. Metal nanowires have excellent optoelectronic properties, but the conductive layer loses adhesion to the substrate during bending, resulting in poor durability. Metal oxides can achieve high electrical conductivity, but due to their inherent properties, they have poor flexibility and light transmittance. Conductive polymers offer excellent mechanical flexibility and a certain degree of light transmittance, but their low electrical conductivity needs to be improved. Flexible silver electrodes have the advantages of good electrical conductivity, stable electrode potential, low polarization potential, and minimal potential fluctuation. Therefore, flexible silver electrodes with high conversion efficiency have become the preferred electrode material.

[0111] Through the above steps, the above flexible sensor array can be prepared. The above flexible sensor array has the following technical benefits:

[0112] The flexible sensor has strong environmental adaptability, good flexibility and ductility, and can even be bent or folded freely. In addition, its structural form is flexible and diverse, and it can be arranged arbitrarily according to the requirements of the measurement conditions. It can very conveniently detect complex curved surfaces and has the characteristics of high integration and intelligence.

Claims

1. A warning sensing device for detecting partial discharge signals in power equipment, characterized in that: include: A flexible ultrasonic sensor array for detecting partial discharge phenomena in electric power facilities and a data processing system for processing data of partial discharge phenomena in electric power facilities detected by the flexible ultrasonic sensor array; The flexible ultrasonic sensor array is made of a flexible piezoelectric composite material formed by a flexible substrate material and a piezoelectric material; The preparation method of the flexible ultrasonic sensor array comprises: The flexible substrate material and the piezoelectric material are prepared in a molar ratio of 3:2; forming the flexible substrate material into a flexible film substrate; Filling the piezoelectric material into the flexible film substrate, so that the piezoelectric material forms a conductive pattern with geometric connections between points through seepage, so as to form the flexible ultrasonic sensor array; The step of forming the flexible substrate material into a flexible film substrate comprises: 12.36 g of potassium hydroxide was added to 100 ml of a water-ethanol solution to obtain a first mixed solution, wherein the volume ratio of water to ethanol was 1:1; 1.35 g of a tetracyano compound was added to the first mixed solution, and the mixture was stirred at 80° C. to react until ammonia gas was released, thereby obtaining a second mixed solution; The pH value of the first filtrate after filtering the second mixed liquid is adjusted to 2-3 with 20% dilute hydrochloric acid to obtain a precipitate; The precipitate was washed with distilled water and then recrystallized from glacial acetic acid / water to obtain 1.21 g of solid 9,9-bis[4-(3,4-dicarboxyphenoxy)phenyl]-4,5-diazafluorene, wherein the volume ratio of glacial acetic acid to water was 1:1; 1 g of solid 9,9-bis[4-(3,4-dicarboxyphenoxy)phenyl]-4,5-diazafluorene was added to 7 ml of acetic anhydride to obtain a third mixed solution; The third mixed solution was redissolved under nitrogen for 24 hours and then filtered to obtain a second filtrate; 14 ml of glacial acetic acid was added to the second filtrate, and after cooling, the second filter residue was filtered to obtain a second filter residue, and the second filter residue was dried under vacuum at 150° C. to obtain 0.47 g of 9,9-bis[4-(3,4-dicarboxyphenoxy)phenyl]-4,5-diazafluorene dianhydride; A mixture of 1 mol of diamine, 1 mol of 9,9-bis[4-(3,4-dicarboxyphenoxy)phenyl]-4,5-diazofluorene anhydride and N-methylpyrrolidone was reacted at room temperature for 24 hours to obtain a fourth mixed solution; 2 mL of toluene was added to the homogeneous fourth mixed solution, and the mixture was reacted at 180° C. for 4 h to obtain a fifth mixed solution; The fifth mixed liquid is added to methanol to obtain fibrous polyimide, which is then filtered to obtain a polyimide solid; After drying the polyimide solid at 80° C., 1 g of the dried polyimide solid was dissolved in 20.2 ml of DMF at 80° C. to obtain a sixth mixed solution; The third filtrate obtained after filtering the sixth mixed liquid was evenly coated on the glass, and dried at 90° C. for 6 hours to obtain a flexible film substrate.

2. The early warning sensing device for detecting partial discharge signals in power equipment according to claim 1, characterized in that: The flexible substrate material is aromatic polyimide containing 4,5-diazafluorene.

3. The early warning sensing device for detecting partial discharge signals in power equipment according to claim 1, characterized in that: The piezoelectric material is (K, Na)NbO3-based lead-free piezoelectric ceramic.

4. The early warning sensing device for detecting partial discharge signals in power equipment according to claim 1, characterized in that: The preparation method of the piezoelectric material comprises: In (Li x Na 0.53 K 0.47-x )NbO3 system is added with BaZrO3 and (Bi 0.5 Na 0.5 ) ZrO3, mixing uniformly and drying to obtain a first mixed material; pre-calcining the first mixed material to obtain a second mixed material; granulating the second mixed material to obtain a green billet; The green blanks were divided into four groups, all heated from room temperature to 600°C, kept warm for 30 minutes to remove binder, and then continued to be heated to 1200°C, 1250°C, 1300°C, and 1350°C respectively. They were sintered at four temperatures for two hours to form porcelain, and piezoelectric materials were obtained. The heating rate was 4°C / min.

5. The early warning sensing device for detecting partial discharge signals in power equipment according to claim 1, characterized in that: The data processing system includes: a transmission module, a data processing module, a detection module and an early warning module. The transmission module is respectively connected to the data processing module and the flexible ultrasonic sensor array, and the early warning module is connected to the data processing module.

6. The early warning sensing device for detecting partial discharge signals in power equipment according to claim 5, characterized in that: The data processing module is also used to perform graded warnings on faults corresponding to the data of the partial discharge phenomenon of the power facility based on the comparison results of the data with the discharge threshold, and send the results of the graded warnings to the warning module so that the warning module can issue an warning.

7. The early warning sensing device for detecting partial discharge signals in power equipment according to claim 5, characterized in that: The data processing module is further configured to determine the location of a fault corresponding to the data on the partial discharge phenomenon of the power facility by identifying an IP address carried by the data on the partial discharge phenomenon of the power facility.

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