An ultrasonic partial discharge acquisition device for electrical equipment

Abstract

The utility model provides a kind of ultrasonic partial discharge collection device for electrical equipment, applied to ultrasonic partial discharge collection technical field.The ultrasonic partial discharge collection device for electrical equipment includes built-in ultrasonic sensor;Ultrasonic sensor output end and first stage amplification circuit input end connection;First stage amplification circuit output end and second stage amplification circuit and narrowband filter circuit input end connection;Second stage amplification circuit and narrowband filter circuit output end and third stage programmable gain amplification circuit input end connection;Third stage programmable gain amplification circuit output end and level conversion circuit input end connection;Level conversion circuit output end and A / D conversion circuit input end connection;A / D conversion circuit output end and protection circuit input end connection;Protection circuit output end and MCU circuit connection.In this way, ultrasonic signal acquisition sensitivity can be improved.

Description

Technical Field

[0001] This utility model relates to the field of ultrasonic partial discharge acquisition technology, and in particular to an ultrasonic partial discharge acquisition device for electrical equipment. Background Technology

[0002] Ultrasonic partial discharge detection is a key online monitoring and fault diagnosis technology for assessing the insulation status of electrical equipment. When there are insulation defects inside electrical equipment, partial discharge will occur, and ultrasonic signals with frequencies usually above 20kHz will be generated. By capturing and analyzing these ultrasonic signals, the degree and location of insulation degradation can be effectively determined, which is of great significance for ensuring the safe and stable operation of the power grid. However, in practical applications, the acquisition of ultrasonic partial discharge signals faces great challenges. The core difficulty lies in the insufficient acquisition sensitivity, which is mainly due to the following aspects: (1) The ultrasonic signals generated by partial discharge are extremely weak and attenuate very quickly when propagating in the air. When the signal reaches the equipment casing and is received by the sensor, its amplitude is usually only on the order of microvolts (µV) or even millivolts (mV). Existing acquisition devices mostly use single-stage or simple two-stage amplification circuits. For such weak signals, the total gain is often insufficient, resulting in the signal not being effectively amplified to the ideal input range of the back-end processing circuit. A large amount of effective fault feature information is submerged in noise, resulting in missed detection; (2) The electromagnetic environment at the site of electrical equipment is complex, with a large amount of low-frequency power frequency interference and high-frequency communication noise. Traditional amplifier circuits lack effective frequency selectivity. While amplifying useful ultrasonic signals, they also amplify out-of-band noise. This not only reduces the signal-to-noise ratio but also easily leads to saturation of the subsequent amplifier, further weakening the system's sensitivity and reliability in detecting weak real discharge signals. (3) Variations in discharge type, discharge quantity, and sensor installation position will result in an extremely wide dynamic range of the received signal strength. Fixed-gain amplification schemes are difficult to handle. If the gain is set too high, strong signals will cause amplifier saturation and clipping distortion. If the gain is set too low, weak signals cannot be effectively extracted. This rigid gain strategy limits the effective detection range of the device, resulting in poor overall sensitivity when facing real discharge signals with varying strengths.

[0003] In summary, existing ultrasonic partial discharge acquisition devices suffer from deficiencies in signal amplification, filtering, dynamic range adaptation, and signal integrity protection, resulting in low overall sensitivity.

[0004] Therefore, there is an urgent need for an ultrasonic partial discharge acquisition device for electrical equipment with high ultrasonic signal acquisition sensitivity. Utility Model Content

[0005] The purpose of this invention is to provide an ultrasonic partial discharge acquisition device for electrical equipment in order to solve the above-mentioned problems.

[0006] This utility model achieves the above objectives through the following technical solutions:

[0007] An ultrasonic partial discharge acquisition device for electrical equipment, comprising:

[0008] An ultrasonic sensor built into the acquisition device;

[0009] The output terminal of the ultrasonic sensor is connected to the input terminal of the first-stage amplifier circuit.

[0010] The output terminal of the first-stage amplifier circuit is connected to the input terminal of the second-stage amplifier circuit and the narrowband filter circuit.

[0011] The output of the second-stage amplifier circuit and the narrowband filter circuit are connected to the input of the third-stage programmable gain amplifier circuit.

[0012] The output terminal of the third-stage programmable gain amplifier circuit is connected to the input terminal of the level conversion circuit.

[0013] The output terminal of the level conversion circuit is connected to the input terminal of the A / D conversion circuit;

[0014] The output terminal of the A / D conversion circuit and the input terminal of the protection circuit are connected;

[0015] The output of the protection circuit is connected to the MCU circuit.

[0016] Furthermore, the output of the first-stage amplifier circuit is also connected to the input of the follower amplifier buffer circuit;

[0017] The output terminal of the follower amplification buffer circuit is connected to the input terminal of the audio modulation circuit;

[0018] The output of the audio modulation circuit is connected to the input of the audio codec.

[0019] The audio codec output is connected to the audio power amplifier input.

[0020] The output of the audio power amplifier is connected to a speaker or headphones.

[0021] Furthermore, the ultrasonic sensor is an air-coupled ultrasonic sensor with a center frequency of 40KHz.

[0022] Furthermore, the amplification factor of the first-stage amplifier circuit is 12 times.

[0023] Furthermore, the amplification factor of the second-stage amplifier circuit and the narrowband filter circuit is 17.5 times, and the 3dB bandwidth is 5KHz.

[0024] Furthermore, the third-stage programmable gain amplifier circuit employs a programmable gain amplifier with a gain factor of 1x, 10x, or 100x.

[0025] Compared with the prior art, the beneficial effects of this utility model are as follows: by adopting a multi-stage amplification circuit (first stage, second stage, and third stage programmable gain amplification), the weak signal output by the ultrasonic sensor is gradually amplified, enhancing the strength of the weak signal; by integrating a narrowband filter circuit, non-target frequency noise signals can be filtered out, reducing noise interference and relatively enhancing the useful ultrasonic signal; the third stage is a programmable gain amplification circuit, which flexibly adjusts the gain according to the signal strength to ensure that the weak signal is fully amplified and not drowned out, improving the ability to capture partial discharge signals of different intensities; through the orderly connection of each circuit component, attenuation and interference during signal transmission are reduced, ensuring signal integrity and thus improving the sensitivity of ultrasonic signal acquisition. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 The diagram shows a circuit diagram of the first-stage amplifier circuit of an ultrasonic partial discharge acquisition device for electrical equipment provided in an embodiment of the present invention.

[0028] Figure 2 The diagram shows a second-stage amplifier circuit and a narrowband filter circuit for an ultrasonic partial discharge acquisition device for electrical equipment, according to an embodiment of the present invention.

[0029] Figure 3 The diagram shows a circuit diagram of the third-stage programmable gain amplifier circuit of an ultrasonic partial discharge acquisition device for electrical equipment provided in an embodiment of the present invention.

[0030] Figure 4 A circuit diagram of a level conversion circuit for an ultrasonic partial discharge acquisition device for electrical equipment, provided by an embodiment of the present invention, is shown.

[0031] Figure 5 A circuit diagram of an A / D conversion circuit for an ultrasonic partial discharge acquisition device for electrical equipment, provided by an embodiment of the present invention, is shown.

[0032] Figure 6A circuit diagram of a protection circuit for an ultrasonic partial discharge acquisition device for electrical equipment, provided by an embodiment of the present invention, is shown.

[0033] Figure 7 The diagram shows a follower amplification buffer circuit for an ultrasonic partial discharge acquisition device for electrical equipment according to an embodiment of the present invention.

[0034] Figure 8 A circuit diagram of an audio modulation circuit for an ultrasonic partial discharge acquisition device for electrical equipment, provided by an embodiment of the present invention, is shown.

[0035] Figure 9 A circuit diagram of an audio codec for an ultrasonic partial discharge acquisition device for electrical equipment, provided by an embodiment of the present invention, is shown.

[0036] Figure 10 A circuit diagram of an audio power amplifier for an ultrasonic partial discharge acquisition device for electrical equipment, provided by an embodiment of the present invention, is shown.

[0037] Figure 11 A block diagram of an ultrasonic partial discharge acquisition device for electrical equipment provided by an embodiment of the present invention is shown. Detailed Implementation

[0038] In the description of this utility model, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. In addition, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0039] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation", "connection" and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components. For those skilled in the art, the specific meaning of the above terms in this utility model can be understood through the specific circumstances.

[0040] The present invention will be further described below with reference to the accompanying drawings:

[0041] like Figures 1-11 As shown, an ultrasonic partial discharge acquisition device for electrical equipment includes:

[0042] An ultrasonic sensor built into the acquisition device;

[0043] The output terminal of the ultrasonic sensor is connected to the input terminal of the first-stage amplifier circuit;

[0044] The output of the first-stage amplifier circuit is connected to the input of the second-stage amplifier circuit and the narrowband filter circuit.

[0045] The output of the second-stage amplifier circuit and the narrowband filter circuit are connected to the input of the third-stage programmable gain amplifier circuit.

[0046] The output of the third-stage programmable gain amplifier circuit is connected to the input of the level conversion circuit.

[0047] The output of the level conversion circuit is connected to the input of the A / D conversion circuit;

[0048] The output terminal of the A / D conversion circuit and the input terminal of the protection circuit are connected;

[0049] The output of the protection circuit is connected to the MCU circuit.

[0050] According to the embodiments of this utility model, by employing a multi-stage amplification circuit, the weak signal output by the ultrasonic sensor is gradually amplified, enhancing the strength of the weak signal; by integrating a narrowband filter circuit, noise signals of non-target frequencies can be filtered out, reducing noise interference and relatively enhancing the useful ultrasonic signal; the third stage is a programmable gain amplifier circuit, which flexibly adjusts the gain according to the signal strength to ensure that the weak signal is fully amplified without being drowned out, improving the ability to capture partial discharge signals of different intensities; through the orderly connection of each circuit component, attenuation and interference during signal transmission are reduced, ensuring signal integrity and thus improving the sensitivity of ultrasonic signal acquisition.

[0051] In some embodiments, the ultrasonic sensor receives the partial discharge ultrasonic signal, which is amplified by the first-stage amplification circuit, then amplified and filtered by the second-stage amplification circuit and the narrowband filter circuit, then amplified by the third-stage programmable gain amplifier circuit, then boosted by the level conversion circuit, then converted from analog to digital by the A / D conversion circuit, and finally sent to the MCU circuit for calculation by the protection circuit.

[0052] According to an embodiment of this utility model, a wide dynamic range ultrasonic signal detection is achieved through a three-stage programmable gain amplification.

[0053] In some embodiments, the MCU uses the HC32F460, which has a 32-bit Cortex-M4 core and integrates an FPU and MPU. The chip has a maximum clock frequency of 200MHz, a hardware data computing unit, peripheral interfaces, and a built-in audio PLL.

[0054] In some embodiments, the output of the first-stage amplifier circuit is also connected to the input of the follower amplifier buffer circuit;

[0055] Connect the output of the follow-up amplification buffer circuit to the input of the audio modulation circuit;

[0056] The output of the audio modulation circuit is connected to the input of the audio codec.

[0057] The audio codec output is connected to the audio power amplifier input.

[0058] Connect the audio power amplifier output to a speaker or headphones.

[0059] In some embodiments, the output of the second-stage amplifier circuit and the narrowband filter circuit is also connected to the input of the follower amplifier buffer circuit. The signal is then modulated by the audio modulation circuit, encoded and decoded by the audio codec, amplified by the audio power amplifier, and then played through a speaker or headphones.

[0060] According to the embodiments of this utility model, by separately amplifying the audio signal, the audio signal-to-noise ratio is improved, and the discharge sound can be heard more clearly on site.

[0061] In some embodiments, the ultrasonic sensor is an air-coupled ultrasonic sensor with a center frequency of 40 kHz, which can convert ultrasonic signals into electrical signals.

[0062] In some embodiments, the amplification factor of the first-stage amplifier circuit is 12 times; the first-stage amplifier circuit employs a low-noise, low-power, and high-precision instrumentation amplifier.

[0063] In some embodiments, the second-stage amplifier circuit and the narrowband filter circuit are cascaded using low-noise dual-channel precision operational amplifiers; the amplification factor of the second-stage amplifier circuit and the narrowband filter circuit is 17.5 times, and the 3dB bandwidth is 5KHz.

[0064] In some embodiments, the third-stage programmable gain amplifier circuit employs a programmable gain amplifier with a gain of 1x, 10x, or 100x.

[0065] In some embodiments, the level conversion circuit uses a precision operational amplifier to build an adder and adjusts the signal reference to 2.048V for subsequent data acquisition.

[0066] In some embodiments, the A / D conversion circuit uses a 1MSPS, 12-bit low-power ADC; the ADC input terminal is equipped with a protection circuit to prevent the input signal from exceeding the ADC input range; the ADC uses a 4.096V power supply, which is incompatible with the MCU's 3.3V power supply, so the ADC output terminal is equipped with a protection circuit for signal conversion.

[0067] In some embodiments, the follower amplification buffer circuit is constructed using a precision operational amplifier, which is cascaded with the follower circuit and the amplification circuit. Then, it is modulated by the audio modulation circuit, which facilitates signal transmission. After that, it is demodulated by the audio codec. The output signal of the audio codec is amplified by the power amplifier and can be played through a speaker or headphones.

[0068] In some embodiments, the ultrasonic signal acquired by the ultrasonic partial discharge acquisition device for electrical equipment is finally processed by the signal processing circuit and reaches the ADC chip. The ADC chip communicates with the MCU via SPI and transmits data according to the set amount by configuring the SPI parameters and frequency.

[0069] In some embodiments, the MCU stores and processes the transmitted data using a dual-buffering method. When one buffer reaches a set data volume, the data transmission address is changed to the other buffer. At this time, the data processing function is notified to process the data. Part of the data is processed according to a 20ms cycle to calculate the root mean square value and the maximum value. The other part of the data is converted by FFT to calculate the 50Hz and 100Hz frequency components. This data is refreshed in real time in the MCU and can be sent out to external devices via serial port according to the data transmission protocol.

[0070] In some embodiments, the ultrasonic partial discharge acquisition device for electrical equipment can represent the acquired ultrasonic signal through audio. The audio chip is ES8388, which supports headphone output playback. The audio is configured to play external audio through the MCU, and the MCU controls the audio modulation circuit to modulate the signal so that the ultrasonic signal is represented through audio.

[0071] The foregoing has shown and described the basic principles, main features and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are only illustrative of the principles of this utility model. Various changes and modifications may be made to this utility model without departing from the spirit and scope of this utility model, and all such changes and modifications fall within the scope of this utility model as claimed.

Claims

1. An ultrasonic partial discharge acquisition device for electrical equipment, characterized in that, include: An ultrasonic sensor built into the acquisition device; The output terminal of the ultrasonic sensor is connected to the input terminal of the first-stage amplifier circuit. The output terminal of the first-stage amplifier circuit is connected to the input terminal of the second-stage amplifier circuit and the narrowband filter circuit. The output of the second-stage amplifier circuit and the narrowband filter circuit are connected to the input of the third-stage programmable gain amplifier circuit. The output terminal of the third-stage programmable gain amplifier circuit is connected to the input terminal of the level conversion circuit. The output terminal of the level conversion circuit is connected to the input terminal of the A / D conversion circuit; The output terminal of the A / D conversion circuit and the input terminal of the protection circuit are connected; The output of the protection circuit is connected to the MCU circuit.

2. The ultrasonic partial discharge acquisition device for electrical equipment according to claim 1, characterized in that: The output of the first-stage amplifier circuit is also connected to the input of the follower amplifier buffer circuit; The output terminal of the follower amplification buffer circuit is connected to the input terminal of the audio modulation circuit; The output of the audio modulation circuit is connected to the input of the audio codec. The audio codec output is connected to the audio power amplifier input. The output of the audio power amplifier is connected to a speaker or headphones.

3. The ultrasonic partial discharge acquisition device for electrical equipment according to claim 1, characterized in that: The ultrasonic sensor is an air-coupled ultrasonic sensor with a center frequency of 40KHz.

4. The ultrasonic partial discharge acquisition device for electrical equipment according to claim 1, characterized in that: The amplification factor of the first-stage amplifier circuit is 12.

5. The ultrasonic partial discharge acquisition device for electrical equipment according to claim 1, characterized in that: The second-stage amplifier circuit and narrowband filter circuit have an amplification factor of 17.5 times and a 3dB bandwidth of 5KHz.

6. The ultrasonic partial discharge acquisition device for electrical equipment according to claim 1, characterized in that: The third-stage programmable gain amplifier circuit uses a programmable gain amplifier with a gain of 1x, 10x, or 100x.

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