CN113504407B - A spherical sensing device and implementation method that can be used for sound intensity detection in the vicinity of UHV transmission lines - Google Patents

Abstract

The invention relates to a sound intensity detection device and an implementation method for an extra-high voltage transmission line adjacent area. In order to adapt to the measuring environment of high potential and strong electric field, the device is designed into a spherical structure with good voltage equalizing performance, and can be applied to an ultra-high voltage direct current environment of +/-1100 kV. The device can synchronously collect sound pressure signals of up to 14 paths at a sound source, solves sound intensity components on three orthogonal axes in real time according to the sound intensity algorithm provided by the invention, and sends the sound intensity signals to a local safety end through a wireless transmission unit. According to the invention, 14 sound pressure sensors are arranged in a pairwise pairing mode in 7 specific directions of the spherical structure, so that sound intensity values in 7 different directions are obtained, and then a redundant linear mapping model is established based on a special position relation among the directions, so that the three-dimensional sound intensity vector of the sound source position can be accurately detected.

Description

A spherical sensing device that can be used for sound intensity detection in the vicinity of UHV transmission lines configuration and implementation

technical field

The invention belongs to the technical field of ultra-high voltage power transmission in power systems, and specifically relates to a spherical sound intensity detection device and an implementation method in the vicinity of an ultra-high voltage transmission line, including the system structure, signal acquisition and sound intensity algorithm of the device, and is especially suitable for complex electromagnetic Sound intensity detection of the location of sound sources in the environment.

Background technique

As the voltage level of UHV transmission lines continues to increase, the electromagnetic environment caused by corona discharge has become one of the decisive factors in line design. Among them, the audible noise caused by corona has attracted extensive attention because people can feel it personally. Studying the characteristics, generation mechanism, propagation law and ground effect of audible noise generated by corona discharge in UHV lines will help to accurately predict and even control the level of audible noise, and is of great significance for the construction of transmission lines that meet environmental protection requirements.

Audible noise will diffuse and attenuate during propagation, and will be reflected on the surface of obstacles such as the ground and buildings. Generally, when the sound pressure level of noise is measured at a height of about 1.5m from the ground, the surrounding environmental noise will also be mixed, and it is difficult to filter out. As a result, audible noise detected near the ground is distorted to varying degrees. In contrast, detecting noise at the sound source in the vicinity of the transmission line can avoid many interferences and help to understand the intrinsic characteristics and laws of the noise. It is undoubtedly a better research method. In addition, the sound pressure level is a physical quantity that represents the strength of the noise radiated by the sound source, but the sound pressure level is a scalar quantity, and the data measured in different environments can be used as a reference. Sound intensity is a vector, which can better reflect the energy, flow and propagation state of the sound source, and has better expressive power for audible noise. At present, sound intensity detection has been widely used in equipment fault diagnosis and quality control, sound power measurement, sound source location, environmental noise monitoring, etc.

The traditional method of measuring the sound pressure level of audible noise on the ground can no longer meet the research needs of the mechanism characteristics of audible noise sources. However, due to the complex electromagnetic environment of UHV transmission lines, the current research has not yet been applied to UHV true transmission. Detection methods for line noise sources. In fact, the adjacent area of the UHV transmission line is the location of the sound source of the corona discharge audible noise, and the information of the noise source can be directly detected. Based on this, the time-frequency domain characteristics and changing rules of the audible noise source can be directly studied and analyzed. Measuring the sound intensity in the vicinity of the UHV transmission line will help us to understand the mechanism and law of the sound source, deepen our scientific understanding of the phenomenon, and guide us to take targeted measures to solve the problem.

Contents of the invention

In order to overcome the above-mentioned problems in the prior art, the present invention discloses a spherical sensing device and implementation method that can be used for sound intensity detection in the vicinity of UHV transmission lines, including a sound intensity algorithm based on the device architecture. The purpose of the present invention is to collect multi-channel sound pressure in parallel at the high-voltage end of an UHV transmission line and calculate a three-dimensional sound intensity vector, and then transmit the detected sound intensity data to a host computer through a wireless transmission module.

In order to achieve the above object, the present invention specifically adopts the following technical solutions: a spherical sensing device that can be used for sound intensity detection in the vicinity of UHV transmission lines and its implementation method. The sensing device includes a spherical fixed structure, 14-way sound pressure sensors, high-speed Data acquisition module, signal processing unit, wireless transmission unit 1 and power supply unit; the implementation method is to calculate the specific sound intensity values in different linear directions through the sound intensity algorithm according to the arrangement rules of the 14-way sensor array on the spherical structure, and then based on each direction The special positional relationship among them establishes a redundant linear mapping model to obtain the sound intensity vector at the center of the sphere.

The spherical fixing structure is installed in the vicinity of the UHV transmission line, wraps other modules of the detection device inside, and can protect the normal operation of the equipment in the open environment. Since the detection device is located in a complex electromagnetic environment in the vicinity of UHV, choosing a spherical structure with the best insulation and voltage equalization effects can effectively avoid tip discharge. The design of the radius of the sphere should consider the size of the adjacent space of the transmission line and the volume of other internal modules to meet the requirements of sound intensity detection. The spherical surface should be polished and smooth, and the surface should be covered with metal mesh, which will not affect the sound intensity detection while increasing the halo field intensity on the surface of the device, so as to ensure the safe and reliable operation of the detection device in the ±1100kV UHV environment.

The 14-way sound pressure sensor is installed on 14 specific points of the spherical structure: a space Cartesian coordinate system is established at the center of the sphere, and 6 intersection points of the coordinate axis and the sphere and 8 quadrants corresponding to the center points of the sphere are selected to obtain 7 14 points in a diameter direction. The 14 sound pressure sensors with the same characteristics are divided into 7 groups on average, and arranged at 14 points on the spherical surface along the above 7 diameter directions, as shown in Figure 2. 7 brackets are specially designed along the 7 diameter directions, and each set of sensors is fixed on both ends of the bracket in a back-mounted manner. The center of the diaphragm of the sensor is symmetrical about the center of the sphere and points to the outer sound field. The sound pressure sensor uses an electret condenser microphone, which has the advantages of a common condenser microphone: wide frequency range, flat frequency response, small sensitivity change, and high long-term stability. At the same time, it avoids the shortcomings of traditional condenser microphones, and does not need to add 200V polarization voltage, which can simplify the design of the power supply unit.

The high-speed data acquisition module includes a conditioning circuit and an AD sampling unit. The conditioning circuit uses a preamplifier to convert the weak high-impedance output voltage collected by the sound pressure sensor into a low-impedance voltage, and at the same time amplifies the voltage to the standard bipolar 10V range; the AD sampling unit uses a 16-bit high-precision 16-channel The collector requires a conversion rate of up to 200kSPS to complete high-precision and high-speed analog-to-digital conversion.

The signal processing unit uses the FPGA chip to receive the data from the high-speed data acquisition module, then performs digital signal processing according to the sound intensity algorithm proposed by the present invention, and sends the sound intensity vector to the security end through the wireless transmission module. FPGA realizes two functions of control and calculation: as a control unit, FPGA enables the AD sampling unit to work, sets the sampling frequency and data output form, and sends sound intensity data and control instructions to the wireless transmission unit; as a calculation unit, FPGA can use the on-chip The advanced hardware multiplier and integrated function block IP core can efficiently complete parallel digital signal processing algorithms such as FFT, FIR, etc., with outstanding advantages in time and power consumption, and can better meet the implementation requirements of sound intensity algorithms.

The wireless transmission unit uses ZigBee transmission technology to provide a transmission distance of not less than 100m, and can accept FPGA instructions and data to send the detected sound intensity to other wireless transmission modules at the remote security end. The wireless transmission unit is installed in a spherical fixed structure, and should point to the ground below the transmission line or on the side of the ground, and then determine the ground area that can receive signals stably through tests, arrange ZigBee receiving devices in this area, and finally transmit the detected sound intensity to the host computer. Used to monitor and analyze sound intensity information at the sound source.

The power supply unit adopts a large-capacity battery to ensure that each module of the sound intensity detection device can supply power for a long time. At the same time, circuits such as boosting, stepping down, voltage stabilization, filtering and coupling need to be built to suppress power supply interference, improve power supply quality, and provide standard power interfaces required for each module.

The implementation method is based on the layout characteristics of the 14-way sound pressure sensors, with the diameter of the sphere as the standard spacing, and according to the sound pressure measured by two paired microphones in a specific direction, the sound intensity at the midpoint in that direction is calculated. In this way, sound intensity values in seven different directions can be obtained, and the sound intensity in each direction can be regarded as the projection of the actual sound intensity vector in this direction. A linear mapping model is established based on the special positional relationship projected in each direction, and a linear equation system containing three unknown quantities can be obtained, as shown below:

In the formula, I _x , I _y , and I _z are the components of the sound intensity vector at the position to be measured in the three-dimensional rectangular coordinate system; I _EF , I _AB , I _CD , I _MR , _ILQ , I _PH , and _ING are seven Sound intensity measurements in specific directions are shown in Figure 5.

Since the number of equations is greater than the number of unknowns, the above-mentioned equations generally do not have exact mathematical solutions, and only approximate engineering solutions can be obtained by using measurement data. The traditional approximate solution is to select some equations equal to the number of unknowns, and then find its mathematical solution, but this cannot make full use of the measurement data, and the solution may have large errors.

In order to minimize the error of the above equations, the linear equations are described in matrix form Including

According to the matrix theory, the pseudo-inverse of the coefficient matrix Q is obtained Let the optimal solution be /> Then the optimal solution is equal to the pseudo-inverse P of the coefficient matrix multiplied by the vector /> Yes /> 3D vector/> That is, the optimal solution of the sound intensity vector at the position to be measured.

The present invention has the following technical effects:

On the one hand, the spherical structure proposed by the present invention can be flexibly installed on the inside or outside of the transmission line. The complete symmetry of the spherical shape reduces the electric field intensity on the surface of the device, and has better voltage equalization and electromagnetic protection effects; due to its good anti-corrosion Interference characteristics, the spherical structure can use wireless transmission technology, avoiding the erection and protection of wired transmission lines, and can safely and reliably detect and transmit audible noise intensity at UHV environmental sound sources. On the other hand, the sensor layout of the spherical structure is more flexible, and multiple typical positions can be selected to measure the sound pressure signal redundantly, and then the sound intensity vector of the point to be measured can be calculated according to the sound intensity algorithm proposed by this patent by using multiple direction data , to reduce random errors in measurement and improve the accuracy of sound intensity detection results.

Description of drawings

Fig. 1 is a schematic diagram of the system architecture of the present invention;

Fig. 2 is a schematic diagram of the arrangement of 14-way sound pressure sensors of the present invention (only part of the sensors are shown in the figure);

Fig. 3 is a structural diagram of a signal processing unit;

Fig. 4 is a schematic diagram of a unidirectional matching sensor;

Fig. 5 is a sensor array layout bitmap of the present invention;

Among them, 1-spherical fixed structure, 2-14 sound pressure sensors, 3-high-speed data acquisition module, 4-signal processing unit, 5-wireless transmission unit 1, 6-power supply unit, 7-wireless transmission unit 2, 8- Host computer, 9-AD sampling unit, 10-FIFO data buffer module, 11-Flash memory, 12-sound intensity vector calculation module.

Detailed ways

The present invention will be described in detail below in conjunction with the accompanying drawings.

The invention relates to a spherical sound intensity detection device and a realization method that can be used in the vicinity of UHV transmission lines. As shown in Figure 1, the present invention includes 1-spherical fixed structure, 2-14 road sound pressure sensors, 3-high-speed data acquisition module, 4-signal processing unit, 5-wireless transmission unit 1, 6-power supply unit, 7- Wireless transmission unit 2, 8-host computer.

The spherical sensing device is installed in the vicinity of the UHV transmission line, and its working principle is as follows: 14 sound pressure sensors with the same characteristics collect 7 sets of sound pressure information near the sound source, and output it as a bipolar high-impedance voltage signal (The specific range is related to the sensitivity of the sound pressure sensor); the high-speed data acquisition module uses a preamplifier to convert the high-impedance signal into a low-impedance signal, and amplifies it into a voltage signal in the standard ±10V range, and uses a 16-bit precision AD sampling unit for synchronous acquisition 14 channels of sound pressure signals; the signal processing unit uses the sound intensity algorithm proposed by FPGA according to the present invention, and converts the sound pressure data in pairs in 7 directions to obtain the sound intensity in one direction, and then converts the sound intensities in 7 different directions to obtain the sound source The sound intensity vector at the location; the wireless transmission unit transmits the sound intensity to the host computer at the security end, which can detect the sound intensity of the sound source in real time.

The spherical fixing structure is used for fixing and protecting each module of the device, so as to ensure safe detection of sound intensity at the sound source of the UHV transmission line. The smooth polished spherical structure can reduce the intensity of the distorted electric field on the surface of the device, improve the voltage equalization performance, and have a better electromagnetic protection effect. The radius of the sphere is reasonably designed through software simulation to change the surface curvature of the device, which also helps to avoid tip corona discharge and prevent the device from being broken down by a strong electric field. Finally, an ultraviolet discharge test should be carried out in a high-potential environment of ±1100kV to confirm that there is no breakdown and corona on the surface and interior of the device, and that the device is not damaged or damaged after the voltage is dropped and grounded. Otherwise, the structural parameters should be re-simulated and designed, the processing technology should be improved, and the installation position should be adjusted to ensure that the sound intensity detection device can work stably and reliably in the UHV environment.

Figure 2 is a schematic diagram of the arrangement of 14 sound pressure sensors. The spherical structure is divided into 8 quadrants by 3 rectangular coordinate axes with the center of the sphere as the origin, and 6 intersection points between the 3 coordinate axes and the spherical surface and the center points of 8 spherical quadrants are determined. According to the symmetry of the sphere, the 14 intersection points are respectively located on the straight lines where the 7 diameters are located. Divide 14 sound pressure sensors with the same characteristics into 7 groups, and arrange them on the spherical surface along the above 7 straight lines. The sensor is fixed on 7 linear brackets, adopts a back-mounted structure, the diaphragm is flush with the spherical surface, and detects the sound pressure at various points near the sound source through the metal mesh that protects the spherical surface. Preferably, the sound pressure sensor is a 40AZ 1/2-inch electret condenser microphone from GRAS Sound & Vibration, Denmark. The measurement frequency range of the microphone is 0.5Hz-20kHz, meeting the frequency range of audible noise; the sound pressure measurement range is 14dB-148dB, and has a high sensitivity of 50mV/Pa. The microphone is small in size, with a diaphragm diameter of 13.2mm and a height of 16.3mm. It can be easily installed on a fixed bracket, fully meeting the requirements of high-precision sound pressure measurement.

The high-speed data acquisition module includes a conditioning circuit and an AD sampling unit. For the 40AZ microphone selected above, its sensitivity is calibrated in a standard anechoic chamber, then the sound pressure range at the noise source is estimated, and the output voltage of the microphone is calculated according to the sensitivity. The conditioning circuit uses a preamplifier to amplify the microphone output signal to the standard bipolar ±10V range while performing impedance transformation, and then converts the standard voltage signal to analog to digital through the AD sampling unit. Preferably, the AD sampling unit uses the AD7616 chip. AD7616 is a 16-bit data acquisition system with a built-in dual 16-bit charge redistribution SAR analog-to-digital converter, which supports dual simultaneous sampling of 16 channels, and the data throughput rate of each channel reaches 1MSPS. The chip can be used to synchronously sample two channels of sound pressure signals that match each other in the same direction, so as to complete the sound pressure acquisition in 7 directions respectively.

The signal processing unit uses FPGA as a control unit and an operation execution unit. Preferably, the FPGA selects the Cyclone series EP4CE10F17C8 chip of Altera Company. On the basis of basic FPGA architecture resources, this chip series device adds clock management unit PLL, embedded memory unit M9K and hardware multiplier. When in use, the M9K module can be configured as a single-port, dual-port RAM, FIFO buffer or ROM to facilitate the storage of various data during operation. Using the multiplier, you can design and realize more efficient parallel structure digital signal processing algorithms such as FFT, FIR and so on. Therefore, the chip can better meet the requirements of data storage and multi-channel parallel FFT operation in signal processing.

As the control unit, the FPGA chip can control the AD sampling unit, FIFO data buffer module, Flash memory, sound intensity vector calculation unit module and wireless transmission unit 1 to work in an orderly manner. Use Verilog HDL to design the input and output, logic control and data operation of the program, then complete the function simulation and timing simulation, and finally download the configured logic circuit to the chip and conduct experimental verification. Preferably, the Flash memory uses an M29W640GT7AN6F chip, which can be powered by 3.3V, has a storage space of 64M bytes, and can store large-scale data.

Figure 4 shows the structure diagram of the signal processing unit. The FIFO data cache module is configured with the M9K module on the FPGA chip, and the 16-bit precision digital signal output by the AD sampling unit is temporarily stored in the module to prevent data from being blocked or lost. The Flash memory is used for large-scale storage of data, including 14 channels of 16-bit precision original sound pressure data and sound intensity vector data obtained by calculation. When the buffer module overflows, the data is transferred to the Flash memory; the sound intensity vector calculation module uses the rich computing resources on the FPGA chip such as hardware multipliers, integrated function block IP cores, etc. to do signal processing, and the collected sound pressure according to this patent The given sound intensity algorithm is converted into sound intensity, and then sent to the security terminal in real time through the wireless transmission unit.

The wireless transmission unit adopts ZigBee module. ZigBee wireless communication technology is a low-speed, low-power, low-complexity, low-cost two-way wireless communication network technology. Compared with Bluetooth or WiFi transmission, the standby time can be increased by dozens of times, and at the same time, the requirements for communication controllers are reduced. , the longest transmission distance is not less than 100m. The Zigbee module includes two parts: sending and receiving, which are respectively installed in the sound intensity detection device at the high-voltage end and the host computer receiving module at the safety end for communication of sound intensity detection results, which can meet the requirements of the design and application.

According to the array sensor arrangement of the spherical structure in 7 specific directions, the sound intensity detection algorithm proposed in this patent is divided into two steps: first, the single-directional sound intensity conversion, that is, through two pairs of matched sound pressure on a specific single line sensor to obtain the sound intensity value in this direction; then the three-dimensional sound intensity vector conversion, that is, to establish a system of equations according to the special geometric mapping relationship in the seven straight line directions, and to minimize the solution error through the pseudo inverse of the coefficient matrix, and calculate the sound intensity Optimal solution for strong vectors.

The sensors arranged on the spherical device measure the sound pressure signal, so this patent proposes a unidirectional sound intensity conversion, which converts the sound pressure measured by two matching sensors on the same straight line into sound intensity. Assuming that the diameter of the spherical device is d, this length is taken as the standard distance between two matching sensors, and the rear arrangement is adopted, as shown in Figure 4, where the reference points 1 and 2 are the two points of the point 0 to be measured. Near points, the distance from both to 0 is equal. This method can approximate the sound intensity at the center point 0 through the sound pressure at the two points 1 and 2.

According to the ideal streaming media motion equation, the relationship between particle vibration velocity and sound pressure is

The sound pressure can be directly measured by the sound pressure sensor, but the sound pressure gradient in formula (1) cannot be directly measured. According to the finite difference principle, the sound pressure gradient at a point 0 in the sound field along the x direction can be approximated by the sound pressure values of two adjacent reference points in this direction, then the vibration velocity of the particle 0 in the x direction is

The sound pressure at point 0 can be approximately expressed as the average value of the sound pressure at two reference points, that is, p=(p ₁ +p ₂ )/2, so the projection component of the transient sound intensity vector at point 0 in the x direction can be expressed as for

The two sound pressure sensors should have the same frequency response characteristics and should be perfectly matched in phase and amplitude. According to equation (3), the mismatch of phase and amplitude directly affects the sound intensity measurement. Therefore, it is necessary to calibrate the phase and amplitude of two matching sensors in a single linear direction before measurement, and take appropriate compensation if necessary to control the measurement error.

The above formula gives the calculation method of the instantaneous sound intensity, but in general, we need to calculate the average sound intensity within a certain period of time, or analyze the distribution characteristics of the sound intensity at each frequency within the period of time, so this patent gives the sound intensity Theoretical derivation of strong frequency distributions.

First calculate the cross-correlation function between the sound pressure p and particle velocity u

The relationship between the average sound intensity and the cross-correlation function in a period is

The cross-correlation function is called the cross-spectrum density function after Fourier transform, and then it is inversely transformed by Fourier to obtain the original function, which can be expressed as

Combining formulas (5) and (6), we have

Equation (7) shows that the cross-spectral density function S _pu (ω) of pressure and vibration velocity is the distribution function of the average sound intensity in the frequency domain. The cross-spectral density function defined in Equation (6) is bilateral and meaningful for both positive and negative frequencies. Here we take the unilateral cross-spectral density function G _pu (ω), and its relationship with the bilateral cross-spectral density function is

Then the distribution function of the sound intensity at the frequency domain point ω in the frequency domain can be expressed as

I(ω)＝S _pu (ω)+S _pu (-ω)＝Re[G _pu (ω)] (9)

Let the Fourier transform of p(t) and u(t) be P(ω) and U(ω), according to the linear and integral characteristics of Fourier transform, we have

According to the Wiener-Hinchin theorem, the cross-spectrum of two signals is the product of the Fourier transform of one signal and the conjugate value of the Fourier transform of the other signal.

Substituting formula (10) into (11), we get

In the formula, G ₂₂ and G ₁₁ are the one-sided autospectral density functions of the sound pressure at point 2 and point 1 respectively, G ₁₂ is the one-sided cross-spectral density function of the sound pressure at point 1 and point 2, and Im represents the imaginary part.

Substituting formula (12) into (9), the frequency distribution function of the average sound intensity can be obtained:

Formula (13) shows that through two matched sound pressure sensors with a distance of d, the average sound intensity at the center point of the standardized spacing can be obtained. Therefore, using this method, the sound intensity values in seven specific directions can be obtained respectively.

The three-dimensional sound intensity vector conversion method is to solve the sound intensity vector at the point to be measured by establishing a system of equations based on the sound intensity values in 7 directions according to its specific geometric relationship. The sensor geometric layout model is shown in Fig. 5. Determine the intersection points A, B, C, D, E, and F of the three coordinate axes and the spherical surface, and arrange three groups of sound pressure sensors on the spherical surface along the diameter direction. Then determine the center points of the eight hanging limits corresponding to the spherical void, and arrange four sets of sensors along the diameter direction.

Note that the sound intensity components of body center 0 in the three orthogonal directions of x, y, and z are I _x , I _y , and I _z , and the unit vectors in the three orthogonal directions are i, j, and k respectively, then at point O The sound intensity Io=I _x i+I _y j+I _z k. The sound intensity values measured in each direction are actually the projection of I _O in this direction, and can also be regarded as the projection of the sound intensity components I _x , I _y , and I _z in three orthogonal directions in this direction. Taking the MR direction of the body diameter as an example, according to the mathematical relationship, the cosine values of the angles between MR and the x-axis, y-axis, and z-axis are:

The sound intensity value I _MR of I _O in the MR direction is equal to the sum of the projections of I _x i+I _y j+I _z k in this direction:

Similarly, projection equations in other diameter directions can be listed, and the following equations can be established:

In the formula, I _x , I _y , and I _z are the components of the sound intensity vector at the body center O point of the position to be measured in the three-dimensional rectangular coordinate system; I _EF , I _AB , I _CD , I _MR , I _LQ , I _PH , I _NG is the sound intensity measurement in 7 specific directions.

Since the sound intensity in a single direction is approximated based on the finite difference principle, the left and right ends of the above equations are approximately equal rather than strictly equal. There are 3 unknowns and 7 equations in the equation system, which belongs to the overdetermined linear equation system, and the exact solution cannot be obtained. In order to minimize the error of the solution of the equations, this patent proposes a sound intensity vector conversion method based on matrix theory. Firstly, the equation system (16) is written in the matrix form of the linear equation system: Including

For the above linear homogeneous equations with no solution, let is the solution that minimizes the error of the system of equations, that is, it can make the norm /> reached the minimum value. According to matrix theory, we know that where P is the pseudo-inverse of the coefficient matrix Q. calculated Then the optimal solution of this system of linear equations under this condition is

According to formula (18), the optimal solution of the sound intensity vector at point O can be obtained:

The applicant of the present invention has explained and described the embodiment of the present invention in detail in conjunction with the accompanying drawings, but those skilled in the art should understand that the above embodiment is only a preferred embodiment of the present invention, and the detailed description is only to help readers better To understand the spirit of the present invention rather than limit the protection scope of the present invention, on the contrary, any improvement or modification made based on the spirit of the present invention shall fall within the protection scope of the present invention.

Claims (5)

1. A spherical sensing device that can be used for sound intensity detection in the vicinity of UHV transmission lines, including a spherical fixed structure, 14-way sound pressure sensors, a high-speed data acquisition module, a signal processing unit, a wireless transmission unit 1 and a power supply unit; Features: The spherical fixing structure is installed in the adjacent area of the split wire, and is used to fix 14 sound pressure sensors, high-speed data acquisition module, signal processing unit, wireless transmission unit 1 and power supply unit, and has the effects of electromagnetic shielding, voltage equalization and insulation; The 14-way sound pressure sensor is arranged on the surface of the spherical fixed structure: a space Cartesian coordinate system is established at the center of the spherical fixed structure, and the 3 coordinate axes generate 6 intersection points with the spherical surface, and the spherical surface is divided into 8 symmetrical spherical segments area, and then take the center point of each spherical void to obtain 14 points on the spherical surface, distributed in 7 different directions; arrange 14 sound pressure sensors with the same characteristics at 14 points to form a sound pressure sensor array, which can measure 14 channels of sound pressure signals in 7 different directions; The high-speed data acquisition module samples and converts the analog signal output by the sensor array into a digital signal after processing; the signal processing unit uses FPGA to resolve 14 sound pressure signals into sound intensity values in 7 different directions. The mapping relationship between establishes an overdetermined linear equation system, and the optimal solution can be obtained to obtain the three-dimensional sound intensity vector of the point to be measured; The overdetermined system of linear equations is described as In the formula, I _x , I _y , and I _z are the components of the three-dimensional sound intensity vector of the point to be measured in the space rectangular coordinate system; I _EF , I _AB , I _CD , I _MR , _ILQ , I _PH , and I _NG are 7 sound intensity values in different directions; The optimal solution minimizes the error of the overdetermined linear equation system, and the overdetermined linear equation system is described as a matrix form Including According to matrix theory, the optimal solution is equal to the pseudo-inverse of the coefficient matrix Q multiplied by the vector Find the optimal solution as /> ; The wireless transmission unit 1 transmits the measurement results to the wireless transmission unit 2 at the remote safe end, and then uploads them to the host computer; the power supply unit uses batteries to provide high-speed data acquisition modules, signal processing units and wireless terminals through voltage conversion and voltage stabilization circuits. The transmission unit 1 supplies power. 2. A kind of spherical sensing device that can be used for sound intensity detection in the vicinity of UHV transmission lines according to claim 1, characterized in that: The spherical fixing structure is used for the installation and fixing of the sound intensity detection device, and the radius of the sphere should consider the size of the adjacent space of the transmission line and the internal 14-way sound pressure sensor, high-speed data acquisition module, signal processing unit, wireless transmission unit 1 and power supply unit. At the same time, the spherical surface is polished and smooth, and the surface is covered with metal mesh to ensure that the spherical fixed structure has good electromagnetic shielding and voltage equalization characteristics. Corona discharge does not occur in a strong electric field environment and does not affect sound intensity measurement. 3. A spherical sensing device that can be used for sound intensity detection in the vicinity of UHV transmission lines according to claim 1, characterized in that: The sound pressure sensor adopts an electret condenser microphone without adding 200V polarization voltage, which can simplify the design of the power supply unit. 4. A spherical sensing device that can be used for sound intensity detection in the vicinity of UHV transmission lines according to claim 1, characterized in that: The high-speed data acquisition module includes a conditioning circuit and an AD sampling unit; the conditioning circuit converts the weak high-impedance voltage collected by the sound pressure sensor into a low-impedance output voltage through a preamplifier, and simultaneously amplifies the voltage to a standard bipolar 10V range; AD sampling unit uses 14 channels to collect standard voltage signals in parallel. 5. A spherical sensing device that can be used for sound intensity detection in the vicinity of UHV transmission lines according to claim 1, characterized in that: The wireless transmission unit 1 uses ZigBee transmission technology to provide a transmission distance of not less than 100m, and can send the detected three-dimensional sound intensity vector to the wireless transmission unit 2 at the remote security end, and then upload it to the host computer.