CN113504407B - Spherical sensing device capable of being used for detecting sound intensity of vicinity of ultra-high voltage transmission line and implementation method - 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

Spherical sensing device capable of being used for detecting sound intensity of vicinity of ultra-high voltage transmission line and implementation method

Technical Field

The invention belongs to the technical field of ultra-high voltage transmission of an electric power system, and particularly relates to a spherical sound intensity detection device and an implementation method of an ultra-high voltage transmission line adjacent region.

Background

Along with the continuous improvement of the voltage level of an ultra-high voltage transmission line, the electromagnetic environment problem caused by corona discharge has become one of the decisive factors of line design, wherein audible noise caused by corona is widely focused at present because people can feel the audible noise in person. The characteristics, the generation mechanism, the propagation rule and the ground effect of audible noise generated by the corona discharge of the extra-high voltage line are researched, the accurate prediction and even control of the audible noise level are facilitated, and the method has important significance for constructing the power transmission line meeting the environmental protection requirement.

Audible noise diffuses and attenuates during the propagation process and reflects on the surfaces of obstacles such as the ground, buildings and the like. Ambient noise is also commonly mixed and difficult to filter at a sound pressure level of the noise measured at a height of about 1.5m from ground. Thus, there are different levels of distortion in the audible noise detected near the ground. In contrast, the detection of noise at the sound source in the vicinity of the transmission line can avoid a plurality of interferences, which is helpful for understanding the intrinsic characteristics and rules of noise, and certainly is a better research method. In addition, sound pressure level is a physical quantity indicating the intensity of sound source radiation noise, but sound pressure level is a scalar quantity, and measured data in different environments is poor in referenceability. The sound intensity is a vector, can better reflect the energy, flow and propagation state of a sound source, and has better expressive force on audible noise. At present, sound intensity detection is widely applied to equipment fault diagnosis and quality control, sound power measurement, sound source localization, environmental noise monitoring and other aspects.

The traditional ground method for measuring the sound pressure level of audible noise can not meet the research requirement on the mechanism characteristics of the audible noise source, but the detection method applied to the noise source of the ultra-high voltage true transmission line is not yet developed in the existing research due to the complex electromagnetic environment of the ultra-high voltage transmission line. In fact, the adjacent area of the ultra-high voltage transmission line is the sound source position of the corona discharge audible noise, and the information of the noise source can be directly detected, so that the time-frequency domain characteristics of the audible noise source and the change rule thereof can be directly researched and analyzed. The sound intensity is measured in the vicinity of the ultra-high voltage transmission line, so that the mechanism and the rule of the sound source can be known in depth, the scientific understanding of the phenomenon is deepened, and the aim of taking targeted measures is guided to solve the problem.

Disclosure of Invention

In order to overcome the problems in the prior art, the invention discloses a spherical sensing device for detecting the sound intensity of an adjacent area of an ultra-high voltage transmission line and an implementation method thereof, wherein the spherical sensing device comprises a sound intensity algorithm based on the device architecture. The invention aims to collect multipath sound pressure at the high-voltage end of an ultra-high voltage transmission line in parallel, calculate a three-dimensional sound intensity vector, and then transmit detected sound intensity data to an upper computer through a wireless transmission module.

In order to achieve the above purpose, the present invention adopts the following technical scheme: the sensing device comprises a spherical fixed structure, 14 paths of sound pressure sensors, a high-speed data acquisition module, a signal processing unit, a wireless transmission unit 1 and a power supply unit; according to the arrangement rule of 14 paths of sensor arrays on a spherical structure, calculating sound intensity values of specific different linear directions through a sound intensity algorithm, and then establishing a redundant linear mapping model based on a specific position relation among the directions so as to obtain sound intensity vectors at the center of the sphere.

The spherical fixing structure is arranged in the vicinity of the ultra-high voltage transmission line, other modules of the detection device are wrapped inside, and the equipment can be protected to work normally in an open air environment. Because the detection device is in the complex electromagnetic environment of the extra-high voltage adjacent area, the spherical structure with the best insulation and voltage equalizing effects is selected, so that the point discharge can be effectively avoided. The sphere radius design needs to consider the size of the adjacent space of the transmission line and the volumes of other modules in the transmission line, so that the requirement of sound intensity detection is met. The spherical surface is polished smoothly, the surface is covered by a metal net, the corona-forming field intensity of the surface of the device is improved, the sound intensity detection is not influenced, and the detection device is ensured to work safely and reliably in an ultra-high voltage environment of +/-1100 kV.

The 14 paths of sound pressure sensors are arranged at 14 specific points of the spherical structure: and establishing a space rectangular coordinate system at the sphere center, and selecting 6 intersection points of the coordinate axis and the sphere and the center point of the sphere corresponding to 8 quadrants to obtain 14 points in 7 diameter directions. The 14 sound pressure sensors with the same characteristics are equally divided into 7 groups, and are arranged at 14 points of the spherical surface along the diameter direction of the 7 groups, as shown in fig. 2. 7 supports are specially designed along the diameter direction of 7, each group of sensors is fixed at two ends of the support in a back-mounted mode, the vibrating diaphragm center of each sensor is symmetrical about the sphere center, and the sensors point to an outside 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. Meanwhile, the defects of the traditional capacitor microphone are avoided, the additional 200V polarization voltage is not needed, and the design of the power supply unit can be simplified.

The high-speed data acquisition module comprises a conditioning circuit and an AD sampling unit. The conditioning circuit adopts a pre-amplifier to convert weak high-impedance output voltage acquired by the sound pressure sensor into low-impedance voltage, and simultaneously amplifies the voltage to a standard bipolar 10V range; the AD sampling unit uses a 16-bit high-precision 16-channel collector, and the required conversion rate can reach 200kSPS so as to complete high-precision high-speed analog-digital conversion.

The signal processing unit receives data of the high-speed data acquisition module by using the FPGA chip, then carries out digital signal processing according to the sound intensity algorithm provided by the invention, and sends sound intensity vectors to the safety end through the wireless transmission module. The FPGA realizes the functions of control and operation: the FPGA is used as a control unit to enable the AD sampling unit to work, set the sampling frequency and the data output form, and simultaneously send sound intensity data and control instructions to the wireless transmission unit; as an operation unit, the FPGA can efficiently complete parallel digital signal processing algorithms such as FFT, FIR and the like by utilizing a hardware multiplier on a chip and an integrated functional block IP core, has prominent advantages in time and power consumption, and can better meet the realization requirement of a sound intensity algorithm.

The wireless transmission unit provides a transmission distance of not less than 100m by using a ZigBee transmission technology, and can receive instructions and data of the FPGA to send detected sound intensity to other wireless transmission modules at a remote safety end. The wireless transmission unit is arranged on the spherical fixed structure and is pointed to the ground below or at the side of the power transmission line, then the ground area capable of stably receiving signals is determined through experiments, the ZigBee receiving device is arranged in the area, and finally the detected sound intensity is transmitted to the upper computer for monitoring and analyzing the sound intensity information at the sound source.

The power supply unit adopts a high-capacity battery to ensure that each module of the sound intensity detection device can supply power for a long time. Meanwhile, circuits such as boosting, reducing, stabilizing, filtering and coupling are also required to be built, so that power supply interference is suppressed, the power supply quality is improved, and a required standard power supply interface is provided for each module.

According to the implementation method, according to the arrangement characteristics of 14 paths of sound pressure sensors, the diameter of a sphere is used as a standard interval, and according to sound pressures measured by two paired microphones in a specific direction, the sound intensity of a midpoint position in the direction is solved. Thus, the sound intensity values of 7 different directions can be obtained, and the sound intensity of each direction can be regarded as the projection of the actual sound intensity vector in the direction. A linear mapping model is established based on the special position relation of the projections in each direction, and a linear equation set containing 3 unknown quantities can be obtained as follows:

in which I _x 、I _y 、I _z The component of the sound intensity vector of the position to be measured under the three-dimensional rectangular coordinate system; i _EF 、I _AB 、I _CD 、I _MR 、I _LQ 、I _PH 、I _NG Is a measure of the sound intensity for 7 particular directions as shown in fig. 5.

Because the number of equations is greater than the number of unknowns, the system of equations generally does not have a mathematically exact solution, and only measurement data can be used to find an approximate solution in engineering. The traditional approximate solution is to select partial equations with the same number as the unknowns and then solve the mathematical solution, but the partial equations cannot fully utilize the measurement data, and the solution may have larger errors.

To minimize the error of the above equation set, the linear equation set is described as a matrix formTherein is provided with

According to matrix theory, obtaining pseudo-inverse of coefficient matrix QLet the optimal solution be->The optimal solution is equal to the pseudo-inverse P of the coefficient matrix multiplied by the vector +.>There is->Three-dimensional vector->And the optimal solution of the sound intensity vector of the position to be detected is obtained.

The invention has the following technical effects:

on one hand, the spherical structure provided by the invention can be flexibly arranged on the inner side or the outer side of a power transmission line, the spherical perfect symmetry reduces the electric field intensity on the surface of the device, and the spherical structure has better voltage equalizing and electromagnetic protection effects; because of the good anti-interference characteristic, the spherical structure can use a wireless transmission technology, so that the problems of erection and protection of a wired transmission line are avoided, and the audible noise intensity can be safely and reliably detected and transmitted at the sound source of the ultra-high pressure environment. On the other hand, the sensor with the spherical structure is more flexible in layout, a plurality of typical positions can be selected to redundantly measure sound pressure signals, then the sound intensity vectors of points to be measured are calculated by utilizing the data in a plurality of directions according to the sound intensity algorithm provided by the patent, so that random errors in measurement are reduced, and the accuracy of sound intensity detection results is improved.

Drawings

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

FIG. 2 is a schematic diagram of a 14-way acoustic pressure sensor arrangement of the present invention (only a portion of the sensors are shown);

fig. 3 is a block diagram of a signal processing unit;

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

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

the device comprises a 1-spherical fixed structure, 2-14 paths of sound pressure sensors, a 3-high-speed data acquisition module, a 4-signal processing unit, a 5-wireless transmission unit 1, a 6-power supply unit, a 7-wireless transmission unit 2, 8-upper computer, a 9-AD sampling unit, a 10-FIFO data buffer module, an 11-Flash memory and a 12-sound intensity vector operation module.

Detailed Description

The present invention will be described in detail with reference to the accompanying drawings.

The invention discloses a spherical sound intensity detection device and an implementation method for an ultra-high voltage transmission line adjacent area. As shown in figure 1, the invention comprises a 1-spherical fixed structure, 2-14 paths of sound pressure sensors, a 3-high-speed data acquisition module, a 4-signal processing unit, a 5-wireless transmission unit 1, 6-power supply unit and a 7-wireless transmission unit 2, 8-upper computer.

The spherical sensing device is arranged in an adjacent area of the ultra-high voltage transmission line, and the working principle is as follows: the 14 paths of sound pressure sensors with the same characteristics collect 7 groups of sound pressure information near a sound source and output the sound pressure information as bipolar high-impedance voltage signals (the specific range is related to the sensitivity of the sound pressure sensors); the high-speed data acquisition module converts a high-impedance signal into a low-impedance signal by using a preamplifier, amplifies the low-impedance signal into a voltage signal in a standard + -10V range, and synchronously acquires 14 paths of sound pressure signals by using a 16-bit-precision AD sampling unit; the signal processing unit uses FPGA according to the sound intensity algorithm provided by the invention, converts the sound pressure data in pairs in 7 directions to obtain unidirectional sound intensity, and then converts the sound intensity in 7 different directions to obtain a sound intensity vector at the sound source; the wireless transmission unit transmits the sound intensity to the upper computer of the safety end, so that the sound intensity of the sound source can be detected in real time.

The spherical fixing structure is used for fixing and protecting each module of the device, and ensuring the safety detection of sound intensity at the sound source of the ultra-high voltage transmission line. The smooth spherical structure of polishing can reduce the intensity of the distorted electric field on the surface of the device, improve the voltage equalizing performance and have better electromagnetic protection effect. The radius of the sphere is reasonably designed through software simulation so as to change the surface curvature of the device, and the device is also beneficial to avoiding tip corona discharge and preventing the device from being broken down by a strong electric field. Finally, ultraviolet discharge tests are carried out in a high-potential environment of +/-1100 kV, and it is determined that no breakdown and corona phenomena occur on the surface and inside of the device, and the device is not damaged or damaged after voltage reduction and grounding. Otherwise, the structural parameters should be re-simulated, the processing technology is improved, and the installation position is adjusted so as to ensure that the sound intensity detection device works in an ultra-high voltage environment stably and reliably.

Fig. 2 shows a schematic diagram of a 14-channel sound pressure sensor arrangement. The spherical structure is divided into 8 quadrants by 3 right-angle coordinate axes with the sphere center as an origin, and 6 intersection points of the 3 coordinate axes and the spherical surface and the center point of the 8 spherical quadrants are determined. According to the symmetry of the sphere, 14 intersection points are respectively positioned on the straight lines with 7 diameters. The 14 sound pressure sensors with the same characteristics are divided into 7 groups, and the 7 groups are respectively arranged on the spherical surface along the 7 straight line directions. The sensor is fixed on the support of 7 straight line directions, adopts back-mounted structure, and the vibrating diaphragm is parallel and level with the sphere, sees through the metal mesh of protection sphere and detects the acoustic pressure of each point position near the sound source. Preferably, the acoustic pressure sensor is a 40AZ 1/2 inch electret condenser microphone from Denmark GRAS Sound & Vibration. The frequency band measured by the microphone is 0.5 Hz-20 kHz, and the frequency band range of audible noise is satisfied; the sound pressure measuring range is 14 dB-148 dB, and the high sensitivity of 50mV/Pa is achieved. The microphone is small in size, the diameter of the vibrating diaphragm is 13.2mm, the height is 16.3mm, the microphone can be conveniently arranged on the fixed support, and the requirement of high-precision sound pressure measurement is completely met.

The high-speed data acquisition module comprises a conditioning circuit and an AD sampling unit. For the above-selected 40AZ type microphone, the sensitivity thereof was calibrated in a standard anechoic chamber, and then the sound pressure range at the noise source was estimated, and the output voltage of the microphone was calculated from the sensitivity. The conditioning circuit adopts a preamplifier to amplify the microphone output signal to the standard bipolar + -10V range while carrying out impedance transformation, and then carries out analog-to-digital conversion on the standard voltage signal through an AD sampling unit. Preferably, the AD sampling unit selects an AD7616 chip. AD7616 is a 16-bit data acquisition system, a two-way 16-bit charge redistribution SAR analog-to-digital converter is arranged in the system, two-way synchronous sampling of 16 channels is supported, and the data throughput rate of each channel reaches 1MSPS. The chip can be used for synchronously sampling two paths of sound pressure signals which are matched with each other in the same direction, so that the sound pressure acquisition in 7 directions is completed respectively.

The signal processing unit uses an FPGA as a control unit and an operation execution unit. Preferably, the FPGA selects the Altera Cyclone series EP4CE10F17C8 chip. The chip serial device is added with a clock management unit PLL, an embedded memory unit M9K and a hardware multiplier on the basis of basic FPGA architecture resources. When in use, the M9K module can be configured into a single-port RAM, a double-port RAM and a FIFO buffer or ROM, so as to facilitate various data storage in the operation process. Using multipliers, digital signal processing algorithms such as FFT, FIR, etc. can be designed that achieve a more efficient parallel structure. Therefore, the chip can better meet the requirements of data storage, multipath parallel FFT operation and the like in signal processing.

The FPGA chip is used as a control unit and can control the AD sampling unit, the FIFO data buffer module, the Flash memory, the sound intensity vector operation unit module and the wireless transmission unit 1 to work cooperatively and orderly. And (3) performing input and output, logic control and data operation by using a Verilog HDL design program, then completing functional simulation and time sequence simulation, and finally downloading the configured logic circuit into a chip and performing experimental verification. Preferably, the Flash memory uses AN M29W640GT7AN6F chip, which can be powered by 3.3V and has 64 Mbyte memory space for storing large-scale data.

Fig. 4 shows a block diagram of the signal processing unit. The FIFO data buffer module is configured by an M9K module on the FPGA chip, and the digital signal with 16-bit precision output by the AD sampling unit is temporarily stored in the module, so that data blocking or loss is prevented. The Flash memory is used for storing data in a large scale, and comprises 14 paths of original sound pressure data with 16-bit precision and sound intensity vector data obtained through operation. When the cache module overflows, data are transferred to a Flash memory; the sound intensity vector operation module uses abundant computing resources such as a hardware multiplier, a comprehensive function block IP core and the like on an FPGA chip to perform signal processing, converts collected sound pressure into sound intensity according to a sound intensity algorithm provided by the patent, and then sends the sound intensity to a safety end in real time through a wireless transmission unit.

The wireless transmission unit adopts a ZigBee module. The ZigBee wireless communication technology is a bidirectional wireless communication network technology with low speed, low power consumption, low complexity and low cost, and compared with Bluetooth or WiFi, the transmission standby time can be improved by tens of times, the requirement on a communication controller is reduced, and the transmission distance is not less than 100m at the longest. The Zigbee module comprises a sending part and a receiving part, is respectively arranged in the sound intensity detection device at the high-voltage end and the upper computer receiving module at the safety end, is used for communication of sound intensity detection results, and can meet the requirements of design application.

According to the spherical structure, the array type sensor is arranged in 7 specific directions, and the sound intensity detection algorithm provided by the patent is divided into two steps: firstly, converting unidirectional sound intensity, namely acquiring sound intensity values in a specific direction through two paired matched sound pressure sensors on a single line; and then three-dimensional sound intensity vector conversion, namely, establishing an equation set according to a special geometric mapping relation in 7 linear directions, minimizing solving errors through pseudo-inverse of a coefficient matrix, and calculating to obtain an optimal solution of the sound intensity vector.

The sound pressure signal is measured by the sensors arranged on the spherical device, so the patent provides unidirectional sound intensity conversion, and the sound pressure measured by the two matched sensors on the same straight line is converted into sound intensity. Assuming that the diameter of the spherical device is d, the length is taken as the standard distance between the two matched sensors, and a back-arranged arrangement mode is adopted, as shown in fig. 4, wherein reference points 1 and 2 are two adjacent points of the point to be measured 0, and the distances from the reference points 1 and 2 to the point to be measured 0 are equal. The method can approximately calculate the sound intensity at the center point 0 through the sound pressures at the points 1 and 2.

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

Sound pressure can be measured directly by a sound pressure sensor, but the sound pressure gradient in formula (1) cannot be measured directly. According to the finite difference principle, the sound pressure gradient along the x-direction at a certain point 0 in the sound field can be approximately estimated by the sound pressure values of two adjacent reference points in the direction, and 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 of the sound pressures at the two reference points, i.e., p= (p ₁ +p ₂ ) 2, the projection component of the transient intensity vector at 0 point in the x-direction can be expressed as

The two sound pressure sensors should have the same frequency response characteristics and the phase and amplitude should be perfectly matched. According to equation (3), the mismatch of phase and amplitude directly affects the sound intensity measurement. Therefore, two matched sensors in a single straight line direction must be phase and amplitude calibrated before measurement, with appropriate compensation being taken as necessary to control measurement errors.

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

First, a cross-correlation function between sound pressure p and particle velocity u is calculated

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

The cross-correlation function is called as a cross-spectral density function through Fourier transformation, and then the cross-correlation function is subjected to inverse Fourier transformation to obtain an original function which can be expressed as

In combination with (5) and (6), there are

The cross-spectral density function of the pressure and the vibration speed is shown in (7)S _pu (ω) is a 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, a single-sided cross spectral density function G is taken _pu (omega) its relation to the bilateral cross-spectral density function is

The distribution function of the sound intensity at the frequency domain mid-frequency point omega can be expressed as

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

Let P (t) and U (t) be Fourier transforms into P (ω) and U (ω), based on the linear and integral characteristics of the Fourier transforms

According to wiener-Xin Qinding theory, the cross spectrum of two signals is the product of one signal Fourier transform and the conjugate value of the other signal Fourier transform, and has

Substituting formula (10) into formula (11) to obtain

G in ₂₂ 、G ₁₁ Single-sided self-spectral density function of sound pressure at point 2 and point 1, G ₁₂ Is a single-sided cross spectral density function of sound pressure at points 1 and 2, im representing the imaginary part.

Substituting equation (12) into (9) yields the frequency distribution function of the average sound intensity:

equation (13) shows that by means of two matched sound pressure sensors with a distance d, the average sound intensity at their center point can be obtained at this normalized distance. Therefore, using this method, the sound intensity values in 7 specific directions can be obtained, respectively.

The three-dimensional sound intensity vector conversion method is to establish an equation set according to the sound intensity values of 7 directions and solve the sound intensity vector at the point to be measured. The sensor geometry model is shown in fig. 5. And determining the intersection points A, B, C, D, E, F of the 3 coordinate axes and the spherical surface, and arranging three groups of sound pressure sensors on the spherical surface along the diameter direction. Then, the center point of the corresponding sphere of the 8 hanging limits is determined, and four groups of sensors are arranged along the diameter direction.

The sound intensity components of the 0 point of the memory core in the x, y and z orthogonal directions are I _x 、I _y 、I _z If the unit vectors of the three orthogonal directions are I, j, and k, respectively, the sound intensity io=i at the O point _x i+I _y j+I _z k. The sound intensity value measured in each direction is I _O The projection in this direction can also be regarded as the sound intensity component I in three orthogonal directions _x 、I _y 、I _z Projection in this direction. Taking the body diameter MR direction as an example, the chord values of the MR and the clamping angles of the x axis, the y axis and the z axis are respectively as follows according to the mathematical relationship:

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

similarly, projection equations in other diametrical directions can be listed, and the following equation set is established:

in which I _x 、I _y 、I _z The sound intensity vector is a component of the sound intensity vector of the body center O point of the position to be detected under a three-dimensional rectangular coordinate system; i _EF 、I _AB 、I _CD 、I _MR 、I _LQ 、I _PH 、I _NG Is a measure of the sound intensity for 7 specific directions.

Since the sound intensity in one direction is approximately obtained according to the finite difference principle, the left and right ends of the above equation set are approximately equal, not exactly equal. The equation set has 3 unknowns and 7 equations, belongs to the overdetermined linear equation set, and cannot be solved accurately. In order to minimize errors of the equation solution, the patent provides a sound intensity vector conversion method based on matrix theory. First, the system of equations (16) is written as a matrix form of a linear system of equations:therein is provided with

For the above linear homogeneous equation set without solution, setIs a solution to minimize the error of the system of equations, i.e. it can make the norm +.>Reaching a minimum. According to the matrix theory, it can be seen that->Where P is the pseudo-inverse of the coefficient matrix Q. Calculated to obtain Then the optimal solution of the system of linear equations under this condition is

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

while the applicant has described and illustrated the examples of the present invention in detail with reference to the drawings of the specification, it should be understood by those skilled in the art that the above examples are only preferred embodiments of the present invention, and the detailed description is only for the purpose of helping the reader to better understand the spirit of the present invention, but not limiting the scope of the present invention, but any improvements or modifications based on the spirit of the present invention should fall within the scope of the present invention.

Claims (5)

1. A spherical sensing device for detecting sound intensity of an ultra-high voltage transmission line adjacent area comprises a spherical fixing structure, 14 paths of sound pressure sensors, a high-speed data acquisition module, a signal processing unit, a wireless transmission unit 1 and a power supply unit; the method is characterized in that:

the spherical fixing structure is arranged in the adjacent area of the split conductor and used for fixing 14 paths of sound pressure sensors, a high-speed data acquisition module, a signal processing unit, a wireless transmission unit 1 and a power supply unit, and has electromagnetic shielding, voltage equalizing and insulating effects;

the 14 paths of sound pressure sensors are arranged on the surface of the spherical fixing structure: establishing a space rectangular coordinate system at the sphere center of the spherical fixing structure, generating 6 intersection points between 3 coordinate axes and the spherical surface, dividing the spherical surface into 8 symmetrical sphere segment areas, and taking the center point of each sphere segment to obtain 14 point positions on the spherical surface, wherein the 14 point positions are distributed in 7 different directions; the 14 sound pressure sensors with the same characteristics are arranged at 14 points to form a sound pressure sensor array, and 14 paths of sound pressure signals in 7 different directions can be measured;

the high-speed data acquisition module processes and samples the analog signals output by the sensor array and converts the processed analog signals into digital signals; the signal processing unit uses the FPGA to calculate 14 paths of sound pressure signals into 7 sound intensity values in different directions, an overdetermined linear equation set is established according to the mapping relation between the directions, and the optimal solution is obtained to obtain a three-dimensional sound intensity vector of a to-be-measured point;

the system of overdetermined linear equations is described as

Wherein I is _x 、I _y 、I _z The component of the three-dimensional sound intensity vector of the to-be-measured point under a space rectangular coordinate system; i _EF 、I _AB 、I _CD 、I _MR 、I _LQ 、I _PH 、I _NG Is the sound intensity value of 7 different directions;

the optimal solution minimizes the error of the overdetermined linear equation set, which is described as a matrix form Therein is provided with

According to matrix theory, the optimal solution is equal to the pseudo-inverse of coefficient matrix Q multiplied by the vectorSolving the optimal solution as->；

The wireless transmission unit 1 transmits the measurement result to the wireless transmission unit 2 of the remote security terminal and then uploads the measurement result to the upper computer; the power supply unit uses a battery to supply power for the high-speed data acquisition module, the signal processing unit and the wireless transmission unit 1 through a voltage conversion and voltage stabilizing circuit.

2. The spherical sensing device for detecting sound intensity in the vicinity of an ultra-high voltage transmission line according to claim 1, wherein:

the spherical fixing structure is used for installing and fixing the sound intensity detection device, and the radius of the sphere is required to consider the size of the adjacent space of the transmission line and the volumes of the internal 14 paths of sound pressure sensors, the high-speed data acquisition module, the signal processing unit, the wireless transmission unit 1 and the power supply unit; meanwhile, the spherical surface is polished smoothly, the surface is covered by a metal net, so that the spherical fixing structure has good electromagnetic shielding and voltage equalizing characteristics, no corona discharge occurs in a strong electric field environment, and sound intensity measurement is not affected.

3. The spherical sensing device for detecting sound intensity in the vicinity of an ultra-high voltage transmission line according to claim 1, wherein:

the sound pressure sensor adopts an electret capacitor microphone, 200V polarization voltage is not needed to be externally applied, and the design of a power supply unit can be simplified.

4. The spherical sensing device for detecting sound intensity in the vicinity of an ultra-high voltage transmission line according to claim 1, wherein:

the high-speed data acquisition module comprises a conditioning circuit and an AD sampling unit; the conditioning circuit converts weak high-impedance voltage acquired by the sound pressure sensor into low-impedance output voltage through the preamplifier, and amplifies the voltage to a standard bipolar 10V range; the AD sampling unit collects standard voltage signals in parallel using 14 channels.

5. The spherical sensing device for detecting sound intensity in the vicinity of an ultra-high voltage transmission line according to claim 1, wherein:

the wireless transmission unit 1 provides a transmission distance of not less than 100m by using a ZigBee transmission technology, and can send the detected three-dimensional sound intensity vector to the wireless transmission unit 2 at a remote safety end and then upload the three-dimensional sound intensity vector to an upper computer.