Transformer substation noise reduction system and method based on plasma

Abstract

The invention discloses a plasma-based transformer substation noise reduction system and method, and belongs to the field of transformer substations. The system comprises a high-voltage power supply device, a corona discharge device, a noise acquisition device and a control module, the high-voltage power supply device is connected with the corona discharge device; the control module is respectively connected with the noise acquisition device and the high-voltage power supply device; the corona discharge device comprises a high-voltage electrode and a low-voltage electrode; the noise acquisition device comprises a reference microphone and an error microphone; the control module comprises a signal acquisition unit and a signal conversion unit. The signal conversion unit comprises an A / D conversion circuit, a DSP processor and a D / A conversion circuit. The plasma active noise reduction technology is adopted, low-frequency noise generated by the transformer substation can be effectively controlled, and meanwhile the noise reduction device is simple in structure, small in size and convenient to install. Through the active noise reduction logic of noise collection-signal processing-inverse sound wave generation, the problem that the low-frequency noise of the transformer substation is difficult to control is solved in a targeted mode, and noise reduction is more direct and efficient.

Description

Technical Field

[0001] This invention relates to the field of substations, and more specifically, to a plasma-based substation noise reduction system and method. Background Technology

[0002] With the acceleration of urbanization and the continuous growth of electricity demand, substations, as a core component of power supply, are widely distributed throughout urban areas. During operation, substations generate noise from equipment such as transformers, electrical switches, circuit breakers, and ventilation systems. Over long-term operation, the noise generated by substations will inevitably have an adverse impact on the lives and even the health of nearby residents.

[0003] To address noise pollution from urban substations, two main measures are currently employed. The first is to optimize the selection, design, and layout of relevant equipment within the substation to reduce noise generation at its source. However, this method often leads to a significant increase in substation construction costs. The second common method is to use passive noise reduction techniques such as sound insulation and sound-absorbing materials to control noise and reduce its propagation to surrounding areas. Patent CN117691496A discloses a substation with noise reduction capabilities and a noise reduction method. This invention eliminates noise generated by transformer resonance through vibration-damping rubber blocks and absorbs noise generated by transformer operation through sound insulation panels, sound-absorbing cotton, and sound-absorbing panels inside the soundproof enclosure, thereby achieving substation noise reduction. Utility model CN222667166U discloses a substation noise reduction device including wall-mounted sound-absorbing components, comprising wall-mounted panels, assembly slots, limiting rods, assembly blocks, positioning slots, and expanding foam. The assembly slots are used for assembling and installing multiple wall-mounted panels, allowing the sound-absorbing components to be installed over a large area on the substation walls. The assembly blocks are engaged with the limiting rods of adjacent wall-mounted panels via the positioning slots, serving as positioning connections between adjacent wall-mounted panels. Expanding foam is finally filled inside the assembly slots and covers the assembly blocks to increase the sound absorption capacity of the gaps during assembly.

[0004] The aforementioned patents primarily employ passive sound absorption for noise reduction. This method typically involves complex structures and large noise reduction devices, and its effectiveness in controlling low-frequency noise in substations is quite limited. Therefore, we propose a plasma-based substation noise reduction system and method. Summary of the Invention

[0005] The purpose of this invention is to provide a plasma-based substation noise reduction system and method to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A plasma-based substation noise reduction system includes a high-voltage power supply unit, a corona discharge unit, a noise acquisition unit, and a control module; the high-voltage power supply unit is connected to the corona discharge unit, and the control module is connected to both the noise acquisition unit and the high-voltage power supply unit. The corona discharge device consists of multiple electrodes, which are fixed to the internal wall of the substation. The electrodes include a high-voltage electrode and a low-voltage electrode. The high-voltage electrode consists of a set of parallel metal wire electrodes, and the low-voltage electrode is a porous metal plate parallel to the high-voltage electrode. The high-voltage power supply is arranged close to the corona discharge device and can output high-voltage direct current and high-voltage alternating current simultaneously. Its high-voltage direct current terminal is connected to the high-voltage electrode of the corona discharge device, and its high-voltage alternating current terminal is connected to the low-voltage electrode of the corona discharge device. The noise acquisition device includes a reference microphone and an error microphone. The reference microphone is arranged close to the outer shell of the noise source in the substation to acquire the original noise signal that is not disturbed in real time. The error microphone is arranged outside the low-voltage electrode of the corona discharge device to acquire the noise-reduced sound signal. The control module is located within the installation area of ​​the corona discharge device or adjacent to the high-voltage power supply device. It includes a signal acquisition unit and a signal conversion unit. The signal conversion unit includes an A / D conversion circuit, a DSP processor, and a D / A conversion circuit. The control module is used to control the output signal of the high-voltage power supply device based on the signal acquired by the noise acquisition device. By adjusting the high-voltage DC and high-voltage AC parameters output by the high-voltage power supply device, the discharge characteristics of the corona discharge device are controlled, so that the corona discharge device generates sound waves with the same amplitude but opposite phase to the substation noise.

[0007] Preferably, the high-voltage power supply device outputs a high-voltage DC voltage of 8kV~9kV and an output high-voltage AC voltage of 200V~500V with a frequency of 50Hz~2000Hz.

[0008] Preferably, the distance between the high-voltage electrode and the low-voltage electrode of the corona discharge device is 6 mm.

[0009] Preferably, the low-pressure porous metal plate has a pore diameter of 3 mm and a porosity of 40%.

[0010] Preferably, there are five corona discharge devices, which are respectively arranged on the inner wall of the top and the inner walls of the four sides of the substation room; Both the control module and the high-voltage power supply are equipped with five signal input and output channels for independent control of each corona discharge device.

[0011] Preferably, it also includes a passive noise reduction device, which is installed at the air inlet and air outlet of the substation.

[0012] Preferably, the corona discharge device further includes an insulating frame, with the high-voltage electrode and the low-voltage electrode fixed on the insulating frame, and the error microphone fixed on the insulating frame near the outside of the low-voltage electrode.

[0013] A plasma-based substation noise reduction method, applied to the aforementioned system, includes the following steps: S1. When the noise source in the substation starts, the corona discharge device is activated simultaneously. S2. Real-time noise signals from substation noise sources are collected via a reference microphone, and noise-reduced sound signals are collected via an error microphone. Both signals are transmitted to the control module. S3. The control module converts two analog signals into digital signals through the A / D conversion circuit of the signal conversion unit. After being processed by the DSP processor, the digital signals are converted back into analog signals through the D / A conversion circuit and output to the high-voltage power supply device. S4. The high-voltage power supply device outputs high-voltage DC power to the high-voltage electrode of the corona discharge device and high-voltage AC power to the low-voltage electrode of the corona discharge device based on the received analog signal. The high-voltage electrode generates charged particles by ionizing the air through corona discharge. The low-voltage electrode controls the movement of charged particles by changing the amplitude, frequency and phase of the AC power, thereby generating sound waves with the same amplitude but opposite phase as the substation noise. S5. The error microphone continuously collects the noise-reduced sound signal and feeds it back to the control module. The control module adjusts the signal output to the high-voltage power supply device according to the feedback signal to achieve continuous noise reduction.

[0014] Preferably, in step S4, the high-voltage DC voltage output by the high-voltage power supply device is 8kV~9kV, the high-voltage AC voltage is 200V~500V, and the frequency is 50Hz~2000Hz; the distance between the high-voltage electrode and the low-voltage electrode of the corona discharge device is 6mm, and the low-voltage electrode is a porous metal plate with a pore diameter of 3mm and a porosity of about 40%.

[0015] Preferably, in step S1, the passive noise reduction devices at the air inlet and outlet of the substation are activated simultaneously, complementing the active noise reduction of the plasma.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) This invention employs plasma active noise reduction technology, which can effectively control low-frequency noise generated in substations. The noise reduction device has a simple structure, small size, and is easy to install. Through the active noise reduction logic of "noise acquisition - signal processing - anti-phase sound wave generation," it specifically addresses the difficulty in controlling low-frequency noise (50Hz~2000Hz) in substations. The control module, through full-process signal optimization of A / D conversion, DSP processing, and D / A conversion, can accurately drive the corona discharge device to generate sound waves with the same amplitude but opposite phase to the noise. Compared to the weak suppression effect of traditional passive noise reduction on low-frequency noise, this solution provides more direct and efficient noise reduction, completely solving the problem of weak low-frequency noise reduction in existing technologies.

[0017] (2) The present invention uses plasma active noise reduction to focus on low-frequency noise, while the passive noise reduction devices (sound absorption coefficient ≥0.85) at the air inlet and outlet cover mid-to-high frequency noise, forming a full-band noise reduction system. This not only prevents noise diffusion inside the substation but also avoids noise leakage from the ventilation openings. The corona discharge device adopts a design of metal wire high-voltage electrode and porous metal plate low-voltage electrode, which can be directly fixed to the internal wall (top and sides) of the substation without occupying a lot of space. It is suitable for the narrow installation environment of various substations, such as closed and open substations in cities, avoiding the problems of large size and complicated installation of traditional passive noise reduction devices. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0019] The following are the labels in the diagram: 1. Transformer; 2. Substation air inlet; 3. Passive noise reduction device for air inlet; 4. Substation air outlet; 5. Passive noise reduction device for air outlet; 6. Corona discharge device; 7. Low voltage stage; 8. High voltage stage; 9. Insulating frame; 10. Reference microphone; 11. Error microphone; 12. Control module; 13. High voltage power supply device. Detailed Implementation

[0020] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0021] Example: Please see Figure 1 A plasma-based substation noise reduction system includes a high-voltage power supply device 13, a corona discharge device 6, a noise acquisition device, and a control module 12; the high-voltage power supply device 13 is connected to the corona discharge device 6, and the control module 12 is connected to both the noise acquisition device and the high-voltage power supply device 13. Multiple corona discharge devices 6 are fixed to the internal wall of the substation, including a high-voltage electrode 8 and a low-voltage electrode 7. The high-voltage electrode 8 consists of a set of parallel arranged metal wire electrodes, and the low-voltage electrode 7 is a porous metal plate parallel to the high-voltage electrode 8. The distance between the high-voltage electrode 8 and the low-voltage electrode 7 of the corona discharge device 6 is 6 mm. The pore diameter of the porous metal plate of the low-voltage electrode 7 is 3 mm, and the porosity is 40%. The distance between the two electrodes is strictly controlled at 6 mm. This distance ensures that the high-voltage direct current ionizes the air to generate a sufficient number of charged particles (electron and positive ion concentration ≥ 10). 5 The porous structure can reduce airflow resistance and does not affect the heat dissipation inside the substation.

[0022] The high-voltage power supply device 13 is arranged close to the corona discharge device 6 and can output high-voltage direct current and high-voltage alternating current at the same time. Its high-voltage direct current terminal is connected to the high-voltage electrode 8 of the corona discharge device 6, and its high-voltage alternating current terminal is connected to the low-voltage electrode 7 of the corona discharge device 6. The noise acquisition device includes a reference microphone 10 and an error microphone 11. The reference microphone 10 is positioned close to the housing of the noise source within the substation to acquire the original, undisturbed noise signal in real time, ensuring that the control module 12 obtains accurate noise reference data. The error microphone 11 is positioned outside the low-voltage electrode of the corona discharge device to acquire the noise-reduced sound signal. The error microphone 11 only acquires the noise-reduced sound signal of the corresponding area to avoid signal interference from other areas. The control module 12 is arranged in the installation area of ​​the corona discharge device 6 or adjacent to the high-voltage power supply device 13. It includes a signal acquisition unit and a signal conversion unit. The signal conversion unit includes an A / D conversion circuit, a DSP processor and a D / A conversion circuit. The control module 12 is used to control the output signal of the high-voltage power supply device 13 according to the signal acquired by the noise acquisition device. By adjusting the high-voltage DC and high-voltage AC parameters output by the high-voltage power supply device 13, the discharge characteristics of the corona discharge device 6 are controlled so that the corona discharge device 6 generates sound waves with the same amplitude and opposite phase to the substation noise.

[0023] The control module 12 is located within the installation area of ​​the corona discharge device 6 or adjacent to the high-voltage power supply device 13 (signal transmission distance ≤ 5m). It includes a signal acquisition unit and a signal conversion unit: the A / D conversion circuit has a sampling rate of 48kHz and a precision of 16 bits, which can accurately capture subtle changes in noise signals; the DSP processor is a TMS320C6748 with a processing speed ≥ 1GHz, which can complete signal analysis and control command generation within 200μs, ensuring real-time synchronization between the inverted acoustic wave and the original noise; the D / A conversion circuit has an output precision of 16 bits, ensuring the stability of the control signal.

[0024] In this application, the high-voltage power supply device 13 outputs a high-voltage DC voltage of 8kV~9kV and an output high-voltage AC voltage of 200V~500V with a frequency of 50Hz~2000Hz.

[0025] In this application, there are five corona discharge devices 6, which are respectively arranged on the inner wall of the top and the inner wall of the four sides of the substation room to form a full space noise reduction coverage and avoid noise dead zones; each corona discharge device 6 consists of a high voltage electrode 8, a low voltage electrode 7 and an insulating frame 9.

[0026] Both the control module 12 and the high-voltage power supply unit 6 are equipped with five signal input and output channels for independent control of each corona discharge device 6. The control module 12 and the high-voltage power supply unit 13 are located adjacent to each other in a corner of the substation. Both have five signal input / output channels, which can independently control the five corona discharge devices 6. Differentiated noise reduction is achieved to avoid energy waste, taking into account the noise intensity differences in different areas of the substation (e.g., noise near the transformer is 65dB~70dB, and noise in the corner area is 55dB~60dB).

[0027] The high-voltage power supply unit 13 is positioned adjacent to the corona discharge unit 6 (wiring length ≤ 3m) to reduce voltage loss. Its output high-voltage DC voltage is stable at 8kV~9kV (ripple coefficient ≤ 0.5%). This voltage range can efficiently ionize air without producing excessive ozone (ozone concentration ≤ 0.1mg / m³, conforming to the "Indoor Air Quality Standard" GB / T 18883-2002). The high-voltage AC voltage is 200V~500V, frequency 50Hz~2000Hz, and can be adjusted in real time according to noise signals to meet the cancellation requirements of different frequency noises. The device has overvoltage, overcurrent, and short-circuit protection functions. When the output voltage is abnormal (exceeding the rated value ±10%) or the current exceeds the limit, the output can be cut off within 50μs to avoid equipment damage and safety hazards.

[0028] This application also includes a passive noise reduction device, which is installed at the air inlet and air outlet of the substation.

[0029] The main source of noise within the substation is transformer 1. To prevent noise propagation through ventilation openings, passive noise reduction devices 3 and 5 are installed at the substation air inlet 2 and air outlet 4, respectively. Both passive noise reduction devices are made of sound-absorbing materials (such as porous sound-absorbing cotton), reducing noise leakage from the ventilation openings through physical sound absorption, thus complementing the plasma active noise reduction system. The passive noise reduction devices complement the plasma active noise reduction system: active noise reduction focuses on low-frequency noise (50Hz~2000Hz), while passive noise reduction covers mid-to-high-frequency noise (250Hz~8kHz), achieving full-frequency noise control. Simultaneously, the airflow resistance of the passive devices is ≤50Pa, ensuring no impact on the substation's ventilation and heat dissipation efficiency (ventilation volume reduction ≤5%).

[0030] In this application, the corona discharge device 6 also includes an insulating frame 9. The high-voltage electrode 8 and the low-voltage electrode 7 are fixed on the insulating frame 9, and the error microphone 11 is fixed on the insulating frame 9 near the outside of the low-voltage electrode 7. The insulating frame 9 is made of epoxy resin (withstanding voltage ≥20kV and high temperature -40℃~85℃), which not only ensures the stable fixation of the high-voltage electrode 8 and the low-voltage electrode 7, but also isolates electric field interference. The error microphone 11 is fixed on the insulating frame 9 near the outside of the low-voltage electrode 7, with a sampling distance ≤0.3m, ensuring the authenticity and timeliness of the sound signal acquisition after noise reduction, and the signal transmission delay ≤100μs.

[0031] A plasma-based substation noise reduction method, applied to the aforementioned system, includes the following steps: S1. When the noise source of the substation (such as transformer 1) is started (the start signal is obtained through linkage of the substation control system, and the response delay is ≤200μs), the corona discharge device 6 and the passive noise reduction device at the air inlet and outlet of the substation are turned on simultaneously. The passive noise reduction device at the air inlet and outlet of the substation complements the active noise reduction of plasma. The passive noise reduction device immediately plays a sound absorption role, and the corona discharge device 6 completes initialization within 1ms to avoid leakage during the noise start-up stage.

[0032] S2. Real-time noise signals from substation noise sources are collected via reference microphone 10, and noise-reduced sound signals are collected via error microphone 11. Both signals are transmitted to control module 12. Real-time noise signals from substation noise sources are collected via reference microphone 10 (sampling interval 11μs), and noise-reduced sound signals are collected via error microphone 11 (sampling interval 11μs). Both signals are transmitted to control module 12 via shielded cable. During transmission, signal attenuation is ≤3dB, and anti-interference capability is strong (can withstand electromagnetic interference intensity ≤100V / m in substation).

[0033] S3, the control module 12 converts two analog signals into digital signals through the A / D conversion circuit of the signal conversion unit. The DSP processor analyzes the amplitude, frequency and phase of the original noise (frequency recognition error ≤1Hz, phase recognition error ≤5°), and generates control signals according to the "anti-phase sound wave cancellation principle". Then, it converts the signals into analog signals through the D / A conversion circuit and outputs them to the high-voltage power supply device 13.

[0034] S4. The high-voltage power supply device 13 outputs high-voltage DC power to the high-voltage electrode of the corona discharge device 6 and high-voltage AC power to the low-voltage electrode 7 of the corona discharge device 6 based on the received analog signal. The high-voltage electrode 8 generates charged particles by ionizing the air through corona discharge. The low-voltage electrode 7 controls the movement of the charged particles by changing the amplitude, frequency and phase of the AC power, generating sound waves with the same amplitude but opposite phase as the substation noise. The high-voltage DC power output by the high-voltage power supply device 13 is 8kV~9kV, the high-voltage AC power is 200V~500V, and the frequency is 50Hz~2000Hz. The distance between the high-voltage electrode 8 and the low-voltage electrode 7 of the corona discharge device 6 is 6mm. The low-voltage electrode 7 is a porous metal plate with a pore size of 3mm and a porosity of about 40%.

[0035] S5. Error microphone 11 continuously collects the noise-reduced sound signal and feeds it back to control module 11. Control module 12 adjusts the signal output to high-voltage power supply device 13 according to the feedback signal to achieve continuous noise reduction.

[0036] Key effect verification Actual measurements showed that the original noise sound pressure level of transformer 1 under rated load was 65dB~70dB (frequency 50Hz~1500Hz). After operation using this method, the average residual noise sound pressure level inside the substation was reduced to 22dB~25dB, the noise leakage from the substation air inlet 2 was reduced to 30dB~32dB, and the noise leakage from the substation air outlet 4 was reduced to 31dB~33dB, all meeting the requirements of Class 1 acoustic environment functional area.

[0037] During system operation, energy consumption is low: the power of a single corona discharge device is ≤30W, the total power of five devices is ≤150W, the passive noise reduction device has no energy consumption, and the overall daily power consumption is ≤3.6kWh, which meets the energy-saving requirements.

[0038] Noise Reduction Process and Working Principle System startup and signal acquisition: When transformer 1 starts up and generates noise, corona discharge device 6, control module 12, high-voltage power supply device 13 and noise acquisition device start up simultaneously: reference microphone 10 acquires the original noise signal of transformer 1, converts it into an analog electrical signal and transmits it to the signal acquisition unit of control module 12; error microphone 11 acquires the uncancelled noise signal in the corresponding area (initially the original noise signal), and also converts it into an analog electrical signal and transmits it to the signal acquisition unit of control module 12.

[0039] Signal processing and command output: After receiving two analog signals, the control module 12 processes them according to the following process: the two analog signals are converted into digital signals through an A / D conversion circuit; the DSP processor analyzes the digital signals, calculates the amplitude, frequency and phase of the original noise, and generates a control signal for driving the high-voltage power supply device 13 based on the "anti-phase sound wave cancellation principle" (this signal corresponds to the voltage parameters required for "sound waves with the same amplitude but opposite phase as the original noise"); the processed digital control signal is converted into an analog control signal through a D / A conversion circuit and output to the high-voltage power supply device 13.

[0040] Corona discharge sound generation and noise cancellation: The high-voltage power supply device 13 adjusts its output parameters according to the received analog control signal: it outputs 8kV~9kV high-voltage DC power to the high-voltage electrode 8 of the corona discharge device 6. This DC power causes corona discharge in the air between the high-voltage electrode 8 and the low-voltage electrode 7, ionizing and generating charged particles (mainly electrons and positive ions); it outputs 200V~500V, 50Hz~2000Hz high-voltage AC power to the low-voltage electrode 7 of the corona discharge device 6. This AC power controls the speed and direction of the charged particles through changes in the electric field, causing the charged particles to collide with air molecules and generate vibrations, thereby radiating sound waves with the same amplitude but opposite phase to the original noise. The anti-phase sound waves meet the original noise generated by the transformer 1 in the internal space of the substation, and the two cancel each other out, achieving noise reduction.

[0041] Real-time feedback and parameter adjustment: Error microphone 11 continuously collects the noise-reduced sound signal and feeds it back to control module 12. If the feedback signal shows that the noise is not completely canceled (the residual noise amplitude exceeds the preset threshold, such as 30dB), control module 12 re-analyzes the signal, adjusts the calculation parameters of the DSP processor, and then corrects the control signal output to high-voltage power supply device 13. High-voltage power supply device 13 adjusts the amplitude, frequency or phase of the output voltage according to the corrected control signal, so that the anti-phase sound wave generated by corona discharge device 6 can more accurately cancel the residual noise, and finally achieve continuous and stable control of noise inside the substation (residual noise amplitude ≤25dB after noise reduction).

[0042] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A plasma-based substation noise reduction system, characterized in that, It includes a high-voltage power supply device, a corona discharge device, a noise acquisition device, and a control module; the high-voltage power supply device is connected to the corona discharge device, and the control module is connected to both the noise acquisition device and the high-voltage power supply device. The corona discharge device comprises multiple devices, fixed to the internal wall of the substation, including a high-voltage electrode and a low-voltage electrode. The high-voltage electrode consists of a set of parallel metal wire electrodes, and the low-voltage electrode is a porous metal plate parallel to the high-voltage electrode. The high-voltage power supply device is arranged adjacent to the corona discharge device and can simultaneously output high-voltage direct current and high-voltage alternating current. Its high-voltage direct current terminal is connected to the high-voltage electrode of the corona discharge device, and its high-voltage alternating current terminal is connected to the low-voltage electrode of the corona discharge device. The noise acquisition device includes a reference microphone and an error microphone. The reference microphone is arranged close to the outer shell of the noise source in the substation to acquire the original noise signal that is not disturbed in real time. The error microphone is arranged outside the low-voltage electrode of the corona discharge device to acquire the noise-reduced sound signal. The control module is located within the installation area of ​​the corona discharge device or adjacent to the high-voltage power supply device. It includes a signal acquisition unit and a signal conversion unit. The signal conversion unit includes an A / D conversion circuit, a DSP processor, and a D / A conversion circuit. The control module is used to control the output signal of the high-voltage power supply device based on the signal acquired by the noise acquisition device. By adjusting the high-voltage DC and high-voltage AC parameters output by the high-voltage power supply device, the discharge characteristics of the corona discharge device are controlled, so that the corona discharge device generates sound waves with the same amplitude but opposite phase to the substation noise.

2. The plasma-based substation noise reduction system according to claim 1, characterized in that: The high-voltage power supply device outputs a high-voltage DC voltage of 8kV~9kV and a high-voltage AC voltage of 200V~500V with a frequency of 50Hz~2000Hz.

3. The plasma-based substation noise reduction system according to claim 1, characterized in that: The distance between the high-voltage electrode and the low-voltage electrode of the corona discharge device is 6 mm.

4. The plasma-based substation noise reduction system according to claim 1, characterized in that: The low-pressure porous metal plate has a pore diameter of 3 mm and a porosity of 40%.

5. A plasma-based substation noise reduction system according to claim 1, characterized in that: The corona discharge device consists of five units, which are respectively arranged on the inner wall of the top and the inner walls of the four sides of the substation room. Both the control module and the high-voltage power supply device are equipped with five signal input and output channels for independent control of each corona discharge device.

6. The plasma-based substation noise reduction system according to claim 1, characterized in that: It also includes passive noise reduction devices, which are installed at the air inlet and air outlet of the substation.

7. A plasma-based substation noise reduction system according to claim 1, characterized in that: The corona discharge device also includes an insulating frame, the high voltage electrode and the low voltage electrode are fixed on the insulating frame, and the error microphone is fixed on the insulating frame near the outside of the low voltage electrode.

8. A plasma-based substation noise reduction method, applied to the system described in any one of claims 1-7, characterized in that, Includes the following steps: S1. When the noise source in the substation starts, the corona discharge device is activated simultaneously. S2. Real-time noise signals from substation noise sources are collected via a reference microphone, and noise-reduced sound signals are collected via an error microphone. Both signals are transmitted to the control module. S3. The control module converts two analog signals into digital signals through the A / D conversion circuit of the signal conversion unit. After being processed by the DSP processor, the digital signals are converted back into analog signals through the D / A conversion circuit and output to the high-voltage power supply device. S4. The high-voltage power supply device outputs high-voltage DC power to the high-voltage electrode of the corona discharge device and high-voltage AC power to the low-voltage electrode of the corona discharge device based on the received analog signal. The high-voltage electrode generates charged particles by ionizing the air through corona discharge. The low-voltage electrode controls the movement of charged particles by changing the amplitude, frequency and phase of the AC power, thereby generating sound waves with the same amplitude but opposite phase as the substation noise. S5. The error microphone continuously collects the noise-reduced sound signal and feeds it back to the control module. The control module adjusts the signal output to the high-voltage power supply device according to the feedback signal to achieve continuous noise reduction.

9. A plasma-based substation noise reduction method according to claim 8, characterized in that: In step S4, the high voltage DC voltage output by the high voltage power supply device is 8kV~9kV, the high voltage AC voltage is 200V~500V, and the frequency is 50Hz~2000Hz; the distance between the high voltage electrode and the low voltage electrode of the corona discharge device is 6mm, and the low voltage electrode is a porous metal plate with a pore diameter of 3mm and a porosity of about 40%.

10. A plasma-based substation noise reduction method according to claim 8, characterized in that: In step S1, the passive noise reduction devices at the air inlet and outlet of the substation are activated simultaneously, complementing the active noise reduction of the plasma.

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