Transformer partial discharge monitoring method based on high frequency response das system

Abstract

This invention discloses a method for monitoring partial discharge in transformers based on a high-frequency response DAS system, comprising: determining a partial discharge monitoring scheme and designing an optical fiber network according to the structure and layout of the transformer to be monitored; winding optical fibers into optical fiber loops, ensuring the loops are uniformly wrapped around the transformer surface; connecting the optical fiber loops on the transformer to a DAS demodulation host device located in an electromagnetic shielding room using optical fiber patch cords; conducting preliminary transformer background noise monitoring and calibrating the transformer background noise; and, after the transformer is put into use, using the DAS demodulation host device to monitor the partial discharge status of the transformer in real time during operation. This invention, based on the transformer's structure and layout characteristics, attaches corresponding optical fiber loops to the transformer surface, and, in conjunction with a DAS host device with a high-frequency response range, achieves the monitoring of partial discharge in the transformer.

Description

Technical Field

[0001] This invention belongs to the field of distributed optical fiber sensing technology, and particularly relates to a method for monitoring partial discharge of transformers based on a high-frequency response DAS system. Background Technology

[0002] A transformer is a device that uses the principle of electromagnetic induction to change alternating current voltage. It mainly consists of an iron core, windings, transformer oil, insulating bushings, and a cooling system. Common types of transformers include power transformers and distribution transformers, which, as fundamental equipment for power transmission and distribution, are widely used in industry, agriculture, transportation, and urban communities.

[0003] During long-term operation, the internal electric field distribution of a transformer becomes scattered. Combined with its complex structure, air and impurities can easily seep into the insulation layers during operation and use. Over time, this accumulation of charge leads to partial discharge. Although partial discharge is brief and low in energy, its prolonged presence can cause significant damage to the insulation material. If not addressed promptly, insulation breakdown can occur, preventing the transformer from operating safely. Therefore, insulation aging and damage often begin with partial discharge. Because partial discharge is very weak, manual and ultrasonic detection methods cannot detect it accurately and promptly. High-sensitivity monitoring instruments are needed to measure partial discharge and continuously monitor the transformer's condition in real time to ensure safe power transmission.

[0004] Optical fiber, as an insulating material composed of quartz glass encased in a polymer material, possesses advantages such as lightness, flexibility, resistance to electromagnetic interference, and long service life. It can be directly attached to transformers, bringing it close to potential partial discharge sources, thus enabling the diagnosis and location of insulation defects. Researchers have attempted to use fiber optic sensors to monitor partial discharge in transformers. Due to the high frequency response of fiber optic interferometers, existing fiber-optic-based partial discharge monitoring sensors are primarily fiber optic interferometers. However, fiber optic interferometers can only monitor vibration signals at one location. Since partial discharge phenomena in transformers occur randomly, monitoring with fiber optic interferometers is prone to missed detections and may even lead to insulation breakdown at localized locations, resulting in poor monitoring performance. Compared to fiber optic interferometers, which can only monitor one location on the transformer, high-frequency response DAS systems can achieve comprehensive distributed monitoring of partial discharge phenomena in transformers. Summary of the Invention

[0005] Technical problem solved: This invention proposes a method for monitoring partial discharge of transformers based on a high-frequency response DAS system. According to the structure and layout characteristics of the transformer, a corresponding optical fiber ring is pasted on the surface of the transformer. By cooperating with a DAS host device with a high frequency response range, the partial discharge of the transformer can be monitored.

[0006] Technical solution:

[0007] A method for monitoring partial discharge in transformers based on a high-frequency response DAS system, the method comprising the following steps:

[0008] S1. Based on the structure and layout of the transformer to be monitored, determine the partial discharge monitoring scheme for the transformer and design the fiber optic network.

[0009] S2, wind the optical fiber into an optical fiber ring, apply epoxy resin to the area where the optical fiber ring is laid, and completely stick the optical fiber ring onto the epoxy resin with glass fiber tape so that the optical fiber ring is evenly wrapped around the surface of the transformer.

[0010] S3 uses fiber optic patch cords to connect the fiber optic ring on the transformer to the DAS demodulation host equipment located in the electromagnetic shielding room; wherein, the end of the fiber optic ring on the transformer is connected to the beginning of the fiber optic patch cord, and the end of the fiber optic patch cord is connected to the DAS demodulation host equipment in the electromagnetic shielding room.

[0011] S4, connect the power supply of the DAS demodulation host equipment, set the system demodulation parameters, carry out preliminary transformer background noise monitoring, and calibrate the transformer background noise;

[0012] S5, after the transformer is put into use, uses DAS demodulation host equipment to monitor the partial discharge status of the transformer in real time during operation.

[0013] Furthermore, in step S1, the process of determining the partial discharge monitoring scheme and designing the fiber optic network based on the structure and layout of the transformer to be monitored includes the following sub-steps:

[0014] S11, Place the transformer to be monitored on the monitoring platform, with the bottom radius of the transformer being less than or equal to half the width of the monitoring platform;

[0015] S12, Analyze the structure and layout of the transformer to be monitored to obtain the vibration area. Calculate the diameter and number of fiber optic rings based on the size parameters of the vibration area and the monitoring accuracy requirements. The diameter of the fiber optic ring multiplied by the number of fiber optic rings should be less than the length of the vibration area. Set the corresponding DAS system demodulation parameters, including measurement distance, pulse repetition frequency, number of blocks, and pulse width.

[0016] S13 uses a metal protective wall to surround the monitoring platform to form a monitoring area, and an oil recovery device is installed at the bottom of the monitoring area; the electromagnetic shielding room is located outside the monitoring area.

[0017] Furthermore, in step S13, gravel is laid at the bottom of the monitoring area, excluding the monitoring platform, to form an oil recovery device.

[0018] Furthermore, the epoxy resin coating and fiberglass tape completely cover the fiber optic ring.

[0019] Furthermore, in step S5, the process of using the DAS demodulation host device to monitor the partial discharge state of the transformer in real time during operation includes:

[0020] The phase change of the backscattered signal transmitted by the fiber optic loop is collected and demodulated to obtain the vibration information along the fiber optic line. Based on the vibration information, the partial discharge power source of the transformer and the insulation defects it causes are diagnosed and located.

[0021] Specifically, partial discharge causes the transformer oil inside the transformer to expand due to heat, which changes the internal pressure of the transformer and causes the tank to vibrate. The fiber optic ring on the surface of the transformer is vibrated, transmitting a backscattered Rayleigh signal carrying phase change information to the DAS demodulation host. Based on the phase change of the backscattered signal, all broadband impact signals are extracted. A short-time Fourier transform is performed on the extracted signal, and the high-frequency signal is observed. If the intensity of the high-frequency signal gradually increases before the transformer device is impacted, and the intensity suddenly drops to the lowest intensity threshold after the impact vibration, and the duration of the drop is less than the preset duration threshold, then it is inferred that the impact signal is a partial discharge signal inside the device.

[0022] Furthermore, the DAS demodulation host device includes a first narrow linewidth laser, a second narrow linewidth laser, an adjustable optical attenuator, an acousto-optic modulator, an erbium-doped fiber amplifier, a first wavelength division multiplexer, a circulator, a second wavelength division multiplexer, a first avalanche photodiode, a second avalanche photodiode, a first low-pass filter, a second low-pass filter, an oscilloscope, and a pulse trigger.

[0023] The first continuous light emitted by the first narrow linewidth laser is transmitted to the wavelength division multiplexer via an adjustable optical attenuator. The second continuous light emitted by the second narrow linewidth laser is modulated by an acousto-optic modulator to generate pulsed light, which is transmitted to the first wavelength division multiplexer. The first wavelength division multiplexer mixes the two beams together to obtain the corresponding probe light, which is transmitted to the circulator and injected into the fiber optic ring by the circulator.

[0024] The second wavelength division multiplexer receives the feedback light returned from the fiber optic loop. The center wavelengths of the two output channels of the second wavelength division multiplexer correspond to the center wavelengths of the continuous light and the pulsed light, respectively. The decomposed continuous light and pulsed light are transmitted to the first avalanche photodiode and the second avalanche photodiode to be converted into corresponding electrical signals. The electrical signals output by the first avalanche photodiode and the second avalanche photodiode are filtered by the first low-pass filter and the second low-pass filter to remove DC, respectively, and then acquired by the oscilloscope.

[0025] The pulse trigger provides synchronous control for the oscilloscope and the acousto-optic modulator.

[0026] The present invention also mentions a transformer partial discharge monitoring system based on a high-frequency response DAS system, the transformer partial discharge monitoring system including an optical fiber ring, optical fiber jumpers, an electromagnetic shielding room and a DAS demodulation host device;

[0027] The fiber optic ring is uniformly wrapped around the surface of the transformer to be monitored by coating it with epoxy resin and fiberglass tape; the end of the fiber optic ring on the transformer is connected to the beginning of the fiber optic patch cord, and the end of the fiber optic patch cord is connected to the DAS demodulation host equipment in the electromagnetic shielding room.

[0028] Before the transformer is put into use, the DAS demodulation host equipment sets the system demodulation parameters, conducts preliminary transformer background noise monitoring, and calibrates the transformer background noise. After the transformer is put into use, the DAS demodulation host equipment collects and demodulates the phase change of the backscattered signal transmitted by the fiber optic loop in real time to obtain the vibration information along the fiber optic line. Based on the vibration information, it diagnoses and locates the partial discharge power source of the transformer and the insulation defects it causes.

[0029] Furthermore, the transformer to be monitored is placed on a monitoring platform, and the bottom radius of the transformer is less than or equal to half the width of the monitoring platform; a metal protective wall is set around the monitoring platform to form a monitoring area, and an oil recovery device is set at the bottom of the monitoring area; the electromagnetic shielding room is located outside the monitoring area.

[0030] Furthermore, gravel is laid at the bottom of the monitoring area, excluding the monitoring platform, to form an oil recovery device.

[0031] Beneficial effects:

[0032] First, the transformer partial discharge monitoring method based on the high frequency response DAS system of the present invention uses optical fiber as an insulating material. It is light, thin and flexible, and can be directly attached to the surface of the power transformer to monitor potential partial discharge sources in the surrounding area. This allows for accurate identification and location of insulation defects. The main material of the optical fiber is quartz glass, wrapped with a polymer material, which is durable and has a long service life.

[0033] Second, the transformer partial discharge monitoring method based on a high-frequency response DAS system of the present invention addresses the issue that partial discharge causes the oil inside the transformer to expand due to heat, which in turn causes a change in its internal pressure, resulting in transformer vibration. The method integrates the phase change information of the backscattered Rayleigh signal caused by this vibration, which is collected by a DAS system with a high-frequency response DFI structure, and analyzes the information to achieve accurate location of the partial discharge source and the spatial location of insulation defects in the transformer.

[0034] Third, the transformer partial discharge monitoring method based on the high-frequency response DAS system of the present invention, as a remote monitoring means, allows the high-frequency response DAS demodulation host to be placed in an electromagnetic shielding room. It is only necessary to attach the sensing optical fiber to the surface of the transformer to realize remote real-time monitoring of transformer partial discharge and insulation defects, thus ensuring the safety of power transmission.

[0035] Fourth, the transformer partial discharge monitoring method based on the high-frequency response DAS system of the present invention can realize distributed measurement, continuously monitor the transformer in time and space, and has extremely high frequency response and vibration sensitivity. Attached Figure Description

[0036] Figure 1 This is a flowchart of a transformer partial discharge monitoring method based on a high-frequency response DAS system, according to an embodiment of the present invention.

[0037] Figure 2 This is a schematic diagram of a DAS system structure that integrates the DFI structure according to an embodiment of the present invention.

[0038] Figure 3 This is a schematic diagram of the light arrangement according to an embodiment of the present invention.

[0039] Figure 4 This is a schematic diagram of the fixing of glass fiber tape and epoxy resin adhesive according to an embodiment of the present invention.

[0040] Figure 5 This is a schematic diagram of the monitoring principle of the present invention.

[0041] Figure 6 This is a time-domain diagram of the partial discharge monitoring signal according to an embodiment of the present invention.

[0042] Figure 7 This is a short-time Fourier transform diagram of the partial discharge monitoring signal according to an embodiment of the present invention.

[0043] Figure 8 This is a three-dimensional short-time Fourier transform of the partial discharge monitoring signal according to an embodiment of the present invention. Detailed Implementation

[0044] The following embodiments are provided to enable those skilled in the art to more fully understand the present invention, but do not limit the invention in any way.

[0045] Taking the transformer simulation device in the high-voltage discharge indoor test field as an example, distributed monitoring of partial discharge in the transformer simulation device is performed to diagnose and locate insulation defects. The flowchart of the sensor optical cable deployment is as follows: Figure 1 As shown in the figure, the specific process of the transformer partial discharge monitoring method based on the high-frequency response DAS system in this embodiment is as follows:

[0046] S1. Based on the structure and layout of the transformer simulation device, determine the partial discharge monitoring scheme for the transformer simulation device and design the sensing fiber optic network, such as... Figure 3 As shown, the cylindrical transformer simulation device is 1m high and has a base radius of 25cm. It is placed on a platform that is 1m long, 1m wide, and 50cm high. The transformer simulation device and the platform are located in the center of the test area enclosed by a metal protective wall. The ground in the test area is covered with pebbles to facilitate the oil leakage from the transformer simulation device into the recovery device at the bottom. Next to the test area in the high-voltage discharge chamber is an electromagnetic shielding room where the monitoring host equipment is placed.

[0047] S2, as Figure 3 As shown, optical fibers are wound into fiber loops, each loop having a diameter of 10cm and consisting of 10 turns of fiber coil. Eight consecutive fiber loops are then wrapped around the center of the transformer simulator surface. Figure 3 (The front shows four fiber optic rings; the four fiber optic rings on the back are not shown.) Figure 4 As shown, epoxy resin is applied and then completely adhered with fiberglass tape, up to 15cm wide, so that the fiber optic ring is completely bonded to the surface of the transformer simulation device. The fiber optic cable is checked for firmness. As an insulating material, fiber optic cable is light, thin, and flexible, and can be directly attached to the surface of the transformer simulation device. It is durable and has a long service life.

[0048] S3, the fiber optic loop end of the transformer simulation device is connected to a 4m long fiber optic patch cord, which enters the electromagnetic shielding room next to the high-voltage discharge test field through a cable conduit, and connects to a DAS monitoring system with high frequency response, such as... Figure 2The DAS system structure shown integrates a distributed feedback interferometer (DFI) structure, further improving the frequency response range of the sensing system based on the original technology. It includes: a first narrow-linewidth laser (NLL1) 1, a second narrow-linewidth laser (NLL2) 2, a tunable optical attenuator (VOA) 3, an acousto-optic modulator (AOM) 4, an erbium-doped fiber amplifier (EDFA) 5, a first wavelength division multiplexer (DWDM1) 6, a circulator 7, a second wavelength division multiplexer (DWDM2) 8, a first avalanche photodiode (ADP1) 9, a second avalanche photodiode (ADP2) 10, and a first low-pass filter. Filter (LPF1) 11, second low-pass filter (LPF2) 12, oscilloscope (OSC) 13, pulse trigger 14, power supply 15, backscattered Rayleigh light 16, fiber optic ring 17, DAS system equipment with integrated DFI structure 18; the arrow between the first narrow linewidth laser (NLL1) 1, tunable optical attenuator (VOA) 3 and the second narrow linewidth laser (NLL2) 2, and acousto-optic modulator (AOM) 4 indicates continuous light (CW) from left to right; the arrow between the acousto-optic modulator (AOM) 4 and erbium-doped fiber amplifier (EDFA) 5 indicates pulsed light from left to right; the arrow between the first wavelength division multiplexer (DWDM1) 6 and circulator 7 indicates probe light from left to right. The solid lines within the first narrow-linewidth laser (NLL1) 1 represent the optical path, the dashed lines represent the circuit, and the arrows indicate the transmission direction. The system light source consists of two narrow-linewidth lasers, the first (NLL1) 1 and the second (NLL2) 2, each with a linewidth of 3.7 kHz. Their center wavelengths are 1561.42 nm and 1550.12 nm, respectively, and the output optical power of the lasers is 8 dBm. The continuous light CW output from the first narrow-linewidth laser (NLL1) 1 passes through port 3 and then through port 1 of port 6. The continuous light CW output from the second narrow-linewidth laser (NLL2) 2 is modulated by an acousto-optic modulator (AOM) 4 to generate pulsed light. The modulated pulsed light passes through an erbium-doped fiber amplifier (EDFA) 5 and then is combined with the first wavelength division multiplexer (DW) 5. The WDM1)6 is connected to port 2 and mixed with the continuous light generated by the first narrow linewidth laser (NLL1)1. It is simultaneously injected into the sensing fiber through the circulator 7. The center wavelengths of the two channels of the second wavelength division multiplexer (DWDM2)8 correspond to the center wavelengths of the continuous light and the pulsed light, and are received by the first avalanche photodiode (ADP1)9 and the second avalanche photodiode (ADP2)10. The signals output by the first avalanche photodiode (ADP1)9 and the second avalanche photodiode (ADP2)10 are respectively de-DC through the first low-pass filter (LPF1)11 and the second low-pass filter (LPF2)12. The two signals are acquired by the oscilloscope (OSC)13. The electromagnetic shielding room prevents the transformer simulation device from generating electromagnetic radiation interference monitoring system during operation.

[0049] S4, the high-frequency response DAS demodulation host is powered on, the pulse repetition frequency is adjusted to 20000Hz, the optical pulse width is 100ns, and the spatial resolution is 10m, so that its frequency response upper limit reaches 35kHz, the back Rayleigh scattering signal along the sensing fiber is acquired, the early transformer background noise monitoring is carried out, and the transformer background noise is calibrated.

[0050] S5, Participate Figure 5 When a transformer is put into operation, its partial discharge state is monitored in real time using a high-frequency response DAS system. Partial discharge causes the transformer oil in the simulation device to expand due to heat, leading to changes in internal pressure and vibration of the tank. The high-frequency response DAS system obtains vibration information along the optical fiber by demodulating the phase change of the backscattered signal, thereby diagnosing and locating the transformer's partial discharge source and the resulting insulation defects. The vibration of the simulation device caused by partial discharge is a broadband impulse signal, as shown in the time-domain diagram. Figure 6 As shown, perform a short-time Fourier transform on it, as follows: Figure 7 , 8 As shown, when observing the high-frequency signal, the intensity of the high-frequency signal gradually increases before the impact of the simulation device, and then drops sharply to the point of almost disappearing after the impact vibration. It can be inferred that it is a partial discharge signal inside the device.

[0051] The transformer partial discharge monitoring method based on a high-frequency response DAS system in this embodiment has extremely high vibration sensitivity. Compared with fiber optic interferometers, which can only monitor vibration signals at one location, the DAS system can achieve distributed measurement, that is, continuous monitoring of transformer partial discharge in time and space. At the same time, the DAS system integrates a DFI structure, further improving the frequency response range of the DAS sensing system. When the transformer experiences partial discharge, the mechanical stress wave generated at the discharge source location or insulation defect location is received by the sensing fiber. Using the demodulation host of the high-frequency response DAS system placed in an electromagnetic shielding room, the backscattered Rayleigh light returned in the sensing fiber is dephased to obtain the location information of the partial discharge source and insulation defect, thus avoiding structural damage to the transformer caused by the long-term existence of insulation defects.

[0052] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should be considered within the scope of protection of the present invention.

Claims

1. A method for monitoring partial discharge in transformers based on a high-frequency response DAS system, characterized in that, The transformer partial discharge monitoring method Includes the following steps: S1. Based on the structure and layout of the transformer to be monitored, determine the partial discharge monitoring scheme for the transformer and design the fiber optic network. S2, wind the optical fiber into an optical fiber ring, apply epoxy resin to the area where the optical fiber ring is laid, and completely stick the optical fiber ring onto the epoxy resin with glass fiber tape so that the optical fiber ring is evenly wrapped around the surface of the transformer. S3 uses fiber optic patch cords to connect the fiber optic ring on the transformer to the DAS demodulation host equipment located in the electromagnetic shielding room; wherein, the end of the fiber optic ring on the transformer is connected to the beginning of the fiber optic patch cord, and the end of the fiber optic patch cord is connected to the DAS demodulation host equipment in the electromagnetic shielding room. S4, Connect the power supply of the DAS demodulation host equipment, set the system demodulation parameters, carry out preliminary transformer background noise monitoring, and calibrate the transformer background noise; S5. After the transformer is put into use, the DAS demodulation host equipment is used to monitor the partial discharge status of the transformer in real time during operation. In step S1, the process of determining the partial discharge monitoring scheme and designing the fiber optic network based on the structure and layout of the transformer to be monitored includes the following sub-steps: S11, Place the transformer to be monitored on the monitoring platform, with the bottom radius of the transformer being less than or equal to half the width of the monitoring platform; S12, Analyze the structure and layout of the transformer to be monitored to obtain the vibration area. Calculate the diameter and number of fiber optic rings based on the size parameters of the vibration area and the monitoring accuracy requirements. The diameter of the fiber optic ring multiplied by the number of fiber optic rings should be less than the length of the vibration area. Set the corresponding DAS system demodulation parameters, including measurement distance, pulse repetition frequency, number of blocks, and pulse width. S13 uses a metal protective wall to surround the monitoring platform to form a monitoring area, and an oil recovery device is installed at the bottom of the monitoring area; the electromagnetic shielding room is located outside the monitoring area.

2. The transformer partial discharge monitoring method based on a high-frequency response DAS system according to claim 1, characterized in that, In step S13, gravel is laid at the bottom of the monitoring area, excluding the monitoring platform, to form an oil recovery device.

3. The transformer partial discharge monitoring method based on a high-frequency response DAS system according to claim 1, characterized in that, The epoxy resin coating and fiberglass tape completely cover the fiber optic ring.

4. The transformer partial discharge monitoring method based on a high-frequency response DAS system according to claim 1, characterized in that, Step S5, the process of using DAS demodulation host equipment to monitor the partial discharge state of the transformer in real time during operation includes: The phase change of the backscattered signal transmitted by the fiber optic loop is collected and demodulated to obtain the vibration information along the fiber optic line. Based on the vibration information, the partial discharge power source of the transformer and the insulation defects it causes are diagnosed and located. Specifically, partial discharge causes the transformer oil inside the transformer to expand due to heat, which changes the internal pressure of the transformer and causes the tank to vibrate. The fiber optic ring on the surface of the transformer is vibrated, transmitting a backscattered Rayleigh signal carrying phase change information to the DAS demodulation host. Based on the phase change of the backscattered signal, all broadband impact signals are extracted. A short-time Fourier transform is performed on the extracted signal, and the high-frequency signal is observed. If the intensity of the high-frequency signal gradually increases before the transformer device is impacted, and the intensity suddenly drops to the lowest intensity threshold after the impact vibration, and the duration of the drop is less than the preset duration threshold, then it is inferred that the impact signal is a partial discharge signal inside the device.

5. The transformer partial discharge monitoring method based on a high-frequency response DAS system according to claim 1, characterized in that, The DAS demodulation host equipment includes a first narrow linewidth laser, a second narrow linewidth laser, an adjustable optical attenuator, an acousto-optic modulator, an erbium-doped fiber amplifier, a first wavelength division multiplexer, a circulator, a second wavelength division multiplexer, a first avalanche photodiode, a second avalanche photodiode, a first low-pass filter, a second low-pass filter, an oscilloscope, and a pulse trigger. The first continuous light emitted by the first narrow linewidth laser is transmitted to the wavelength division multiplexer via an adjustable optical attenuator. The second continuous light emitted by the second narrow linewidth laser is modulated by an acousto-optic modulator to generate pulsed light, which is transmitted to the first wavelength division multiplexer. The first wavelength division multiplexer mixes the two beams together to obtain the corresponding probe light, which is transmitted to the circulator and injected into the fiber optic ring by the circulator. The second wavelength division multiplexer receives the feedback light returned from the fiber optic loop. The center wavelengths of the two output channels of the second wavelength division multiplexer correspond to the center wavelengths of the continuous light and the pulsed light, respectively. The decomposed continuous light and pulsed light are transmitted to the first avalanche photodiode and the second avalanche photodiode to be converted into corresponding electrical signals. The electrical signals output by the first avalanche photodiode and the second avalanche photodiode are filtered by the first low-pass filter and the second low-pass filter to remove DC, respectively, and then acquired by the oscilloscope. The pulse trigger provides synchronous control for the oscilloscope and the acousto-optic modulator.

6. A transformer partial discharge monitoring system based on a high-frequency response DAS system, characterized in that, The transformer partial discharge monitoring system includes an optical fiber ring, optical fiber jumpers, an electromagnetic shielding room, and a DAS demodulation host device. The structure and layout of the transformer to be monitored are analyzed to obtain the vibration area. Based on the size parameters of the vibration area and the monitoring accuracy requirements, the diameter and number of fiber optic rings are calculated. The diameter of the fiber optic ring multiplied by the number of fiber optic rings should be less than the length of the vibration area. The fiber optic rings are uniformly wrapped around the surface of the transformer to be monitored by coating with epoxy resin and fiberglass tape. The tail end of the fiber optic ring on the transformer is connected to the head end of the fiber optic patch cord, and the tail end of the fiber optic patch cord is connected to the DAS demodulation host equipment in the electromagnetic shielding room. Before the transformer is put into use, the DAS demodulation host equipment sets the system demodulation parameters, conducts preliminary transformer background noise monitoring, and calibrates the transformer background noise. After the transformer is put into use, the DAS demodulation host equipment collects and demodulates the phase change of the backscattered signal transmitted by the optical fiber loop in real time to obtain the vibration information along the optical fiber. Based on the vibration information, the local discharge power source of the transformer and the insulation defects it causes are diagnosed and located.

7. The transformer partial discharge monitoring system based on a high-frequency response DAS system according to claim 6, characterized in that, The transformer to be monitored is placed on the monitoring platform, and the bottom radius of the transformer is less than or equal to half the width of the monitoring platform. A metal protective wall is set around the monitoring platform to form a monitoring area, and an oil recovery device is set at the bottom of the monitoring area. The electromagnetic shielding room is located outside the monitoring area.

8. The transformer partial discharge monitoring system based on a high-frequency response DAS system according to claim 7, characterized in that, Stones are laid at the bottom of the monitoring area, excluding the monitoring platform, to form an oil recovery device.

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