Ultrahigh frequency partial discharge positioning monitoring system
By deploying multiple distributed UHF partial discharge monitoring devices on GIL equipment and utilizing fiber optic connections and synchronization modules, the problem of blind spots in long-distance GIL equipment monitoring was solved, achieving full-section coverage and accurate positioning, and improving equipment operation safety.
Patent Information
- Application Number
- CN202511330932.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-17
- Publication Date
- 2025-11-14
AI Technical Summary
Existing UHF partial discharge monitoring systems have monitoring blind spots on long-distance GIL devices, leading to missed detection of partial discharge signals and failure in localization.
Multiple distributed UHF partial discharge monitoring devices are set at intervals along the length of the GIL equipment and connected by optical fiber. Time synchronization is achieved by combining the host synchronization module and the sub-synchronization module, and the server is used to calculate the time difference to eliminate monitoring blind spots.
It achieves full-segment coverage of long-distance GIL equipment, avoids monitoring blind spots, ensures accurate location of partial discharge signals, and improves equipment operation safety.
Smart Images
Figure CN120948984A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of power transmission line monitoring technology, specifically to an ultra-high frequency partial discharge location monitoring system. Background Technology
[0002] Partial discharge is an important early sign of insulation degradation in power equipment. Due to its strong anti-interference ability and high sensitivity, ultra-high frequency partial discharge monitoring technology is widely used in condition monitoring of enclosed power equipment such as GIS (Gas Insulated Switchgear) and GIL.
[0003] Existing UHF partial discharge monitoring systems mostly use a single device for positioning, relying on synchronous acquisition: a single device uses multi-channel sensors to collect partial discharge signals and achieves positioning based on the signal arrival time difference. This solution can meet basic positioning requirements for GIS equipment with a centralized structure, but GIL equipment is mostly used in long-distance power transmission scenarios (such as underground tunnels and cross-river passages), where the length of a single barrel metal structure can reach hundreds or even thousands of meters. The monitoring coverage of a single monitoring device is limited, inevitably leading to monitoring blind spots, meaning that some GIL segments cannot be effectively covered by the sensors. This results in missed partial discharge signals and positioning failures, seriously affecting the operational safety of GIL equipment. Summary of the Invention
[0004] To address the problems of existing technologies, this invention provides an ultra-high frequency partial discharge location and monitoring system, comprising: Multiple distributed UHF partial discharge monitoring devices are used to eliminate the monitoring blind spots of a single device; The distributed UHF partial discharge monitoring devices are spaced apart along the length of the GIL equipment, and adjacent distributed UHF partial discharge monitoring devices are connected by optical fiber. Multiple ultra-high frequency partial discharge sensors are connected one-to-one with the distributed ultra-high frequency partial discharge monitoring device to collect ultra-high frequency partial discharge signals of GIL power equipment and transmit them to the distributed ultra-high frequency partial discharge monitoring device. The synchronization module group includes a host synchronization module and multiple sub-synchronization modules; The host synchronization module and the plurality of sub-synchronization modules are communicatively connected; The host synchronization module is connected to the satellite positioning module to obtain a high-precision time signal. The host synchronization module generates a pulse signal with a specific transmission frequency based on the obtained high-precision time signal and transmits it to each sub-synchronization module. The sub-synchronization module is connected to the distributed UHF partial discharge monitoring device in a one-to-one correspondence. The sub-synchronization module receives the pulse signal and sends time information to the corresponding distributed UHF partial discharge monitoring device based on the pulse signal. After receiving the signal transmitted by the UHF partial discharge sensor, the distributed UHF partial discharge monitoring device generates a dataset by combining the time information sent by the sub-synchronization module, and then transmits the dataset to the server through a switch. After receiving the datasets from each distributed UHF partial discharge monitoring device, the server performs time difference calculation and waveform fine adjustment based on the waveform data corresponding to different device IDs. After obtaining the final time difference, it combines the signal wave velocity to calculate the location where the partial discharge occurs, thereby eliminating the blind spot of GIL power equipment monitoring.
[0005] Furthermore, the dataset includes timestamps, waveform signals, channel identifiers, and device identifiers.
[0006] Furthermore, the distributed ultra-high frequency partial discharge monitoring device is a dual-channel acquisition system; The distributed ultra-high frequency partial discharge monitoring device includes: a filter, an RF amplifier, and a logarithmic detector connected in sequence, as well as an AD+FPGA module and an ARM module connected to the logarithmic detector; The AD+FPGA module is used for data acquisition, and the ARM module is used for data processing.
[0007] Furthermore, the ultra-high frequency partial discharge sensor uses the same metal material as GIL power equipment; The ultra-high frequency partial discharge sensor includes: a flange, a sensor probe, and a balun; One end of the flange is connected to the GIL power equipment, the other end of the flange is connected to one end of the sensor probe, the other end of the sensor probe is connected to one end of the balun, and the other end of the balun is connected to the signal input terminal of the distributed UHF partial discharge monitoring device.
[0008] Furthermore, each acquisition channel of the distributed UHF partial discharge monitoring device is equipped with an independent filter, RF amplifier, and logarithmic detector; the UHF partial discharge sensor is electrically connected to each acquisition channel of the distributed UHF partial discharge monitoring device in a one-to-one correspondence.
[0009] Furthermore, the GPS module of the host synchronization module is electrically connected to the time receiving pin of each distributed UHF partial discharge monitoring device via the time synchronization pin.
[0010] Furthermore, the process of the server performing time difference calculation and waveform fine adjustment includes: matching multiple sets of waveform data corresponding to the same partial discharge event based on the device ID of each distributed UHF partial discharge monitoring device; calibrating the rising edge of each set of waveform data to eliminate deviations caused by signal transmission delay and device response differences; and comparing the timestamps of the calibrated waveform data to determine the time difference of the partial discharge signal arriving at different distributed UHF partial discharge monitoring devices.
[0011] The beneficial effects of this invention are: By deploying multiple distributed UHF partial discharge monitoring devices at intervals along the length of the GIL equipment, and connecting adjacent devices through optical fibers to achieve coordination, the signal acquisition capabilities of each device are combined to form full-segment coverage of the long-distance GIL equipment. At the same time, the server performs time difference calculation and positioning based on the dataset uploaded by each device, which makes up for the coverage defects of a single device, avoids the partial discharge signal missed due to blind spots, and solves the positioning failure problem of traditional systems.
[0012] The host synchronization module acquires high-precision time via GPS, generating a pps (pulse per second) signal. This signal is then transmitted to each monitoring device via photoelectric conversion and sub-synchronization modules. The host GPS module is directly associated with the devices via a time synchronization pin, ensuring timestamp consistency across multiple devices. The distributed monitoring device is a dual-channel system, with each channel equipped with an independent filter, RF amplifier, and logarithmic detector. The data is then acquired in real-time by an AD+FPGA module and preprocessed by an ARM module, ensuring waveform data accuracy. The server matches waveform data of the same partial discharge event using the device ID, calibrates the rising edge of the waveform to eliminate transmission delay / device differences, and then compares the timestamps to determine the time difference. Combined with the signal velocity, the partial discharge location is calculated, significantly reducing positioning errors and avoiding the problems of positioning failure or large positioning deviations in traditional systems. Attached Figure Description
[0013] Figure 1 This is a schematic diagram of the monitoring system connection provided by the present invention; Figure 2 A schematic diagram illustrating the implementation process of the synchronization method provided by the present invention; Figure 3 A schematic diagram of the synchronization module provided by the present invention; Figure 4 This is a schematic diagram of the internal connection method of the monitoring system provided by the present invention; Figure 5 This is a schematic diagram of the sensor structure connection provided by the present invention.
[0014] Figure label: In the diagram: 1 is the sensor probe, and 2 is the flange. Detailed Implementation
[0015] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0016] Please see Figure 1-5This invention provides an ultra-high frequency partial discharge location and monitoring system, comprising: Multiple distributed UHF partial discharge monitoring devices are used to eliminate the monitoring blind spots of a single device; The distributed UHF partial discharge monitoring devices are spaced apart along the length of the GIL equipment, and adjacent distributed UHF partial discharge monitoring devices are connected by optical fiber. Multiple ultra-high frequency partial discharge sensors are connected one-to-one with the distributed ultra-high frequency partial discharge monitoring device to collect ultra-high frequency partial discharge signals of GIL power equipment and transmit them to the distributed ultra-high frequency partial discharge monitoring device. Synchronization module group; including host synchronization module and multiple sub-synchronization modules; The host synchronization module and the plurality of sub-synchronization modules are communicatively connected; The host synchronization module is connected to the satellite positioning module to obtain a high-precision time signal and generates a pps second pulse signal once per second. The pulse signal is then processed by photoelectric conversion and transmitted to each sub-synchronization module. The sub-synchronization module is connected to the distributed UHF partial discharge monitoring device in a one-to-one correspondence, and is used to convert the received signal into an electrical signal and send time information to the corresponding distributed UHF partial discharge monitoring device. After receiving the signal transmitted by the UHF partial discharge sensor, the distributed UHF partial discharge monitoring device generates a dataset by combining the time information sent by the sub-synchronization module, and then transmits the dataset to the server through a switch. After receiving the datasets from each distributed UHF partial discharge monitoring device, the server performs time difference calculation and waveform fine adjustment based on the waveform data corresponding to different device IDs. After obtaining the final time difference, it combines the signal wave velocity to calculate the location where the partial discharge occurs, thereby eliminating the blind spot of GIL power equipment monitoring.
[0017] Among them, the distributed UHF partial discharge monitoring device is used to eliminate the monitoring blind spot of a single device. The distributed UHF partial discharge monitoring device is adapted to the long-distance single-cylinder metal structure of GIL equipment.
[0018] Given that the length of a single cylindrical metal structure in GIL equipment can reach hundreds to thousands of meters, the coverage limitations of traditional single-unit devices are overcome through "spacing deployment + fiber optic collaboration," as detailed below: Interval layout: Along the length of the GIL equipment, multiple devices are evenly spaced according to the effective monitoring range of a single distributed monitoring device (avoiding local signal attenuation blind spots), ensuring that the monitoring ranges of adjacent devices have reasonable overlap, forming "seamless full-section coverage" of the long-distance monotube structure of GIL, and completely eliminating monitoring blind spots caused by excessive equipment length.
[0019] Fiber optic collaborative connection: Adjacent distributed UHF partial discharge monitoring devices are directly connected by fiber optic cables. On the one hand, this enables stable communication between devices and ensures collaborative operation; on the other hand, fiber optic transmission can reduce signal attenuation and interference over long distances, adapting to the cabling needs of GIL devices in long-distance application scenarios such as underground tunnels and river crossings.
[0020] To address the shielding and sealing requirements of the GIL monotube metal casing for signal acquisition, efficient signal acquisition is achieved through optimization of sensor materials and installation methods. Compatible with sensors of the same material: The UHF partial discharge sensor uses the same metal material as the single-cylinder metal shell of the GIL device, replacing the traditional epoxy cast type sensor. This can avoid the risk of air gap discharge at the "metal-epoxy" interface caused by material differences (adapting to the insulation characteristics of the metal structure), and reduce the signal transmission loss between the sensor and the GIL shell, thereby improving the efficiency of raw signal acquisition.
[0021] Sealed installation adapter: The sensor is sealed to the single-tube metal shell of the GIL device via a flange. The flange and shell are designed with a leak-proof structure, which not only meets the sealing requirements of the GIL device (which is normally filled with insulating gas), but also allows the sensor probe to be in close contact with the surface of the metal shell, directly collecting the UHF partial discharge signal propagating inside the single tube, avoiding signal attenuation caused by shell shielding or gap leakage.
[0022] To address the need for multi-location signal acquisition in long-distance GIL structures, the distributed monitoring device adopts a dual-channel acquisition architecture to enhance the coverage capability and signal processing accuracy of a single device. Dual-channel independent acquisition: Each distributed UHF partial discharge monitoring device is a dual-channel acquisition system. Each channel is equipped with an independent "filter + RF amplifier + logarithmic detector" component, which can simultaneously connect to two UHF partial discharge sensors to acquire partial discharge signals from different positions of the GIL monocular. This is equivalent to a single device achieving "dual-point monitoring", which indirectly expands the coverage of a single device and reduces the total number of devices deployed in long-distance scenarios.
[0023] Hardware-level signal optimization: Independent filters can specifically filter out power frequency noise and electromagnetic interference conducted by the GIL metal structure; RF amplifiers can amplify weak partial discharge signals that attenuate after long-distance propagation; Logarithmic detectors (10ns rise time) can accurately extract signal waveform characteristics, ensuring that the signal can still maintain high fidelity after long-distance transmission, providing a reliable data foundation for subsequent positioning calculations.
[0024] In a GIL long-distance architecture, time consistency among multiple distributed devices is a core prerequisite for time-of-flight positioning, which is achieved through a "dual synchronization mechanism": GPS high-precision synchronization: The host synchronization module connects to the GPS satellite positioning module to obtain time signals with nanosecond-level precision, generates a pps second pulse signal once per second, and transmits it to each sub-synchronization module (corresponding one-to-one with the distributed devices) after photoelectric conversion, providing a unified time reference for all devices and adapting to the requirement of "multiple devices deployed in a distributed manner but with unified time" over long distances.
[0025] Pin-to-pin calibration: The GPS module of the host synchronization module is directly electrically connected to the time receiving pin of each distributed UHF partial discharge monitoring device through the time synchronization pin, forming a dual synchronization guarantee of "pulse signal transmission + hardware pin calibration". This avoids time deviation caused by signal transmission delay over long distances, ensures that the timestamps generated by multiple devices are completely consistent, and meets the accuracy requirements of time difference calculation.
[0026] To address the centralized processing needs of data from multiple devices in long-distance GIL deployments, a "hierarchical transmission architecture" is used to achieve efficient data adaptation. Distributed-Switch Aggregation: After each distributed monitoring device generates a dataset containing "timestamp, waveform signal, channel identifier, and device identifier", it connects to the switch through a local communication link. The switch then aggregates the data from multiple devices deployed over long distances, avoiding transmission delays and packet loss caused by a single device communicating directly with a remote server.
[0027] Fiber optic / stable link transmission: The switch and the back-end server are connected by fiber optic or industrial-grade stable network links, which are suitable for the deployment mode of "distributed devices and centralized servers" in GIL long-distance scenarios. This ensures that the data of devices hundreds to thousands of meters away can still be stably transmitted to the server, providing a complete and real-time dataset for subsequent positioning calculations.
[0028] The UHF partial discharge sensor directly collects the UHF partial discharge signal generated inside the GIL power equipment and transmits the collected raw signal to the corresponding distributed UHF partial discharge monitoring device to provide raw data for subsequent signal processing.
[0029] The synchronization module group includes one main synchronization module and multiple sub-synchronization modules, the same number as the distributed UHF partial discharge monitoring devices.
[0030] After receiving the UHF partial discharge signal transmitted by the UHF partial discharge sensor, the distributed UHF partial discharge monitoring device first performs preprocessing such as filtering, amplification, and detection on the signal. Then, it combines the time information sent by the sub-synchronization module to generate a dataset containing complete monitoring data. This dataset is then connected to a switch via a communication link, and the switch aggregates the datasets and transmits them to the server. After receiving the datasets from each distributed UHF partial discharge monitoring device, the server calculates the specific location of the partial discharge using the conversion relationship of time difference × wave velocity = distance difference, thereby completely eliminating the monitoring blind spots of the GIL power equipment.
[0031] In some embodiments, the dataset includes timestamps, waveform signals, channel identifiers, and device identifiers.
[0032] The timestamp is generated by the distributed UHF partial discharge monitoring device based on the time information sent by the sub-synchronization module. Its accuracy is consistent with the GPS time accuracy of the host synchronization module, and it is used to mark the acquisition time of the waveform signal.
[0033] The waveform signal is obtained by filtering and removing clutter from the original signal transmitted by the sensor using a distributed UHF partial discharge monitoring device, then amplifying it with an RF amplifier, and finally extracting features using a logarithmic detector. This waveform data can accurately reflect the signal characteristics of partial discharge.
[0034] Channel identifiers are used to distinguish the two independent acquisition channels of the dual-channel acquisition system of the distributed UHF partial discharge monitoring device, and to clarify which channel the waveform signal originates from.
[0035] The device identifier is a unique number for each distributed UHF partial discharge monitoring device, which is used by the server to identify the waveform data acquisition device and realize the association and matching of multiple sets of data for the same partial discharge event.
[0036] In some embodiments, the distributed UHF partial discharge monitoring device is a dual-channel acquisition system; The distributed ultra-high frequency partial discharge monitoring device includes: a filter, an RF amplifier, and a logarithmic detector connected in sequence, as well as an AD+FPGA module and an ARM module connected to the logarithmic detector; The AD+FPGA module is used for data acquisition, and the ARM module is used for data processing.
[0037] The filter is used to filter out power frequency noise and electromagnetic interference signals in the UHF partial discharge signal, retaining only the effective UHF partial discharge signal.
[0038] The radio frequency amplifier is used to amplify the filtered weak ultra-high frequency partial discharge signal to ensure that the signal amplitude meets the requirements of subsequent detection and acquisition.
[0039] The logarithmic detector uses a device manufactured by Analog Devices with a rising edge response time of 10ns to extract the waveform characteristics of the amplified signal, ensuring the steepness of the waveform's rising edge and providing an accurate waveform basis for subsequent time difference calculations.
[0040] The AD+FPGA module is used for data acquisition. Its AD unit converts the analog waveform signal output by the logarithmic detector into a digital signal, and the FPGA unit realizes real-time buffering and preliminary acquisition of the digital signal to ensure the real-time performance and integrity of the signal acquisition.
[0041] The ARM module is used for data processing, specifically including format conversion and data filtering of the digital signals acquired by the AD+FPGA module, adding timestamps by combining the time information of the sub-synchronization module, associating channel identifiers and device identifiers, and finally generating a dataset that meets the transmission requirements.
[0042] In some embodiments, the ultra-high frequency partial discharge sensor is made of the same metal material as GIL power equipment; The ultra-high frequency partial discharge sensor includes: flange 2, sensor probe 1, and balun; One end of the flange is connected to the GIL power equipment, the other end of the flange is connected to one end of the sensor probe, the other end of the sensor probe is connected to one end of the balun, and the other end of the balun is connected to the signal input terminal of the distributed UHF partial discharge monitoring device.
[0043] The ultra-high frequency partial discharge sensor uses the same metal material as the primary equipment of GIL power equipment. Compared with traditional epoxy cast type sensors, it can avoid safety hazards such as epoxy gap discharge and sensor cracking from the material level, and improve the safety and stability of the sensor in long-term operation.
[0044] The flange is made of metal. One end of the flange is connected to the housing of the GIL power equipment through a sealed installation structure to ensure the fit and sealing between the sensor and the GIL equipment, and to prevent external interference from entering or internal signal leakage. The other end of the flange is fixedly connected to one end of the sensor probe to provide installation support for the sensor probe, so that the sensor probe can be close to the surface of the GIL equipment housing and directly collect the ultra-high frequency partial discharge signal inside the GIL equipment.
[0045] The sensor probe is a metal detection unit, and its other end is electrically connected to one end of the balun to transmit the acquired raw UHF partial discharge signal to the balun.
[0046] The selected balun models are Mini-Circuits ZBA-1W and 1:1 broadband balun.
[0047] The other end of the balun is electrically connected to the signal input terminal of the distributed UHF partial discharge monitoring device. Its core function is to realize impedance transformation and signal balance between the GIL power equipment and the distributed UHF partial discharge monitoring device, reduce signal loss during transmission, and ensure that the effective signal is transmitted completely to the monitoring device.
[0048] In some embodiments, each acquisition channel of the distributed UHF partial discharge monitoring device is equipped with an independent filter, RF amplifier, and logarithmic detector; the UHF partial discharge sensor is electrically connected to each acquisition channel of the distributed UHF partial discharge monitoring device in a one-to-one correspondence.
[0049] In this distributed UHF partial discharge monitoring device, each acquisition channel is equipped with an independent filter, RF amplifier, and logarithmic detector. That is, in the dual-channel acquisition system, the first acquisition channel is equipped with an independent set of filter, RF amplifier, and logarithmic detector, and the second acquisition channel is also equipped with an independent set of filter, RF amplifier, and logarithmic detector. The two sets of components are independent of each other to avoid signal interference between different channels and ensure the accuracy of the waveform signal acquired by each channel.
[0050] The UHF partial discharge sensors are electrically connected one-to-one with the acquisition channels of the distributed UHF partial discharge monitoring device. That is, each distributed UHF partial discharge monitoring device is equipped with two UHF partial discharge sensors, which are respectively connected to the signal input terminals of the two independent acquisition channels of the device. This realizes a signal acquisition mode where one sensor corresponds to one acquisition channel, enabling the dual channels to simultaneously acquire UHF partial discharge signals from different locations of the GIL device, thereby improving the monitoring coverage and acquisition efficiency of a single device.
[0051] In some embodiments, the GPS module of the host synchronization module is electrically connected to the time receiving pin of each distributed UHF partial discharge monitoring device via a time synchronization pin.
[0052] The host synchronization module's GPS module outputs a time reference signal with nanosecond-level precision via its time synchronization pin. Each distributed UHF partial discharge monitoring device receives this time reference signal via its time receiving pin. This signal, along with the pps second pulse signal transmitted by the sub-synchronization module, forms a dual time calibration, further ensuring the consistency of the timestamps generated by all distributed UHF partial discharge monitoring devices. This avoids errors in server time difference calculations due to time deviations, providing a time-level guarantee for partial discharge positioning accuracy.
[0053] In some embodiments, the process of the server performing time difference calculation and waveform fine adjustment includes: matching multiple sets of waveform data corresponding to the same partial discharge event based on the device ID of each distributed UHF partial discharge monitoring device; calibrating the rising edge of each set of waveform data to eliminate deviations caused by signal transmission delay and device response differences; and comparing the timestamps of the calibrated waveform data to determine the time difference of the partial discharge signal arriving at different distributed UHF partial discharge monitoring devices.
[0054] The process of the server performing time difference calculation and waveform fine-tuning includes: The first step is data matching: Based on the device identifier (device ID) of each distributed UHF partial discharge monitoring device, multiple sets of waveform data corresponding to the same partial discharge event are filtered out. Since the UHF signal generated by the partial discharge event will propagate to the surrounding area, it will be collected simultaneously by multiple distributed UHF partial discharge monitoring devices deployed along the GIL device. The server associates these waveform data from different devices but corresponding to the same event through the device ID. The second step is waveform calibration: The rising edge of each set of selected waveform data is calibrated. The calibration targets include the delay of signal transmission in the optical fiber (the difference in transmission time caused by the different distances between different devices and the partial discharge point) and the difference in the response of each device (such as the difference in the response speed of logarithmic detectors and amplifiers). The above deviations are eliminated by a preset calibration algorithm to ensure that the time reference of each set of waveform data is consistent. The preset calibration algorithm, based on a two-dimensional calibration algorithm of "hardware parameter compensation + reference waveform alignment," combines the core objectives of waveform calibration in the document, which require eliminating "fiber optic transmission delay" and "device response differences." The preset calibration algorithm follows a logical design of "parameter pre-storage - real-time compensation - alignment verification," and the specific process is as follows: Algorithm core principles Using a single distributed UHF partial discharge monitoring device as a benchmark (hereinafter referred to as the "benchmark device"), the waveform time deviation of different devices is calculated in real time by pre-storing the inherent hardware parameters (fiber length, device delay) of each device. Then, the two types of deviations are eliminated by aligning the benchmark waveform, so that the waveform time benchmark of all devices is unified.
[0055] Algorithm preparation: Pre-store hardware calibration parameters During the system deployment phase, data is acquired and stored in the server database through actual measurements and factory calibration to provide basic data for real-time calibration. Specific parameters include: Fiber length L of each device n (n=1,2,...N, where N is the total number of distributed devices): Measure the actual length of the optical fiber between each distributed device and its adjacent devices (e.g., the optical fiber length L1 from device 1 to the switch, and the optical fiber length L2 from device 2 to the switch), in meters (m).
[0056] The response delay T_dev of each device n : Through factory calibration, the inherent response delay of the "filter → RF amplifier → logarithmic detector" link of each device is tested (i.e., the time difference between the rising edge of the device output waveform and the rising edge of the standard signal after the same standard signal is input), in nanoseconds (ns).
[0057] Reference device settings: Select one device with the most stable device response and a medium fiber length as the "reference device", and denote its fiber length as L0 and device response delay as T_dev. 00 All subsequent device calibrations will be based on this device.
[0058] Real-time calibration steps (executed on the server side) Once the server receives the same partial discharge event waveform data uploaded by each device, it performs calibration according to the following steps: Step 1: Extract raw data and calibration parameters Retrieved synchronously from the dataset and database: The raw timestamps T_raw of waveform data from each device n (Time stamp of the rising edge of the waveform acquired by device n); Pre-stored fiber optic lengths L for each device n Device response delay T_dev n ; The reference device's L0 and T_dev0.
[0059] Step 2: Eliminate fiber optic transmission delay deviation (distance difference compensation) Calculate fiber optic transmission delay: Given that the signal transmission speed in an optical fiber is v≈2×10 8 m / s (typical transmission speed of ultra-high frequency signals in single-mode fiber), then the fiber transmission delay ΔT_fiber of device n n =(L n -L0) / v.
[0060] (Principle: If the fiber optic cable of device n is longer than that of the reference device, its waveform will take longer to transmit to the server, requiring the use of "L"...) n -L0” calculates additional latency.
[0061] Fiber optic delay compensation: The original timestamp of device n is compensated to obtain the fiber-compensated timestamp T_fiber. n =T_raw n -ΔT_fiber n .
[0062] (Example: If L2 of device 2 is 100m longer than the reference L0, then ΔT_fiber2=(100) / (2×10) 8 =500ns, T_fiber2 = T_raw2 - 500ns, to eliminate the delay caused by the difference in fiber length.
[0063] Step 3: Eliminate device response differences (hardware characteristic compensation) Compute device response delay difference: The device response delay difference ΔT_dev between device n and the reference device n =T_dev n -T_dev0.
[0064] (Principle: If the device response of device n is slower than that of the reference device, the rising edge of its output waveform will lag behind, ΔT_dev) n If positive, reverse compensation is required.
[0065] Device delay compensation: The timestamp after fiber compensation is further corrected to obtain the final calibration timestamp T_cal. n =T_fiber n -ΔT_dev n .
[0066] (Example: If device 3's T_dev3 is 30ns larger than the reference T_dev0, then ΔT_dev3 = 30ns, T_cal3 = T_fiber3 - 30ns, thus eliminating the hysteresis caused by the difference in device response speed).
[0067] Step 4: Waveform rising edge alignment verification The timestamp T_cal after calibration of all devices n The corresponding rising edges of the waveforms are compared, and if each T_cal n If the error is ≤5ns (half of the 10ns rising edge response time of the document logarithmic detector, which meets the positioning accuracy requirements), the calibration is deemed valid; if the error exceeds the range, the server automatically recalls the pre-stored parameters for re-examination (such as whether the fiber length has changed due to loose deployment or whether the device parameters have aged) until the error meets the standard.
[0068] The third step is to determine the time difference: by comparing the timestamps of each group of waveform data after calibration, the time difference between the arrival of the partial discharge signal at different distributed UHF partial discharge monitoring devices is calculated. This time difference is the core parameter for subsequent calculation of the partial discharge location, and its accuracy directly determines the accuracy of the positioning result.
[0069] In addition, the specific monitoring procedures of this system are as follows: Deployment of distributed monitoring devices: Multiple distributed UHF partial discharge monitoring devices are set at intervals along the length of the GIL equipment. Adjacent devices are connected by optical fiber to achieve collaborative communication. The spacing distance needs to be combined with the monitoring coverage range of a single device (avoiding the coverage limitations of traditional single devices) to ensure that multiple devices form "seamless coverage of the entire road section" for the GIL equipment.
[0070] Sensor matching and installation: Connect the UHF partial discharge sensor to the distributed monitoring device one by one. The sensor uses the same metal material as the GIL device (to avoid the risk of air gap discharge and cracking of epoxy cast type sensors). It is sealed to the housing of the GIL device through a flange, so that the sensor probe is close to the surface of the GIL device and directly collects the UHF partial discharge signal inside the device.
[0071] Synchronization module group connection: A synchronization architecture of "1 host synchronization module and N sub-synchronization modules" is established; the host synchronization module is connected to the satellite positioning module (GPS), and the sub-synchronization modules are electrically connected to the distributed monitoring devices one by one. At the same time, the GPS module of the host synchronization module is directly associated with the time receiving pin of each distributed monitoring device through the time synchronization pin, forming a dual synchronization guarantee of "pulse transmission + direct pin connection".
[0072] Time synchronization calibration: Ensures consistency of timestamps across multiple devices; To provide a high-precision time reference for subsequent time difference calculations, continuous time synchronization calibration is required before and during monitoring. The steps are as follows: High-precision time acquisition: The host synchronization module receives high-precision time signals from satellites via the GPS module and generates a pps second pulse signal once per second (at a specific frequency) (time accuracy reaches the nanosecond level).
[0073] Synchronization signal transmission: After photoelectric conversion, the PPS second pulse signal is transmitted to each sub-synchronization module through the communication link; the sub-synchronization module converts the optical signal back into an electrical signal and sends real-time time information to the corresponding distributed monitoring device.
[0074] Dual calibration verification: Combining the "sub-synchronization module pulse signal + GPS module pin direct connection signal", the time base of the distributed monitoring device is calibrated to ensure that the timestamps of all monitoring devices are completely consistent, eliminating positioning errors caused by time deviation.
[0075] Partial discharge signal acquisition: preprocessing and dataset generation; After receiving sensor signals, the distributed monitoring device completes signal preprocessing and generates a standardized dataset. The specific process is as follows: Raw signal acquisition: The UHF partial discharge sensor acquires the raw UHF partial discharge signal generated inside the GIL device and transmits the signal to the corresponding distributed monitoring device (each device is a dual-channel acquisition system, with each channel corresponding to one sensor).
[0076] Signal preprocessing: Each acquisition channel of the monitoring device is equipped with an independent "filter → RF amplifier → logarithmic detector" link.
[0077] Filter: Filters out power frequency noise and electromagnetic interference from the original signal, while retaining the effective ultra-high frequency partial discharge signal (frequency matching partial discharge characteristic frequency band).
[0078] Radio frequency amplifier: amplifies weak effective signals to ensure that the signal amplitude meets the requirements of subsequent detection and acquisition.
[0079] Logarithmic detector (using a device with a rise time of 10ns): extracts the waveform characteristics of the amplified signal, ensures the steepness of the waveform rise, and provides an accurate waveform basis for time difference calculation.
[0080] Data Acquisition and Processing: The preprocessed analog signal is input into the AD+FPGA module, where the AD unit completes the "analog signal → digital signal" conversion, and the FPGA unit realizes real-time buffering and initial acquisition of the digital signal. Subsequently, the ARM module performs format conversion and data filtering on the acquired digital signal, adds a timestamp based on the time information sent by the sub-synchronization module, and associates it with the "channel identifier" (to distinguish between dual channels) and the "device identifier" (a unique number for each device), finally generating a standardized dataset.
[0081] Unified data transmission: data is aggregated to the server; Each distributed monitoring device is connected to the switch via a communication link. The switch aggregates the datasets from multiple devices and then transmits all datasets to the backend server via a stable network link, ensuring no data loss and no delay, and providing complete data support for subsequent centralized computing.
[0082] Server location calculation: time difference analysis and location determination; The server, based on multi-device datasets, achieves partial discharge localization through four steps: "data matching → waveform calibration → time difference calculation → location conversion," as detailed below: Data matching: The server filters out multiple sets of waveform data corresponding to the same partial discharge event based on the "device identifier" in the dataset (the same partial discharge signal will be collected by multiple distributed devices, forming multiple sets of related data).
[0083] Waveform fine-tuning: Rising edge calibration is performed on multiple sets of matched waveform data to eliminate two types of deviations. Signal transmission delay deviation: The difference in signal transmission time in optical fiber / air is caused by the different distances between the partial discharge point and different devices; Device response differences: Waveform deviations caused by the different response speeds of filters, amplifiers, and detectors in different devices; By using a preset calibration algorithm, the time base of all waveform data is made completely uniform.
[0084] Time difference calculation: By comparing the "timestamp" of the calibrated waveform data, the time difference (Δt) of the UHF partial discharge signal arriving at different distributed monitoring devices is determined.
[0085] Location determination: Based on the physical relationship of "time difference × signal wave speed = distance difference" (the signal wave speed is a known constant, preset based on the medium characteristics of GIL devices), combined with the deployment coordinates of each distributed device, the specific location of partial discharge is calculated, thereby achieving precise positioning of GIL devices.
[0086] Continuous monitoring and blind spot elimination; The system achieves a continuous monitoring mode of "real-time acquisition - synchronous transmission - dynamic positioning" through the above steps: full-segment coverage by multiple distributed devices + real-time positioning calculation by the server, completely eliminating the monitoring blind spots of traditional single devices, avoiding missed detection of partial discharge signals, and ensuring the safe operation of GIL equipment.
[0087] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A high-frequency partial discharge location and monitoring system, characterized in that, include: Multiple distributed UHF partial discharge monitoring devices are used to eliminate the monitoring blind spots of a single device; The distributed UHF partial discharge monitoring devices are spaced apart along the length of the GIL equipment, and adjacent distributed UHF partial discharge monitoring devices are connected by optical fiber. Multiple ultra-high frequency partial discharge sensors are connected one-to-one with the distributed ultra-high frequency partial discharge monitoring device to collect ultra-high frequency partial discharge signals of GIL power equipment and transmit them to the distributed ultra-high frequency partial discharge monitoring device. Synchronization module group; Includes a host synchronization module and multiple sub-synchronization modules; The host synchronization module and the plurality of sub-synchronization modules are communicatively connected; The host synchronization module is connected to the satellite positioning module to obtain a high-precision time signal. The host synchronization module generates a pulse signal with a specific transmission frequency based on the obtained high-precision time signal and transmits it to each sub-synchronization module. The sub-synchronization module is connected to the distributed UHF partial discharge monitoring device in a one-to-one correspondence. The sub-synchronization module receives the pulse signal and sends time information to the corresponding distributed UHF partial discharge monitoring device based on the pulse signal. After receiving the signal transmitted by the UHF partial discharge sensor, the distributed UHF partial discharge monitoring device generates a dataset by combining the time information sent by the sub-synchronization module, and then transmits the dataset to the server through a switch. After receiving the datasets from each distributed UHF partial discharge monitoring device, the server performs time difference calculation and waveform fine adjustment based on the waveform data corresponding to different device IDs. After obtaining the final time difference, it combines the signal wave velocity to calculate the location where the partial discharge occurs, thereby eliminating the blind spot of GIL power equipment monitoring.
2. The ultra-high frequency partial discharge location and monitoring system according to claim 1, characterized in that, The dataset includes timestamps, waveform signals, channel identifiers, and device identifiers.
3. The ultra-high frequency partial discharge location and monitoring system according to claim 1, characterized in that, The distributed ultra-high frequency partial discharge monitoring device is a dual-channel acquisition system; The distributed ultra-high frequency partial discharge monitoring device includes: a filter, an RF amplifier, and a logarithmic detector connected in sequence, as well as an AD+FPGA module and an ARM module connected to the logarithmic detector; The AD+FPGA module is used for data acquisition, and the ARM module is used for data processing.
4. The ultra-high frequency partial discharge location and monitoring system according to claim 1, characterized in that, The ultra-high frequency partial discharge sensor uses the same metal material as GIL power equipment; The ultra-high frequency partial discharge sensor includes: a flange, a sensor probe, and a balun; One end of the flange is connected to the GIL power equipment, the other end of the flange is connected to one end of the sensor probe, the other end of the sensor probe is connected to one end of the balun, and the other end of the balun is connected to the signal input terminal of the distributed UHF partial discharge monitoring device.
5. The ultra-high frequency partial discharge location and monitoring system according to claim 3, characterized in that, Each acquisition channel of the distributed UHF partial discharge monitoring device is equipped with an independent filter, RF amplifier, and logarithmic detector; the UHF partial discharge sensor is electrically connected to each acquisition channel of the distributed UHF partial discharge monitoring device in a one-to-one correspondence.
6. The ultra-high frequency partial discharge location and monitoring system according to claim 1, characterized in that, The GPS module of the host synchronization module is electrically connected to the time receiving pin of each distributed UHF partial discharge monitoring device via the time synchronization pin.
7. The ultra-high frequency partial discharge location and monitoring system according to claim 1, characterized in that, The process of the server performing time difference calculation and waveform fine adjustment includes: matching multiple sets of waveform data corresponding to the same partial discharge event based on the device ID of each distributed UHF partial discharge monitoring device; calibrating the rising edge of each set of waveform data to eliminate deviations caused by signal transmission delay and device response differences; and comparing the timestamps of the calibrated waveform data to determine the time difference of the partial discharge signal arriving at different distributed UHF partial discharge monitoring devices.