Partial discharge detection system and method

Abstract

The system comprises a sensor array module, an optical fiber module, a multi-channel acquisition module and an analysis positioning module, the sensor array module is connected with the optical fiber module, acquires a partial discharge signal and outputs the partial discharge signal to the multi-channel acquisition module, and the multi-channel acquisition module acquires the partial discharge signal and outputs the partial discharge signal to the analysis positioning module. Storing and outputting to the analysis positioning module; the multi-path acquisition module comprises a storage unit, a multi-path switch and a high-speed acquisition unit, one end of the multi-path switch is connected with the optical fiber module and used for receiving the partial discharge signal, the other end of the multi-path switch is connected with the high-speed acquisition unit, and the high-speed acquisition unit is connected to the storage unit. Through intelligent switching of the multi-way switch, the high-speed acquisition unit is started only when partial discharge is detected, data redundancy is reduced by more than 90%, accidental signal capturing capacity is remarkably improved, ultrahigh frequency and ultrasonic sensor data are combined, detection reliability under complex working conditions is improved, and discharge type recognition accuracy is larger than 98%.

Description

Technical Field

[0001] The present invention relates to the technical field of power equipment status monitoring, and in particular to a partial discharge detection system and method for gas insulated switchgear, transformers and switch cabinets. Background Art

[0002] Existing partial discharge detection technology has the following limitations:

[0003] 1. Difficulty in capturing occasional signals: Partial discharge signals are random and instantaneous, and traditional single sensors or fixed multi-channel systems are prone to miss detection;

[0004] 2. Data redundancy and resource waste: Continuous data collection by multiple sensors results in a huge amount of data, and high-speed acquisition cards run at full load for a long time, resulting in high hardware costs and shortened lifespan;

[0005] 3. Insufficient positioning accuracy: The existing system is difficult to quickly locate the discharge source in a complex electromagnetic environment, which affects the efficiency of fault diagnosis. Summary of the invention

[0006] The object of the present invention is to provide a partial discharge detection system and method, which are used to solve the problems of difficulty in capturing occasional partial discharge signals, excessive data volume and inaccurate positioning.

[0007] The present invention solves the technical problem by adopting the following technical solution:

[0008] A partial discharge detection system, comprising: a sensor array module, an optical fiber module, a multi-channel acquisition module and an analysis and positioning module, wherein the sensor array module is connected to the optical fiber module, collects partial discharge signals and outputs them to the multi-channel acquisition module, and the multi-channel acquisition module obtains partial discharge signals, stores them and outputs them to the analysis and positioning module;

[0009] The multi-channel acquisition module includes: a storage unit, a multi-channel switch and a high-speed acquisition unit, wherein one end of the multi-channel switch is connected to the optical fiber module for receiving partial discharge signals, and the other end is connected to the high-speed acquisition unit, and the high-speed acquisition unit is connected to the storage unit.

[0010] Preferably, the optical fiber module comprises: a photoelectric conversion unit and a single-mode optical fiber unit, wherein the sensor array module outputs a partial discharge signal, which is connected to the photoelectric conversion unit and the single-mode optical fiber unit and output to the multi-channel acquisition module.

[0011] Preferably, the sensor array module includes: a UHF sensor and an ultrasonic sensor.

[0012] Preferably, the single-mode optical fiber unit transmission rate is ≥10 Gbps and the transmission distance is ≤500m.

[0013] Preferably, the multi-way switch automatically triggers the switch based on the signal amplitude threshold and the waveform matching algorithm, and the response time is ≤1 μs.

[0014] Preferably, the high-speed acquisition unit has a sampling rate range of 1G / s-5G / s, a resolution of 16 bits, and a storage depth of ≥128MB.

[0015] Preferably, the analysis and positioning module includes: an FPGA real-time trigger module, a time difference positioning module and a PRPD spectrum generation module.

[0016] Preferably, the multi-way switch is provided with 128 parallel channels, the dynamic adjustment range of the trigger threshold is 10 mV to 1 V, and the adjustment step is ≤ 5 mV.

[0017] A partial discharge detection method comprises the following steps:

[0018] Step 1, collecting partial discharge signals, converting the signals through an optical fiber module and outputting them to a multi-channel collection module;

[0019] Step 2: When the signal amplitude exceeds the dynamic threshold or meets the pre-stored electrical waveform characteristics, the multi-way switch is triggered to switch to the high-speed sampling unit;

[0020] Step 3, record and store the time domain waveform of the trigger channel, and output it to the analysis and positioning module, with a sampling rate of ≥1G / s;

[0021] Step 4: The analysis and positioning module calculates the three-dimensional coordinates of the local discharge source, outputs the PRPD spectrum to identify the discharge type, and locates the local discharge source.

[0022] Preferably, the dynamic threshold is adjusted in real time according to the root mean square value of the ambient noise, and the adjustment formula is: V threshold = k·RMS+V offset , where k = 2 to 5, V offset =5~20mV.

[0023] The present invention uses intelligent switching of multi-way switches to enable the high-speed acquisition unit only when partial discharge is detected, reducing data redundancy by more than 90%, significantly improving the ability to capture sporadic signals; the trigger response time is ≤1μs, ensuring the complete capture of instantaneous signals; combining ultra-high frequency and ultrasonic sensor data to improve detection reliability under complex working conditions, the discharge type recognition accuracy is >98%, and the anti-interference ability is strong; the high-speed acquisition unit works on demand, the hardware life is extended by 40%, the optical fiber transmission delay is ≤2.5μs / 500m, remote monitoring and encryption functions are supported, and the need for manual inspections is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a connection diagram of the system of the present invention. DETAILED DESCRIPTION

[0025] The technical solution of the present invention is further described below in conjunction with the embodiments and drawings.

[0026] In order to solve the problem of being able to capture occasional partial discharge signals in a timely and accurate manner, the present invention provides a partial discharge detection system, including: a sensor array module, an optical fiber module, a multi-channel acquisition module and an analysis and positioning module, the sensor array module is connected to the optical fiber module, collects partial discharge signals and outputs them to the multi-channel acquisition module, the multi-channel acquisition module obtains partial discharge signals, stores them and outputs them to the analysis and positioning module;

[0027] Specifically, the sensor array module is used to collect partial discharge signals, the optical fiber module is connected to the sensor array module to realize signal transmission, the multi-channel acquisition module includes a storage unit, a multi-channel switch and a high-speed acquisition unit, which are used to acquire, store and output partial discharge signals, and the analysis and positioning module is used to analyze and locate the partial discharge source. The sensor array module transmits the collected partial discharge signal to the multi-channel acquisition module through the optical fiber module. The multi-channel switch in the multi-channel acquisition module connects the high-speed acquisition unit for high-speed acquisition according to the signal situation, and outputs it to the storage unit for storage and processing. Finally, the signal is analyzed and located by the analysis and positioning module. Through the intelligent switching of the multi-channel switch, the high-speed acquisition unit is enabled only when partial discharge is detected, and data redundancy is reduced by more than 90%, which significantly improves the ability to capture occasional signals.

[0028] The multi-channel acquisition module is integrated in the cabinet, and includes: a storage unit, a multi-channel switch and a high-speed acquisition unit, wherein one end of the multi-channel switch is connected to the optical fiber module for receiving partial discharge signals and outputting them to the storage unit, and the other end is connected to the high-speed acquisition unit, and the high-speed acquisition unit is connected to the storage unit.

[0029] The sensor array module maintains normal monitoring under normal circumstances. The UHF and ultrasonic sensors continuously output low-bandwidth signals to multiple channels, and only record the baseline noise output to the storage unit. When the signal amplitude exceeds the dynamic threshold or meets the pre-stored electrical waveform characteristics, the multi-channel switch automatically switches to the high-speed acquisition unit, and the dynamic threshold can be adjusted in the range of 10mV-1V.

[0030] In a further embodiment of the present invention, the optical fiber module includes: a photoelectric conversion unit and a single-mode optical fiber unit, wherein the sensor array module outputs a partial discharge signal, which is connected to the photoelectric conversion unit and the single-mode optical fiber unit and output to the multi-channel acquisition module.

[0031] The photoelectric conversion unit converts the local discharge signal output by the sensor array module from an electrical signal into an optical signal, and the single-mode optical fiber unit is used to transmit the optical signal. Through the cooperation of the photoelectric conversion unit and the single-mode optical fiber unit, the signal output by the sensor array module can be effectively transmitted to the multi-channel acquisition module, thereby realizing long-distance and low-loss transmission of the signal and improving the stability and reliability of signal transmission.

[0032] The photoelectric conversion unit uses a photoelectric conversion device, such as a photodiode or a phototransistor. The single-mode fiber unit uses a standard single-mode fiber, which has the characteristics of low loss and high bandwidth in long-distance transmission, which can not only reduce the attenuation of the signal during transmission, but also effectively avoid electromagnetic interference.

[0033] In a further embodiment of the present invention, the sensor array module includes: a UHF sensor and an ultrasonic sensor for detecting partial discharge signals.

[0034] UHF sensors can capture high-frequency discharge signals, and ultrasonic sensors are used to detect ultrasonic signals. The combined acoustic and electrical detection method can more comprehensively capture local discharge signals, improve the accuracy and reliability of signal detection, and more comprehensively cover different types of discharge signals, reducing the possibility of missed detection and enhancing the detection capability of the system.

[0035] In a further embodiment of the present invention, the transmission rate of the single-mode optical fiber unit is ≥10 Gbps, and the transmission distance is ≤500 m.

[0036] The transmission rate and distance of the single-mode fiber unit are achieved by using high-performance single-mode fiber materials and advanced optoelectronic conversion technology, optimizing the layout and connection method of the fiber optic network, reducing the loss of fiber connection points and connectors, and using signal processing and error correction technology to improve the signal's anti-interference ability and transmission quality.

[0037] The single-mode fiber unit also includes fiber amplifiers and repeaters for high-quality signal transmission over short distances.

[0038] In a further embodiment of the present invention, the multi-way switch automatically triggers the switch based on the signal amplitude threshold and the waveform matching algorithm, and the response time is ≤1 μs.

[0039] In order to achieve a multi-way switch response time of ≤1μs, it is necessary to coordinate hardware structure optimization and real-time algorithm design. The specific implementation method is as follows:

[0040] 1. Hardware structure optimization

[0041] High-speed solid-state switching devices: Using GaN field-effect transistors or SiC MOSFETs as core switching elements, the switching speed can reach 1-10ns;

[0042] Signal path optimization: shorten PCB trace length, reduce parasitic inductance and capacitance, and reduce signal transmission delay to less than 50ns.

[0043] High-speed drive circuit: Use a dedicated driver chip to quickly charge and discharge the gate capacitance of the switching device to increase the switching speed.

[0044] Parallel trigger architecture: Each channel is independently configured with a comparator circuit to monitor the signal amplitude and threshold in real time, avoiding the serial delay of centralized processing.

[0045] Priority arbitration logic: Priority judgment during multi-channel triggering is implemented through hardware logic (such as FPGA), and the decision time is ≤10ns.

[0046] 2. Real-time Algorithm Design

[0047] Hardware level trigger logic

[0048] Implement the following functions in FPGA:

[0049] Real-time threshold comparison: Directly compare sensor signals with dynamic thresholds via digital comparators without CPU intervention.

[0050] Waveform feature matching: Pre-store typical discharge waveform templates and achieve fast matching through hardware-accelerated convolution operations, making the delay less than 20ns.

[0051] Pre-trigger buffer technology: Set up a ring buffer to continuously store sensor signals, with a storage depth of ≥1μs. After the trigger, immediately extract the data before and after the trigger point to avoid signal omission.

[0052] Dynamic priority scheduling: When multiple channels are triggered simultaneously, the highest priority channel is quickly selected according to preset rules, and the arbitration time is ≤30ns.

[0053] 3. System Integration and Anti-interference Measures

[0054] Optical Isolation and Signal Shaping

[0055] Insert a high-speed optocoupler, such as HCPL-0723, in the control signal path to isolate the high-voltage and low-voltage circuits and prevent interference.

[0056] Use differential signal transmission to reduce the impact of common mode noise and ensure a pure trigger signal.

[0057] Timing synchronization design: Use a global clock network to unify the clock sources of each module and avoid timing errors caused by clock offset.

[0058] Electromagnetic compatibility optimization: The switch module adopts a multi-layer shielding cover and internal layout partitioning to isolate analog / digital / power supply and suppress electromagnetic interference caused by high-speed switching.

[0059] Laboratory test: Single-channel switching time (GaN FET): 3ns (on) + 2ns (off) = 5ns; signal comparison and arbitration logic delay: 50ns; total response time: ≤800ns, meeting the ≤1μs requirement.

[0060] Field application: As in Example 2, the measured trigger response time of the 550 kV GIS substation is 0.8 μs, which is consistent with the theoretical design.

[0061] In a further implementation manner of the present invention, the high-speed acquisition unit has a sampling rate range of 1G / s-5G / s, a resolution of 16bit, and a storage depth ≥128MB. It has the technical characteristics of high sampling rate, high resolution and large storage depth, ensuring that high-precision discharge signal data can be accurately captured and stored in partial discharge detection, thereby improving the performance and reliability of the detection system.

[0062] After the multi-way switch triggers the high-speed acquisition unit, the high-speed acquisition unit records at least 10 μs waveform data at a sampling rate of 5 G / s and transmits it to the storage unit via Gigabit Ethernet.

[0063] In a further embodiment of the present invention, the analysis and positioning module includes: an FPGA real-time trigger module, a time difference positioning module and a PRPD spectrum generation module. The analysis and positioning module calculates the local discharge source coordinates based on the sensor array topology, and the positioning error is ≤0.5m.

[0064] The FPGA real-time trigger module is mainly used to quickly respond to and process local discharge signals. Its implementation method includes using FPGA chips to write dedicated logic control programs to achieve real-time capture and processing of local discharge signals; the time difference positioning module is used to calculate the three-dimensional coordinates of the local discharge source, and adopts multi-channel signal reception and processing technology to determine the location of the discharge source by calculating the time difference between signals received by different sensors; the PRPD spectrum generation module is used to generate a spectrum of local discharge types. By collecting and analyzing the phase and amplitude characteristics of local discharge signals, the corresponding PRPD spectrum is generated to identify and classify different types of local discharges.

[0065] Furthermore, the FPGA real-time trigger module can be implemented through a high-performance FPGA chip, with a response time at the microsecond level, ensuring that partial discharge signals can be quickly captured. The time difference positioning module improves the accuracy and reliability of positioning through the collaborative work of multiple sensors. The PRPD spectrum generation module combines advanced signal processing algorithms to improve the accuracy and resolution of the spectrum.

[0066] The time difference positioning algorithm calculates the discharge source coordinates using the following formula:

[0067]

[0068] Among them, (x, y, z) is the coordinate of the discharge source, (x i ,y i ,z i )、(x j ,y j ,z j ) is the sensor position and v is the signal propagation speed.

[0069] In a further embodiment of the present invention, the multi-way switch is provided with 128 parallel channels, the trigger threshold value has a dynamic adjustment range of 10 mV to 1 V, and the adjustment step is ≤ 5 mV.

[0070] A further embodiment of the present invention, compared with the prior art, solves the problem of easy missed detection of traditional single sensor or fixed multi-channel system through multi-point acquisition of sensor array module. The optical fiber module realizes efficient transmission of signals and reduces signal loss. The multi-way switch and high-speed acquisition unit in the multi-way acquisition module can effectively process and store signals and avoid data redundancy. The analysis and positioning module realizes accurate positioning of the discharge source through analysis and processing of signals, so that the present invention has significantly improved the detection accuracy and effectiveness.

[0071] Example 2

[0072] A partial discharge detection method comprises the following steps:

[0073] Step 1, collecting partial discharge signals, converting the signals through an optical fiber module and outputting them to a multi-channel collection module;

[0074] Step 2: When the signal amplitude exceeds the dynamic threshold or meets the pre-stored electrical waveform characteristics, the multi-way switch is triggered to switch to the high-speed sampling unit;

[0075] Step 3, record and record the time domain waveform of the trigger channel and output it to the analysis and positioning module, with a sampling rate ≥ 1G / s;

[0076] Step 4: The analysis and positioning module calculates the three-dimensional coordinates of the local discharge source, outputs the PRPD spectrum to identify the discharge type, and locates the local discharge source.

[0077] In a further embodiment of the present invention, the dynamic threshold is adjusted in real time according to the root mean square value of the ambient noise, and the adjustment formula is: V threshold = k·RMS+V offset , where k = 2 to 5, V offset =5~20mV.

[0078] In a further embodiment of the present invention, partial discharge detection is carried out on site at a 550 kV GIS substation, 12 UHF sensors are installed at the flange of the GIS cavity with a spacing of 1.5 m, and 6 ultrasonic sensors are arranged on the surface of the housing;

[0079] Trigger conditions: The multi-way switch threshold is set to 100mV, and the waveform matching library contains 5 typical discharge modes;

[0080] Detection results: 5 surface discharge events were captured, with a trigger response time of 0.8μs and a positioning error of 0.25m. The data storage capacity was only 8% of the traditional full-channel acquisition, and the system ran continuously for 30 days without any faults. The host computer software successfully warned of a potential insulation fault, and maintenance confirmed the presence of residual metal particles.

[0081] A further embodiment of the present invention simulates partial discharge detection test in a 220 kV transformer laboratory; parameters: injecting a partial discharge signal with an amplitude of 50 mV-500 mV, superimposing 50 Hz power frequency noise with an amplitude of 200 mV;

[0082] Test content: Dynamic threshold adaptability: When the noise RMS is 30mV, the system automatically adjusts the threshold to 65mV, k = 2.1; Multi-source discharge positioning: Simulate two simultaneous discharges with a distance of 1.2m. The system accurately separates the signals and positions them, with an error of ≤0.4m;

[0083] Conclusion: The false trigger rate is <0.05%, and the accuracy of discharge type recognition is >98%.

[0084] In a further embodiment of the present invention, in the long-term operation of 10kV switch cabinet, occasional long-duration signals of partial discharge are monitored. Four UHF sensors are installed at the busbar and cable joint of the switch cabinet, and two ultrasonic sensors are arranged on the surface of the cabinet. After continuous operation for 6 months, the cumulative triggering is 132 times, and the effective alarm rate is 95%;

[0085] Conclusion: In high temperature (45°C) and high humidity (85% RH) environments, the positioning error of the system is stable within 0.5m; compared with the traditional fixed acquisition system, the hardware life is extended by 40%.

[0086] A further implementation of the present invention performs anti-interference verification in a complex electromagnetic environment, specifically deploying the system in a GIS device near a 500kV transmission line, with a background noise RMS of 80mV; enabling an adaptive threshold algorithm, k=4, V offset =15mV, waveform correlation filtering;

[0087] Results: The system false trigger rate dropped to 0.2%, the discharge signal signal-to-noise ratio increased to 12dB, and the data validity increased from 60% to 92% compared with when the anti-interference strategy was not enabled.

[0088] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A partial discharge detection system, characterized in that: include: A sensor array module, an optical fiber module, a multi-channel acquisition module and an analysis and positioning module. The sensor array module is connected to the optical fiber module, collects partial discharge signals and outputs them to the multi-channel acquisition module. The multi-channel acquisition module obtains partial discharge signals, stores them and outputs them to the analysis and positioning module. The multi-channel acquisition module includes: a storage unit, a multi-channel switch and a high-speed acquisition unit, wherein one end of the multi-channel switch is connected to the optical fiber module for receiving partial discharge signals, and the other end is connected to the high-speed acquisition unit, and the high-speed acquisition unit is connected to the storage unit.

2. The partial discharge detection system and method according to claim 1, characterized in that: The optical fiber module includes: a photoelectric conversion unit and a single-mode optical fiber unit, wherein the sensor array module outputs a partial discharge signal, which is connected to the photoelectric conversion unit and the single-mode optical fiber unit and output to the multi-channel acquisition module.

3. The partial discharge detection system and method according to claim 1, characterized in that: The sensor array module includes: a UHF sensor and an ultrasonic sensor.

4. The partial discharge detection system and method according to claim 1, characterized in that: The transmission rate of the single-mode optical fiber unit is ≥10 Gbps, and the transmission distance is ≤500m.

5. The partial discharge detection system and method according to claim 1, characterized in that: The multi-way switch automatically triggers the switch based on the signal amplitude threshold and waveform matching algorithm, and the response time is ≤1μs.

6. The partial discharge detection system and method according to claim 1, characterized in that: The high-speed acquisition unit has a sampling rate range of 1G / s-5G / s, a resolution of 16bit, and a storage depth of ≥128MB.

7. The partial discharge detection system and method according to claim 1, characterized in that: The analysis and positioning module includes: an FPGA real-time trigger module, a time difference positioning module and a PRPD spectrum generation module.

8. The partial discharge detection system and method according to claim 1, characterized in that: The multi-way switch is provided with 128 parallel channels, the trigger threshold dynamic adjustment range is 10mV to 1V, and the adjustment step length is ≤5mV.

9. A partial discharge detection method, characterized in that: The following steps are involved: Step 1, collecting partial discharge signals, converting the signals through an optical fiber module and outputting them to a multi-channel collection module; Step 2: When the signal amplitude exceeds the dynamic threshold or meets the pre-stored electrical waveform characteristics, the multi-way switch is triggered to switch to the high-speed sampling unit; Step 3, record and store the time domain waveform of the trigger channel, and output it to the analysis and positioning module, with a sampling rate of ≥1G / s; Step 4: The analysis and positioning module calculates the three-dimensional coordinates of the local discharge source, outputs the PRPD spectrum to identify the discharge type, and locates the local discharge source.

10. A partial discharge detection method according to claim 9, characterized in that: The dynamic threshold is adjusted in real time according to the root mean square value of the ambient noise, and the adjustment formula is: V threshold =k·RMS+V offset , where k = 2 to 5, V offset =5~20mV.

Images