Pulse current partial discharge sensor and working method thereof

Abstract

The invention discloses a pulse current partial discharge sensor and a working method thereof. The sensor comprises a pulse current acquisition module, a de-noising anti-interference module, a signal processing module, a wireless communication module and a self-power-taking module. A pulse current signal is acquired through an insulator type capacitive sensor of an electrified display device of the high-voltage switch cabinet, and after filtering, amplification, analog-to-digital conversion and feature extraction, the data is sent to a remote monitoring terminal through a wireless communication module, so that real-time online monitoring of partial discharge is realized. The system has the advantages of high measurement precision, strong anti-interference capability, convenience in installation, no maintenance, self power supply and the like, is widely applied to a high-voltage switch cabinet with the voltage level of 3kV-36kV, and effectively improves the operation safety and the intelligent level of power equipment.

Description

Technical Field

[0001] This invention relates to the field of electrical equipment condition monitoring technology, and in particular to a pulse current partial discharge sensor and its working method. Background Technology

[0002] Partial discharge (PD) is a significant indicator of insulation degradation in high-voltage electrical equipment. Prolonged presence of PD accelerates insulation aging and can even lead to equipment failure. Traditional methods for detecting partial discharge mainly include ultrasonic methods, ultra-high frequency methods, and pulsed current methods. Among these, the pulsed current method is widely used in offline laboratory testing due to its high measurement accuracy, quantitative results, and well-defined standards.

[0003] However, in real-world operating environments, due to factors such as strong electromagnetic interference, complex equipment operating conditions, and limited installation space, the pulse current method is difficult to directly apply to online monitoring. Existing technologies, such as some solutions using external capacitive sensors, battery power, or wired transmission, suffer from the following problems: The installation is complex, requiring additional wiring and sensors; it has poor anti-interference capabilities and low measurement accuracy; it relies on batteries for power supply, resulting in high maintenance costs; and it cannot achieve real-time online monitoring and remote data transmission. Therefore, there is an urgent need for a pulse current partial discharge sensor that is compact, easy to install, has strong anti-interference capabilities, requires no external power supply, and can achieve real-time online monitoring. Summary of the Invention

[0004] The purpose of this invention is to provide a pulse current partial discharge sensor and its working method, which solves the technical problems existing in the prior art, such as offline detection being unable to reflect the device status in real time; poor anti-interference capability of online monitoring devices; complex installation and high cost; and reliance on batteries for power supply, requiring frequent maintenance.

[0005] The technical solution adopted in this invention is: A pulse current partial discharge sensor, suitable for online monitoring of partial discharge in high-voltage switchgear, includes: The pulse current acquisition module is used to acquire the pulse current signal generated by partial discharge through the insulator-type capacitive sensor of the live display device built into the high-voltage switchgear; The noise reduction and anti-interference module is connected to the pulse current acquisition module and is used to filter the acquired pulse current signal to suppress high-order harmonic interference and common-mode interference in the power grid. The signal processing module, connected to the noise reduction and anti-interference module, is used to amplify, convert analog to digital and extract partial discharge features from the filtered signal. A wireless communication module, connected to the signal processing module, is used to wirelessly transmit the processed partial discharge data to a remote monitoring terminal. The self-powered module is used to obtain electrical energy from the live sensors in the high-voltage switchgear to power the various modules of the sensors.

[0006] Preferably, the noise reduction and anti-interference module includes: Analog filters are used to filter out high-frequency noise; Digital filters are used to further suppress interference signals in specific frequency bands; The interference identification algorithm unit is used to identify and mark non-partial discharge interference signals.

[0007] Preferably, the signal processing module includes: An amplifier is used to amplify weak pulse signals; An analog-to-digital converter (ADC) is used to convert analog signals into digital signals. The partial discharge identification algorithm unit is used to identify partial discharge pulses and calculate their apparent discharge quantity.

[0008] Preferably, the wireless communication module uses the 433MHz frequency band for data transmission, and the transmission distance can reach 800 meters in open environments, with the ability to penetrate metal cabinets.

[0009] Preferably, the self-powered module obtains power from the charged sensor through capacitive coupling, without the need for an external power source or battery.

[0010] Preferably, the sensor is installed using a magnetic suction method, has an IP6X protection rating, and is suitable for high-voltage switchgear with voltage levels from 3kV to 36kV.

[0011] The present invention also provides a method for operating a pulse current partial discharge sensor, comprising the following steps: Step 1: Acquire the pulse current signal generated by partial discharge through the equivalent capacitance sensor of the charged display device. This sensor uses the principle of capacitive coupling to efficiently detect the transient discharge current and convert the original signal into a processable electrical signal.

[0012] Step 2: Filter the acquired signal, using a low-pass filter to remove high-frequency noise and high-order harmonics, and apply common-mode rejection technology to eliminate common-mode interference, ensuring signal purity and improving the accuracy of subsequent processing.

[0013] Step 3: Amplify the filtered signal to an appropriate level, then convert it into a digital signal via an analog-to-digital converter (ADC). Next, perform feature extraction to extract key features such as peak value, rise time, and frequency, and use a pattern recognition algorithm to accurately identify partial discharge events.

[0014] Step 4: The processed data is sent to the remote monitoring terminal via a wireless communication module, including Wi-Fi or LoRa, to achieve reliable remote data transmission and ensure data integrity and security during the communication process.

[0015] Step 5: On the remote monitoring terminal, the data is stored in the database and processed in real time through analysis algorithms; the results are displayed in real time on the visualization interface, including charts and alarm systems, realizing real-time monitoring and early warning functions, which facilitates timely intervention.

[0016] The filtering process in step two includes two stages: analog filtering and digital filtering. The digital filtering uses an adaptive algorithm to dynamically adjust the filtering parameters.

[0017] The feature extraction in step three includes the extraction of partial discharge characteristic parameters such as pulse amplitude, pulse number, and phase distribution.

[0018] Compared with the prior art, the present invention has the following beneficial effects: High-precision measurement: The pulse current method is used, combined with an anti-interference algorithm, and the measurement results are in pC (picocoulombs). Wiring-free installation: The existing charged sensor is used as a coupling capacitor, eliminating the need for additional sensor installation or wiring; Self-powered: It draws power from itself via capacitor coupling, requiring no maintenance or battery replacement; Wireless transmission: It adopts 433MHz wireless communication, with long transmission distance and strong penetration, and is suitable for complex electromagnetic environments; Compact structure and easy installation: magnetic installation, IP6X protection level, suitable for various voltage levels (3kV~36kV). Real-time online monitoring: Enables real-time monitoring, data uploading, and remote early warning of partial discharge status. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the pulse current partial discharge sensor of the present invention; Figure 2 This is a wiring diagram of the present invention; Figure 3 This is a schematic diagram of the installation position of the present invention; Figure 4 This is a connection topology diagram of the wireless communication module and the remote monitoring system of the present invention; Detailed Implementation

[0020] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings. To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0021] The detection principle of the pulse current method is as follows: When partial discharge occurs in an insulating medium, apparent charges are generated at both ends of the medium. A current loop is then established across the medium, and a pulse current is generated in this loop. By measuring the pulse voltage across the detection impedance in this loop, the partial discharge can be measured. There are generally two types of measurement circuits for the pulse current method, such as... Figure 1 As shown.

[0022] Where Z represents the filter, C is the sample being detected, ck is the coupling capacitance, and Zm is the detection impedance. Figure 1 (a) is a parallel test circuit, which is suitable for cases where the capacitance of the sample is large and it is easy to break down during the test, or where the sample cannot be separated from the ground electrode. This circuit is widely used in engineering practice. Figure 1 (b) is a series test circuit, suitable for cases where the sample capacitance C is small and the breakdown voltage is high. Its advantage is that stray capacitance can be used as the coupling capacitor C. k Meanwhile, the coupling capacitor C k In addition, the capacitor also has a filtering function.

[0023] The pulse current partial discharge sensor of the present invention includes: Pulse current acquisition module: Acquires pulse current generated by partial discharge through an equivalent capacitance sensor with a live display device; Noise reduction and anti-interference module: includes analog filters, digital filters and interference identification algorithm unit, used to filter out high-frequency noise and common-mode interference; Signal processing module: includes amplifiers, analog-to-digital converters and partial discharge identification algorithm units, used for signal amplification, conversion and feature extraction; Wireless communication module: Uses the 433MHz frequency band to send data to the remote terminal; Self-powered module: It obtains electrical energy from charged sensors through capacitive coupling to achieve self-powering.

[0024] Anti-interference processing procedure like Figure 1 and 4 As shown, the workflow of the noise reduction and anti-interference module is as follows: The input signal first passes through an analog filter to remove high-frequency noise; then it enters a digital filter to further suppress interference in specific frequency bands; the interference identification algorithm unit identifies the signal and marks non-partial discharge interference signals; finally, a clean pulse signal is output for subsequent processing.

[0025] The signal processing module's workflow is as follows: The signal is first amplified for gain processing; then converted into a digital signal by an analog-to-digital converter; the partial discharge identification algorithm unit analyzes the digital signal, extracting key features such as pulse amplitude, quantity, phase, frequency, pulse width, and rise time; after extracting these features, signal feature fusion and pattern recognition are performed to construct a pulse feature database, which is then applied to a real-time monitoring and fault diagnosis system; a classification model is trained using machine learning algorithms to achieve automatic identification of pulse anomaly types, and trend analysis is performed using historical data to improve diagnostic accuracy and system reliability; it is integrated into an intelligent maintenance platform to achieve automated decision support and preventive maintenance strategy optimization; finally, a partial discharge data packet is generated for transmission by the wireless transmission module.

[0026] The wireless communication module sends data to the remote monitoring system, which includes: a data receiving terminal; a cloud server; and a user monitoring platform (PC / mobile terminal); enabling functions such as data storage, trend analysis, and alarm push notifications.

[0027] like Figure 2 and 3 As shown, the sensor adopts a magnetic installation method, adhering to the vicinity of the live sensor in the high-voltage switchgear. The installation process does not require power outages, drilling, or wiring, greatly simplifying the construction process.

[0028] The working method of this invention includes the following steps: First, a pulse current signal is acquired to ensure that raw data is obtained from the device; then, the signal is filtered to effectively remove environmental noise and interference; next, the processed signal is amplified and converted to extract key features for subsequent analysis; subsequently, the data is transmitted wirelessly to ensure efficient transmission; a remote terminal receives the data and performs real-time analysis, including pattern recognition and anomaly detection; finally, real-time monitoring and early warning of partial discharge status are achieved, thereby timely detection of potential faults and improvement of system reliability.

[0029] Specifically, pulse current signals are acquired using a high-frequency current sensor to ensure high-precision capture of partial discharge activity within the equipment. The filtering stage employs an adaptive digital filter, dynamically adjusting parameters for different power frequency environments to effectively separate the target signal from background noise. In the signal amplification and conversion stage, a programmable gain amplifier adjusts the signal amplitude, and a high-speed ADC module completes the digital sampling of the signal.

[0030] The feature extraction algorithm focuses on the amplitude, phase, repetition frequency, and waveform characteristics of the discharge pulse, forming a set of key parameters characterizing the discharge state. Wireless transmission employs low-power wide-area network (LPWAN) technology to ensure reliable data transmission in complex industrial environments. Remote terminals deploy intelligent analysis models that combine historical databases for discharge pattern recognition and trend prediction. When an abnormal increase in discharge intensity or a specific dangerous mode is detected, the system automatically triggers a multi-level early warning mechanism and displays the equipment insulation status assessment results and maintenance recommendations in real time through a visual interface.

[0031] To facilitate understanding of the contents of this manual, the following terms are defined: Pulse current method: The measurement results are expressed in pC (picocoulombs) and reflect the insulation status of electrical equipment.

[0032] Live indicator: A device installed on a high-voltage switchgear to indicate whether the equipment is energized, typically including an equivalent capacitance sensor.

[0033] Self-powered module: Obtains electrical energy from high-voltage equipment through capacitive coupling to provide power for the sensor.

[0034] Noise reduction and anti-interference module: A circuit or algorithm unit used to filter out high-order harmonics, common-mode interference and other electromagnetic interference in the power grid.

[0035] Wireless communication module: A wireless module that uses the 433MHz frequency band for data transmission and has the ability to penetrate metal cabinets.

[0036] Remote monitoring terminal: includes a data receiving terminal, server and user interface, used to receive, store, analyze and display partial discharge data.

[0037] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments that can be applied to other fields. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A pulse current partial discharge sensor, suitable for online monitoring of partial discharge in high-voltage switchgear, characterized in that, include: The pulse current acquisition module is used to acquire the pulse current signal generated by partial discharge through the insulator-type capacitive sensor of the live display device built into the high-voltage switchgear; The noise reduction and anti-interference module is connected to the pulse current acquisition module and is used to filter the acquired pulse current signal to suppress high-order harmonic interference and common-mode interference in the power grid. The signal processing module, connected to the noise reduction and anti-interference module, is used to amplify, convert analog to digital and extract partial discharge features from the filtered signal. A wireless communication module, connected to the signal processing module, is used to wirelessly transmit the processed partial discharge data to a remote monitoring terminal. The self-powered module is used to obtain electrical energy from the live sensors in the high-voltage switchgear to power the various modules of the sensors.

2. The pulse current partial discharge sensor according to claim 1, characterized in that, The noise reduction and anti-interference module includes: an analog filter for filtering out high-frequency noise; a digital filter for suppressing interference signals in a specific frequency band; and an interference identification algorithm unit for identifying and marking non-partial discharge interference signals.

3. The pulse current partial discharge sensor according to claim 1 or 2, characterized in that, The signal processing module includes: An amplifier is used to amplify weak pulse signals; An analog-to-digital converter (ADC) is used to convert analog signals into digital signals. The partial discharge identification algorithm unit is used to identify partial discharge pulses and calculate their apparent discharge quantity.

4. The pulse current partial discharge sensor according to any one of claims 1 to 3, characterized in that, The wireless communication module uses the 433MHz frequency band for data transmission, with a transmission distance of up to 800 meters in open environments and the ability to penetrate metal cabinets.

5. The pulse current partial discharge sensor according to any one of claims 1 to 4, characterized in that, The self-powered module obtains power from the charged sensor through capacitive coupling, eliminating the need for an external power source or battery.

6. The pulse current partial discharge sensor according to any one of claims 1 to 5, characterized in that, The sensor adopts a magnetic mounting method, has an IP6X protection rating, and is suitable for high-voltage switchgear with voltage levels from 3kV to 36kV.

7. A method for operating a pulse current partial discharge sensor, characterized in that, Includes the following steps: Step 1: Acquire the pulse current signal generated by partial discharge through the equivalent capacitance sensor of the charged display device. This sensor uses the principle of capacitive coupling to efficiently detect the transient discharge current and convert the original signal into a processable electrical signal. Step 2: Filter the acquired signal, using a low-pass filter to remove high-frequency noise and high-order harmonics, and applying common-mode rejection technology to eliminate common-mode interference, ensuring signal purity and improving the accuracy of subsequent processing; Step 3: Amplify the filtered signal to an appropriate level, then convert it into a digital signal via an analog-to-digital converter (ADC); next, perform feature extraction to extract key features such as peak value, rise time, and frequency, and use a pattern recognition algorithm to accurately identify partial discharge events. Step 4: The processed data is sent to the server via the wireless communication module and the remote monitoring terminal to achieve reliable remote data transmission and ensure data integrity and security during the communication process; Step 5: On the remote monitoring terminal, the data is stored in the database and processed in real time through analysis algorithms; the results are displayed in real time on the visualization interface, including charts and alarm systems, realizing real-time monitoring and early warning functions, which facilitates timely intervention.

8. The working method according to claim 7, characterized in that, The filtering process in step two includes two stages: analog filtering and digital filtering. The digital filtering uses an adaptive algorithm to dynamically adjust the filtering parameters.

9. The working method according to claim 7 or 8, characterized in that, The feature extraction in step three includes the extraction of partial discharge characteristic parameters such as pulse amplitude, pulse number, and phase distribution.

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