Partial discharge fusion detection method and system based on multiple sensors

Abstract

The invention discloses a partial discharge fusion detection method and system based on multiple sensors. The method comprises the steps that a data sensing unit collects a generated transient voltage-to-ground signal, a generated ultrahigh frequency electromagnetic wave signal and a generated sound wave signal; the partial discharge acquisition unit processes the received signal and selects whether to start early warning or not according to a judgment result; the partial discharge acquisition unit establishes communication with the comprehensive online detection unit; and the comprehensive online detection unit analyzes, processes and stores the data, and performs centralized long-term detection on equipment in the power distribution network of the power system through man-machine interaction and a mobile terminal. According to the invention, multiple signals related to partial discharge are obtained based on multiple groups of sensors, the characteristics of partial discharge are obtained from different angles, analysis and determination are carried out in combination with the partial discharge acquisition unit, and data interaction with the comprehensive online detection unit is carried out, so that the accuracy of equipment detection in a power system is improved; and the maintenance efficiency of the partial discharge phenomenon of the power distribution network is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of electric power monitoring, and in particular relates to a partial discharge fusion detection method and system based on multiple sensors. Background Art

[0002] The power distribution network of the power system includes many primary equipment such as substations, switch cabinets / ring main units, circuit breakers, capacitors, reactors, etc. The operating conditions of such equipment are related to the safety of the power network. The distribution equipment has high requirements for operating stability, but environmental interference is inevitable during long-term operation. For example, high temperature can easily cause insulation aging of the equipment, high humidity can easily cause surface discharge of the equipment insulation, overload can affect the performance of the equipment, the insulators and metal bodies of the primary equipment accumulate charges due to the electric field strength at the sharp corners and burrs, and the electrical connection between the conductors is poor. All kinds of interference are most likely to cause partial discharge of the equipment.

[0003] The partial discharge phenomenon at the power grid connection points such as distribution rooms, substations, switch cabinets / ring main units, and circuit breakers is a gradual process. Inside the high-voltage switch, due to excessive electrical stress, lightning wave impact, defects and aging of the insulating medium, the electric field affecting the surface of the equipment becomes unevenly distributed, resulting in a local increase in the electric field strength. The discharge phenomenon generated at the higher field strength position is called partial discharge. The main damage mechanisms of partial discharge to the insulation structure are: charged particles (electrons, ions, etc.) impact the insulation layer, destroying its molecular structure, such as fiber fragmentation, and thus the insulation is damaged. Due to the impact of charged ions, the insulation has a local temperature increase, which can easily cause overheating of the insulation, and in severe cases, carbonization will occur. Ozone and nitrogen oxides generated by partial discharge will corrode the insulation. When encountering moisture, nitric acid will be produced, which will corrode the insulation more violently. At present, partial discharge in the power distribution network of the power system will accelerate the aging of the insulation material, reduce its insulation performance, and shorten the service life of the equipment; it is easy to cause equipment leakage, short circuit and other faults, affecting the safe and reliable operation of the equipment; the noise and electromagnetic interference generated by partial discharge will also affect the operation of surrounding equipment and the normal power supply in the power distribution area. Since partial discharge can occur on the surface of the insulation and inside the insulation, and it is difficult to observe the damage to the insulation performance in the early stage, the current detection method of partial discharge in the power distribution network of the power system has the problems of low detection signal frequency, susceptibility to external interference, and the need for power outage detection, so it is difficult to apply to on-site live detection. Summary of the invention

[0004] The present invention provides a partial discharge fusion detection method and system based on multiple sensors, aiming to solve the problems of the current partial discharge detection method in the power distribution network of the power system, namely, low detection signal frequency, susceptibility to external interference, and difficulty in application to on-site live detection due to the need for power outage detection.

[0005] In order to achieve the above object, the present invention adopts the following technical scheme: The present invention provides a partial discharge fusion detection method based on multiple sensors, comprising the following steps: S1. When partial discharge occurs in the power distribution network, a transient voltage-to-ground sensor is used to detect the transient voltage-to-ground signal; an ultra-high frequency electromagnetic wave signal is generated by using an ultra-high frequency sensor; and an ultrasonic sensor is used to detect the sound wave signal. S2, transmitting the transient voltage-to-ground signal, the ultra-high frequency electromagnetic wave signal and the acoustic wave signal to the partial discharge acquisition unit, which pre-processes the received signal, calculates the discharge point position, analyzes the discharge characteristics and judges the discharge identification result, and chooses whether to start the early warning according to the judgment result; the partial discharge acquisition unit establishes communication with the comprehensive online detection unit; S3. The comprehensive online detection unit analyzes, processes and stores the data uploaded by the partial discharge acquisition unit, and performs centralized long-term detection of the equipment in the power system distribution network through human-computer interaction and mobile terminals.

[0006] In some embodiments, in S1 , an ultrasonic sensor is used to detect a sound wave signal with a frequency between 20 kHz and 200 kHz generated during partial discharge.

[0007] In some embodiments, in S1, a transient voltage-to-ground sensor is configured on a capacitor of a device in a power distribution network. The transient voltage-to-ground sensor is used to detect a transient voltage-to-ground signal and convert the detected signal into an analog signal and transmit it to a partial discharge acquisition unit.

[0008] In some embodiments, in S1, the UHF sensor is used to detect UHF electromagnetic wave signals through a UHF coupler installed in a device in the power system distribution network, and establish communication with the partial discharge acquisition unit through a LoRa wireless method.

[0009] In some embodiments, in S1, the ultrasonic sensor uses a piezoelectric sensor, and the ultrasonic sensor converts the detected ultrasonic signal into an electrical signal, and then performs subsequent AD conversion after signal conditioning and amplification, and transmits it to the partial discharge acquisition unit.

[0010] In some embodiments, in S2, the partial discharge acquisition unit includes a power supply module, an MCU main control module, and a plurality of inter-board plug-in boards, and the partial discharge acquisition unit is used to realize the processing of sensor signals.

[0011] Further, in S2, several inter-board plug-in boards can be expanded to access switch quantity input module acquisition boards, relay output module boards, multi-channel RS485 access terminals and temperature and humidity acquisition modules; Several inter-board plug-in boards can be connected to the industrial control screen display unit, which is arranged on the switch cabinet panel. The industrial control screen display unit is used to realize on-site monitoring of the operating status of the power equipment.

[0012] In some embodiments, in S2, the discharge point position calculation specifically includes: calculating the discharge point position by comparing the signal strength and time difference detected by different sensors; the discharge characteristic analysis includes: extracting characteristic parameters such as frequency, amplitude and phase of the discharge signal; and the discharge identification result judgment includes: classifying the discharge type and evaluating the discharge intensity.

[0013] In some embodiments, in S3, the integrated online detection unit is used to record the data used by each sensor, draw a data curve, and display it on the mobile terminal through human-computer interaction.

[0014] The present invention also provides a system based on a partial discharge fusion detection method based on multiple sensors, the system comprising a data sensing module, a partial discharge acquisition module and a comprehensive online detection module, wherein: The data sensing module is used to detect and collect and upload to the partial discharge acquisition module: transient ground voltage signals, ultra-high frequency electromagnetic wave signals and sound wave signals; The partial discharge acquisition module is used to pre-process transient ground voltage signals, ultra-high frequency electromagnetic wave signals and acoustic wave signals, calculate the discharge point position, analyze the discharge characteristics and judge the discharge identification results, choose whether to start the early warning according to the judgment results, and establish communication with the comprehensive online detection unit; The comprehensive online detection module is used to analyze, process and store the data uploaded by the partial discharge acquisition unit, and to conduct centralized long-term detection of equipment in the power system distribution network through human-computer interaction and mobile terminals.

[0015] Compared with the prior art, the partial discharge fusion detection method and system based on multiple sensors of the present invention has the following beneficial effects: The present invention provides a partial discharge fusion detection method based on multiple sensors, comprising the following steps: S1, when a partial discharge phenomenon occurs in a power system distribution network, a transient voltage-to-ground signal is generated by detecting a transient voltage-to-ground sensor; an ultra-high frequency electromagnetic wave signal is generated by detecting an ultra-high frequency sensor; and an ultrasonic sensor is used to detect a sound wave signal; S2, the transient voltage-to-ground signal, the ultra-high frequency electromagnetic wave signal and the sound wave signal are transmitted to a partial discharge acquisition unit, the partial discharge acquisition unit pre-processes the received signal, calculates the discharge point position, analyzes the discharge characteristics and judges the discharge identification result, and selects whether to start an early warning according to the judgment result; the partial discharge acquisition unit establishes communication with an integrated online detection unit; S3, the integrated online detection unit analyzes, processes and stores the data uploaded by the partial discharge acquisition unit, and performs centralized long-term detection on the equipment in the power system distribution network through human-computer interaction and a mobile terminal. Based on the above, the present invention realizes partial discharge detection on the basis of the system by integrating various partial discharge fusion detections such as transient voltage-to-ground detection, ultra-high frequency detection, ultrasonic detection, etc., and integrating a human-computer interaction module according to application requirements. Finally, the collected data is uploaded to the comprehensive online detection system in a network communication manner. In the comprehensive online detection system, the characteristics of partial discharge information are analyzed by computer, and multiple power equipment are centrally monitored for a long time and diagnosed and analyzed. The present invention can obtain multiple signals at the same time, improve the detection efficiency, reduce manual intervention and improve work efficiency through automated data analysis and processing functions. The present invention predicts and analyzes the insulation operating conditions through long-term operation data, and through multi-fusion sensor detection and data analysis, it can detect anomalies as early as possible and handle these distribution equipment with partial discharge, avoid further deterioration of equipment performance and failures leading to large-scale power outages, and improve the stability of the power distribution network. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The drawings in the specification are used to provide further understanding of the present invention and constitute a part of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0017] Figure 1 It is a schematic diagram of the early warning determination process of the local acquisition unit in the method and system for partial discharge fusion detection based on multiple sensors of the present invention; Figure 2 It is a schematic diagram of the signal processing flow of a transient earth voltage (TEV) sensor in a partial discharge fusion detection method and system based on multiple sensors of the present invention; Figure 3 It is a schematic diagram of the signal processing flow of an ultrasonic detection sensor in a method and system for partial discharge fusion detection based on multiple sensors of the present invention; Figure 4It is a schematic diagram of the signal processing flow of an ultra-high frequency (UHF) sensor in a partial discharge fusion detection method and system based on multiple sensors of the present invention; Figure 5 It is a schematic diagram of a hardware development platform of a partial discharge monitoring unit in a partial discharge fusion detection method and system based on multiple sensors of the present invention. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0019] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0021] In the description of the embodiments of the present invention, it should be noted that if the terms "upper", "lower", "horizontal", "inner", etc. indicate an orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the invention is usually placed when in use, it is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0022] In addition, if the term "horizontal" appears, it does not mean that the component must be absolutely horizontal, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", which does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0023] In the description of the embodiments of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0024] How to effectively realize the monitoring and analysis functions of partial discharge phenomena of switch cabinets, circuit breakers and other equipment in the field of distribution network automation, so as to discover potential weak points in the insulation of electrical equipment as early as possible.

[0025] like Figure 1 As shown, the present invention provides a partial discharge fusion detection method based on multiple sensors, comprising the following steps: S1. When partial discharge occurs in the power distribution network, a transient voltage-to-ground sensor is used to detect the transient voltage-to-ground signal; an ultra-high frequency electromagnetic wave signal is generated by using an ultra-high frequency sensor; and an ultrasonic sensor is used to detect the sound wave signal. S2, transmitting the transient voltage-to-ground signal, the ultra-high frequency electromagnetic wave signal and the acoustic wave signal to the partial discharge acquisition unit, which pre-processes the received signal, calculates the discharge point position, analyzes the discharge characteristics and judges the discharge identification result, and chooses whether to start the early warning according to the judgment result; the partial discharge acquisition unit establishes communication with the comprehensive online detection unit; S3. The comprehensive online detection unit analyzes, processes and stores the data uploaded by the partial discharge acquisition unit, and performs centralized long-term detection of the equipment in the power system distribution network through human-computer interaction and mobile terminals.

[0026] The present invention can simultaneously obtain a variety of signals related to partial discharge by combining a transient ground voltage sensor, an ultra-high frequency sensor and an ultrasonic sensor, reflecting the characteristics of partial discharge from different angles. The partial discharge acquisition unit of the present invention analyzes and determines the data collected by the rising sensor group, and interacts with the comprehensive online detection unit, thereby improving the accuracy of detection when partial discharge occurs in the power distribution network through data processing, analysis and judgment.

[0027] The present invention compares and analyzes the advantages and disadvantages of various current partial discharge detection methods, combines the operating characteristics and structural features of distribution network equipment, and realizes centralized status monitoring of multiple switch cabinet power equipment based on the data performance characteristics of partial discharge.

[0028] In some embodiments, the partial discharge acquisition unit software of the present invention introduces the open source FreeRTOS operating system, adopts a functional modular design, and fully utilizes MCU resources such as DMA and FMC to ensure efficient data acquisition and processing.

[0029] like Figure 4 As shown, the partial discharge acquisition unit of the present invention is designed on the existing hardware and software development platform, and is composed of an acquisition host and multiple partial discharge sensors. The acquisition host is designed based on the ARM platform, and mainly involves a power module, an MCU main control module (integrated with wired and Lora wireless communication modules), and several inter-board plug-in boards. The power module realizes AC and DC power supply and the working power supply of the main chips of other modules, and realizes the sensor signal acquisition, data processing and communication functions as a whole.

[0030] like Figure 2 As shown, in the partial discharge fusion detection method of the present invention, the transient voltage-to-ground sensor detects the transient voltage-to-ground signal by attaching the capacitor of the equipment in the power system distribution network, and converts the detected signal into an analog signal and transmits it to the partial discharge acquisition unit. When partial discharge occurs in the equipment part in the switch cabinet, the electric field energy will gather to the grounded metal part adjacent to the grounding point due to the high and low electric potential, and the electromagnetic waves caused by the pulse current group will induce a voltage to the ground in the grounded metal cabinet. In actual working conditions, the present invention can detect the transient voltage-to-ground signal (TEV) through the capacitor attached to the outside of the metal box. The transient voltage-to-ground detection method of partial discharge has the characteristics of high detection sensitivity and fast response to the change speed of partial discharge pulses.

[0031] Among them, on the outer wall of the metal box of the switch cabinet, a capacitive sensor is placed to detect the transient voltage signal to the ground. The capacitive sensor is a thin copper sheet laid on the surface of the switch cabinet as a metal electrode. A capacitor medium is added between the metal electrode and the switch cabinet body to form a capacitor C1. The transient voltage signal to the ground can be coupled to the set detection capacitor C2 through the capacitor C1. The transient voltage signal to the ground needs to be converted into an analog signal through circuit preprocessing and enter the partial discharge monitoring unit.

[0032] The ultra-high frequency sensor of the present invention detects ultra-high frequency electromagnetic wave signals through a UHF coupler installed in a device in a power system distribution network, and establishes communication with a partial discharge acquisition unit through a LoRa wireless method.

[0033] In actual working conditions, the ultra-high frequency (UHF) sensor of the present invention detects the ultra-high frequency electromagnetic wave signal when partial discharge occurs through a UHF coupler installed on the housing of the power equipment. In order to avoid high-frequency interference from other external devices on site, a shielding cover can be installed on the outside of the coupler. The ultra-high frequency sensor communicates with the partial discharge acquisition host through LoRa wireless mode, adopts battery power supply mode, the power supply voltage is 3.7V, and the data upload interval time is adjustable, usually 30 minutes. The host collects the extreme value, average value and discharge number of partial discharge data of each sensor respectively. The sensor module is composed of a filter circuit, an amplification circuit, a detection circuit, a power supply, an MCU, a 485 and its EMC protection circuit. The detection of the ultra-high frequency (UHF) sensor has the characteristics of strong anti-electromagnetic interference ability and high sensitivity. The detection frequency range is adjustable, and it can effectively detect various types of discharges such as surface discharge, surface creepage, tip discharge, internal discharge, corona discharge, etc.

[0034] like Figure 3 As shown, the present invention uses an ultrasonic sensor to detect the sound wave signal with a frequency between 20kHz and 200kHz generated during partial discharge. During the entire partial discharge process, the sound wave signal changes in a wide range, and the frequency and intensity of the subsequent waves are relatively low, so the partial discharge sound source is a point sound source. It is suitable for partial discharge detection of power equipment such as power cables and their accessories, transformers, and switch cabinets.

[0035] Specifically, since local discharge is a rapid charge release or migration process, the electric field stress, mechanical stress and particle force around the discharge point lose their balance and produce an oscillating change process; the rapid oscillation of mechanical stress and particle force causes the medium around the discharge point to vibrate, thereby generating an acoustic signal. The spectrum of acoustic waves generated by local discharge is very wide, ranging from tens of Hz to several MHz, among which signals with a frequency lower than 20kHz can be heard by the human ear, while ultrasonic signals higher than this frequency must be received by an ultrasonic sensor. Based on this, the present invention can infer the strength of the discharge by measuring the sound pressure of the ultrasonic signal for the acoustic signal with a frequency between 20kHz and 200kHz generated by local discharge, thereby providing a basis for subsequent data analysis and processing.

[0036] Ultrasonic detection sensors can be composed of piezoelectric sensors (piezoelectric ceramics) and installed on the metal box walls of equipment such as transformers and switch cabinets. The sensor element first converts the detected ultrasonic signal into an electrical signal, and then transmits the electrical signal to the partial discharge acquisition unit. Usually, the voltage after the ultrasonic probe conversion is only at the uV level, and it needs to be conditioned and amplified for subsequent AD conversion. In the signal processing and conversion unit, hardware filtering, digital filtering, and signal amplification processing are required to filter out various types of noise and interference signals, and achieve the purpose of improving the signal-to-noise ratio of the partial discharge signal. The signal acquisition unit is processed by ADC to convert the analog signal into a digital signal that can be further processed.

[0037] like Figure 4 As shown, the partial discharge acquisition unit includes a power module, an MCU main control module and several inter-board plug-in boards, and the partial discharge acquisition unit is used to process sensor signals. Among them, several inter-board plug-in boards can be expanded to access switch input module acquisition boards, relay output module boards, multi-channel RS485 access terminals and temperature and humidity acquisition modules.

[0038] The main functions of the software in the partial discharge acquisition unit include: signal acquisition to data preprocessing, discharge location determination, discharge feature extraction and discharge result analysis. The partial discharge acquisition unit can connect to multiple sensors at the same time. The partial discharge acquisition unit uploads to the monitoring system background through communication, and implements data management functions in the monitoring system background, including result storage, query and deletion, and displays historical data in a curve chart. The partial discharge acquisition unit uses different sensors, and the partial discharge pulse frequency bands that can be measured are also different. The data characteristics are shown in Table 1 below: Table 1 Data acquisition characteristics of partial discharge sensor unit

[0039] like Figure 5 As shown, in some embodiments, the partial discharge acquisition unit of the present invention, by adopting a connector structure design, reserves a unified interface, can expand the switch input module acquisition board, relay output module board, multi-channel RS485 access collection terminal, and supports the access of multiple partial discharge detection sensors and the access of temperature and humidity acquisition modules. Furthermore, the partial discharge acquisition unit can be connected to an ultrasonic sensor to detect the electromagnetic field signal at the partial discharge site through acoustic wave signal detection, or through an ultra-high frequency sensor. The two principles are combined to conduct all-round detection of the equipment, making the monitoring of partial discharge more accurate and comprehensive. The partial discharge acquisition unit can also record the data of each sensor and draw a data curve, so that the curve trend of the partial discharge extreme value and the number of discharges can be intuitively viewed. The partial discharge acquisition unit can process and judge the partial discharge data collected to the end, and perform alarm processing on the numerical points that exceed the limit. The partial discharge data monitoring system judges the insulation performance of each detected part through historical data and curve trends.

[0040] The partial discharge acquisition unit can be installed in the switch cabinet according to the on-site conditions. During maintenance, all data can be viewed by connecting the display screen to the partial discharge acquisition unit via a network cable. Ultrasonic and ultra-high frequency partial discharge sensors can support the installation of the switch cabinet without power failure, and the installation of the partial discharge sensor of the switch cabinet does not affect the normal operation of the distribution room. The partial discharge acquisition host of the present invention can be connected to the partial discharge data monitoring system in the background through the RS485 serial port or the network port, and the data of each sensor can be reported in real time. It can also transmit important data to the cloud platform through optical fiber, Ethernet, and other methods. When the partial discharge exceeds the limit data, it can be pushed to the mobile terminal of the operation and maintenance personnel for data communication.

[0041] The present invention discloses a partial discharge fusion detection method and system based on multiple sensors. The method and system utilize multiple partial discharge fusion detection and data extraction such as transient ground voltage detection, ultra-high frequency detection, and ultrasonic detection to reflect information parameters of the operating status of electrical equipment. When the partial discharge characteristics of a circuit breaker or a switch cabinet are abnormal, an alarm is issued and the data is analyzed and determined so that measures can be taken in time, thereby effectively improving the reliability and operating efficiency of power system equipment, reducing accident risks and maintenance costs, and being able to perform centralized long-term monitoring and diagnostic analysis on multiple power equipment.

[0042] Finally, it should be noted that the above is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any ordinary technician in the industry can smoothly implement the present invention as shown in the specification and described above, and any equivalent changes, modifications and evolutions made by using the technical content disclosed above are all equivalent embodiments of the present invention. At the same time, any equivalent changes, modifications and evolutions made to the above embodiments based on the essential technology of the present invention are still within the protection scope of the technical solution of the present invention.

Claims

1. A partial discharge fusion detection method based on multiple sensors, characterized in that: The specific steps include: S1. When partial discharge occurs in the power distribution network, a transient voltage-to-ground sensor is used to detect the transient voltage-to-ground signal; an ultra-high frequency electromagnetic wave signal is generated by using an ultra-high frequency sensor; and an ultrasonic sensor is used to detect the sound wave signal. S2, transmitting the transient voltage-to-ground signal, the ultra-high frequency electromagnetic wave signal and the acoustic wave signal to the partial discharge acquisition unit, which pre-processes the received signal, calculates the discharge point position, analyzes the discharge characteristics and determines the discharge identification result, and selects whether to start the warning according to the determination result; The partial discharge acquisition unit establishes communication with the comprehensive online detection unit; S3. The comprehensive online detection unit analyzes, processes and stores the data uploaded by the partial discharge acquisition unit, and performs centralized long-term detection of the equipment in the power system distribution network through human-computer interaction and mobile terminals.

2. The partial discharge fusion detection method based on multiple sensors according to claim 1 is characterized in that: In S1, an ultrasonic sensor is used to detect a sound wave signal with a frequency between 20 kHz and 200 kHz generated during partial discharge.

3. The partial discharge fusion detection method based on multiple sensors according to claim 1 is characterized in that: In S1, a transient voltage-to-ground sensor is configured on a capacitor of equipment in a power distribution network. The transient voltage-to-ground sensor is used to detect a transient voltage-to-ground signal and convert the detected signal into an analog signal and transmit it to a partial discharge acquisition unit.

4. The partial discharge fusion detection method based on multiple sensors according to claim 1 is characterized in that: In S1, the UHF sensor is used to detect the UHF electromagnetic wave signal through the UHF coupler installed in the power distribution network of the power system, and establish communication with the partial discharge acquisition unit through the LoRa wireless method.

5. The partial discharge fusion detection method based on multiple sensors according to claim 1 is characterized in that: In S1, the ultrasonic sensor adopts a piezoelectric sensor, and the ultrasonic sensor converts the detected ultrasonic signal into an electrical signal, and then performs subsequent AD conversion after signal conditioning and amplification, and transmits it to the partial discharge acquisition unit.

6. The partial discharge fusion detection method based on multiple sensors according to claim 1 is characterized in that: In S2, the partial discharge acquisition unit includes a power supply module, an MCU main control module and a plurality of inter-board plug-in boards, and the partial discharge acquisition unit is used to realize the processing of sensor signals.

7. The partial discharge fusion detection method based on multiple sensors according to claim 6 is characterized in that: In S2, several inter-board plug-in boards can be expanded to access switch quantity input module acquisition boards, relay output module boards, multi-channel RS485 access terminals and temperature and humidity acquisition modules; Several inter-board plug-in boards can be connected to the industrial control screen display unit, which is arranged on the switch cabinet panel. The industrial control screen display unit is used to realize on-site monitoring of the operating status of the power equipment.

8. The partial discharge fusion detection method based on multiple sensors according to claim 1 is characterized in that: In S2, the discharge point position calculation specifically includes: realizing the discharge point position calculation by comparing the signal strength and time difference detected by different sensors; the discharge characteristic analysis includes: extracting characteristic parameters such as frequency, amplitude and phase of the discharge signal; the discharge identification result judgment includes: classifying the discharge type and evaluating the discharge intensity.

9. The partial discharge fusion detection method based on multiple sensors according to claim 1, characterized in that: In S3, the integrated online detection unit is used to record the data used by each sensor, draw a data curve, and display it on the mobile terminal through human-computer interaction.

10. A system based on the partial discharge fusion detection method based on multiple sensors as described in any one of claims 1 to 9, characterized in that: The system includes a data sensing module, a partial discharge acquisition module and a comprehensive online detection module, wherein: The data sensing module is used to detect and collect and upload to the partial discharge acquisition module: transient ground voltage signals, ultra-high frequency electromagnetic wave signals and sound wave signals; The partial discharge acquisition module is used to pre-process transient ground voltage signals, ultra-high frequency electromagnetic wave signals and acoustic wave signals, calculate the discharge point position, analyze the discharge characteristics and judge the discharge identification results, choose whether to start the early warning according to the judgment results, and establish communication with the comprehensive online detection unit; The comprehensive online detection module is used to analyze, process and store the data uploaded by the partial discharge acquisition unit, and to conduct centralized long-term detection of equipment in the power system distribution network through human-computer interaction and mobile terminals.

Images