A partial discharge inspection and positioning device and method for a ring main unit

Abstract

The present invention relates to the technical field of power equipment status detection, and discloses a partial discharge inspection and positioning device and method for a ring main unit. The partial discharge inspection and positioning device is installed on the ring main unit, and a three-phase signal processing system in a device housing of the partial discharge inspection and positioning device receives three-phase partial discharge signals collected from a charged indicator inside the ring main unit. The three-phase partial discharge signals are analyzed to generate analysis data, which is then transmitted to a handheld terminal for detection and analysis, thereby realizing PRPD spectrum detection and phase-to-phase positioning of partial discharge sources.

Description

Technical Field

[0001] The present invention relates to the technical field of power equipment status detection, and in particular to a partial discharge inspection and positioning device and method for a ring main unit. Background Art

[0002] Ring main unit (RMU) cabinets (RMUs) are widely used in power distribution networks due to their simple structure, reliable and safe operation, and minimal maintenance. The primary cause of internal RMU failures is insulation failure, which can be caused by two main factors. First, process defects during early manufacturing or installation can lead to uneven electric field distribution in certain areas of the insulation system, which can damage the insulation. Second, during operation, if the cabinet is exposed to factors such as strong vibration, high and low temperatures, and abnormal humidity, areas of the insulation system may deteriorate. In high-voltage systems, these two factors can lead to weak insulation areas that are highly susceptible to partial discharge.

[0003] The main technologies for detecting partial discharge in ring main units (RMUs) include ultra-high frequency (UHF), ultrasonic, and transient ground wave (TGE) detection. All three methods share a common device architecture, consisting of sensors, signal conditioning circuits, signal acquisition circuits, and a human-machine interface (HMI) terminal. There are two primary methods for detecting partial discharge in RMUs: live inspection and online monitoring. Live inspection involves personnel carrying testing equipment to regularly inspect the RMUs, identifying and recording any problems. Online monitoring involves installing a partial discharge detection device within the RMU for real-time monitoring, identifying faults, and uploading the information in real time.

[0004] Currently, existing partial discharge detection devices based on three technologies—UHF, ultrasonic, and transient ground wave—are difficult to use in patrol equipment applications. Ultrasonic signals can only overflow from gaps to the outside of the cabinet, resulting in signal overflow wherever there are gaps, making it impossible to accurately determine the interval and phase of the discharge. Transient ground wave signals are generated on the metal shells of all intervals, making it impossible to effectively locate the location of the partial discharge. However, the sensors of detection devices based on UHF, ultrasonic, and transient ground wave methods cannot guarantee the consistency of the signal coupling path during each measurement, making it impossible to perform horizontal comparisons between ring main units or between intervals. Furthermore, existing detection devices cannot perform differential measurements of the three phases, making it impossible to distinguish signals between phases, resulting in low fault detection capabilities. Summary of the Invention

[0005] The present invention provides a ring main unit partial discharge inspection and positioning device and method, which solves the technical problem that the prior art cannot perform different measurements of three phases, is difficult to achieve phase-to-phase signal differentiation, and thus is difficult to achieve phase-to-phase positioning of partial discharge sources.

[0006] A first aspect of the present invention provides a method for inspecting and locating partial discharge in a ring main unit, comprising:

[0007] Obtaining a three-phase partial discharge signal of the ring main unit, and preprocessing the three-phase partial discharge signal to determine an average discharge intensity value of each phase;

[0008] Comparing the average discharge intensity value of each phase with a preset discharge intensity value respectively;

[0009] When the average discharge intensity value of any phase is greater than the preset discharge intensity value, the partial discharge PRPD spectrum associated with the average discharge intensity value greater than the preset discharge intensity value is used as the fault phase spectrum;

[0010] Inputting the fault phase map into a preset partial discharge fault type map library for retrieval;

[0011] If a partial discharge fault type spectrum that is consistent with the fault phase spectrum is matched, then based on the number of the fault phase spectrums, it is determined whether the fault phase spectrum of each phase meets the preset fault phase condition, and the partial discharge source of the ring main unit is located according to the determination result.

[0012] Optionally, the acquiring of a three-phase partial discharge signal of the ring main unit, and preprocessing the three-phase partial discharge signal to determine an average discharge intensity value of each phase includes:

[0013] Obtain the initial amplitude and analysis data of the three-phase partial discharge signal of the ring main unit;

[0014] updating the setting parameters of the amplifiers in the impedance matching module and the program-controlled amplification and filtering module in the partial discharge inspection and positioning device of the ring main unit according to the initial amplitude;

[0015] Based on the setting parameters, a preset data calibration method is used to correct the analysis data to generate calibrated analysis data;

[0016] Drawing a partial discharge PRPD spectrum of each phase using the calibration analysis data;

[0017] According to the partial discharge PRPD spectrum of each phase, the average discharge intensity value of each phase is determined.

[0018] Optionally, it also includes:

[0019] When the average discharge intensity value of each phase is less than or equal to the preset discharge intensity value, it is determined that there is no discharge phenomenon.

[0020] Optionally, it also includes:

[0021] If no partial discharge fault type map consistent with the fault phase map is matched, obtaining the number of discharges within a preset time period according to the fault phase map;

[0022] Comparing the number of discharges with a preset discharge number threshold;

[0023] If the number of discharges is less than the preset discharge number threshold, determining that the three-phase partial discharge signal associated with the fault phase map is a noise signal;

[0024] If the number of discharges is greater than or equal to the preset discharge number threshold, determining whether all frequency band combinations of the programmable amplifying and filtering modules in the ring main unit partial discharge inspection and positioning device have been traversed;

[0025] If all frequency band combinations of the programmable amplifying and filtering modules in the ring main unit partial discharge inspection and positioning device have not been traversed, the setting parameters of the first filter in the programmable amplifying and filtering module are adjusted, and the process jumps to the step of correcting the analysis data based on the setting parameters using a preset data calibration method to generate calibration analysis data until all frequency band combinations are traversed;

[0026] If all frequency band combinations of the programmable amplifying and filtering modules in the ring main unit partial discharge inspection and positioning device are traversed, it is determined that the three-phase partial discharge signal associated with the fault phase spectrum is a noise signal.

[0027] Optionally, if a partial discharge fault type spectrum consistent with the fault phase spectrum is matched, judging whether the fault phase spectrum of each phase meets a preset fault phase condition based on the number of the fault phase spectrums, and locating the partial discharge source of the ring main unit according to the judgment result, including:

[0028] If a partial discharge fault type spectrum that is consistent with the fault phase spectrum is matched, determining the number of the fault phase spectrum;

[0029] If the number of the fault phase maps is a first preset number, then the phase associated with the fault phase map is determined to be the fault phase;

[0030] If the number of the fault phase maps is a second preset number, determining whether the fault phase maps of each phase meet a preset fault phase condition;

[0031] The preset fault phase condition is that the cluster area in the fault phase spectrum satisfies the symmetrical distribution between the first quadrant and the third quadrant;

[0032] Obtaining a maximum discharge intensity value associated with the fault phase map that meets the preset fault phase condition;

[0033] A maximum value is selected from the multiple maximum discharge intensity values, and the phase of the fault phase map associated with the maximum value is determined as the fault phase.

[0034] A second aspect of the present invention provides a ring main unit partial discharge inspection and positioning device, the ring main unit partial discharge inspection and positioning device is used to implement any of the ring main unit partial discharge inspection and positioning methods described above, the ring main unit partial discharge inspection and positioning device includes a device housing;

[0035] The device housing is installed on the ring network cabinet;

[0036] A three-phase signal processing system is provided in the housing of the device;

[0037] The three-phase signal processing system includes a three-phase main control module, a high-speed AD module, an FPGA module and a communication module electrically connected in sequence;

[0038] The three-phase main control module is used to obtain the three-phase partial discharge signal of the ring network cabinet;

[0039] The FPGA module is electrically connected to the three-phase main control module, and is used to pre-process the three-phase partial discharge signals, determine the average discharge intensity value of each phase, and compare the average discharge intensity value of each phase with a preset discharge intensity value. When the average discharge intensity value of any phase is greater than the preset discharge intensity value, the partial discharge PRPD spectrum associated with the average discharge intensity value greater than the preset discharge intensity value is used as the fault phase spectrum;

[0040] The FPGA module is communicatively connected to the handheld terminal via the communication module. The handheld terminal is used to input the fault phase map into a preset partial discharge fault type map library for retrieval. If a partial discharge fault type map consistent with the fault phase map is matched, whether the fault phase map of each phase meets the preset fault phase condition is determined based on the number of the fault phase maps, and the partial discharge source of the ring main unit is located according to the determination result.

[0041] Optionally, the three-phase main control module includes three main control modules;

[0042] The three main control modules are respectively connected to the three signal input interfaces in a one-to-one correspondence, and are used to obtain the three-phase partial discharge signal of the ring network cabinet;

[0043] The three main control modules are all electrically connected to the high-speed AD module;

[0044] The three main control modules are all electrically connected to the FPGA module.

[0045] The FPGA module includes:

[0046] A data acquisition unit, used to obtain the initial amplitude and analysis data of the three-phase partial discharge signal of the ring main unit;

[0047] An updating unit, configured to update the setting parameters of the amplifiers in the impedance matching module and the program-controlled amplification and filtering module in the partial discharge inspection and positioning device of the ring main unit according to the initial amplitude;

[0048] a calibration unit, configured to correct the analysis data based on the setting parameters using a preset data calibration method to generate calibrated analysis data;

[0049] A spectrum drawing unit, used for drawing a partial discharge PRPD spectrum of each phase using the calibration analysis data;

[0050] The average discharge intensity value unit is used to determine the average discharge intensity value of each phase according to the partial discharge PRPD spectrum of each phase.

[0051] Optionally, the handheld terminal includes:

[0052] A retrieval unit, configured to input the fault phase map into a preset partial discharge fault type map library for retrieval;

[0053] a first matching unit, configured to determine the number of the fault phase maps if a partial discharge fault type map consistent with the fault phase map is matched;

[0054] a second determining unit, configured to determine, when the number of the fault phase maps is a first preset number, that the phase associated with the fault phase map is a fault phase;

[0055] a first judging unit, configured to judge whether the fault phase map of each phase satisfies a preset fault phase condition if the number of the fault phase maps is a second preset number;

[0056] a maximum discharge intensity value unit, configured to obtain a maximum discharge intensity value associated with the fault phase map that meets the preset fault phase condition;

[0057] a third determination unit, configured to select a maximum value from the plurality of maximum discharge intensity values, and determine the phase of the fault phase map associated with the maximum value as the fault phase;

[0058] The preset fault phase condition is to ensure that the clustered areas in the fault phase map are symmetrically distributed between the first quadrant and the third quadrant.

[0059] Optionally, the handheld terminal further includes:

[0060] a discharge number acquisition unit, configured to acquire the discharge number within a preset time period according to the fault phase map if a partial discharge fault type map consistent with the fault phase map is not matched;

[0061] a second comparing unit, configured to compare the number of discharges with a preset discharge number threshold;

[0062] a noise signal unit, configured to determine that the three-phase partial discharge signal associated with the fault phase map is a noise signal if the number of discharges is less than the preset discharge number threshold;

[0063] A second judgment unit is configured to judge whether all frequency band combinations of the programmable amplifying and filtering modules in the ring main unit partial discharge inspection and positioning device have been traversed if the number of discharges is greater than or equal to the preset discharge number threshold;

[0064] a jump unit, configured to adjust the setting parameters of the first filter in the programmable amplifying and filtering module if all frequency band combinations of the programmable amplifying and filtering modules in the ring main unit partial discharge inspection and positioning device have not been traversed, and jump to the step of correcting the analysis data based on the setting parameters using a preset data calibration method to generate calibration analysis data, until all frequency band combinations have been traversed;

[0065] The fourth determination unit is configured to determine that the three-phase partial discharge signal associated with the fault phase spectrum is a noise signal if all frequency band combinations of the programmable amplification and filtering modules in the ring main unit partial discharge inspection and positioning device are traversed.

[0066] It can be seen from the above technical solutions that the present invention has the following advantages:

[0067] The present invention provides a ring main unit partial discharge inspection and positioning device and method. The partial discharge inspection and positioning device is installed on the ring main unit. A three-phase signal processing system in a device housing of the partial discharge inspection and positioning device receives three-phase partial discharge signals collected from a charged indicator inside the ring main unit, analyzes the three-phase partial discharge signals, generates analysis data, and then transmits the data to a handheld terminal for detection and analysis, thereby realizing PRPD spectrum detection and phase-to-phase positioning of partial discharge sources. Compared with existing ring main unit partial discharge detection devices, the partial discharge signal is obtained from a core phase hole, ensuring that the coupling paths of signals from different ring main units, different intervals, and different phases are consistent, and the obtained signals can be compared horizontally. Through the calibration process of phase information and pulse amplitude, a more accurate phase accuracy of the partial discharge PRPD spectrum is obtained, thereby adapting to ring main units of different manufacturers and providing more accurate basic data for determining the type of partial discharge. At the same time, after pulse amplitude calibration, a more accurate pulse amplitude of the partial discharge signal can be obtained, providing a more accurate threshold diagnosis standard, and more accurately evaluating the insulation condition of the ring main unit. Three-phase synchronous measurement can capture the propagation characteristics of the same PD source across the three phases. This technology effectively improves the accuracy of PD detection and accurately locates PD sources within ring main units. BRIEF DESCRIPTION OF THE DRAWINGS

[0068] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0069] Figure 1 This is a structural diagram of a partial discharge inspection and positioning device for a ring main unit according to an embodiment of the present invention;

[0070] Figure 2 Schematic diagram of a three-phase signal processing system of a partial discharge inspection and positioning device for a ring main unit according to an embodiment of the present invention;

[0071] Figure 3 Schematic diagram of an impedance matching module according to an embodiment of the present invention;

[0072] Figure 4 This is a schematic diagram of a programmable amplification and filtering module according to an embodiment of the present invention;

[0073] Figure 5 This is a working flow diagram of the partial discharge inspection and positioning device for a ring main unit according to an embodiment of the present invention;

[0074] Figure 6 This is a schematic diagram of the corona / tip discharge fault type spectrum of 91% discharge intensity of the present invention;

[0075] Figure 7 This is a schematic diagram of the corona / tip discharge fault type spectrum of 94% discharge intensity of the present invention;

[0076] Figure 8 This is a schematic diagram of the insulation defect discharge fault type spectrum of 90% discharge intensity of the present invention;

[0077] Figure 9 This is a schematic diagram of the insulation defect discharge fault type spectrum of 96% discharge intensity of the present invention;

[0078] Figure 10 This is a schematic diagram of the suspension discharge fault type spectrum of 86% discharge intensity of the present invention;

[0079] Figure 11 This is a schematic diagram of the suspended discharge fault type spectrum of 93% discharge intensity of the present invention;

[0080] Figure 12 This is a schematic diagram of the free particle discharge fault type spectrum of 90% discharge intensity of the present invention;

[0081] Figure 13 This is a schematic diagram of the free particle discharge fault type spectrum at 95% discharge intensity of the present invention;

[0082] Figure 14 Schematic diagram of the PRPD spectrum of phase A partial discharge in Application Example 1 of the present invention;

[0083] Figure 15 Schematic diagram of the PRPD spectrum of phase B partial discharge in Application Example 1 of the present invention;

[0084] Figure 16 Schematic diagram of the PRPD spectrum of phase C partial discharge in Application Example 1 of the present invention;

[0085] Figure 17 Schematic diagram of the fault phase spectrum of phase A of Application Example 2 of the present invention;

[0086] Figure 18 Schematic diagram of the B-phase fault spectrum of Application Example 2 of the present invention;

[0087] Figure 19 Schematic diagram of the C-phase fault phase spectrum of Application Example 2 of the present invention;

[0088] Figure 20 Schematic diagram of the fault phase spectrum of phase A of Application Example 3 of the present invention;

[0089] Figure 21 Schematic diagram of the B-phase fault spectrum of Application Example 3 of the present invention;

[0090] Figure 22 This is a schematic diagram of the C-phase fault phase spectrum of Application Example 3 of the present invention.

[0091] The meanings of the reference numerals are as follows:

[0092] 1. Device housing; 2. Signal input interface; 3. Housing bottom plate; 4. Main control module; 41. Impedance matching module; 411. Analog switch; 412. Capacitor group; 413. Resistor group; 42. Programmable amplification and filtering module; 421. Programmable amplifier; 422. First filter; 423. Second filter; 424. Amplifier; 425. Comparator; 5. High-speed AD module; 6. FPGA module; 7. Communication module; 8. Handheld terminal. DETAILED DESCRIPTION

[0093] The embodiments of the present invention provide a ring main unit partial discharge inspection and positioning device and method for solving the technical problem that the prior art cannot perform different measurements on the three phases, is difficult to distinguish phase signals, and thus is difficult to achieve phase-to-phase positioning of the partial discharge source.

[0094] In order to make the purpose, features, and advantages of the present invention more obvious and easy to understand, 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 embodiments described below are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0095] At present, the detection devices based on the UHF method, ultrasonic method and transient ground wave method have the following problems when applied on site:

[0096] 1) In online monitoring applications, cabinet modifications are required. The corresponding detection device must be equipped with a corresponding sensor, which must be installed inside the ring main cabinet or on the metal shell. These sensors are used to detect the ultra-high frequency (UHF) signals, ultrasonic signals, and transient ground wave signals generated by partial discharge. When using online monitoring technology, cabinet modifications are required to accommodate the sensor installation.

[0097] 2) High investment costs reduce detection performance. Due to the large number of ring main units (RMUs), installing online monitoring devices on operating RMUs is prohibitively expensive. To reduce costs, current online monitoring devices streamline the monitoring terminal configuration, removing the phase-resolved partial discharge (PRPD) pattern data detection function and instead only uploading the PD signal strength and discharge count.

[0098] 3) Unable to directly reflect the severity of partial discharge in the ring main unit. These three methods are indirect detection methods, inconsistent with the test results of the standard "GB / T7354 High Voltage Test Technology Partial Discharge Measurement", and cannot directly determine the partial discharge situation.

[0099] 4) Fault location is difficult. In patrol inspection applications, UHF detection equipment is difficult to use in metal-shielded ring main units. Ultrasonic signals can only overflow from gaps to the outside of the unit. This results in signal overflow wherever there are gaps, making it impossible to accurately determine the interval and phase of the discharge. Transient ground wave signals are generated on all metal enclosures, making it impossible to effectively locate the location of the partial discharge.

[0100] The present invention provides a ring main unit partial discharge inspection and positioning device suitable for ring main units, which realizes the inspection and maintenance detection of partial discharge of the ring main unit and the positioning of the partial discharge source under energized operating conditions, obtains the partial discharge conditions of each time interval in the distribution ring main unit, and locates the partial discharge source phase by phase based on the intensity of the partial discharge signal of each phase and the phase information of the PRPD spectrum, laying the foundation for the safe and stable operation of the ring main unit.

[0101] The present invention uses the charged indicator device of the ring main unit as the detection sensor, obtains the three-phase partial discharge signal through the core phase hole of the charged indicator device, and develops a handheld inspection device for the detection and analysis of the three-phase partial discharge signal, realizing the detection of the PRPD spectrum and the phase-to-phase positioning of the partial discharge source.

[0102] The present invention has the following advantages:

[0103] (1) The overall structural design of this device. The overall structural design realizes the consistency of the coupling path of the partial discharge signal and the coordination of the propagation of the same signal source in the three phases ABC. The difference from the existing partial discharge inspection device of the ring network cabinet is that: 1) The detection device is based on the ultra-high frequency method, ultrasonic method and transient ground wave method. The sensor cannot guarantee the consistency of the coupling path of the signal during each measurement, and cannot perform horizontal comparison between the ring network cabinets and between each interval. 2) The existing device cannot perform different measurements of the three phases and cannot distinguish the phase signals, which reduces the ability to detect faults.

[0104] (2) Positioning Operational Process. The workflow proposed in this invention enables the positioning of PD sources in the specific scenario of a ring main unit (RMU). Current technology, whether using online monitoring equipment or inspection equipment, makes it difficult to achieve phase-to-phase positioning of PD sources under a RMU.

[0105] See also Figure 1 and Figure 2 The present invention provides a ring main unit partial discharge inspection and positioning device, the ring main unit partial discharge inspection and positioning device includes a device housing 1;

[0106] The device housing 1 is installed on the ring main unit;

[0107] A three-phase signal processing system is provided in the device housing 1;

[0108] The three-phase signal processing system includes a three-phase main control module, a high-speed AD module 5, an FPGA module 6 and a communication module 7 which are electrically connected in sequence;

[0109] The three-phase master control module is used to obtain the three-phase partial discharge signal of the ring main unit;

[0110] The FPGA module 6 is electrically connected to the three-phase main control module. The FPGA module 6 is used to pre-process the three-phase partial discharge signal to obtain a fault phase spectrum;

[0111] The FPGA module 6 is connected to the handheld terminal 8 through the communication module 7. The handheld terminal 8 is used to input the fault phase spectrum into the preset partial discharge fault type spectrum library for retrieval. If a partial discharge fault type spectrum consistent with the fault phase spectrum is matched, then based on the number of fault phase spectra, it is judged whether the fault phase spectrum of each phase meets the preset fault phase condition, and the partial discharge source of the ring main cabinet is located according to the judgment result.

[0112] It should be noted that the partial discharge inspection and positioning device is installed on the ring main unit, and the three-phase signal processing system in the device shell 1 of the partial discharge inspection and positioning device receives the three-phase partial discharge signal collected from the charged indicator inside the ring main unit, and pre-processes the three-phase partial discharge signal to obtain the fault phase spectrum, which is then transmitted to the handheld terminal 8 for analysis, thereby realizing the detection of the PRPD spectrum and the phase-to-phase positioning of the partial discharge source.

[0113] It should be noted that the partial discharge inspection and positioning device mainly includes a three-phase main control module, a high-speed AD (Analog-to-Digital) module 5, an FPGA (Field Programmable Gate Array) module 6, a communication module 7 and a handheld terminal 8.

[0114] Communication module 7: This module can communicate between the handheld terminal 8 and the FPGA module 6 using either wired or wireless communication methods. Examples include USB, serial, Ethernet, Bluetooth, and Wi-Fi. This module is used to upload test results from the FPGA module 6 and issue commands from the handheld terminal 8.

[0115] Handheld terminal 8: This can be a smartphone, tablet computer, laptop computer, or other device. Its functions include: installing control software, analyzing data, drawing and displaying the ABC three-phase partial discharge (PRPD) spectrum, issuing control commands, and locating the partial discharge source.

[0116] It is worth mentioning that the electrical connection in the present invention is specifically achieved by wire connection.

[0117] It is worth mentioning that since the shell of the ring network cabinet is made of metal, the partial discharge inspection and positioning device can be provided with a magnetic suction component on the device shell 1, which is used to adsorb the partial discharge inspection and positioning device on the ring network cabinet; the magnetic suction component includes a steel sleeve and a magnet; the magnet outer shell is provided with a steel sleeve, and the magnet is fixed to the surface of the device shell 1 by fixing screws. During the test, there is no need for the tester to hold the partial discharge inspection and positioning device by hand. Only one tester needs to hold the terminal 8 to perform the detection work. By magnetic suction, the built-in grounding wire of the partial discharge inspection and positioning device is connected to the shell of the ring network cabinet through the magnet, and the ring network cabinet grounding and the grounding wire of the partial discharge inspection and positioning device of the ring network cabinet are connected together to realize the connection of the signal ground, thereby ensuring the safety of the tester. At the same time, one grounding wire is reduced by the magnetic connection, which is convenient for on-site operation.

[0118] It should be noted that the magnets are neodymium iron boron magnets with steel sleeves. The steel sleeve is attached to the housing of the partial discharge inspection and positioning device for the ring main unit (RMU). The magnets are attached to the RMU housing. Using magnets with steel sleeves can address the brittleness of neodymium iron boron magnets.

[0119] The magnetic component has two functions:

[0120] One is to attach the partial discharge inspection and positioning device of the ring main unit to the ring main unit to facilitate on-site operation;

[0121] Second, a magnet is used to electrically connect the RMU PD inspection and locating device to the RMU. This connects the RMU ground wire to the RMU PD inspection and locating device ground wire, achieving a signal ground connection. This also protects the safety of testers, and the magnetic connection eliminates one ground wire, facilitating on-site operation.

[0122] Both sides of the device housing 1 are designed with rounded corners, which makes it easy to grasp with one hand on site, ensuring that the operation process meets the one-handed operation requirements of power operation.

[0123] The device housing 1 is made of aluminum alloy, and the fixing screws used to fix the magnets can achieve electrical conductivity between the ring network cabinet housing and the device housing.

[0124] As an optional embodiment, the partial discharge inspection and positioning device can also be installed on the ring network cabinet through a snap-on assembly. For example, a male snap is provided on the device housing 1 and a female snap is provided on the ring network cabinet. Then, the device housing 1 and the ring network cabinet are snap-connected. Furthermore, the built-in grounding wire of the partial discharge inspection and positioning device is connected to the external grounding wire on the ring network cabinet.

[0125] It should be noted that the partial discharge inspection and positioning device can also be installed on the ring network cabinet through other fixed connection methods, such as bolt connection, providing a mounting frame for placing the partial discharge inspection and positioning device on the ring network cabinet, etc., all of which can realize the installation of the partial discharge inspection and positioning device on the ring network cabinet.

[0126] See also Figure 1 The present invention provides a ring main unit partial discharge inspection and positioning device, wherein the housing bottom plate 3 of the device housing 1 is provided with three signal input interfaces 2 for electrically connecting to the three-phase core phase holes of the power indicator of the ring main unit to transmit the three-phase partial discharge signal to the three-phase signal processing system;

[0127] Among them, the three signal input interfaces 2 are respectively an A-phase signal input interface, a B-phase signal input interface and a C-phase signal input interface.

[0128] It should be noted that the shell bottom plate 3 of the device shell 1 is provided with three signal input interfaces 2, which are used to electrically connect to the three-phase core phase holes of the live indicator of the ring network cabinet to transmit the three-phase partial discharge signal to the three-phase signal processing system; among them, the three signal input interfaces 2 are respectively A-phase signal input interface, B-phase signal input interface and C-phase signal input interface, and each signal input interface 2 corresponds to the three-phase core phase hole connected to the live indicator, such as the A-phase signal input interface is electrically connected to the A-phase core phase hole of the live indicator through a signal line, the B-phase signal input interface is electrically connected to the B-phase core phase hole of the live indicator through a signal line, and the C-phase signal input interface is electrically connected to the C-phase core phase hole of the live indicator through a signal line.

[0129] It is worth mentioning that the signal input interface 2 uses a 4mm diameter banana connector to keep consistent with the size of the phase hole of the power indicator, which is convenient for on-site wiring.

[0130] It should be noted that as a device for locating partial discharges in ring main units (RMUs), the device acquires three-phase partial discharge signals from the phase-core holes of the RMU's built-in live indicator. This ensures spatial consistency in the installation position and signal coupling method of the sensors used for each interval detection in the RMU, providing a consistent standard for partial discharge intensity analysis and improving positioning accuracy. The ABC three-phase signal synchronous measurement ensures temporal coordination of partial discharge signals, providing a consistent signal source for intensity comparison of the three-phase PRPD patterns. This spatial and temporal consistency and coordination further ensures the accuracy of phase-to-phase localization of partial discharge signals based on PRPD patterns.

[0131] See also Figure 1 The present invention provides a ring main unit partial discharge inspection and positioning device, wherein the shell bottom plate 3 is made of insulating material.

[0132] It should be noted that the shell bottom plate 3 of the device shell 1 is made of a plate made of insulating material, such as epoxy resin, silicone rubber, etc.; it has two functions: first, the insulating plate can achieve insulation isolation between signal input ports; second, when the communication mode adopts wireless mode, it can ensure the effective transmission of wireless signals.

[0133] See also Figure 2-Figure 4 , the present invention provides a ring main unit partial discharge inspection and positioning device, the three-phase main control module includes three main control modules 4;

[0134] The three main control modules 4 are connected to the three signal input interfaces 2 in a one-to-one correspondence. The three main control modules 4 are used to obtain the three-phase partial discharge signal of the ring network cabinet;

[0135] The three main control modules 4 are all electrically connected to the high-speed AD module 5;

[0136] The three main control modules 4 are all electrically connected to the FPGA module 6 .

[0137] It should be noted that the three-phase main control module includes three main control modules 4 for receiving partial discharge signals of each phase respectively. The three main control modules 4 are connected to the three signal input interfaces 2 one by one. The three main control modules 4 are respectively A-phase main control module, B-phase main control module and C-phase main control module; they are respectively connected to the A-phase signal input interface, the B-phase signal input interface and the C-phase signal input interface one by one. The three main control modules 4 are all electrically connected to the high-speed AD module 5, and the three main control modules 4 are all electrically connected to the FPGA module 6.

[0138] See also Figure 2-Figure 4 The present invention provides a ring main unit partial discharge inspection and positioning device, wherein the main control module 4 includes an impedance matching module 41 and a program-controlled amplification and filtering module 42 electrically connected in sequence;

[0139] The impedance matching module 41 is used to respond to the switch control signal of the FPGA module 6, adjust the setting parameters of the live indicator suitable for the ring main unit and receive the A phase / B phase / C phase partial discharge signal;

[0140] The program-controlled amplification and filtering module 42 is used to process the received A-phase / B-phase / C-phase partial discharge signals to generate three-phase partial discharge amplified analog signals and square wave analog signals;

[0141] The output end of the program-controlled amplification and filtering module 42 is electrically connected to the high-speed AD module 5;

[0142] High-speed AD module 5, used for performing analog-to-digital conversion on the three-phase partial discharge amplified analog signal and the square wave analog signal to generate a three-phase partial discharge amplified digital signal and a square wave digital signal;

[0143] The output end of the programmable amplification and filtering module 42 is electrically connected to the FPGA module 6 .

[0144] It should be noted that the internal structures of the three main control modules 4 are consistent. The three main control modules 4 all include an impedance matching module 41 and a programmable amplification and filtering module 42 electrically connected in sequence. The impedance matching module 41 is used to respond to the switch control signal of the FPGA module 6, adjust the setting parameters of the live indicator suitable for the ring network cabinet and receive the A-phase / B-phase / C-phase partial discharge signal. The programmable amplification and filtering module 42 is used to process the received A-phase / B-phase / C-phase partial discharge signal to generate a three-phase partial discharge amplified analog signal and a square wave analog signal, wherein the three-phase partial discharge signal includes the A-phase partial discharge signal, the B-phase partial discharge signal and the C-phase partial discharge signal. For example, when the main control module 4 is the A-phase main control module, it receives the A-phase partial discharge signal transmitted from the live indicator. The programmable amplification and filtering module 42 processes the received phase A partial discharge signal to generate a three-phase partial discharge amplified analog signal and a square wave analog signal. The main control modules 4 for the remaining phases are similar and are not described in detail here. The output of the programmable amplification and filtering module 42 is electrically connected to a high-speed AD module 5. The high-speed AD module 5 performs analog-to-digital conversion on the three-phase partial discharge amplified analog signal and the square wave analog signal output by the programmable amplification and filtering module 42 to generate a three-phase partial discharge amplified digital signal and a square wave digital signal. The high-speed AD module 5 can be two ADM9226 dual-channel high-speed AD modules 5. The output of the programmable amplification and filtering module 42 is electrically connected to an FPGA module 6, which transmits the square wave digital signal to the FPGA module 6. The high-speed AD module 5 collects the analog signal output by the programmable amplification and filtering module 42 at a sampling frequency of no less than 10MS / s and transmits the sampling results to the FPGA module 6.

[0145] See also Figure 3 , the present invention provides a ring main unit partial discharge inspection and positioning device, the impedance matching module 41 is an impedance matching circuit;

[0146] The impedance matching circuit includes an analog switch 411, a capacitor group 412 and a resistor group 413;

[0147] A first end of the capacitor bank 412 is electrically connected to the three-phase core phase hole of the power indicator;

[0148] The second end of the capacitor group 412 is electrically connected to the analog switch 411;

[0149] The third end of the capacitor group 412 is electrically connected to the first end of the resistor group 413;

[0150] The analog switch 411 is electrically connected to the second end of the resistor group 413;

[0151] The third end of the resistor group 413 is connected to a built-in ground wire;

[0152] The analog switch 411 is electrically connected to the FPGA module 6;

[0153] The analog switch 411 is used to adjust the capacitance and resistance of the impedance matching circuit in response to receiving the switch control signal to adapt to the ring main unit at the work site;

[0154] The resistor group 413 is connected to the housing of the ring main unit through a built-in grounding wire.

[0155] It should be noted that the impedance matching module 41 is an impedance matching circuit, which includes an analog switch 411, a capacitor group 412 and a resistor group 413, and is composed of a series loop of the analog switch 411, the capacitor group 412 and the resistor group 413. The first end of the capacitor group 412 is electrically connected to the three-phase core phase hole of the power indicator; the second end of the capacitor group 412 is electrically connected to the analog switch 411; the third end of the capacitor group 412 is electrically connected to the first end of the resistor group 413; the analog switch 411 is electrically connected to the second end of the resistor group 413; the third end of the resistor group 413 is connected to a built-in grounding wire; the analog switch 411 is electrically connected to the FPGA module 6; the analog switch 411 is used to respond to the received switch control signal and adjust the capacitance value and resistance value of the impedance matching circuit to adapt to the ring network cabinet at the work site; the resistor group 413 is connected to the casing of the ring network cabinet through the built-in grounding wire.

[0156] It's worth noting that the control signal for analog switch 411 is provided by FPGA module 6, which adjusts the settings for the live indicator, including resistance and capacitance values, to suit the ring main unit (RMU). The live indicator and bushing parameters used by different manufacturers vary, so impedance matching module 41 must be adjusted to maximize the acquisition of partial discharge signals. By switching between resistance and capacitance values, the system can accommodate a wider range of RMU types.

[0157] See also Figure 4 The present invention provides a ring main unit partial discharge inspection and positioning device, wherein the program-controlled amplification and filtering module 42 includes a program-controlled amplifier 421, a first filter 422, a second filter 423, an amplifier 424 and a comparator 425;

[0158] The input end of the programmable amplifier 421 is electrically connected to the output end of the impedance matching module 41;

[0159] The input ends of the first filter 422 and the second filter 423 are both electrically connected to the output of the programmable amplifier 421;

[0160] The output end of the first filter 422 is electrically connected to the amplifier 424;

[0161] An amplifier 424 is used to amplify the three-phase partial discharge signal to generate a three-phase partial discharge amplified analog signal;

[0162] The output end of the second filter 423 is electrically connected to the comparator 425;

[0163] The comparator 425 is used to perform shaping processing on the power frequency signal to generate a square wave analog signal.

[0164] It should be noted that the programmable amplification and filtering module 42 includes a programmable amplifier 421, a first filter 422, a second filter 423, an amplifier 424 and a comparator 425. The input end of the programmable amplification and filtering module 42 is connected to the output end of the impedance matching module 41. The control signal of the programmable amplification and filtering module 42 is provided by the FPGA module 6. Among them, the first filter 422 is a programmable filter, and its frequency band can be adjusted within the range of 10kHz-10MHz. The parameter adjustment of the programmable filter is provided by the FPGA module 6. The initial bandwidth of the first filter 422 is generally set to 100kHz-400kHz. The second filter 423 is a low-pass filter with a frequency band range of 0-100Hz to realize filtering of the industrial frequency signal. The amplifier 424 is a common-phase proportional amplifier to further amplify the local discharge signal. The comparator 425 shapes the industrial frequency signal into a square wave.

[0165] The present invention provides a ring main unit partial discharge inspection and positioning device, wherein the FPGA module 6 includes:

[0166] A data acquisition unit, used to obtain the initial amplitude and analysis data of the three-phase partial discharge signal of the ring main unit;

[0167] An updating unit, configured to update the setting parameters of the amplifier 424 in the impedance matching module 41 and the program-controlled amplification and filtering module 42 in the partial discharge inspection and positioning device of the ring main unit according to the initial amplitude;

[0168] It should be noted that the initial amplitude of the three-phase partial discharge signal is obtained, and the setting parameters of the amplifier 424 in the impedance matching module 41 and the programmable amplification and filtering module 42 are updated according to the initial amplitude; the initial amplitude of the three-phase partial discharge signal is obtained from the FPGA module 6 through the handheld terminal 8, and the resistor group 413 and the capacitor group 412 of the impedance matching module 41 are adjusted to maximize the signal amplitude, and then the amplification factor of the programmable amplification and filtering module 42 is adjusted so that the maximum value of the signal can meet the measurement range of the high-speed AD module 5.

[0169] A calibration unit, configured to correct the analysis data based on the set parameters using a preset data calibration method to generate calibrated analysis data;

[0170] It should be noted that the pulse amplitude and phase information of the three-phase partial discharge signal after S1 adjustment is obtained from the FPGA module 6 through the handheld terminal 8. At the same time, the phase and amplitude of the obtained three-phase partial discharge signal are calibrated according to the setting parameters of the impedance matching module 41 and the setting parameters of the programmable amplification and filtering module 42.

[0171] The setting parameters of the impedance matching module 41 include resistance value and capacitance value, the setting parameters of the programmable amplification and filtering module 42 include amplification factor, and the calibration analysis data includes calibration pulse amplitude and calibration phase information;

[0172] Phase information calibration method: Calculate the phase shift at 50 Hz based on the resistance and capacitance values of the impedance matching module 41, and subtract the calculated phase shift from the obtained phase value to obtain the phase information of the final pulse signal;

[0173] In a specific implementation, to facilitate the implementation of the method, the above process can be converted into a formula encapsulation form, wherein the specific formula for calibrating the phase information can be as follows:

[0174] τ ca =τ0-(R·C)

[0175] Where, τ ca Represents the calibration phase information, τ0 represents the phase information before calibration, R represents the resistance value, and C represents the capacitance value;

[0176] Pulse amplitude calibration method: the acquired amplitude is divided by the amplification factor of the program-controlled amplification and filtering module 42 to obtain the final amplitude information.

[0177] In a specific implementation, in order to facilitate the implementation of the method, the above process can be converted into a formula encapsulation form, wherein the specific formula for calibrating the pulse amplitude can be as follows:

[0178]

[0179] Where A ca represents the calibration pulse amplitude, A0 represents the pulse amplitude before calibration, and M represents the amplification factor of the programmable amplification and filtering module 42.

[0180] A spectrum drawing unit, used for drawing the partial discharge PRPD spectrum of each phase using the calibration analysis data;

[0181] It should be noted that the handheld terminal 8 uses multiple sets of calibrated pulse amplitude and phase information of three-phase partial discharge signals to draw the PRPD spectrum of ABC three-phase partial discharge. This is a conventional PRPD spectrum drawing and will not be repeated here.

[0182] The average discharge intensity value unit is used to determine the average discharge intensity value of each phase according to the partial discharge PRPD spectrum of each phase;

[0183] It should be noted that the average discharge intensity value of each phase can be directly obtained according to the partial discharge PRPD spectrum of each phase.

[0184] It is worth mentioning that the maximum discharge intensity value of each phase can also be directly obtained based on the partial discharge PRPD spectrum. In the following comparison and judgment, the average discharge intensity value or the maximum discharge intensity value can be used.

[0185] A first comparison unit is used to compare the average discharge intensity value of each phase with a preset discharge intensity value;

[0186] It should be noted that the average discharge intensity value of each phase is compared with the preset discharge intensity value.

[0187] The fault phase map unit is used to use the partial discharge PRPD map associated with the average discharge intensity value greater than the preset discharge intensity value as the fault phase map when the average discharge intensity value of any phase is greater than the preset discharge intensity value.

[0188] It should be noted that when the average discharge intensity value of any phase is greater than the preset discharge intensity value, the partial discharge PRPD maps associated with all average discharge intensity values greater than the preset discharge intensity value are used as the fault phase map.

[0189] The analysis data is specifically processed by the output signals of the high-speed AD module 5 and the programmable amplification and filtering module 42 to obtain the analysis data, which includes pulse amplitude and phase information.

[0190] It should be noted that the FPGA module 6 also includes:

[0191] A first determination unit is configured to determine that there is no discharge phenomenon when the average discharge intensity value of each phase is less than or equal to a preset discharge intensity value;

[0192] It should be noted that when the average discharge intensity values of each phase are less than or equal to the preset discharge intensity value, that is, when the average discharge intensity values of each phase are not greater than the preset discharge intensity value, the average discharge intensity values of each phase may be partially less than or partially equal to the preset discharge intensity value; then it is determined that there is no discharge phenomenon in this interval.

[0193] It should be noted that the FPGA module 6 also includes a first processing module, a second processing module and a third processing module;

[0194] A first processing module, configured to generate a switch control signal based on the analysis data and issue the signal for execution;

[0195] The second processing module is used to generate a program-controlled control signal for adjusting the amplification factor of the program-controlled amplification and filtering module 42 according to the analysis data and issue it for execution;

[0196] The third processing module is used to transmit the fault phase map to the communication module 7, and then transmit it to the handheld terminal 8 through the communication module 7.

[0197] It should be noted that the data acquisition unit reads the output digital signal of the high-speed AD module 5, performs a pulse search inside the FPGA module 6, and obtains the amplitude of the pulse. At the same time, the square wave signal output by the programmable amplification and filtering module 42 is output to the FPGA module 6. The FPGA module 6 uses the rising edge of the square wave signal as the timing starting point. While obtaining the pulse amplitude signal, it obtains the time difference of the pulse relative to the most recent square wave rising edge, and then converts the time difference into phase information. Among them, converting the time difference into phase information is a conventional conversion method, which will not be repeated here. The pulse amplitude and phase information are used as the detection results.

[0198] The first processing module, in order to adapt to the ring network cabinets of different manufacturers, the FPGA module 6 can send switch control signal instructions to the handheld terminal 8 module, adjust the analog switch 411 of the control impedance matching module 41, and select different combinations of resistors and capacitors to adapt to bushings with different parameters.

[0199] The second processing module adjusts the amplification factor of the programmable amplification and filtering module 42 to improve the dynamic range of the device. When the signal is weak, the FPGA module 6 outputs an amplification programmable control signal instruction to the programmable amplification and filtering module 42 to increase the amplification factor; when the signal is strong, the FPGA module 6 outputs a reduction programmable control signal instruction to the programmable amplification and filtering module 42 to reduce the amplification factor.

[0200] The third processing module, communication control, FPGA module 6 is directly connected to the communication module 7, and sends the pulse amplitude and phase information in the first processing module to the communication module 7. At the same time, the communication module 7 receives the control instructions of the handheld terminal 8 and transmits them to the FPGA module 6.

[0201] See also Figure 5 The present invention provides a ring main unit partial discharge inspection and positioning device, the handheld terminal 8 includes:

[0202] A retrieval unit, used for inputting the fault phase map into a preset partial discharge fault type map library for retrieval;

[0203] It is worth mentioning that the preset partial discharge fault type map library here is a key-value pair database, which refers to a key-value pair database established based on the map feature association between the fault phase map and the partial discharge fault type map. In this case, the fault phase map is the key and the partial discharge fault type map is the value.

[0204] It should be noted that each fault phase spectrum is input into a preset partial discharge fault type spectrum library for retrieval; that is, the fault phase spectrum is input into the preset partial discharge fault type spectrum library for spectrum retrieval to search whether there is a partial discharge fault type spectrum consistent with the fault phase spectrum in the preset partial discharge fault type spectrum library.

[0205] For easier understanding, see Figure 6-Figure 13 .

[0206] a first matching unit, configured to determine the number of fault phase maps if a partial discharge fault type map consistent with the fault phase map is matched;

[0207] It should be noted that if a partial discharge fault type spectrum that is consistent with the fault phase spectrum is matched, the number of the fault phase spectrum is determined.

[0208] a second determining unit, configured to determine, when the number of the fault phase maps is a first preset number, that the phase associated with the fault phase map is the fault phase;

[0209] It should be noted that the first preset number is 1. When the number of the fault phase map is 1, the phase associated with the fault phase map is directly determined to be the fault phase.

[0210] a first judging unit, configured to judge whether the fault phase spectrum of each phase meets a preset fault phase condition if the number of the fault phase spectrum is a second preset number;

[0211] It should be noted that the second preset number is 2 or 3. When the number of fault phase maps is 2 or 3, it is determined whether the fault phase map of each phase meets the preset fault phase condition, wherein the preset fault phase condition is that the clustering area in the fault phase map meets the symmetrical distribution in the first quadrant and the third quadrant.

[0212] A maximum discharge intensity value unit is used to obtain a maximum discharge intensity value associated with a fault phase map that meets a preset fault phase condition;

[0213] It should be noted that, that is, by comparing whether the clustered areas in the fault phase spectrum satisfy the symmetrical distribution of the first quadrant and the third quadrant in the power frequency cycle, the fault phase spectrum that satisfies the symmetrical distribution of the first quadrant and the third quadrant is selected, and then the associated maximum discharge intensity value can be directly obtained according to each fault phase spectrum.

[0214] a third determination unit, configured to select a maximum value from the plurality of maximum discharge intensity values, and determine the phase of the fault phase map associated with the maximum value as the fault phase;

[0215] It should be noted that the maximum value is selected from multiple maximum discharge intensity values, the fault phase spectrum associated with the maximum discharge intensity value of the maximum value is selected, and then the phase associated with the fault phase spectrum is determined to be the fault phase.

[0216] The preset fault phase condition is that the clustered area in the fault phase map satisfies the symmetrical distribution between the first quadrant and the third quadrant.

[0217] For easier understanding, see Figures 14-22 , the following are three specific application examples:

[0218] Application Example 1:

[0219] See also Figure 14-16 , Figure 14 Schematic diagram of the PRPD spectrum of phase A;

[0220] Figure 15 Schematic diagram of the PRPD spectrum of phase B partial discharge;

[0221] Figure 16 Schematic diagram of the PRPD spectrum of phase C partial discharge;

[0222] according to Figure 14-16 It can be seen that the average discharge intensity value (or maximum discharge intensity value) associated with the partial discharge PRPD spectra of phases ABC is less than 10dB (the preset discharge intensity value), and the clustering area of each phase spectrum has no obvious characteristics, so it is determined that there is no partial discharge.

[0223] Application Example 2:

[0224] See also Figure 17-Figure 19 , Figure 17 It is a schematic diagram of the fault phase spectrum of phase A;

[0225] Figure 18 Schematic diagram of the fault phase spectrum of phase B;

[0226] Figure 19 It is a schematic diagram of the fault phase spectrum of phase C;

[0227] according to Figure 17-Figure 19 It can be seen that the average discharge intensity value (or maximum discharge intensity value) associated with the fault phase spectrum of phases ABC exceeds 10dB (the preset discharge intensity value) in two phases, the maximum discharge intensity value of phase C is the largest, and the two clustered areas of the fault phase spectrum of phase C conform to the 1st and 3rd quadrant distributions. The local discharge source can be located in phase C.

[0228] Application Example 3:

[0229] See also Figure 20-22 , Figure 20 It is a schematic diagram of the fault phase spectrum of phase A;

[0230] Figure 21 Schematic diagram of the fault phase spectrum of phase B;

[0231] Figure 22 It is a schematic diagram of the fault phase spectrum of phase C;

[0232] according to Figure 20-22 It can be seen that the average discharge intensity value (or maximum discharge intensity value) associated with the fault phase spectra of phases ABC exceeds 10dB (the preset discharge intensity value) for the three phases. Phase A has the largest maximum discharge intensity value, and the two clustered areas of the phase A spectrum conform to the 1st and 3rd quadrant distributions. At the same time, the spectrum cluster areas of phases BC do not satisfy the 1st and 3rd quadrant distributions. Therefore, the local discharge source can be located in phase A.

[0233] The handheld terminal 8 also includes:

[0234] a discharge number acquisition unit, configured to acquire the discharge number within a preset time period according to the fault phase map if a partial discharge fault type map consistent with the fault phase map is not matched;

[0235] It should be noted that if a partial discharge fault type map consistent with the fault phase map is not matched, the number of discharges within a preset time period is obtained according to the fault phase map, and the number of discharges can be directly obtained from the fault phase map.

[0236] A second comparison unit is used to compare the number of discharges with a preset discharge number threshold;

[0237] It should be noted that the number of discharges is compared with a preset discharge number threshold.

[0238] a noise signal unit, configured to determine that the three-phase partial discharge signal associated with the fault phase spectrum is a noise signal if the number of discharges is less than a preset discharge number threshold;

[0239] It should be noted that if the number of discharges is less than the preset discharge number threshold, it is determined that the three-phase partial discharge signal associated with the fault phase map is a noise signal.

[0240] The second judgment unit is used to judge whether the frequency band combinations of all programmable amplification and filtering modules 42 in the partial discharge inspection and positioning device of the ring main unit have been traversed if the number of discharges is greater than or equal to a preset discharge number threshold;

[0241] It should be noted that if the number of discharges is greater than or equal to the preset discharge number threshold, a determination is made as to whether all frequency band combinations of the programmable amplification and filtering module 42 have been exhausted. For example, the initial frequency band combination of the three-phase partial discharge signal is 100kHz-400kHz, and other frequency band combinations include 200kHz-500kHz, 300kHz-600kHz, 400kHz-700kHz, 500kHz-800kHz, 600kHz-900kHz, and 700kHz-1MHz. Therefore, it is necessary to determine whether all frequency band combinations of the programmable amplification and filtering module 42 have been exhausted.

[0242] A jump unit is configured to adjust the setting parameters of the first filter 422 in the programmable amplifying and filtering module 42 if all frequency band combinations of the programmable amplifying and filtering modules 42 in the partial discharge inspection and positioning device for the ring main unit have not been traversed, and jump to the step of correcting the analysis data using a preset data calibration method based on the setting parameters to generate calibration analysis data until all frequency band combinations have been traversed;

[0243] It should be noted that if all frequency band combinations of the programmable amplification and filtering module 42 have not been traversed, the setting parameters of the first filter 422 in the programmable amplification and filtering module 42 are adjusted to gradually deviate from the initial frequency band combination, and jump to the step of correcting the analysis data based on the setting parameters using the preset data calibration method to generate calibration analysis data, and then perform the judgment process for the next frequency band combination. It should be noted that adjusting the setting parameters of the first filter 422 in the programmable amplification and filtering module 42 will not change the pulse amplitude and phase information. The setting parameters of the first filter 422 are adjusted to filter out noise interference until all frequency band combinations are traversed. If the current fault phase map still does not match a partial discharge fault type map that is consistent with the fault phase map, the three-phase partial discharge signal associated with the fault phase map is determined to be a noise signal.

[0244] The fourth determination unit is configured to determine that the three-phase partial discharge signal associated with the fault phase spectrum is a noise signal if all frequency band combinations of the programmable amplification and filtering modules 42 in the partial discharge inspection and positioning device for the ring main unit are traversed.

[0245] It should be noted that, when all frequency band combinations of the programmable amplifying and filtering modules 42 are traversed, the three-phase partial discharge signal associated with the fault phase spectrum is determined to be a noise signal.

[0246] See also Figure 5 The working process of the partial discharge inspection and positioning device for the ring main unit is as follows:

[0247] Step 1: Install the partial discharge inspection and positioning device of the ring main unit on the surface of the metal shell of each compartment of the ring main unit, close to the charged indicator. Use the test line to connect the core phase hole of the ABC three-phase of the charged indicator to the signal input interface 2 of this device, start the handheld terminal 8 and the device power supply, and start the measurement.

[0248] Step 2: First, the handheld terminal 8 obtains the initial amplitude of the partial discharge pulse signal from the FPGA module 6, adjusts the resistor group 413 and the capacitor group 412 of the impedance matching module 41 to maximize the signal amplitude, and then adjusts the amplification factor of the programmable amplifier module so that the maximum value of the signal can meet the measurement range of the high-speed AD module 5.

[0249] Step 3: The handheld terminal 8 obtains the pulse amplitude and phase information of the partial discharge pulse signal from the FPGA module 6, and calibrates the pulse amplitude and phase information of the partial discharge pulse signal according to the setting parameters of the impedance matching module 41 and the setting parameters of the programmable amplification and filtering module 42.

[0250] Phase information calibration method: Calculate the phase shift at 50 Hz based on the resistance and capacitance values of the impedance matching module 41, and subtract the calculated phase shift from the obtained phase value to obtain the phase information of the final pulse signal;

[0251] Pulse amplitude calibration method: the acquired amplitude is divided by the amplification factor of the program-controlled amplification and filtering module 42 to obtain the final amplitude information.

[0252] Step 4: Use the amplitudes and phases of multiple sets of calibrated partial discharge pulse signals to draw a PRPD spectrum of the ABC three-phase partial discharge on the handheld terminal 8, and make a judgment based on the threshold. When the average discharge intensity (or maximum discharge intensity) of the three-phase PRPD spectrum is lower than the threshold, there is no fault in this interval.

[0253] Step 5: When the average discharge intensity (or maximum discharge intensity) of one or more phases in this interval is higher than the threshold, the PRPD spectrum of the three-phase partial discharge above the threshold is used as the fault phase spectrum to further determine whether the PRPD spectrum of the fault phase matches the spectrum characteristics of the partial discharge fault type.

[0254] Step 6: If the fault phase spectrum does not match the spectrum characteristics of the partial discharge fault type, further determine the number of discharges per unit time. If the number of discharges is less than the set value, the measurement result is a noise signal.

[0255] If the value is greater than the set value, the parameters of the first filter 422 of the programmable amplification and filtering module 42 are adjusted to gradually deviate from the initial frequency band, and the process jumps to step 3. If all frequency band combinations are traversed and the spectrum characteristics of the partial discharge fault type still do not match, the measurement result is determined to be a noise signal. If the fault phase spectrum matches the spectrum characteristics of the partial discharge fault type, the fault location is determined in step 7.

[0256] Step 7: If the average discharge intensity (or maximum discharge intensity) of the fault phase spectrum of only one phase exceeds the threshold, the phase exceeding the threshold is directly located as the fault phase.

[0257] If the average discharge intensity (or maximum discharge intensity) of the fault phase spectrum of two or more phases exceeds the threshold, the maximum value is selected according to the maximum discharge intensity value of the fault phase spectrum, and the phase of the fault phase spectrum associated with the maximum value is determined as the fault phase.

[0258] The principle is as follows: compare whether the clustered areas in the fault phase spectrum satisfy the symmetrical distribution of quadrants 1 and 3 in the power frequency cycle, and locate the fault phase that satisfies the symmetrical distribution of quadrants 1 and 3 as the phase where the partial discharge source is located.

[0259] The present invention provides a ring main unit partial discharge inspection and positioning device for accurately detecting and locating partial discharge in a running ring main unit. Compared with the current ring main unit partial discharge detection device, the partial discharge signal is obtained from the core phase hole to ensure that the paths of signal coupling between different ring main units, different intervals, and different phases are consistent, and the obtained signal can be compared horizontally; through the calibration process of phase information and pulse amplitude, a more accurate phase accuracy of the partial discharge PRPD spectrum is obtained to adapt to the ring main units of different manufacturers and provide more accurate basic data for judging the type of partial discharge. At the same time, after pulse amplitude calibration, a more accurate pulse amplitude of the partial discharge signal can be obtained, providing a more accurate threshold diagnostic standard and more accurate evaluation of the insulation state of the ring main unit. Three-phase synchronous measurement can obtain the propagation characteristics of the same partial discharge source between the three phases. The above technology can effectively improve the accuracy of partial discharge detection and achieve the positioning accuracy of the partial discharge source in the ring main unit.

[0260] The present invention provides a positioning method for a partial discharge inspection and positioning device for a ring main unit, comprising:

[0261] Step 101: Acquire three-phase partial discharge signals of a ring main unit, pre-process the three-phase partial discharge signals, and determine an average discharge intensity value of each phase.

[0262] Step 102: Compare the average discharge intensity value of each phase with the preset discharge intensity value;

[0263] Step 103: When the average discharge intensity value of any phase is greater than a preset discharge intensity value, the partial discharge PRPD spectrum associated with the average discharge intensity value greater than the preset discharge intensity value is used as the fault phase spectrum;

[0264] Step 104: input the fault phase map into a preset partial discharge fault type map library for retrieval.

[0265] Step 105: If a partial discharge fault type spectrum that is consistent with the fault phase spectrum is matched, then based on the number of fault phase spectrums, determine whether the fault phase spectrum of each phase meets the preset fault phase condition, and locate the partial discharge source of the ring main unit according to the determination result.

[0266] Furthermore, step 101 may include the following sub-steps:

[0267] S11. Obtaining the initial amplitude and analysis data of the three-phase partial discharge signal of the ring main unit;

[0268] S12, updating the setting parameters of the amplifier 424 in the impedance matching module 41 and the program-controlled amplification and filtering module 42 in the partial discharge inspection and positioning device of the ring main unit according to the initial amplitude;

[0269] S13. Based on the set parameters, the analysis data is corrected using a preset data calibration method to generate calibrated analysis data;

[0270] S14, using the calibration analysis data to draw a partial discharge PRPD spectrum of each phase;

[0271] S15. Determine an average discharge intensity value of each phase based on the partial discharge PRPD spectrum of each phase.

[0272] Furthermore, the method further comprises the following steps:

[0273] Step 103a: When the average discharge intensity value of each phase is less than or equal to the preset discharge intensity value, it is determined that there is no discharge phenomenon.

[0274] Furthermore, the method further comprises the following steps:

[0275] Step 106: If no partial discharge fault type map is matched with the fault phase map, the number of discharges within a preset time period is obtained according to the fault phase map;

[0276] Step 107: Compare the number of discharges with a preset discharge number threshold;

[0277] Step 108: If the number of discharges is less than the preset discharge number threshold, the three-phase partial discharge signal associated with the fault phase spectrum is determined to be a noise signal;

[0278] Step 109: If the number of discharges is greater than or equal to the preset discharge number threshold, determine whether all frequency band combinations of the programmable amplifying and filtering modules 42 in the ring main unit partial discharge inspection and positioning device have been traversed;

[0279] Step 1010: If all frequency band combinations of the programmable amplifying and filtering modules 42 in the ring main unit partial discharge inspection and positioning device have not been traversed, then the setting parameters of the first filter 422 in the programmable amplifying and filtering module 42 are adjusted, and the process jumps to the step of correcting the analysis data based on the setting parameters using a preset data calibration method to generate calibrated analysis data until all frequency band combinations have been traversed.

[0280] Step 1011: If all frequency band combinations of the programmable amplifying and filtering modules 42 in the ring main unit partial discharge inspection and positioning device are traversed, it is determined that the three-phase partial discharge signal associated with the fault phase spectrum is a noise signal.

[0281] Furthermore, step 105 may include the following sub-steps:

[0282] S21. If a partial discharge fault type spectrum that is consistent with the fault phase spectrum is matched, the number of the fault phase spectrum is determined;

[0283] S22: If the number of fault phase maps is a first preset number, determining that the phase associated with the fault phase map is a fault phase;

[0284] S23. If the number of fault phase maps is the second preset number, determine whether the fault phase maps of each phase meet the preset fault phase condition;

[0285] S24, obtaining a maximum discharge intensity value associated with a fault phase map that meets a preset fault phase condition;

[0286] S25 . Select a maximum value from the multiple maximum discharge intensity values, and determine the phase of the fault phase spectrum associated with the maximum value as the fault phase.

[0287] Furthermore, the preset fault phase condition is to ensure that the clustered areas in the fault phase map are symmetrically distributed between the first quadrant and the third quadrant.

[0288] In an embodiment of the present invention, a partial discharge inspection and positioning device is installed on a ring main unit. A three-phase signal processing system in a device housing 1 of the partial discharge inspection and positioning device receives three-phase partial discharge signals collected from a charged indicator inside the ring main unit, pre-processes the three-phase partial discharge signals, obtains a fault phase spectrum, and then transmits the fault phase spectrum to a handheld terminal 8 for analysis, thereby realizing the detection of the PRPD spectrum and the phase-to-phase positioning of the partial discharge source.

[0289] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0290] In the several embodiments provided in this application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of the units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

[0291] As described above, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions described in the above embodiments can still be modified, or some of the technical features thereof can be replaced by equivalents. 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 method for inspecting and locating partial discharge of a ring main unit, characterized in that: include: Obtaining a three-phase partial discharge signal of the ring main unit, and preprocessing the three-phase partial discharge signal to determine an average discharge intensity value of each phase; Comparing the average discharge intensity value of each phase with a preset discharge intensity value respectively; When the average discharge intensity value of any phase is greater than the preset discharge intensity value, the partial discharge PRPD spectrum associated with the average discharge intensity value greater than the preset discharge intensity value is used as the fault phase spectrum; Inputting the fault phase map into a preset partial discharge fault type map library for retrieval; If a partial discharge fault type spectrum that is consistent with the fault phase spectrum is matched, then based on the number of the fault phase spectrums, whether the fault phase spectrum of each phase meets the preset fault phase condition is determined, and the partial discharge source of the ring main unit is located according to the determination result; If a partial discharge fault type spectrum that is consistent with the fault phase spectrum is matched, then based on the number of the fault phase spectrums, whether the fault phase spectrum of each phase meets a preset fault phase condition is determined, and the partial discharge source of the ring main unit is located according to the determination result, including: If a partial discharge fault type spectrum that is consistent with the fault phase spectrum is matched, determining the number of the fault phase spectrum; If the number of the fault phase maps is a first preset number, then the phase associated with the fault phase map is determined to be the fault phase; The first preset number is 1; If the number of the fault phase maps is a second preset number, determining whether the fault phase maps of each phase meet a preset fault phase condition; The second preset number is 2 or 3; The preset fault phase condition is that the cluster area in the fault phase spectrum satisfies the symmetrical distribution between the first quadrant and the third quadrant; Obtaining a maximum discharge intensity value associated with the fault phase map that meets the preset fault phase condition; A maximum value is selected from the multiple maximum discharge intensity values, and the phase of the fault phase map associated with the maximum value is determined as the fault phase.

2. The method for inspecting and locating partial discharge of a ring main unit according to claim 1, characterized in that: The obtaining of the three-phase partial discharge signal of the ring main unit, pre-processing the three-phase partial discharge signal, and determining the average discharge intensity value of each phase includes: Obtain the initial amplitude and analysis data of the three-phase partial discharge signal of the ring main unit; updating the setting parameters of the amplifiers in the impedance matching module and the program-controlled amplification and filtering module in the partial discharge inspection and positioning device of the ring main unit according to the initial amplitude; Based on the setting parameters, a preset data calibration method is used to correct the analysis data to generate calibrated analysis data; Drawing a partial discharge PRPD spectrum of each phase using the calibration analysis data; According to the partial discharge PRPD spectrum of each phase, the average discharge intensity value of each phase is determined.

3. The method for inspecting and locating partial discharge of a ring main unit according to claim 1, characterized in that: Also includes: When the average discharge intensity value of each phase is less than or equal to the preset discharge intensity value, it is determined that there is no discharge phenomenon.

4. The method for inspecting and locating partial discharge of a ring main unit according to claim 2, characterized in that: Also includes: If no partial discharge fault type map consistent with the fault phase map is matched, obtaining the number of discharges within a preset time period according to the fault phase map; Comparing the number of discharges with a preset discharge number threshold; If the number of discharges is less than the preset discharge number threshold, determining that the three-phase partial discharge signal associated with the fault phase map is a noise signal; If the number of discharges is greater than or equal to the preset discharge number threshold, determining whether all frequency band combinations of the programmable amplifying and filtering modules in the ring main unit partial discharge inspection and positioning device have been traversed; If all frequency band combinations of the programmable amplifying and filtering modules in the ring main unit partial discharge inspection and positioning device have not been traversed, the setting parameters of the first filter in the programmable amplifying and filtering module are adjusted, and the process jumps to the step of correcting the analysis data based on the setting parameters using a preset data calibration method to generate calibration analysis data until all frequency band combinations are traversed; If all frequency band combinations of the programmable amplifying and filtering modules in the ring main unit partial discharge inspection and positioning device are traversed, it is determined that the three-phase partial discharge signal associated with the fault phase spectrum is a noise signal.

5. A partial discharge inspection and positioning device for a ring main unit, characterized in that: The ring main unit partial discharge inspection and positioning device is used to implement a ring main unit partial discharge inspection and positioning method according to any one of claims 1 to 4, and the ring main unit partial discharge inspection and positioning device includes a device housing; The device housing is installed on the ring network cabinet; A three-phase signal processing system is provided in the housing of the device; The three-phase signal processing system includes a three-phase main control module, a high-speed AD module, an FPGA module and a communication module electrically connected in sequence; The three-phase main control module is used to obtain the three-phase partial discharge signal of the ring network cabinet; The FPGA module is electrically connected to the three-phase main control module, and is used to pre-process the three-phase partial discharge signals, determine the average discharge intensity value of each phase, and compare the average discharge intensity value of each phase with a preset discharge intensity value. When the average discharge intensity value of any phase is greater than the preset discharge intensity value, the partial discharge PRPD spectrum associated with the average discharge intensity value greater than the preset discharge intensity value is used as the fault phase spectrum; The FPGA module is communicatively connected to the handheld terminal via the communication module. The handheld terminal is configured to input the fault phase map into a preset partial discharge fault type map library for retrieval. If a partial discharge fault type map consistent with the fault phase map is found, the fault phase map of each phase is judged based on the number of the fault phase maps to determine whether the fault phase map meets a preset fault phase condition. The partial discharge source of the ring main unit is located based on the judgment result. The handheld terminal includes: A retrieval unit, configured to input the fault phase map into a preset partial discharge fault type map library for retrieval; a first matching unit, configured to determine the number of the fault phase maps if a partial discharge fault type map consistent with the fault phase map is matched; a second determining unit, configured to determine, when the number of the fault phase maps is a first preset number, that the phase associated with the fault phase map is a fault phase; The first preset number is 1; a first judging unit, configured to judge whether the fault phase map of each phase satisfies a preset fault phase condition if the number of the fault phase maps is a second preset number; The second preset number is 2 or 3; a maximum discharge intensity value unit, configured to obtain a maximum discharge intensity value associated with the fault phase map that meets the preset fault phase condition; a third determination unit, configured to select a maximum value from the plurality of maximum discharge intensity values, and determine the phase of the fault phase map associated with the maximum value as the fault phase; The preset fault phase condition is to ensure that the clustered areas in the fault phase map are symmetrically distributed between the first quadrant and the third quadrant.

6. The partial discharge inspection and positioning device for a ring main unit according to claim 5, characterized in that: The three-phase main control module includes three main control modules; The three main control modules are respectively connected to the three signal input interfaces in a one-to-one correspondence, and are used to obtain the three-phase partial discharge signal of the ring network cabinet; The three main control modules are all electrically connected to the high-speed AD module; The three main control modules are all electrically connected to the FPGA module.

7. The partial discharge inspection and positioning device for a ring main unit according to claim 5, characterized in that: The FPGA module includes: A data acquisition unit, used to obtain the initial amplitude and analysis data of the three-phase partial discharge signal of the ring main unit; An updating unit, configured to update the setting parameters of the amplifiers in the impedance matching module and the program-controlled amplification and filtering module in the partial discharge inspection and positioning device of the ring main unit according to the initial amplitude; a calibration unit, configured to correct the analysis data based on the setting parameters using a preset data calibration method to generate calibrated analysis data; A spectrum drawing unit, used for drawing a partial discharge PRPD spectrum of each phase using the calibration analysis data; The average discharge intensity value unit is used to determine the average discharge intensity value of each phase according to the partial discharge PRPD spectrum of each phase.

8. The ring main unit partial discharge inspection and positioning device according to claim 7, characterized in that: The handheld terminal further includes: a discharge number acquisition unit, configured to acquire the discharge number within a preset time period according to the fault phase map if a partial discharge fault type map consistent with the fault phase map is not matched; a second comparing unit, configured to compare the number of discharges with a preset discharge number threshold; a noise signal unit, configured to determine that the three-phase partial discharge signal associated with the fault phase map is a noise signal if the number of discharges is less than the preset discharge number threshold; A second judgment unit is configured to judge whether all frequency band combinations of the programmable amplifying and filtering modules in the ring main unit partial discharge inspection and positioning device have been traversed if the number of discharges is greater than or equal to the preset discharge number threshold; a jump unit, configured to adjust the setting parameters of the first filter in the programmable amplifying and filtering module if all frequency band combinations of the programmable amplifying and filtering modules in the ring main unit partial discharge inspection and positioning device have not been traversed, and jump to the step of correcting the analysis data based on the setting parameters using a preset data calibration method to generate calibration analysis data, until all frequency band combinations have been traversed; The fourth determination unit is configured to determine that the three-phase partial discharge signal associated with the fault phase spectrum is a noise signal if all frequency band combinations of the programmable amplification and filtering modules in the ring main unit partial discharge inspection and positioning device are traversed.

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