Partial discharge inspection and positioning apparatus and method for ring main unit

Abstract

A partial discharge inspection and positioning apparatus and method for a ring main unit. The partial discharge inspection and positioning apparatus is mounted on the ring main unit. A three-phase partial discharge signal acquired from a charged indicator inside the ring main unit is received by means of a three-phase signal processing system in an apparatus housing of the partial discharge inspection and positioning apparatus, the three-phase partial discharge signal is analyzed to generate analysis data, and then the analysis data is transmitted to a handheld terminal for detection and analysis, so as to implement detection of a PRPD pattern and inter-phase positioning of a partial discharge source.

Description

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

[0001] The present application claims priority to the Chinese patent application No. 202411136112.X, filed on August 19, 2024, and entitled "A partial discharge inspection positioning device and method for ring main unit", the whole content of which is incorporated herein by reference. TECHNICAL FIELD

[0002] The present application relates to the technical field of power equipment state detection, and in particular to a partial discharge inspection positioning device and method for ring main unit. BACKGROUND

[0003] The ring main unit is widely used in power distribution network due to its simple structure, reliable and safe operation, and small maintenance amount. The main cause of internal failure of the ring main unit is insulation failure, and the main reasons for damage to the insulation of the cabinet are as follows. Firstly, if there are process problems in the early manufacturing or installation process, the uneven distribution of electric field in some areas of the insulation system will occur, which will damage the insulation system. Secondly, during operation, if affected by strong vibration, high and low temperature, abnormal humidity and other factors, the insulation system of the cabinet will age in some areas. In high-voltage systems, the weak insulation position caused by the above two reasons is prone to partial discharge.

[0004] The main technologies for detecting partial discharge of the ring main unit are ultra-high frequency method, ultrasonic method and transient ground wave method. The three detection methods have the same device architecture, including four parts of sensor, signal conditioning circuit, signal acquisition circuit and human-computer interaction terminal. There are mainly two ways for detecting partial discharge of the ring main unit, one is live inspection detection technology, and the other is online monitoring technology. The live inspection detection is that the detection personnel carries the detection equipment to regularly inspect the ring main unit, finds the problem and records it. The online monitoring is to install a partial discharge detection device in the ring main unit to monitor in real time and find the fault and upload in real time.

[0005] At present, the existing partial discharge detection devices based on the three methods of ultra-high frequency method, ultrasonic method and transient ground wave method are difficult to be applied in the metal shell shielded ring network cabinet in the application scene of the equipment inspection. The ultrasonic signal can only overflow from the gap to the outside of the cabinet, so that as long as there is a gap, the signal will overflow, and the interval and phase of the discharge cannot be accurately obtained. The transient ground wave signal will be generated on the metal shell of all intervals, and the partial discharge position cannot be effectively located. However, the sensors of the detection devices based on the ultra-high frequency method, ultrasonic method and transient ground wave method cannot guarantee the consistency of the coupling path of the signal in each measurement, cannot perform horizontal comparison between the ring network cabinets and between each interval, and the existing detection devices cannot perform different measurements of three phases, cannot distinguish the interphase signals, and have low fault detection capability. SUMMARY

[0006] The application provides a ring network cabinet partial discharge inspection positioning device and method, which solves the technical problem that the prior art cannot perform different measurements of three phases, cannot distinguish interphase signals, and cannot realize interphase positioning of the partial discharge source.

[0007] The application provides a ring network cabinet partial discharge inspection positioning device and method, which solves the technical problem that the prior art cannot perform different measurements of three phases, cannot distinguish interphase signals, and cannot realize interphase positioning of the partial discharge source.

[0008] The three-phase partial discharge signals of the ring network cabinet are acquired, and the three-phase partial discharge signals are preprocessed to determine the average discharge intensity values of each phase.

[0009] The average discharge intensity values of each phase are compared with preset discharge intensity values, respectively.

[0010] When the average discharge intensity value of any phase is greater than the preset discharge intensity value, the partial discharge PRPD pattern associated with the average discharge intensity value greater than the preset discharge intensity value is taken as a fault phase pattern.

[0011] The fault phase pattern is input into a preset partial discharge fault type pattern library for searching.

[0012] If a partial discharge fault type pattern consistent with the fault phase pattern is matched, whether the fault phase patterns of each phase satisfy a preset fault phase condition is judged based on the number of fault phase patterns, and the ring network cabinet is positioned for a partial discharge source according to the judgment result.

[0013] Optionally, the acquisition of the three-phase partial discharge signals of the ring network cabinet and the preprocessing of the three-phase partial discharge signals to determine the average discharge intensity values of each phase comprises:

[0014] The initial amplitude and analysis data of the three-phase partial discharge signals of the ring network cabinet are acquired.

[0015] According to the initial amplitude, the setting parameters of the amplifiers in the impedance matching module and the program-controlled amplification and filtering module of the partial discharge inspection and positioning device of the ring main unit are updated;

[0016] Based on the setting parameters, the preset data calibration method is used to correct the analysis data to generate calibrated analysis data;

[0017] The partial discharge PRPD spectrum of each phase is drawn using the calibrated analysis data;

[0018] According to the partial discharge PRPD spectrum of each phase, the average discharge intensity value of each phase is determined.

[0019] Optionally, it further comprises:

[0020] 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.

[0021] Optionally, it further comprises:

[0022] If the partial discharge fault type spectrum consistent with the fault phase spectrum is not matched, the discharge times in a preset period are obtained according to the fault phase spectrum;

[0023] The discharge times are compared with a preset discharge times threshold;

[0024] If the discharge times are less than the preset discharge times threshold, it is determined that the three-phase partial discharge signal associated with the fault phase spectrum is a noise signal;

[0025] If the discharge times are greater than or equal to the preset discharge times threshold, it is determined whether all frequency band combinations of the program-controlled amplification and filtering modules in the partial discharge inspection and positioning device of the ring main unit are traversed;

[0026] If all frequency band combinations of the program-controlled amplification and filtering modules in the partial discharge inspection and positioning device of the ring main unit are not traversed, the setting parameters of the first filter in the program-controlled amplification and filtering module are adjusted, and the step of correcting the analysis data using the preset data calibration method based on the setting parameters to generate calibrated analysis data is jumped to until all frequency band combinations are traversed;

[0027] If all frequency band combinations of the program-controlled amplification and filtering modules in the partial discharge inspection and positioning device of the ring main unit are traversed, it is determined that the three-phase partial discharge signal associated with the fault phase spectrum is a noise signal.

[0028] Optionally, if the partial discharge fault type atlas consistent with the fault phase atlas is matched, whether the fault phase atlas of each phase meets a preset fault phase condition is judged based on the number of the fault phase atlas, and the ring main unit is positioned for partial discharge according to a judgment result, comprising:

[0029] If the partial discharge fault type atlas consistent with the fault phase atlas is matched, the number of the fault phase atlas is determined.

[0030] If the number of the fault phase atlas is a first preset number, the phase associated with the fault phase atlas is determined as a fault phase.

[0031] If the number of the fault phase atlas is a second preset number, whether the fault phase atlas of each phase meets a preset fault phase condition is judged.

[0032] The preset fault phase condition is that the aggregation area in the fault phase atlas meets a first quadrant and a third quadrant symmetric distribution.

[0033] The maximum discharge intensity value associated with the fault phase atlas meeting the preset fault phase condition is obtained.

[0034] The maximum value is selected from a plurality of the maximum discharge intensity values, and the phase of the fault phase atlas associated with the maximum value is determined as a fault phase.

[0035] The second aspect of the application provides a ring main unit partial discharge inspection positioning device, which is used to realize the ring main unit partial discharge inspection positioning method.

[0036] The device housing is installed on the ring main unit.

[0037] The device housing is provided with a three-phase signal processing system.

[0038] The three-phase signal processing system comprises a three-phase main control module, a high-speed AD module, an FPGA module and a communication module connected in sequence.

[0039] The three-phase main control module is used to obtain three-phase partial discharge signals of the ring main unit.

[0040] The FPGA module is electrically connected with the three-phase main control module, and the FPGA module is used to pre-process the three-phase partial discharge signals, determine the average discharge intensity value of each phase, respectively compare the average discharge intensity value of each phase with a preset discharge intensity value, and when the average discharge intensity value of any phase is greater than the preset discharge intensity value, the partial discharge PRPD atlas associated with the average discharge intensity value greater than the preset discharge intensity value is taken as a fault phase atlas.

[0041] The FPGA module is in communication connection with a handheld terminal through the communication module, and the handheld terminal is used for inputting the fault phase spectrum into a preset partial discharge fault type spectrum library for searching, if a partial discharge fault type spectrum consistent with the fault phase spectrum is matched, then based on the number of the fault phase spectrum, it is judged whether the fault phase spectrum of each phase meets a preset fault phase condition, and the ring main unit is positioned according to the judgment result.

[0042] Optionally, the three-phase master control module comprises three master control modules;

[0043] The three master control modules are connected with the three signal input interfaces one by one respectively, and are used for acquiring three-phase partial discharge signals of the ring main unit;

[0044] The three master control modules are electrically connected with the high-speed AD module;

[0045] The three master control modules are electrically connected with the FPGA module.

[0046] The FPGA module comprises:

[0047] A data acquisition unit is configured to acquire initial amplitude and analysis data of three-phase partial discharge signals of the ring main unit;

[0048] An updating unit is configured to update setting parameters of an amplifier in an internal impedance matching module and a program-controlled amplification filtering module of the ring main unit partial discharge inspection positioning device according to the initial amplitude;

[0049] A calibration unit is configured to correct the analysis data by using a preset data calibration method based on the setting parameters to generate calibrated analysis data;

[0050] A spectrum drawing unit is configured to draw partial discharge PRPD spectra of each phase by using the calibrated analysis data;

[0051] An average discharge intensity value unit is configured to determine average discharge intensity values of each phase according to the partial discharge PRPD spectra of each phase.

[0052] Optionally, the handheld terminal comprises:

[0053] A searching unit is configured to input the fault phase spectrum into a preset partial discharge fault type spectrum library for searching;

[0054] A first matching unit is configured to determine the number of the fault phase spectrum if a partial discharge fault type spectrum consistent with the fault phase spectrum is matched;

[0055] The second determining unit is configured to determine that the phase associated with the fault phase atlas is a fault phase when the number of the fault phase atlas is a first preset number.

[0056] The first determining unit is configured to determine whether the fault phase atlas of each phase satisfies a preset fault phase condition when the number of the fault phase atlas is a second preset number.

[0057] The maximum discharge intensity value unit is configured to obtain a maximum discharge intensity value associated with the fault phase atlas that satisfies the preset fault phase condition.

[0058] The third determining unit is configured to select a maximum value from a plurality of maximum discharge intensity values, and determine that the phase of the fault phase atlas associated with the maximum value is a fault phase.

[0059] The preset fault phase condition is that the aggregation area in the fault phase atlas satisfies a first quadrant and a third quadrant symmetric distribution.

[0060] Optionally, the handheld terminal further comprises:

[0061] The discharge frequency obtaining unit is configured to obtain a discharge frequency in a preset period according to the fault phase atlas when no local discharge fault type atlas consistent with the fault phase atlas is matched.

[0062] The second comparing unit is configured to compare the discharge frequency with a preset discharge frequency threshold.

[0063] The noise signal unit is configured to determine that the three-phase local discharge signal associated with the fault phase atlas is a noise signal when the discharge frequency is less than the preset discharge frequency threshold.

[0064] The second determining unit is configured to determine whether all frequency band combinations of the program-controlled amplification filtering module in the ring main unit local discharge inspection positioning device are traversed when the discharge frequency is greater than or equal to the preset discharge frequency threshold.

[0065] The jump unit is configured to adjust the setting parameter of the first filter in the program-controlled amplification filtering module when all frequency band combinations of the program-controlled amplification filtering module in the ring main unit local discharge inspection positioning device are not traversed, and jump to the step of correcting the analysis data by using a preset data calibration method based on the setting parameter to generate calibrated analysis data until all the frequency band combinations are traversed.

[0066] The fourth determining unit is configured to determine that the three-phase local discharge signal associated with the fault phase atlas is a noise signal when all frequency band combinations of the program-controlled amplification filtering module in the ring main unit local discharge inspection positioning device are traversed.

[0067] From the above technical solution can be seen, the present application has the following advantages:

[0068] The partial discharge inspection positioning device and method of the ring main unit provided by the application is installed on the ring main unit, the three-phase partial discharge signal collected by the live indicator inside the ring main unit is received by the three-phase signal processing system in the device shell of the partial discharge inspection positioning device, the three-phase partial discharge signal is analyzed, analysis data is generated, and then transmitted to the handheld terminal for detection and analysis, so that the detection of the PRPD map and the inter-phase positioning of the partial discharge source are realized; compared with the existing partial discharge detection device of the ring main unit, the partial discharge signal is obtained from the core phase hole, the path of the signal coupling of different ring main units, different intervals and different phase signals is consistent, and the signal can realize horizontal comparison; through the calibration process of the phase information and the pulse amplitude, the phase accuracy of the partial discharge PRPD map is more accurate, so as to provide more accurate basic data for judging the partial discharge type of different manufacturers of ring main units, and after the pulse amplitude calibration, the pulse amplitude of the partial discharge signal is more accurate, and more accurate threshold diagnostic criteria are provided to more accurately evaluate the insulation state of the ring main unit. Three-phase synchronous measurement can obtain the propagation characteristics of the same partial discharge source among three phases. The above technologies can effectively improve the accuracy of partial discharge detection and realize the positioning accuracy of the partial discharge source in the ring main unit. BRIEF DESCRIPTION OF DRAWINGS

[0069] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only some embodiments of the application, and for those skilled in the art, other drawings can also be obtained without creative labor.

[0070] Fig. 1 is a structural schematic diagram of the partial discharge inspection positioning device of the ring main unit according to the embodiment of the application;

[0071] Fig. 2 is a schematic diagram of the three-phase signal processing system of the partial discharge inspection positioning device of the ring main unit according to the embodiment of the application;

[0072] Fig. 3 is a schematic diagram of the impedance matching module according to the embodiment of the application;

[0073] Fig. 4 is a schematic diagram of the program-controlled amplification and filtering module according to the embodiment of the application;

[0074] Fig. 5 is a work flow diagram of the partial discharge inspection positioning device of the ring main unit according to the embodiment of the application;

[0075] Fig. 6 is a schematic diagram of the corona / point discharge fault type map of 91% discharge intensity according to the application;

[0076] Figure 7 is a schematic diagram of a corona / point discharge fault pattern map at 94% discharge strength of the present application;

[0077] Figure 8 is a schematic diagram of an insulation defect discharge fault pattern map at 90% discharge strength of the present application;

[0078] Figure 9 is a schematic diagram of an insulation defect discharge fault pattern map at 96% discharge strength of the present application;

[0079] Figure 10 is a schematic diagram of a floating discharge fault pattern map at 86% discharge strength of the present application;

[0080] Figure 11 is a schematic diagram of a floating discharge fault pattern map at 93% discharge strength of the present application;

[0081] Figure 12 is a schematic diagram of a free particle discharge fault pattern map at 90% discharge strength of the present application;

[0082] Figure 13 is a schematic diagram of a free particle discharge fault pattern map at 95% discharge strength of the present application;

[0083] Figure 14 is a schematic diagram of a phase A partial discharge PRPD pattern map of Application Example 1 of the present application;

[0084] Figure 15 is a schematic diagram of a phase B partial discharge PRPD pattern map of Application Example 1 of the present application;

[0085] Figure 16 is a schematic diagram of a phase C partial discharge PRPD pattern map of Application Example 1 of the present application;

[0086] Figure 17 is a schematic diagram of a phase A fault phase pattern map of Application Example 2 of the present application;

[0087] Figure 18 is a schematic diagram of a phase B fault phase pattern map of Application Example 2 of the present application;

[0088] Figure 19 is a schematic diagram of a phase C fault phase pattern map of Application Example 2 of the present application;

[0089] Figure 20 is a schematic diagram of a phase A fault phase pattern map of Application Example 3 of the present application;

[0090] Figure 21 is a schematic diagram of a phase B fault phase pattern map of Application Example 3 of the present application;

[0091] Figure 22 is a schematic diagram of a phase C fault phase pattern map of Application Example 3 of the present application.

[0092] Wherein, the reference signs have the following meanings: 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, program-controlled amplification and filtering module; 421, program-controlled 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 embodiment of the application provides a ring net cabinet local discharge inspection positioning device and method, and aims to solve the technical problems that the prior art cannot perform different measurements of three phases, it is difficult to distinguish phase-to-phase signals, and thus it is difficult to realize phase-to-phase positioning of a local discharge source.

[0094] In order to make the application purpose, features and advantages of the application more obvious and easy to understand, the technical solutions in the embodiments of the application will be clearly and completely described below in combination with the drawings in the embodiments of the application. Obviously, the following described embodiments are only some of the embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the application.

[0095] At present, the detection devices using the three methods of ultra-high frequency method, ultrasonic method and transient ground wave method have the following problems in field application:

[0096] 1) In the online monitoring application scene, the cabinet body needs to be modified. The corresponding detection device needs to be equipped with a corresponding sensor, and the sensor is installed in the ring net cabinet or on the surface of the metal shell to obtain the ultra-high frequency signal, ultrasonic signal and transient ground wave signal generated when the local discharge occurs. When the online monitoring technology is used, the cabinet body needs to be modified to adapt to the installation of the sensor.

[0097] 2) The detection performance is reduced due to excessive investment cost. Because the amount of ring net cabinets is huge, the online monitoring device is installed in the running ring net cabinet, and the investment cost is too high. In order to reduce the cost, the current online monitoring device reduces the configuration of the monitoring terminal, deletes the partial discharge PRPD (phase-resolved partial discharge) spectrum data detection function, and only uploads the partial discharge signal strength and discharge times.

[0098] 3) The severity of the ring net cabinet local discharge cannot be directly reflected. The three methods are indirect detection methods, which are inconsistent with the detection results of the standard "GB / T7354 High Voltage Test Technology Partial Discharge Measurement", and cannot directly determine the local discharge condition.

[0099] 4) Difficulty in achieving fault location. In inspection equipment application scenarios, UHF detection equipment is difficult to apply to metal-shielded ring main units. Ultrasonic signals can only leak out of the cabinet through gaps, resulting in signal leakage wherever there is a gap, making it impossible to accurately obtain the interval and phase of discharge. Transient ground wave signals will be generated on the metal shell of all intervals, which also cannot effectively locate the location of partial discharge.

[0100] This invention provides a partial discharge inspection and positioning device for ring main units (RNBs), enabling the inspection and detection of partial discharge in RNBs under energized operation and the location of partial discharge sources. It obtains the partial discharge status at various time intervals within the power distribution RNB and uses the intensity of partial discharge signals in each phase and the phase information of the PRPD (Partial Discharge Perimeter) spectrum to locate the partial discharge sources between phases, laying the foundation for the safe and stable operation of the RNB.

[0101] This invention uses the live indicator device built into the ring main unit as a detection sensor. It acquires three-phase partial discharge signals through the phase hole of the live indicator device and develops a handheld inspection device for the detection and analysis of three-phase partial discharge signals, realizing the detection of PRPD spectrum and the phase-to-phase location of partial discharge sources.

[0102] This invention has the following advantages:

[0103] (1) Overall structural design of this device. The overall structural design achieves consistency in the coupling path of partial discharge signals and coordination in the propagation of the same signal source in the three phases A, B, and C. It differs from existing ring main unit partial discharge inspection devices in that: 1) Detection devices based on ultra-high frequency, ultrasonic, and transient ground wave methods cannot guarantee the consistency of the signal coupling path during each measurement, and cannot perform lateral comparisons between ring main units or between different bays. 2) Existing devices cannot perform different measurements of the three phases, cannot distinguish between phase signals, and reduce the ability to detect faults.

[0104] (2) Positioning Operation Process. The workflow proposed in this invention enables the positioning of partial discharge power sources in the specific scenario of a ring main unit. Current technology, whether for online monitoring equipment or inspection equipment, makes it difficult to achieve phase-to-phase positioning of partial discharge power sources within a ring main unit.

[0105] Please refer to Figures 1 and 2. The present invention provides a partial discharge inspection and positioning device for a ring main unit, which includes a device housing 1.

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

[0107] A three-phase signal processing system is installed inside the housing 1 of the device;

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

[0109] The three-phase main control module is used for acquiring three-phase partial discharge signals of the ring main unit.

[0110] The FPGA module 6 is electrically connected with the three-phase main control module, and the FPGA module 6 is used for pre-processing the three-phase partial discharge signals to obtain a fault phase atlas.

[0111] The FPGA module 6 is in communication connection with the handheld terminal 8 through the communication module 7, and the handheld terminal 8 is used for inputting the fault phase atlas into a preset partial discharge fault type atlas library for searching, if a partial discharge fault type atlas consistent with the fault phase atlas is matched, then based on the number of the fault phase atlas, it is judged whether the fault phase atlas of each phase meets a preset fault phase condition, and according to the judgment result, the ring main unit is subjected to partial discharge source positioning.

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

[0113] It should be noted that the partial discharge inspection and positioning device mainly comprises 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] The communication module 7: can realize communication between the handheld terminal 8 and the FPGA module 6 in wired and wireless modes. For example, USB interface, serial interface, network port, Bluetooth, WIFI and other types of communication modules 7. The function is to realize uploading of the detection results of the FPGA module 6 and issuing of instructions of the handheld terminal 8.

[0115] The handheld terminal 8: can adopt smart phones, tablet computers, notebook computers and other devices. The function is to install control software to realize analysis, drawing and display of the ABC three-phase partial discharge PRPD atlas, issuing of control instructions, positioning of the partial discharge source and the like.

[0116] It is worth mentioning that the electrical connection in the present application is specifically realized by using wires.

[0117] It is worth mentioning that, since the shell of the ring main unit is made of metal material, the partial discharge inspection positioning device can be adsorbed on the ring main unit by setting a magnetic assembly on the device shell 1; the magnetic assembly includes a steel sleeve and a magnet; the magnet sleeve is provided with a steel sleeve, and the magnet is fixed to the surface of the device shell 1 by a fixing screw. During testing, the tester does not need to hold the partial discharge inspection positioning device, but only needs to hold the terminal 8 to realize the detection work. The partial discharge inspection positioning device adopts a magnetic adsorption mode, the grounding wire built-in the partial discharge inspection positioning device is connected with the shell of the ring main unit through the magnet, the grounding of the ring main unit and the grounding wire of the partial discharge inspection positioning device of the ring main unit are connected together to realize the connection of the signal ground, which ensures the safety of the tester. At the same time, the connection through the magnet reduces one grounding wire, which is convenient for on-site operation.

[0118] It should be noted that the magnet is a neodymium iron boron magnet with a steel sleeve, and the side with the steel sleeve is installed on the shell of the partial discharge inspection positioning device of the ring main unit by a fixing screw. The magnet side is adsorbed on the shell of the ring main unit. The magnet with a steel sleeve can solve the brittleness problem of the neodymium iron boron magnet.

[0119] The magnetic assembly has two functions:

[0120] Firstly, the partial discharge inspection positioning device of the ring main unit is adsorbed on the ring main unit, which is convenient for on-site operation.

[0121] Secondly, the magnet realizes the electrical connection between the partial discharge inspection positioning device of the ring main unit and the ring main unit, connects the grounding of the ring main unit and the grounding wire of the partial discharge inspection positioning device of the ring main unit together to realize the connection of the signal ground. At the same time, it also protects the safety of the tester. The connection through the magnet reduces one grounding wire, which is convenient for on-site operation.

[0122] The two sides of the device shell 1 adopt a round corner structure design, which is convenient for single-handed holding on site, and ensures that the operation process meets the single-handed operation requirements of power operation.

[0123] The device shell 1 is made of aluminum alloy material, and the fixing screw for fixing the magnet can realize the conduction between the shell of the ring main unit and the shell of the device.

[0124] As an alternative embodiment, the partial discharge inspection positioning device can also be installed on the ring main unit through a buckle assembly, for example, a male buckle is provided on the device shell 1, and a female buckle is provided on the ring main unit, then the device shell 1 and the ring main unit are connected by the buckle, further, the grounding wire built-in the partial discharge inspection positioning device is connected with the external grounding wire on the ring main unit.

[0125] It should be noted that the partial discharge inspection positioning device can also be installed on the ring main unit by other fixed connection modes, such as bolt connection, providing a mounting frame for the partial discharge inspection positioning device on the ring main unit, and the like, which can all achieve the installation of the partial discharge inspection positioning device on the ring main unit.

[0126] Referring to FIG. 1, the ring main unit partial discharge inspection positioning device provided by the application is provided with three signal input interfaces 2 on the shell bottom plate 3 of the device shell 1, which are electrically connected with three-phase nuclear phase holes of a live indicator of the ring main unit to transmit three-phase partial discharge signals to a three-phase signal processing system.

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

[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 electrically connected with three-phase nuclear phase holes of a live indicator of the ring main unit to transmit three-phase partial discharge signals to a three-phase signal processing system; among them, the three signal input interfaces 2 are A-phase signal input interface, B-phase signal input interface and C-phase signal input interface respectively, and each signal input interface 2 is connected with a three-phase nuclear phase hole of the live indicator, such as the A-phase signal input interface which is electrically connected with the A-phase nuclear phase hole of the live indicator through a signal line, the B-phase signal input interface which is electrically connected with the B-phase nuclear phase hole of the live indicator through a signal line, and the C-phase signal input interface which is electrically connected with the C-phase nuclear phase hole of the live indicator through a signal line.

[0129] It is worth mentioning that the signal input interface 2 adopts a 4mm diameter banana joint seat to keep consistent with the size of the nuclear phase hole of the live indicator and facilitate field wiring.

[0130] It should be noted that as a ring main unit partial discharge positioning device, three-phase partial discharge signals are obtained from the nuclear phase hole of a live indicator of the ring main unit, which ensures the consistency of the installation position of each interval detection sensor and the signal coupling mode of the ring main unit in space, provides a consistent standard for partial discharge strength analysis, and improves the positioning accuracy. The synchronous measurement of ABC three-phase signals ensures the synergy of partial discharge signals in time, and provides a consistent signal source for the strength comparison of three-phase PRPD graphs. The consistency and coordination in space and time further ensure the accuracy of the partial discharge signal interphase positioning based on the PRPD graph.

[0131] Referring to FIG. 1, the ring main unit partial discharge inspection positioning device provided by the application is provided with three signal input interfaces 2 on the shell bottom plate 3 of the device shell 1, which are electrically connected with three-phase nuclear phase holes of a live indicator of the ring main unit to transmit three-phase partial discharge signals to a three-phase signal processing system.

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

[0133] Referring to FIGS. 2-4, the partial discharge inspection positioning device for the ring main unit provided by the application, the three-phase main control module includes three main control modules 4;

[0134] The three main control modules 4 are connected one by one with the three signal input interfaces 2, and the three main control modules 4 are used to obtain the three-phase partial discharge signals of the ring main unit.

[0135] The three main control modules 4 are electrically connected with the high-speed AD module 5.

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

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

[0138] Referring to FIGS. 2-4, the partial discharge inspection positioning device for the ring main unit provided by the application, the main control module 4 includes an impedance matching module 41 and a program-controlled amplification and filtering module 42 connected in sequence.

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

[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 amplification analog signals and square wave analog signals.

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

[0142] The high-speed AD module 5 is used to perform analog-to-digital conversion on the three-phase partial discharge amplification analog signals and the square wave analog signals to generate three-phase partial discharge amplification digital signals and square wave digital signals.

[0143] The output end of the program-controlled amplification and filtering module 42 is electrically connected with the FPGA module 6.

[0144] It should be noted that the structure inside the three master modules 4 is consistent, and the inside of the three master modules 4 includes an impedance matching module 41 and a program-controlled amplification filtering module 42 connected in sequence; the impedance matching module 41 is used for adjusting the setting parameters suitable for the live indicator of the ring main unit in response to the switch control signal of the FPGA module 6 and receiving the A phase / B phase / C phase partial discharge signal, and the program-controlled amplification filtering module 42 is used for processing the received A phase / B phase / C phase partial discharge signal to generate a three-phase partial discharge amplification analog signal and a square wave analog signal, wherein the three-phase partial discharge signal includes an A phase partial discharge signal, a B phase partial discharge signal and a C phase partial discharge signal, for example, when the master module 4 is an A phase master module, the A phase partial discharge signal transmitted from the live indicator is received, the program-controlled amplification filtering module 42 is used for processing the received A phase partial discharge signal to generate a three-phase partial discharge amplification analog signal and a square wave analog signal, and the rest of the phase master module 4 is similar and will not be described here; the output end of the program-controlled amplification filtering module 42 is electrically connected with the high-speed AD module 5, the high-speed AD module 5 is used for analog-to-digital conversion of the three-phase partial discharge amplification analog signal and the square wave analog signal output by the program-controlled amplification filtering module 42 to generate a three-phase partial discharge amplification digital signal and a square wave digital signal, wherein the high-speed AD module 5 can be two pieces of ADM9226 dual-channel high-speed AD module 5, the output end of the program-controlled amplification filtering module 42 is electrically connected with the FPGA module 6, and the program-controlled amplification filtering module 42 is used for transmitting the square wave digital signal to the FPGA module 6. The high-speed AD module 5: its function is to collect the analog signal output by the program-controlled amplification filtering module 42, the sampling frequency is not less than 10MS / s, and the sampling result is transmitted to the FPGA module 6.

[0145] Please refer to FIG. 3, the present application provides a kind of ring main unit partial discharge inspection positioning device, impedance matching module 41 is impedance matching circuit;

[0146] Impedance matching circuit includes analog switch 411, capacitor group 412 and resistance group 413;

[0147] The first end of capacitor group 412 is electrically connected with the three-phase nuclear phase hole of live indicator;

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

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

[0150] Analog switch 411 is electrically connected with the second end of resistance group 413;

[0151] The third end of resistance group 413 is connected with built-in ground wire;

[0152] Analog switch 411 is electrically connected with FPGA module 6;

[0153] The analog switch 411 is used for adjusting the capacitance value and resistance value of the impedance matching circuit to adapt to the ring main unit of the working site in response to receiving a switch control signal.

[0154] The resistance group 413 is connected with the shell of the ring main unit through the built-in grounding wire.

[0155] It should be noted that the impedance matching module 41 is an impedance matching circuit, which comprises the analog switch 411, the capacitance group 412 and the resistance group 413, and is composed of a loop of the analog switch 411, the capacitance group 412 and the resistance group 413, the first end of the capacitance group 412 is electrically connected with the three-phase nuclear phase hole of the live indicator; the second end of the capacitance group 412 is electrically connected with the analog switch 411; the third end of the capacitance group 412 is electrically connected with the first end of the resistance group 413; the analog switch 411 is electrically connected with the second end of the resistance group 413; the third end of the resistance group 413 is connected with the built-in grounding wire; the analog switch 411 is electrically connected with the FPGA module 6; the analog switch 411 is used for adjusting the capacitance value and resistance value of the impedance matching circuit to adapt to the ring main unit of the working site in response to receiving a switch control signal; the resistance group 413 is connected with the shell of the ring main unit through the built-in grounding wire.

[0156] It is worth mentioning that the control signal of the analog switch 411 is provided by the FPGA module 6, and the setting parameters suitable for the live indicator of the ring main unit are adjusted, and the setting parameters include the resistance value and the capacitance value. The parameters of the live indicator and the bushing used by ring main units of different manufacturers have certain differences, and the impedance matching module 41 needs to be adjusted in combination with the bushing parameters to maximize the acquisition of the partial discharge signal. By switching the resistance value and the capacitance value, more types of ring main units can be adapted.

[0157] Referring to FIG. 4, the application provides a ring main unit partial discharge inspection positioning device, and the program-controlled amplification filtering module 42 comprises 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 program-controlled amplifier 421 is electrically connected with the output end of the impedance matching module 41.

[0159] The input ends of the first filter 422 and the second filter 423 are electrically connected with the output of the program-controlled amplifier 421.

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

[0161] The amplifier 424 is used for amplifying 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 with the comparator 425.

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

[0164] It should be noted that the programmable amplification and filtering module 42 comprises 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 with the output end of the impedance matching module 41, and the control signal of the programmable amplification and filtering module 42 is provided by the FPGA module 6, wherein the first filter 422 is a programmable filter, the frequency band of which can be adjusted in the range of 10 kHz-10 MHz, the parameter adjustment of the programmable filter is provided by the FPGA module 6, and the initial bandwidth of the first filter 422 is generally set to 100 kHz-400 kHz; the second filter 423 is a low-pass filter, the frequency band range of which is 0-100 Hz, so as to realize the filtering of the power frequency signal; the amplifier 424 is a same-phase proportional amplifier, which further amplifies the partial discharge signal; and the comparator 425 performs shaping on the power frequency signal to generate a square wave.

[0165] The application provides a partial discharge inspection and positioning device for a ring main unit, and the FPGA module 6 comprises:

[0166] a data acquisition unit configured to acquire initial amplitudes of three-phase partial discharge signals of the ring main unit and analysis data;

[0167] an updating unit configured to update setting parameters of an amplifier 424 in the impedance matching module 41 and the programmable amplification and filtering module 42 of the partial discharge inspection and positioning device for the ring main unit according to the initial amplitudes;

[0168] It should be noted that the initial amplitudes of the three-phase partial discharge signals are acquired, 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 amplitudes; the initial amplitudes of the three-phase partial discharge signals are acquired from the FPGA module 6 by the handheld terminal 8, the resistance group 413 and the capacitance group 412 of the impedance matching module 41 are adjusted so that the signal amplitude reaches the maximum, and then the amplification multiple 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 by using a preset data calibration method based on the setting parameters to generate calibrated analysis data;

[0170] It should be noted that the pulse amplitudes and phase information of the three-phase partial discharge signals after S1 adjustment are acquired from the FPGA module 6 by the handheld terminal 8, and the phase and amplitude of the obtained three-phase partial discharge signals 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 program-controlled amplification and filtering module 42 include amplification multiple, and the calibration analysis data includes calibration pulse amplitude value and calibration phase information.

[0172] The phase information calibration method is: according to the resistance value and the capacitance value of the impedance matching module 41, the phase shift at 50 Hz is calculated, and the obtained phase value is subtracted from the calculated phase shift to obtain the phase information of the final pulse signal.

[0173] In the specific implementation, for the convenience of the implementation of the method, the above process can be converted into a formula encapsulation form, and the specific formula for calibrating the phase information can be as follows: τ ca = τ0-(R·C)

[0174] In the formula, 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.

[0175] The pulse amplitude calibration method is: the obtained amplitude value is divided by the amplification multiple of the program-controlled amplification and filtering module 42 to obtain the final amplitude value.

[0176] In the specific implementation, for the convenience of the implementation of the method, the above process can be converted into a formula encapsulation form, and the specific formula for calibrating the pulse amplitude value can be as follows:

[0177] In the formula, A ca represents the calibration pulse amplitude value, A0 represents the pulse amplitude value before calibration, and M represents the amplification multiple of the program-controlled amplification and filtering module 42.

[0178] The atlas drawing unit is configured to draw the partial discharge PRPD atlas of each phase by using the calibration analysis data.

[0179] It should be noted that the pulse amplitude value and the phase information of the three-phase partial discharge signal after calibration are used to draw the PRPD atlas of the ABC three-phase partial discharge on the handheld terminal 8. Here, it is the drawing of the conventional PRPD atlas, which will not be described here.

[0180] The average discharge intensity value unit is configured to determine the average discharge intensity value of each phase according to the partial discharge PRPD atlas of each phase.

[0181] It should be noted that the average discharge intensity value of each phase can be directly obtained according to the partial discharge PRPD atlas of each phase.

[0182] It is worth mentioning that the maximum discharge intensity value of each phase can also be directly obtained according to the partial discharge PRPD atlas. In the comparison and judgment described below, the average discharge intensity value or the maximum discharge intensity value can be used.

[0183] The first comparison unit is configured to compare the average discharge intensity value of each phase with the preset discharge intensity value respectively.

[0184] It should be noted that the average discharge intensity value of each phase is compared with the preset discharge intensity value respectively.

[0185] The fault phase atlas unit is configured to, when the average discharge intensity value of any phase is greater than the preset discharge intensity value, associate the partial discharge PRPD atlas associated with the average discharge intensity value greater than the preset discharge intensity value as the fault phase atlas.

[0186] 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 atlas associated with all average discharge intensity values greater than the preset discharge intensity value is associated as the fault phase atlas.

[0187] The analysis data is specifically obtained by processing the output signals of the high-speed AD module 5 and the program-controlled amplification and filtering module 42, so as to obtain the analysis data, and the analysis data includes pulse amplitude and phase information.

[0188] It should be noted that the FPGA module 6 further includes:

[0189] The first determination unit is configured to, when the average discharge intensity value of each phase is less than or equal to the preset discharge intensity value, determine that there is no discharge phenomenon.

[0190] It should be noted that, when the average discharge intensity value of each phase is less than or equal to the preset discharge intensity value, that is, when the average discharge intensity value of each phase is not greater than the preset discharge intensity value, the average discharge intensity value of each phase can be partially less than and partially equal to; it is determined that there is no discharge phenomenon in this interval.

[0191] It should be noted that the FPGA module 6 further includes a first processing module, a second processing module and a third processing module.

[0192] The first processing module is configured to generate a switch control signal according to the analysis data and issue the switch control signal for execution.

[0193] The second processing module is configured to generate a program-controlled control signal for adjusting the amplification multiple of the program-controlled amplification and filtering module 42 according to the analysis data and issue the program-controlled control signal for execution.

[0194] The third processing module is configured to transmit the fault phase atlas to the communication module 7, and transmit the fault phase atlas to the handheld terminal 8 through the communication module 7.

[0195] It should be noted that the data acquisition unit reads the output digital signal of the high-speed AD module 5, performs pulse search in the FPGA module 6, obtains the amplitude of the pulse, at the same time, the square wave signal output by the program-controlled amplification and filtering module 42 is output to the FPGA module 6, the FPGA module 6 takes the rising edge of the square wave signal as the timing starting point, obtains the time difference of the pulse relative to the nearest square wave rising edge while obtaining the pulse amplitude signal, and then converts the time difference into phase information, wherein the conversion of the time difference into the phase information is a conventional conversion method, which will not be described here again, and the pulse amplitude and the phase information are taken as the detection results.

[0196] The first processing module is used for adapting to ring network cabinets of different manufacturers, the FPGA module 6 can output switch control signal instructions to the module of the handheld terminal 8 to adjust the analog switch 411 of the impedance matching module 41, and select different combinations of resistors and capacitors to adapt to bushings with different parameters.

[0197] The second processing module is used for adjusting the amplification multiple of the program-controlled amplification and filtering module 42 and improving the dynamic range of the device, when the signal is weak, the FPGA module 6 outputs an amplification program-controlled control signal instruction to the program-controlled amplification and filtering module 42 to improve the amplification multiple, and when the signal is strong, the FPGA module 6 outputs a reduction program-controlled control signal instruction to the program-controlled amplification and filtering module 42 to reduce the amplification multiple.

[0198] The third processing module is used for communication control, the FPGA module 6 is directly connected with the communication module 7, the pulse amplitude and the phase information in the first processing module are transmitted to the communication module 7, and the communication module 7 receives the control instructions of the handheld terminal 8 and transmits the control instructions to the FPGA module 6.

[0199] Please refer to FIG. 5, the device for local partial discharge inspection and positioning of a ring network cabinet provided by the application, the handheld terminal 8 comprises:

[0200] The retrieval unit is used for inputting the fault phase atlas into a preset local partial discharge fault type atlas library for retrieval.

[0201] It is worth mentioning that the preset local partial discharge fault type atlas library is a key-value pair database, which means that the key-value pair database is established according to the atlas feature correlation between the fault phase atlas and the local partial discharge fault type atlas. The fault phase atlas is taken as the key, and the local partial discharge fault type atlas is taken as the value.

[0202] It should be noted that each fault phase atlas is input into the preset local partial discharge fault type atlas library for retrieval, that is, the fault phase atlas is input into the preset local partial discharge fault type atlas library for atlas retrieval, and it is determined whether there is a local partial discharge fault type atlas consistent with the fault phase atlas in the preset local partial discharge fault type atlas library.

[0203] For ease of understanding, refer to Figs. 6-13, which are partial discharge fault type maps in a preset partial discharge fault type map library;

[0204] Figs. 6 and 7 are schematic diagrams of corona / point discharge fault type maps;

[0205] Figs. 8 and 9 are schematic diagrams of insulation defect discharge fault type maps;

[0206] Figs. 10 and 11 are schematic diagrams of suspension discharge fault type maps;

[0207] Figs. 12 and 13 are schematic diagrams of free particle discharge fault type maps.

[0208] The first matching unit is configured to determine the number of fault phase maps if the partial discharge fault type map consistent with the fault phase map is matched;

[0209] It should be noted that the number of fault phase maps is determined if the partial discharge fault type map consistent with the fault phase map is matched.

[0210] The second determination unit is configured to determine the phase associated with the fault phase map as the fault phase if the number of fault phase maps is the first preset number.

[0211] It should be noted that the first preset number is 1, and when the number of fault phase maps is 1, the phase associated with the fault phase map is directly determined as the fault phase.

[0212] The first determination unit is configured to determine whether the fault phase maps of each phase meet a preset fault phase condition if the number of fault phase maps is the second preset number.

[0213] It should be noted that the second preset number is 2 or 3, and when the number of fault phase maps is 2 or 3, it is determined whether the fault phase maps of each phase meet a preset fault phase condition, wherein the preset fault phase condition is that the aggregation area in the fault phase map meets the symmetric distribution of the first quadrant and the third quadrant.

[0214] The maximum discharge intensity value unit is configured to obtain the maximum discharge intensity value associated with the fault phase map that meets the preset fault phase condition.

[0215] It should be noted that, that is, whether the aggregation area in the fault phase map meets the symmetric distribution of the first quadrant and the third quadrant in the power frequency cycle is compared, the fault phase map that meets the symmetric 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 map.

[0216] The third determining unit is configured to select a maximum value from the plurality of maximum discharge intensity values, and determine the phase of the fault phase pattern associated with the maximum value as the fault phase;

[0217] It should be noted that the maximum value is selected from the plurality of maximum discharge intensity values, the fault phase pattern associated with the maximum discharge intensity value of the maximum value is selected, and then the phase associated with the fault phase pattern is determined as the fault phase.

[0218] The preset fault phase condition is that the aggregation area in the fault phase pattern satisfies the symmetric distribution of the first quadrant and the third quadrant.

[0219] For ease of understanding, please refer to FIGS. 14-22, and the following are three specific application examples:

[0220] Application Example 1:

[0221] Please refer to FIGS. 14-16, FIG. 14 is a schematic diagram of the PRPD pattern of partial discharge of phase A;

[0222] FIG. 15 is a schematic diagram of the PRPD pattern of partial discharge of phase B;

[0223] FIG. 16 is a schematic diagram of the PRPD pattern of partial discharge of phase C;

[0224] According to FIGS. 14-16, the average discharge intensity value (or the maximum discharge intensity value) associated with the PRPD pattern of partial discharge of the three phases ABC is less than 10 dB (preset discharge intensity value), and the aggregation area of each phase pattern has no obvious characteristics, and it is determined that there is no partial discharge.

[0225] Application Example 2:

[0226] Please refer to FIGS. 17-19, FIG. 17 is a schematic diagram of the fault phase pattern of phase A;

[0227] FIG. 18 is a schematic diagram of the fault phase pattern of phase B;

[0228] FIG. 19 is a schematic diagram of the fault phase pattern of phase C;

[0229] According to FIGS. 17-19, the average discharge intensity value (or the maximum discharge intensity value) associated with the fault phase pattern of the three phases ABC exceeds 10 dB (preset discharge intensity value) in two phases, the maximum discharge intensity value of phase C is the largest, and the two aggregation areas of the fault phase pattern of phase C meet the 1, 3 quadrant distribution, so the partial discharge source can be positioned in phase C.

[0230] Application Example 3:

[0231] Please refer to FIGS. 20-22, FIG. 20 is a schematic diagram of the fault phase pattern of phase A;

[0232] FIG. 21 is a schematic diagram of the fault phase pattern of phase B;

[0233] Figure 22 is a schematic diagram of the C-phase fault phase diagram;

[0234] As shown in Figures 20-22, the average discharge intensity (or maximum discharge intensity) associated with the fault phase spectrum of phases A, B, and C exceeds 10 dB (preset discharge intensity value) for all three phases. Phase A has the largest maximum discharge intensity, and the two clustering areas in the spectrum of phase A conform to the distribution of quadrants 1 and 3. Meanwhile, the clustering areas in the spectrum of phases B and C do not conform to the distribution of quadrants 1 and 3. Therefore, the partial discharge source can be located in phase A.

[0235] Handheld terminal 8 also includes:

[0236] The discharge count acquisition unit is used to acquire the discharge count within a preset time period based on the fault phase map if no partial discharge fault type map matching the fault phase map is found.

[0237] It should be noted that if no partial discharge fault type map matching the fault phase map is found, the number of discharges within a preset time period is obtained from the fault phase map. The number of discharges can be directly obtained from the fault phase map.

[0238] The second comparison unit is used to compare the number of discharges with a preset discharge number threshold.

[0239] It should be noted that the number of discharges is compared with the preset discharge threshold.

[0240] The noise signal unit is used 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.

[0241] It should be noted that 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.

[0242] The second judgment unit is used to determine whether all frequency band combinations of the programmable amplification and filtering modules 42 in the ring network cabinet 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.

[0243] It should be noted that if the number of discharges is greater than or equal to a preset discharge count threshold, it is necessary to determine whether all frequency band combinations of the programmable amplifier and filter module 42 have been traversed. 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 amplifier and filter module 42 have been traversed.

[0244] The jump unit is configured to, if all frequency band combinations of the program-controlled amplification and filtering module 42 in the ring main unit partial discharge inspection and positioning device are not traversed, adjust the setting parameter of the first filter 422 in the program-controlled amplification and filtering module 42, and jump to the step of correcting the analysis data based on the setting parameter by using the preset data calibration method to generate calibrated analysis data until all frequency band combinations are traversed.

[0245] It should be noted that, if all frequency band combinations of the program-controlled amplification and filtering module 42 are not traversed, the setting parameter of the first filter 422 in the program-controlled amplification and filtering module 42 is adjusted to gradually deviate from the initial frequency band combination, and the step of correcting the analysis data based on the setting parameter by using the preset data calibration method to generate calibrated analysis data is jumped to for the judgment process of the next frequency band combination. It should be noted that adjusting the setting parameter of the first filter 422 in the program-controlled amplification and filtering module 42 does not change the pulse amplitude and phase information. The setting parameter of the first filter 422 is adjusted to filter out noise interference until all frequency band combinations are traversed. If the current fault phase spectrum still does not match the partial discharge fault type spectrum consistent with the fault phase spectrum, it is determined that the three-phase partial discharge signal associated with the fault phase spectrum is a noise signal.

[0246] The fourth determination unit is configured to, if all frequency band combinations of the program-controlled amplification and filtering module 42 in the ring main unit partial discharge inspection and positioning device are traversed, determine that the three-phase partial discharge signal associated with the fault phase spectrum is a noise signal.

[0247] It should be noted that, if all frequency band combinations of the program-controlled amplification and filtering module 42 are traversed, it is determined that the three-phase partial discharge signal associated with the fault phase spectrum is a noise signal.

[0248] Referring to FIG. 5, the working process of the ring main unit partial discharge inspection and positioning device is as follows:

[0249] Step 1: The ring main unit partial discharge inspection and positioning device is installed on the surface of the metal shell of each interval of the ring main unit in turn, close to the live indicator. The test line is used to connect the nuclear phase hole of the three-phase live indicator with the signal input interface 2 of the device, and the handheld terminal 8 and the device power supply are started to start the measurement.

[0250] Step 2: The handheld terminal 8 first obtains the initial amplitude of the partial discharge pulse signal from the FPGA module 6, adjusts the resistance group 413 and the capacitance group 412 of the impedance matching module 41 to make the signal amplitude reach the maximum, and then adjusts the amplification multiple of the program-controlled amplification module to make the maximum value of the signal meet the measurement range of the high-speed AD module 5.

[0251] 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 obtained 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 program-controlled amplification and filtering module 42.

[0252] The phase information calibration method is: according to the resistance value and the capacitance value of the impedance matching module 41, the phase shift at 50 Hz is calculated, and the obtained phase value is subtracted from the calculated phase shift to obtain the final phase information of the pulse signal.

[0253] The pulse amplitude calibration method is: the obtained amplitude is divided by the amplification multiple of the program-controlled amplification and filtering module 42 to obtain the final amplitude information.

[0254] Step 4: The ABC three-phase partial discharge PRPD spectrum is drawn in the handheld terminal 8 by using a plurality of sets of calibrated partial discharge pulse signal amplitudes and phases, and the average discharge intensity (or the maximum discharge intensity) of the three-phase PRPD spectrum is judged according to the threshold value. If the average discharge intensity (or the maximum discharge intensity) of the three-phase PRPD spectrum is lower than the threshold value, then the interval is fault-free.

[0255] Step 5: If the average discharge intensity (or the maximum discharge intensity) of a certain phase or several phases in the interval is higher than the threshold value, then the PRPD spectrum of the three-phase partial discharge higher than the threshold value is taken as the fault phase spectrum, and it is further judged whether the fault phase spectrum matches the spectrum characteristics of the partial discharge fault type.

[0256] Step 6: If the fault phase spectrum does not match the spectrum characteristics of the partial discharge fault type, it is further judged that the discharge frequency per unit time is less than the set value, and the measurement result is a noise signal.

[0257] If it is greater than the set value, the first filter 422 parameter of the program-controlled amplification and filtering module 42 is adjusted to gradually deviate from the initial frequency band, and the step 3 is continued to be executed. Until all the frequency band combinations are traversed and still do not match the spectrum characteristics of the partial discharge fault type, it is determined that the measurement result is a noise signal. If the fault phase spectrum matches the spectrum characteristics of the partial discharge fault type, step 7 is performed.

[0258] Step 7: If only one fault phase spectrum average discharge intensity (or maximum discharge intensity) exceeds the threshold value, the phase position exceeding the threshold value is directly determined as the fault phase position.

[0259] If there are two or more fault phase spectrum average discharge intensities (or maximum discharge intensities) exceeding the threshold value, the maximum value is selected according to the maximum discharge intensity value of the fault phase spectrum, and the phase position of the fault phase spectrum associated with the maximum value is determined as the fault phase position.

[0260] The principle is as follows: whether the aggregation area in the fault phase atlas meets the symmetrical distribution in the 1 and 3 quadrants in the power frequency cycle, and the fault phase positioning that meets the symmetrical distribution in the 1 and 3 quadrants is the phase where the partial discharge source is located.

[0261] The application provides a local discharge inspection positioning device for ring network cabinets, which is used for accurately detecting and positioning local discharge of the running ring network cabinet. Compared with the current local discharge detection device for ring network cabinets, the local discharge signal is obtained from the core phase hole, the path of signal coupling of different ring network cabinets, different intervals and different phase signals is consistent, and the obtained signal can realize horizontal comparison; through the calibration process of phase information and pulse amplitude, the phase accuracy of the more accurate local discharge PRPD atlas is obtained, so as to adapt to ring network cabinets of different manufacturers, provide more accurate basic data for judging the local discharge type, and after pulse amplitude calibration, the pulse amplitude of the more accurate local discharge signal can be obtained, more accurate threshold diagnostic criteria are provided, and the insulation state of the ring network cabinet is more accurately evaluated. Three-phase synchronous measurement can obtain the propagation characteristics of the same local discharge source among three phases. The above technologies can effectively improve the accuracy of local discharge detection and realize the positioning accuracy of the local discharge source in the ring network cabinet.

[0262] The application provides a positioning method applied to the local discharge inspection positioning device for ring network cabinets, and the positioning method comprises the following steps.

[0263] Step 101: three-phase local discharge signals of the ring network cabinet are obtained, and the three-phase local discharge signals are preprocessed to determine the average discharge intensity values of the phases.

[0264] Step 102: the average discharge intensity values of the phases are compared with preset discharge intensity values respectively.

[0265] Step 103: when the average discharge intensity value of any phase is greater than the preset discharge intensity value, the local discharge PRPD atlas associated with the average discharge intensity value greater than the preset discharge intensity value is taken as a fault phase atlas.

[0266] Step 104: the fault phase atlas is input into a preset local discharge fault type atlas library for searching.

[0267] Step 105: if the local discharge fault type atlas consistent with the fault phase atlas is matched, whether the fault phase atlases of the phases meet preset fault phase conditions is judged based on the number of the fault phase atlases, and the local discharge source of the ring network cabinet is positioned according to the judgment result.

[0268] Further, step 101 can comprise the following substeps.

[0269] S11: initial amplitudes and analysis data of the three-phase local discharge signals of the ring network cabinet are obtained.

[0270] S12, updating the setting parameters of the amplifier 424 in the impedance matching module 41 and the program-controlled amplification and filtering module 42 of the local discharge inspection and positioning device of the ring main unit according to the initial amplitude;

[0271] S13, correcting the analysis data by using a preset data calibration method based on the setting parameters to generate calibrated analysis data;

[0272] S14, drawing a local discharge PRPD spectrum of each phase by using the calibrated analysis data;

[0273] S15, determining the average discharge intensity value of each phase according to the local discharge PRPD spectrum of each phase.

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

[0275] Step 103a, when the average discharge intensity value of each phase is less than or equal to a preset discharge intensity value, it is determined that there is no discharge phenomenon.

[0276] Further, the method further comprises the following steps:

[0277] Step 106, if no local discharge fault type spectrum consistent with the fault phase spectrum is matched, the number of discharges in a preset time period is obtained according to the fault phase spectrum;

[0278] Step 107, comparing the number of discharges with a preset discharge number threshold;

[0279] Step 108, if the number of discharges is less than the preset discharge number threshold, it is determined that the three-phase local discharge signal associated with the fault phase spectrum is a noise signal;

[0280] Step 109, if the number of discharges is greater than or equal to the preset discharge number threshold, it is determined whether all frequency band combinations of the program-controlled amplification and filtering module 42 in the local discharge inspection and positioning device of the ring main unit are traversed;

[0281] Step 1010, if all frequency band combinations of the program-controlled amplification and filtering module 42 in the local discharge inspection and positioning device of the ring main unit are not traversed, the setting parameters of the first filter 422 in the program-controlled amplification and filtering module 42 are adjusted, and the step of correcting the analysis data by using a preset data calibration method based on the setting parameters to generate calibrated analysis data is jumped to until all frequency band combinations are traversed;

[0282] Step 1011, if all frequency band combinations of the program-controlled amplification and filtering module 42 in the local discharge inspection and positioning device of the ring main unit are traversed, it is determined that the three-phase local discharge signal associated with the fault phase spectrum is a noise signal.

[0283] Further, step 105 can comprise the following sub-steps:

[0284] S21, if the partial discharge fault type pattern consistent with the fault phase pattern is matched, the number of fault phase patterns is determined;

[0285] S22, if the number of fault phase patterns is the first preset number, the phase associated with the fault phase pattern is determined as the fault phase;

[0286] S23, if the number of fault phase patterns is the second preset number, whether the fault phase pattern of each phase satisfies the preset fault phase condition is judged;

[0287] S24, the maximum discharge intensity value associated with the fault phase pattern satisfying the preset fault phase condition is obtained;

[0288] S25, the maximum value is selected from the plurality of maximum discharge intensity values, and the phase of the fault phase pattern associated with the maximum value is determined as the fault phase.

[0289] Further, the preset fault phase condition is that the aggregation area in the fault phase pattern satisfies the first quadrant and the third quadrant symmetric distribution.

[0290] In the embodiment of the application, the partial discharge inspection and positioning device is installed on the ring network cabinet, the three-phase local discharge signal collected from the live indicator inside the ring network cabinet is received by the three-phase signal processing system in the device shell 1 of the partial discharge inspection and positioning device, the three-phase local discharge signal is preprocessed to obtain the fault phase pattern, and then transmitted to the handheld terminal 8 for analysis, so as to realize the detection of the PRPD pattern and the inter-phase positioning of the partial discharge source.

[0291] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of the system, device and unit described above can refer to the corresponding process in the foregoing method embodiments, which will not be repeated here.

[0292] In several embodiments provided in the present application, it should be understood that the disclosed system, device and method can be implemented in other ways. For example, the device embodiments described above are only schematic, for example, the division of the units is only a logical function division, and actual implementation can have another division manner, for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the units shown or discussed can be indirect coupling or communication connection through some interfaces, devices or units, and can be electrical, mechanical or other forms.

[0293] The above-described embodiments are only used to illustrate the technical solutions of the present application, and are not intended to limit the present application; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that the technical solutions recorded in the foregoing embodiments can still be modified, or some technical features can be replaced by equivalent replacements; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A partial discharge inspection positioning method for a ring main unit, characterized in that, The method comprises the following steps: acquiring three-phase partial discharge signals of the ring main unit, and preprocessing the three-phase partial discharge signals to determine average discharge intensity values of each phase; respectively comparing the average discharge intensity values of each phase with preset discharge intensity values; when the average discharge intensity value of any phase is greater than the preset discharge intensity value, taking the partial discharge PRPD pattern associated with the average discharge intensity value greater than the preset discharge intensity value as a fault phase pattern; inputting the fault phase pattern into a preset partial discharge fault type pattern library for searching; if a partial discharge fault type pattern consistent with the fault phase pattern is matched, judging whether the fault phase patterns of each phase satisfy preset fault phase conditions based on the number of the fault phase patterns, and positioning partial discharge sources of the ring main unit according to the judgment result.

2. The partial discharge inspection positioning method for the ring main unit according to claim 1, characterized in that, The method of acquiring three-phase partial discharge signals of the ring main unit and preprocessing the three-phase partial discharge signals to determine average discharge intensity values of each phase comprises the following steps: acquiring initial amplitudes and analysis data of the three-phase partial discharge signals 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 of the ring main unit partial discharge inspection and positioning device according to the initial amplitudes; based on the setting parameters, correcting the analysis data by using a preset data calibration method to generate calibrated analysis data; using the calibrated analysis data to draw partial discharge PRPD patterns of each phase; determining average discharge intensity values of each phase according to the partial discharge PRPD patterns of each phase.

3. The partial discharge inspection positioning method for the ring main unit according to claim 1, characterized in that, The method further comprises the following steps: when the average discharge intensity values of each phase are all less than or equal to the preset discharge intensity values, determining that there is no discharge phenomenon.

4. The partial discharge inspection positioning method for the ring main unit according to claim 2, characterized in that, The method further comprises the following steps: if a partial discharge fault type pattern consistent with the fault phase pattern is not matched, acquiring the number of discharges within a preset time period according to the fault phase pattern; comparing the number of discharges with a preset discharge number threshold value; if the number of discharges is less than the preset discharge number threshold value, determining that the three-phase partial discharge signals associated with the fault phase pattern are noise signals; if the number of discharges is greater than or equal to the preset discharge number threshold value, judging whether all frequency band combinations of the program-controlled amplification and filtering modules in the ring main unit partial discharge inspection and positioning device have been traversed; if all the frequency band combinations of the program-controlled amplification and filtering modules in the ring main unit partial discharge inspection and positioning device have not been traversed, adjusting the setting parameters of the first filter in the program-controlled amplification and filtering module, and jumping to the step of correcting the analysis data by using a preset data calibration method based on the setting parameters to generate calibrated analysis data until all the frequency band combinations are traversed; if all the frequency band combinations of the program-controlled amplification and filtering modules in the ring main unit partial discharge inspection and positioning device have been traversed, determining that the three-phase partial discharge signals associated with the fault phase pattern are noise signals.

5. The partial discharge inspection positioning method for ring main unit according to claim 1, characterized in that, The method of matching a partial discharge fault type pattern consistent with the fault phase pattern, judging whether the fault phase patterns of each phase satisfy preset fault phase conditions based on the number of the fault phase patterns, and positioning partial discharge sources of the ring main unit according to the judgment result comprises the following steps: If a partial discharge fault type atlas consistent with the fault phase atlas is matched, the number of the fault phase atlas is determined; If the number of the fault phase atlas is a first preset number, the phase associated with the fault phase atlas is determined as a fault phase; If the number of the fault phase atlas is a second preset number, whether the fault phase atlas of each phase meets a preset fault phase condition is determined; The preset fault phase condition is that the aggregation area in the fault phase atlas meets a first quadrant and a third quadrant symmetric distribution; A maximum discharge intensity value associated with the fault phase atlas meeting the preset fault phase condition is obtained; A maximum value is selected from a plurality of maximum discharge intensity values, and a phase of the fault phase atlas associated with the maximum value is determined as a fault phase.

6. A partial discharge inspection positioning device for ring main unit, characterized in that, The ring main unit partial discharge inspection positioning device is used to realize the ring main unit partial discharge inspection positioning method of any one of claims 1-5, and the ring main unit partial discharge inspection positioning device comprises a device shell; The device shell is installed on the ring main unit; A three-phase signal processing system is arranged in the device shell; The three-phase signal processing system comprises a three-phase main control module, a high-speed AD module, an FPGA module and a communication module which are electrically connected in sequence; The three-phase main control module is used to obtain three-phase partial discharge signals of the ring main unit; The FPGA module is electrically connected with the three-phase main control module, and the FPGA module is used to pre-process the three-phase partial discharge signals, determine average discharge intensity values of each phase, respectively compare the average discharge intensity values of each phase with a preset discharge intensity value, and when the average discharge intensity value of any phase is greater than the preset discharge intensity value, the partial discharge PRPD atlas associated with the average discharge intensity value greater than the preset discharge intensity value is taken as a fault phase atlas; The FPGA module is in communication connection with a handheld terminal through the communication module, and the handheld terminal is used to input the fault phase atlas into a preset partial discharge fault type atlas library for retrieval. If a partial discharge fault type atlas consistent with the fault phase atlas is matched, the number of the fault phase atlas is determined, and whether the fault phase atlas of each phase meets a preset fault phase condition is determined based on the number of the fault phase atlas, and the ring main unit is positioned according to the judgment result.

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

8. The partial discharge inspection and positioning device for ring main unit according to claim 6, characterized in that, The FPGA module comprises: A data acquisition unit is used to obtain initial amplitude values and analysis data of the three-phase partial discharge signals of the ring main unit; An updating unit is used to update the setting parameters of the amplifiers in the impedance matching module and the program-controlled amplification and filtering module of the ring main unit partial discharge inspection positioning device according to the initial amplitude values; A calibration unit is used to correct the analysis data by using a preset data calibration method based on the setting parameters, and generate calibrated analysis data. The atlas mapping unit is configured to map a partial discharge PRPD atlas of each phase by using the calibration analysis data. The average discharge intensity value unit is configured to determine an average discharge intensity value of each phase according to the partial discharge PRPD atlas of each phase.

9. The partial discharge inspection and positioning device for ring main unit according to claim 6, characterized in that, The handheld terminal comprises: The retrieval unit is configured to input the fault phase atlas into a preset partial discharge fault type atlas library for retrieval. The first matching unit is configured to determine the number of fault phase atlases if a partial discharge fault type atlas consistent with the fault phase atlas is matched. The second determination unit is configured to determine that the phase associated with the fault phase atlas is a fault phase if the number of fault phase atlases is a first preset number. The first determination unit is configured to determine whether the fault phase atlases of each phase satisfy a preset fault phase condition if the number of fault phase atlases is a second preset number. The maximum discharge intensity value unit is configured to obtain a maximum discharge intensity value associated with the fault phase atlas that satisfies the preset fault phase condition. The third determination unit is configured to select a maximum value from a plurality of maximum discharge intensity values, and determine the phase of the fault phase atlas associated with the maximum value as a fault phase. The preset fault phase condition is that the aggregation area in the fault phase atlas satisfies a first quadrant and a third quadrant symmetrical distribution.

10. The partial discharge inspection and positioning device for ring main unit according to claim 8, characterized in that, The handheld terminal further comprises: The discharge frequency obtaining unit is configured to obtain a discharge frequency in a preset time period according to the fault phase atlas if a partial discharge fault type atlas consistent with the fault phase atlas is not matched. The second comparison unit is configured to compare the discharge frequency with a preset discharge frequency threshold. The noise signal unit is configured to determine that the three-phase partial discharge signal associated with the fault phase atlas is a noise signal if the discharge frequency is less than the preset discharge frequency threshold. The second determination unit is configured to determine whether all frequency band combinations of the program-controlled amplification filtering module in the ring network cabinet partial discharge inspection positioning device are traversed if the discharge frequency is greater than or equal to the preset discharge frequency threshold. The jump unit is configured to adjust the setting parameter of the first filter in the program-controlled amplification filtering module and jump to the step of correcting the analysis data by using a preset data calibration method based on the setting parameter to generate calibration analysis data until all the frequency band combinations are traversed if all the frequency band combinations of the program-controlled amplification filtering module in the ring network cabinet partial discharge inspection positioning device are not traversed. The fourth determination unit is configured to determine that the three-phase partial discharge signal associated with the fault phase atlas is a noise signal if all the frequency band combinations of the program-controlled amplification filtering module in the ring network cabinet partial discharge inspection positioning device are traversed.

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