Partial discharge monitoring system for variable frequency motor and insulation defect analysis method

Abstract

The invention discloses a partial discharge monitoring system and an insulation defect analysis method for a variable frequency motor, and relates to the technical field of motor monitoring and diagnosis, a second end of a voltage measurement probe is configured at an installation position of a partial discharge coupler, a third end is electrically connected with a partial discharge signal acquisition and analysis device, and the voltage measurement probe is used for measuring a partial discharge reference voltage signal; the partial discharge coupler is used for determining a monitoring signal of the variable frequency motor by taking the partial discharge reference voltage signal as a trigger, and transmitting the monitoring signal to the filter; the filter is electrically connected with the partial discharge signal acquisition and analysis device and is used for filtering interference signals in the monitoring signals to obtain partial discharge signals; the partial discharge signal acquisition and analysis device is used for acquiring the partial discharge signal and the partial discharge reference voltage signal in a preset time period according to a preset period, determining an edge reference diagram corresponding to the partial discharge signal by taking the partial discharge reference voltage signal as a reference, and determining an insulation defect type corresponding to the variable frequency motor by analyzing a map of the edge reference diagram.

Description

Technical Field

[0001] The present invention relates to the technical field of motor monitoring and diagnosis, and in particular to a partial discharge monitoring system and an insulation defect analysis method for a variable frequency motor. Background Art

[0002] Frequency converters are widely used in motor speed control systems. They are generally connected to the stator windings of high-voltage or low-voltage motors. The speed of the motor is regulated by adjusting the stator voltage and frequency. In addition, in doubly-fed motors, such as low-voltage, small-capacity and variable-speed constant-frequency doubly-fed wind turbines, and high-voltage, large-capacity variable-speed pumped-storage generators, frequency converters are connected to the rotor windings of the motors. The speed or stator output power is regulated by controlling the amplitude and frequency of the rotor voltage. Regardless of the form, the stator windings or rotor windings directly connected to the frequency converter are electrically subjected to the high-frequency PWM pulse voltage output by the frequency converter, such as Figure 1 As shown, it is obviously different from the electric field action principle of the industrial frequency sinusoidal power supply motor device. The insulation is subjected to higher electrical stress, and the probability of partial discharge and electrical aging increases. In addition, the motor device itself is subjected to external factors such as mechanical stress and thermal cycle stress during operation, which makes partial discharge of the insulation inevitable, especially for high-voltage motor devices.

[0003] Therefore, special considerations are generally made for the insulation of the stator winding or rotor winding of the motor device with variable frequency power supply. Once the partial discharge continues to develop and deteriorate, the thermal effect, chemical corrosion effect, etc. it produces will have an irreversible impact on the insulation of the motor device, eventually leading to insulation aging and causing motor device failure. Therefore, it is necessary to monitor the partial discharge of the motor device. However, in the above scenario, the difficulties in realizing partial discharge monitoring are mainly:

[0004] 1. The PWM pulse voltage itself has a wide frequency band and a high amplitude, especially the amplitude far exceeds the partial discharge, which causes strong interference to the monitoring system and even cannot effectively identify the real partial discharge.

[0005] 2. The characteristics of partial discharge under pulse voltage are significantly different from those of traditional sinusoidal voltage. The traditional analysis method based on sinusoidal phase is not effective. After partial discharge is detected, it is difficult to analyze the insulation defects indicated by the partial discharge. Summary of the invention

[0006] In order to solve at least one of the problems in the above-mentioned background technology part, the present application provides a partial discharge monitoring system and an insulation defect analysis method for a variable frequency motor, which can effectively identify true partial discharge and, after monitoring partial discharge, accurately analyze the type of insulation defect indicated by the partial discharge.

[0007] In a first aspect, an embodiment of the present invention provides a partial discharge monitoring system for a variable frequency motor, comprising a partial discharge coupler, a filter, a voltage measurement probe, and a partial discharge signal acquisition and analysis device, wherein:

[0008] The first end of the voltage measuring probe is electrically connected to the reference end, the second end of the voltage measuring probe is configured at the installation position of the partial discharge coupler, and the third end of the voltage measuring probe is electrically connected to the partial discharge signal acquisition and analysis device, and is used to measure the partial discharge reference voltage signal of the partial discharge monitoring system;

[0009] The first end of the partial discharge coupler is electrically connected to the variable frequency motor, the second end of the partial discharge coupler is electrically connected to the filter, and the third end of the partial discharge coupler is electrically connected to the reference end, and is used to determine the monitoring signal of the variable frequency motor with the partial discharge reference voltage signal as a trigger, and transmit the monitoring signal to the filter;

[0010] The filter is electrically connected to the partial discharge signal acquisition and analysis device, and is used to filter out interference signals in the monitoring signal to obtain a partial discharge signal;

[0011] The partial discharge signal acquisition and analysis device is used to acquire the partial discharge signal and the partial discharge reference voltage signal, and determine the edge reference graph corresponding to the partial discharge signal with reference to the partial discharge reference voltage signal, and determine the insulation defect type corresponding to the variable frequency motor by analyzing the spectrum of the edge reference graph.

[0012] In some optional embodiments of this embodiment, the lower cutoff frequency of the filter is configured to be greater than the upper cutoff frequency of the interference signal.

[0013] In some optional aspects of this embodiment, the installation position of the partial discharge coupler is related to the type of the variable frequency motor, wherein the types of the variable frequency motor include stator winding variable frequency power supply and rotor winding variable frequency power supply.

[0014] In some optional aspects of this embodiment, in response to the type of the variable frequency motor being variable frequency power supply for the stator winding, the installation position of the partial discharge coupler is:

[0015] Inside the stator winding lead terminal box or on the power supply cable close to the stator winding lead terminal box; wherein the position of the reference end is the grounding point.

[0016] In some optional aspects of this embodiment, in response to the type of the variable frequency motor being variable frequency power supply for the rotor winding, the installation position of the partial discharge coupler is:

[0017] On a power supply cable between the slip ring and the frequency converter and close to the slip ring; wherein the end of the partial discharge coupler is electrically connected to the rotor shaft, and the position of the reference end is the rotor shaft.

[0018] In some optional aspects of this embodiment, the partial discharge reference voltage signal includes a positive polarity edge and / or a negative polarity edge, and the partial discharge signal acquisition and analysis device is further used for:

[0019] In response to the partial discharge reference voltage signal being the positive polarity edge, a positive polarity edge reference graph corresponding to the partial discharge signal is determined with the positive polarity edge as a reference; and the insulation defect type corresponding to the variable frequency motor is determined by analyzing the spectrum of the positive polarity edge reference graph;

[0020] In response to the partial discharge reference voltage signal being the negative polarity edge, a negative polarity edge reference graph corresponding to the partial discharge signal is determined with the negative polarity edge as a reference; and the insulation defect type corresponding to the variable frequency motor is determined by analyzing the spectrum of the negative polarity edge reference graph;

[0021] In response to the partial discharge reference voltage signal being the positive polarity edge and the negative polarity edge, a first partial discharge electronic signal sampled at the positive polarity edge and a second partial discharge electronic signal sampled at the negative polarity edge are respectively extracted from the partial discharge signal; a positive polarity edge reference graph corresponding to the first partial discharge electronic signal is determined with the positive polarity edge as a reference; a negative polarity edge reference graph corresponding to the second partial discharge electronic signal is determined with the negative polarity edge as a reference; and the insulation defect type corresponding to the variable frequency motor is determined by analyzing the spectrum of the positive polarity edge reference graph and / or the spectrum of the negative polarity edge reference graph.

[0022] In some optional aspects of this embodiment, determining the insulation defect type corresponding to the variable frequency motor by analyzing the spectrum of the positive polarity edge reference graph includes:

[0023] Obtain a positive polarity preset defect discharge mode reference diagram, and determine whether the positive polarity edge reference diagram matches the positive polarity preset defect discharge mode reference diagram; if so, determine the insulation defect type corresponding to the variable frequency motor based on the positive polarity preset defect discharge mode reference diagram; if not, determine the insulation defect type corresponding to the variable frequency motor based on the spectrum shape of the positive polarity edge reference diagram;

[0024] In some optional aspects of this embodiment, determining the insulation defect type corresponding to the variable frequency motor by analyzing the spectrum of the negative polarity edge reference graph includes:

[0025] Obtain a negative polarity preset defect discharge mode reference diagram, and determine whether the negative polarity edge reference diagram matches the negative polarity preset defect discharge mode reference diagram; if matched, determine the insulation defect type corresponding to the variable frequency motor based on the negative polarity preset defect discharge mode reference diagram; if not matched, determine the insulation defect type corresponding to the variable frequency motor based on the spectrum shape of the negative polarity edge reference diagram;

[0026] In some optional methods of this embodiment, determining the insulation defect type corresponding to the variable frequency motor by analyzing the spectrum of the positive polarity edge reference map and the spectrum of the negative polarity edge reference map includes:

[0027] Obtain a positive and negative polarity preset defect discharge mode reference diagram, and determine whether the positive polarity edge reference diagram and the negative polarity edge reference diagram match the positive and negative polarity preset defect discharge mode reference diagram; if they match, determine the insulation defect type corresponding to the variable frequency motor based on the positive and negative polarity preset defect discharge mode reference diagram; if they do not match, determine the insulation defect type corresponding to the variable frequency motor based on the spectrum shape of the positive polarity edge reference diagram and / or the spectrum shape of the negative polarity edge reference diagram.

[0028] In some optional aspects of this embodiment, determining the insulation defect type corresponding to the variable frequency motor based on the spectrum shape of the positive polarity edge reference graph and the spectrum shape of the negative polarity edge reference graph includes:

[0029] Determine whether the spectrum shape in the positive polarity edge reference diagram is consistent with the spectrum shape in the negative polarity edge reference diagram; if consistent, determine whether the partial discharge amplitude in the negative polarity edge reference diagram is greater than the partial discharge amplitude in the positive polarity edge reference diagram; if so, determine that the insulation defect type is a defect with polarity advantage.

[0030] In a second aspect, an embodiment of the present invention further provides an insulation defect analysis method based on the partial discharge monitoring system according to the first aspect, the method comprising:

[0031] Acquire the collected partial discharge signal and partial discharge reference voltage signal, wherein the partial discharge reference voltage signal includes a positive polarity edge and / or a negative polarity edge;

[0032] Taking the partial discharge reference voltage signal as a reference, an edge reference graph corresponding to the partial discharge signal is determined, and the insulation defect type corresponding to the variable frequency motor is determined by analyzing the spectrum of the edge reference graph.

[0033] In some optional methods of this embodiment, the edge reference graph corresponding to the partial discharge signal is determined by taking the partial discharge reference voltage signal as a reference, and the insulation defect type corresponding to the variable frequency motor is determined by analyzing the spectrum of the edge reference graph, including:

[0034] In response to the partial discharge reference voltage signal being the positive polarity edge, a positive polarity edge reference graph corresponding to the partial discharge signal is determined with the positive polarity edge as a reference; and the insulation defect type corresponding to the variable frequency motor is determined by analyzing the spectrum of the positive polarity edge reference graph;

[0035] In response to the partial discharge reference voltage signal being the negative polarity edge, a negative polarity edge reference graph corresponding to the partial discharge signal is determined with the negative polarity edge as a reference; and the insulation defect type corresponding to the variable frequency motor is determined by analyzing the spectrum of the negative polarity edge reference graph;

[0036] In response to the partial discharge reference voltage signal being the positive polarity edge and the negative polarity edge, a first partial discharge electronic signal sampled at the positive polarity edge and a second partial discharge electronic signal sampled at the negative polarity edge are respectively extracted from the partial discharge signal; a positive polarity edge reference graph corresponding to the first partial discharge electronic signal is determined with the positive polarity edge as a reference; a negative polarity edge reference graph corresponding to the second partial discharge electronic signal is determined with the negative polarity edge as a reference; and the insulation defect type corresponding to the variable frequency motor is determined by analyzing the spectrum of the positive polarity edge reference graph and / or the spectrum of the negative polarity edge reference graph.

[0037] In some optional aspects of this embodiment, determining the insulation defect type corresponding to the variable frequency motor by analyzing the spectrum of the positive polarity edge reference graph includes:

[0038] Obtain a positive polarity preset defect discharge mode reference diagram, and determine whether the positive polarity edge reference diagram matches the positive polarity preset defect discharge mode reference diagram; if so, determine the insulation defect type corresponding to the variable frequency motor based on the positive polarity preset defect discharge mode reference diagram; if not, determine the insulation defect type corresponding to the variable frequency motor based on the spectrum shape of the positive polarity edge reference diagram;

[0039] In some optional aspects of this embodiment, determining the insulation defect type corresponding to the variable frequency motor by analyzing the spectrum of the negative polarity edge reference graph includes:

[0040] Obtain a negative polarity preset defect discharge mode reference diagram, and determine whether the negative polarity edge reference diagram matches the negative polarity preset defect discharge mode reference diagram; if matched, determine the insulation defect type corresponding to the variable frequency motor based on the negative polarity preset defect discharge mode reference diagram; if not matched, determine the insulation defect type corresponding to the variable frequency motor based on the spectrum shape of the negative polarity edge reference diagram;

[0041] In some optional methods of this embodiment, determining the insulation defect type corresponding to the variable frequency motor by analyzing the spectrum of the positive polarity edge reference map and the spectrum of the negative polarity edge reference map includes:

[0042] Obtain a positive and negative polarity preset defect discharge mode reference diagram, and determine whether the positive polarity edge reference diagram and the negative polarity edge reference diagram match the positive and negative polarity preset defect discharge mode reference diagram; if they match, determine the insulation defect type corresponding to the variable frequency motor based on the positive and negative polarity preset defect discharge mode reference diagram; if they do not match, determine the insulation defect type corresponding to the variable frequency motor based on the spectrum shape of the positive polarity edge reference diagram and / or the spectrum shape of the negative polarity edge reference diagram.

[0043] In some optional aspects of this embodiment, determining the insulation defect type corresponding to the variable frequency motor based on the spectrum shape of the positive polarity edge reference graph and the spectrum shape of the negative polarity edge reference graph includes:

[0044] Determine whether the spectrum shape in the positive polarity edge reference diagram is consistent with the spectrum shape in the negative polarity edge reference diagram; if consistent, determine whether the partial discharge amplitude in the negative polarity edge reference diagram is greater than the partial discharge amplitude in the positive polarity edge reference diagram; if so, determine that the insulation defect type is a defect with polarity advantage.

[0045] In a third aspect, an embodiment of the present invention further provides an insulation defect analysis device, the device comprising:

[0046] An acquisition module is configured to acquire the collected partial discharge signal and partial discharge pulse reference voltage signal, wherein the partial discharge reference voltage signal includes a positive polarity edge and / or a negative polarity edge;

[0047] The insulation defect analysis module is configured to determine an edge reference graph corresponding to the partial discharge signal with reference to the partial discharge reference voltage signal, and determine the insulation defect type corresponding to the variable frequency motor by analyzing the spectrum of the edge reference graph.

[0048] In a fourth aspect, an embodiment of the present invention further provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the above insulation analysis method when executing the computer program.

[0049] In a fifth aspect, an embodiment of the present invention further provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and the computer program implements the above-mentioned insulation analysis method when executed by a processor.

[0050] In a sixth aspect, an embodiment of the present invention further provides a computer program product, wherein the computer program product includes a computer program, and the computer program implements the above insulation analysis method when executed by a processor.

[0051] The embodiments of the present invention provide a partial discharge monitoring system and insulation defect analysis method for a variable frequency motor. By setting a filter to filter out interference signals, the interference caused by the PWM pulse voltage on the monitoring system can be overcome, thereby effectively identifying the true partial discharge. In addition, after the partial discharge is detected, the present application analyzes the partial discharge signal with the partial discharge reference voltage signal as a reference, and can accurately analyze the type of insulation defect indicated by the partial discharge. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the prior art descriptions. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. In the drawings:

[0053] Figure 1 Schematic diagram of a PWM pulse voltage output by a three-level high-voltage inverter in an embodiment of the present invention;

[0054] Figure 2 Schematic diagram of the structure of a partial discharge monitoring system for a variable frequency motor in an embodiment of the present invention;

[0055] Figure 3 It is a schematic diagram of a monitoring system on a stator circuit in an embodiment of the present invention;

[0056] Figure 4 It is a schematic diagram of a monitoring system on a rotor circuit in an embodiment of the present invention;

[0057] Figure 5 A schematic diagram of a frequency converter pulse voltage and a partial discharge pulse voltage measured by a partial discharge measurement system in an embodiment of the present invention;

[0058] Figure 6A schematic diagram of interference and partial discharge spectrum in an embodiment of the present invention;

[0059] Figure 7 This is a workflow diagram of a monitoring system in an embodiment of the present invention;

[0060] Figure 8a It is a conventional sine reference schematic diagram in the prior art;

[0061] Figure 8b A pulse edge reference schematic diagram proposed in an embodiment of the present invention;

[0062] Fig. 9 Schematic diagram of half voltage edge and full voltage edge in an embodiment of the present invention;

[0063] Fig.10 is a positive polarity edge reference diagram in an embodiment of the present invention;

[0064] Fig.11 is a negative polarity edge reference diagram in an embodiment of the present invention;

[0065] Fig.12 A reference diagram of the positive polarity edge of partial discharge of a winding wear defect in an embodiment of the present invention;

[0066] Fig.13 A reference diagram of the positive polarity edge of the partial discharge of the winding corona defect in the embodiment of the present invention;

[0067] Fig.14 Schematic diagram of negative polarity edge reference characteristics in an embodiment of the present invention;

[0068] Fig.15 This is one of the flow charts of the insulation defect analysis method according to an embodiment of the present invention;

[0069] Fig.16 The second flowchart of the insulation defect analysis method according to the embodiment of the present invention;

[0070] Fig.17 The third flowchart of the insulation defect analysis method according to the embodiment of the present invention;

[0071] Fig.18 The fourth flowchart of the insulation defect analysis method according to the embodiment of the present invention;

[0072] Fig.19 Schematic diagram of the insulation defect analysis method according to the fifth embodiment of the present invention;

[0073] Fig. 20 This is one of the structural schematic diagrams of the insulation defect analysis device in an embodiment of the present invention;

[0074] Fig.21This is a second structural schematic diagram of the insulation defect analysis device in an embodiment of the present invention;

[0075] Fig. 22 A schematic diagram of the physical structure of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0076] To make the purpose, technical solution and advantages of the embodiments of the present invention more clear, the embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings. Here, the exemplary embodiments of the present invention and their descriptions are used to explain the present invention, but are not intended to limit the present invention.

[0077] Existing partial discharge monitoring and analysis technologies are all based on the action of sinusoidal voltage. For example, the partial discharge online monitoring devices used in thermal power and hydropower generator sets do not introduce additional interference because the stator voltage of their motor devices is close to the ideal sinusoidal high voltage. Their anti-interference mainly considers the suppression of low-frequency (tens of kHz to several MHz) interference, which is relatively small and easier to suppress.

[0078] In addition, the existing technologies are all aimed at monitoring partial discharges in stator windings, and no relevant research has been found on partial discharge monitoring of rotor windings in the rotating state of the motor device. The existing technology adopts a partial discharge analysis method based on sinusoidal phase, which measures the sinusoidal voltage and partial discharge signal and synchronizes them, and uses the phase distribution characteristics of partial discharge within a sinusoidal cycle to identify possible partial discharge defect modes, such as internal gap discharge of the main insulation, corona discharge on the insulation surface, metal tip discharge, etc. Figure 1 This method is obviously not applicable under the action of the PWM pulse voltage shown.

[0079] Based on this, Figure 2 As shown, the present application proposes a partial discharge monitoring system 1 for variable frequency motors, comprising a partial discharge coupler 10, a filter 11, a voltage measurement probe 12 and a partial discharge signal acquisition and analysis device 13, wherein:

[0080] The first end of the voltage measuring probe 12 is connected to the reference end ( Figure 2 The first end of the partial discharge coupler 10 is electrically connected to the variable frequency motor, the second end of the partial discharge coupler 10 is electrically connected to the filter 11, and the third end of the partial discharge coupler 10 is electrically connected to the reference end; the filter 11 is electrically connected to the partial discharge signal acquisition and analysis device 13.

[0081] The voltage measurement probe 12 is used to measure the partial discharge reference voltage signal of the partial discharge monitoring system 1; the partial discharge coupler 10 is used to determine the monitoring signal of the variable frequency motor with the partial discharge reference voltage signal as a trigger, and transmit the monitoring signal to the filter 11; the filter 11 is used to filter out the interference signal in the monitoring signal to obtain a partial discharge signal; the partial discharge signal acquisition and analysis device 13 is used to acquire the partial discharge signal and the partial discharge reference voltage signal (for example, the partial discharge signal and the partial discharge reference voltage signal of a preset time period are acquired according to a preset cycle), and with the partial discharge reference voltage signal as a reference, determine the edge reference graph corresponding to the partial discharge signal, and determine the insulation defect type corresponding to the variable frequency motor by analyzing the spectrum of the edge reference graph.

[0082] In some optional aspects of this embodiment, the installation position of the partial discharge coupler is related to the type of the variable frequency motor, wherein the type of the variable frequency motor includes: Figure 3 The stator winding is powered by variable frequency and Figure 4 The rotor winding shown is powered by variable frequency.

[0083] See also Figure 3 The variable frequency motor includes a frequency converter, a power supply cable, a stator housing, a three-phase stator winding and a stator lead terminal box ( Figure 3 ), wherein: the stator housing is grounded; the three-phase stator winding is electrically connected to the inverter through the power supply cable; the installation position of the partial discharge coupler is: inside the stator lead terminal box or on the power supply cable close to the stator lead terminal box.

[0084] See also Figure 4 The variable frequency motor includes a frequency converter, a power supply cable, a collector ring, an excitation end shaft ( Figure 4 Not shown), the rotor shaft (i.e. Figure 4 The present invention relates to a rotating shaft in the inverter) and a three-phase rotor winding, wherein: the three-phase rotor winding is electrically connected to the inverter through a power supply cable; the slip ring is arranged on the power supply cable close to the inverter; the installation position of the partial discharge coupler is: between the slip ring and the inverter and on the power supply cable close to the slip ring; wherein the end of the partial discharge coupler (i.e., the third end of the partial discharge coupler) is electrically connected to the rotor shaft.

[0085] Specifically, the partial discharge of the three-phase winding is coupled and sensed by the partial discharge couplers installed on the three-phase winding. Since partial discharge mainly occurs in the coil with high potential, and the lead wire and the first turn coil are subjected to higher overvoltage, partial discharge is more likely to occur. Therefore, coupling the partial discharge signal at the outlet end is closer to the real partial discharge source and more in line with the monitoring requirements. From the perspective of on-site installation conditions, the capacitor coupler method is preferred. The first end of the capacitor coupler is directly connected to the primary high voltage, the outer shell is directly grounded, the partial discharge signal is output, and it is connected to the partial discharge monitoring device. Figure 3 The partial discharge coupler can be installed in the stator lead terminal box. If the installation space is limited, it can also be installed on the cable from the inverter output to the stator winding, but it should be as close to the stator winding terminal box as possible.

[0086] because Figure 4 The rotor winding is in a rotating state. Installing a coupler inside the winding has a great impact on the reliability of the rotor itself, and the space is limited, so it is generally not possible. Therefore, the partial discharge coupler should be installed on the power supply cable of the static part outside the collector ring, close to the rotor winding. The end of the capacitive coupler should be in good contact with the nearest rotor shaft, so as to form a pulse current loop nearby and achieve higher measurement sensitivity. This is because the neutral point of the rotor winding is not connected to the rotor shaft, and the rotor shaft is grounded at one end. Then the partial discharge pulse current of the rotor winding is generated between the insulation and the rotor shaft. The partial discharge pulse flows through the shaft nearby. The path is the smallest compared to the ground loop formed by grounding the rotor shaft. It does not pass through the distributed parameters such as the inductance and capacitance of the rotor winding, and the pulse attenuation loss is smaller. To this end, the preferred solution is to install a monitoring carbon brush on the excitation end shaft body, which is in good contact with the shaft body, and the end of the carbon brush is connected to the end of the coupling capacitor to form a loop.

[0087] The capacitance value of the capacitive coupler is generally not greater than 80pF. The larger the capacitance value, the lower the lower cut-off frequency of the sensor, which is more unfavorable for interference suppression. The capacitive coupler should be able to withstand PWM pulses for a long time without generating partial discharge.

[0088] It should be noted that when the variable frequency motor type is stator winding variable frequency power supply, the reference end position is Figure 3 When the variable frequency motor type is the rotor winding variable frequency power supply, the reference end position is the rotor shaft, in some optional embodiments of this embodiment, such as Figure 4 As shown, the variable frequency motor also includes a carbon brush mounted on the excitation end shaft, wherein the end of the partial discharge coupler is also electrically connected to the end of the carbon brush, and the position of the reference end is the carbon brush.

[0089] In the present application, the phase voltage of the motor stator winding or rotor winding to ground is measured by a high-voltage and high-bandwidth measurement probe, and the output signal enters a partial discharge acquisition device as a reference voltage for the partial discharge signal.

[0090] Specifically, Figure 3 In the process, a voltage measuring probe is installed at the same node as the PD coupler installation point. The probe is required to be able to directly measure DC high voltage within 10kV, with a bandwidth greater than or equal to 50MHz, and measure the three-phase voltage of the stator winding to the ground as the reference voltage of the phase PD signal to realize the PD analysis function. Similarly, Figure 4 A three-phase voltage probe is also used to measure the three-phase-to-axis (ground) voltage of the rotor winding.

[0091] In some optional aspects of this embodiment, the lower cutoff frequency of the filter is configured to be greater than the upper cutoff frequency of the interference signal of the high-voltage pulse output by the frequency converter coupled to the partial discharge measurement system.

[0092] like Figure 5 As shown in the figure, the monitoring signal may contain both the partial discharge signal and the interference signal caused by the inverter pulse voltage, but there are obvious differences between the two: (1) Rising edge time, the interference rising edge time is long, and the partial discharge rising edge time is short. Taking the figure as an example, the partial discharge rising edge is only 17ns, and the interference is 127ns.

[0093] Correspondingly, Figure 6 The spectrum diagrams of the two are given. It can be seen that the upper limit frequency of the interference signal is fm, while the upper limit frequency of the partial discharge signal is much higher than fm. In the frequency band less than fm, the two spectra overlap, and the amplitude of the interference signal is much higher than the partial discharge signal. Therefore, the interference suppression method proposed in the present invention is: Figure 3 and Figure 4 The lower cutoff spectrum of the measurement system composed of the partial discharge coupler and the filter is greater than fm, thereby filtering out interference signals.

[0094] In a specific example, the partial discharge signal output by the capacitive coupler needs to be filtered by a high-pass or band-pass filter when necessary to fully remove the residual switching pulse. The lower cut-off frequency of the filter should generally be ≥30MHz.

[0095] In the present application, a local discharge signal is coupled on the high-voltage side of the motor stator winding or rotor winding through a local discharge coupler with a certain high-pass characteristic, and the coupler output signal is filtered through a certain high-pass or band-pass filter to achieve interference suppression of local discharge, and the filtered signal is input into a local signal acquisition and analysis device.

[0096] In some optional aspects of this embodiment, the partial discharge signal acquisition and analysis device includes a monitoring host and a monitoring background, wherein:

[0097] The monitoring host is used to collect local discharge signals and local reference voltage signals of a preset time period according to a preset cycle, and upload the collected local discharge signals and local reference voltage signals to the monitoring background; the monitoring background is used to determine the edge reference graph corresponding to the local discharge signal with reference to the local discharge reference voltage signal, and determine the insulation defect type corresponding to the variable frequency motor by analyzing the spectrum of the edge reference graph.

[0098] Specifically, the monitoring host can automatically or manually sample the partial discharge signal and reference voltage signal within a certain period of time and display them synchronously. The sampling bandwidth should be ≥1GHz, and the sampling rate should be able to reach 4GHz, with sufficient cache storage. It has the function of uploading data, and can regularly upload the analyzed and processed partial discharge data to the remote analysis background using appropriate communication methods to avoid storing a large amount of real-time sampling data on site; the monitoring background can analyze the maximum value and change trend of the partial discharge through certain algorithms, analyze the partial discharge mode, preliminarily judge the possible defect type, and give certain suggestions to guide the operation and maintenance of the motor.

[0099] In a specific example, the workflow of the partial discharge signal acquisition and analysis device is as follows: Figure 7 As shown, first, timing sampling is performed, including reference signal acquisition, reference signal triggering and partial discharge pulse acquisition; second, data caching, preprocessing and feature data remote transmission and recording are performed, wherein the preprocessing includes reference classification, pattern generation and working condition recording; secondly, it is determined whether the maximum partial discharge value exceeds the limit, if so, an abnormality is prompted; if not, the above operations are repeated.

[0100] In this application, the applicant found that the traditional method using fundamental sinusoidal voltage as reference (such as Figure 8a The time dimension is too macroscopic and cannot directly reflect the PD characteristics under pulse voltage. A PD analysis method based on PWM pulse edge reference is proposed (as shown in Figure 8b As shown), the pulse reference voltage comes from Figure 3 and Figure 4 The reference voltage measured in .

[0101] Among them, from the start of partial discharge sampling, the pulse reference voltage of the rotor winding and the stator winding to the ground is measured in real time, and this voltage is used as the trigger signal. The partial discharge signal acquisition is synchronously triggered at the starting stage of the pulse reference voltage. At the same time, the positive and negative polarity of the voltage indicates the edge polarity of the pulse voltage, that is, the positive step of the pulse voltage starting from zero is a positive polarity edge, and the negative step starting from zero is a negative polarity edge.

[0102] That is to say, the partial discharge reference voltage signal of the present application includes a positive polarity edge and / or a negative polarity edge. In particular, for a three-level inverter, such as Fig. 9As shown, the edge can be divided into a positive polarity half voltage edge and a positive polarity full voltage edge. The half voltage edge refers to the edge from zero to 1 / 2Vdc (Vdc is the DC bus voltage of the inverter), and the full voltage edge refers to the edge from 1 / 2Vdc to Vdc. Similarly, a multi-level converter can have more subdivided edges such as 1 / 4Vdc, 1 / 8Vdc, etc., so there are positive / negative edge reference diagrams corresponding to 1 / 4Vdc, 1 / 8Vdc, etc.

[0103] It should be noted that, in this application, the positive step is uniformly referred to as a positive polarity edge, and the negative step is uniformly referred to as a negative polarity edge. The partial discharge signal acquisition and analysis device is further used for:

[0104] In response to the partial discharge reference voltage signal being the positive polarity edge, a positive polarity edge reference graph corresponding to the partial discharge signal is determined with the positive polarity edge as a reference; and the insulation defect type corresponding to the variable frequency motor is determined by analyzing the spectrum of the positive polarity edge reference graph.

[0105] Specifically, during the period from the start time to the end time of the partial discharge sampling, all partial discharge signals collected under the positive polarity edge are plotted into an edge reference graph, which is called the positive polarity edge reference graph, such as Fig.10 As shown, the dot represents a discharge, the ordinate indicates the amplitude of the discharge (mV), the abscissa indicates the relative time relationship of the discharge to the trigger moment (i.e., the pulse start moment), and the number of dots indicates the number of discharges; the color of the dots indicates the amplitude of the discharge (which can also be seen from the PD ordinate), which can be divided into several categories as needed. In the example, the darker the color, the larger the discharge amplitude.

[0106] In response to the partial discharge reference voltage signal being the negative polarity edge, a negative polarity edge reference graph corresponding to the partial discharge signal is determined with the negative polarity edge as a reference; and the insulation defect type corresponding to the variable frequency motor is determined by analyzing the spectrum of the negative polarity edge reference graph.

[0107] Specifically, during the period from the start time to the end time of the partial discharge sampling, all partial discharge signals collected under the negative polarity edges are plotted into an edge reference graph, which is called the negative polarity edge reference graph, such as Fig.11 As shown; the dot represents a discharge, the ordinate indicates the amplitude of the discharge (mV), the abscissa indicates the relative time relationship of the discharge to the trigger moment (i.e., the pulse start moment), and the number of dots indicates the number of discharges; the color of the dots indicates the amplitude of the discharge, which can be divided into several categories as needed. In the example, the darker the color, the larger the discharge amplitude.

[0108] In response to the partial discharge reference voltage signal being the positive polarity edge and the negative polarity edge, a first partial discharge electronic signal sampled at the positive polarity edge and a second partial discharge electronic signal sampled at the negative polarity edge are respectively extracted from the partial discharge signal; a positive polarity edge reference graph corresponding to the first partial discharge electronic signal is determined with the positive polarity edge as a reference; a negative polarity edge reference graph corresponding to the second partial discharge electronic signal is determined with the negative polarity edge as a reference; and the insulation defect type corresponding to the variable frequency motor is determined by analyzing the spectrum of the positive polarity edge reference graph and / or the spectrum of the negative polarity edge reference graph.

[0109] In some optional aspects of this embodiment, determining the insulation defect type corresponding to the variable frequency motor by analyzing the spectrum of the positive polarity edge reference graph includes:

[0110] Obtain a positive polarity preset defect discharge mode reference diagram, and determine whether the positive polarity edge reference diagram matches the positive polarity preset defect discharge mode reference diagram; if so, determine the insulation defect type corresponding to the variable frequency motor based on the positive polarity preset defect discharge mode reference diagram; if not, determine the insulation defect type corresponding to the variable frequency motor based on the spectrum shape of the positive polarity edge reference diagram;

[0111] In some optional aspects of this embodiment, determining the insulation defect type corresponding to the variable frequency motor by analyzing the spectrum of the negative polarity edge reference graph includes:

[0112] Obtain a negative polarity preset defect discharge mode reference diagram, and determine whether the negative polarity edge reference diagram matches the negative polarity preset defect discharge mode reference diagram; if matched, determine the insulation defect type corresponding to the variable frequency motor based on the negative polarity preset defect discharge mode reference diagram; if not matched, determine the insulation defect type corresponding to the variable frequency motor based on the spectrum shape of the negative polarity edge reference diagram;

[0113] In some optional methods of this embodiment, determining the insulation defect type corresponding to the variable frequency motor by analyzing the spectrum of the positive polarity edge reference map and the spectrum of the negative polarity edge reference map includes:

[0114] Obtain a positive and negative polarity preset defect discharge mode reference diagram, and determine whether the positive polarity edge reference diagram and the negative polarity edge reference diagram match the positive and negative polarity preset defect discharge mode reference diagram; if they match, determine the insulation defect type corresponding to the variable frequency motor based on the positive and negative polarity preset defect discharge mode reference diagram; if they do not match, determine the insulation defect type corresponding to the variable frequency motor based on the spectrum shape of the positive polarity edge reference diagram and / or the spectrum shape of the negative polarity edge reference diagram.

[0115] In some optional aspects of this embodiment, determining the insulation defect type corresponding to the variable frequency motor based on the spectrum shape of the positive polarity edge reference graph and the spectrum shape of the negative polarity edge reference graph includes:

[0116] Determine whether the spectrum shape in the positive polarity edge reference diagram is consistent with the spectrum shape in the negative polarity edge reference diagram; if consistent, determine whether the partial discharge amplitude in the negative polarity edge reference diagram is greater than the partial discharge amplitude in the positive polarity edge reference diagram; if so, determine that the insulation defect type is a defect with polarity advantage.

[0117] Specifically, the insulation analysis implemented in this embodiment has the following two methods:

[0118] 1) According to the edge reference diagram, the defect mode is determined by analogy with the standard defect discharge pattern diagram obtained in advance. Fig.12 and Fig.13 Two typical positive discharge edge reference spectra are given. Fig.12 As shown in Figure 2, the discharge spectrum of the main insulation internal defects (such as wear defects, moisture defects, etc.) is pyramid-shaped, while Fig.13 As shown, the discharge spectrum of the main insulation surface defects (such as corona defects) appears square.

[0119] 2) Polarity advantage method. Fig.13 and Fig.14 , compare the positive polarity edge reference map with the negative polarity edge reference map in a certain sampling. Under the premise that the shapes of the partial discharge spectra are consistent, when the partial discharge amplitude in the negative polarity edge reference map is significantly larger than that in the positive polarity edge reference map or vice versa, it proves that the defect has a polarity advantage, which corresponds to a certain discharge defect with polarity advantage, such as corona discharge.

[0120] The embodiment of the present invention also provides an insulation defect analysis method based on the partial discharge monitoring system of the above embodiment, as described in the following embodiment. Since the principle of solving the problem by this method is similar to that of the partial discharge monitoring system, the implementation of this method can refer to the implementation of the partial discharge monitoring system, and the repeated parts will not be repeated.

[0121] like Fig.15 As shown, the method includes:

[0122] Step S10, acquiring the collected partial discharge signal and partial discharge reference voltage signal, wherein the partial discharge reference voltage signal includes a positive polarity edge and / or a negative polarity edge;

[0123] Step S20: using the partial discharge reference voltage signal as a reference, determining an edge reference graph corresponding to the partial discharge signal, and determining the insulation defect type corresponding to the variable frequency motor by analyzing the spectrum of the edge reference graph.

[0124] In some optional methods of this embodiment, the edge reference graph corresponding to the partial discharge signal is determined by taking the partial discharge reference voltage signal as a reference, and the insulation defect type corresponding to the variable frequency motor is determined by analyzing the spectrum of the edge reference graph, including:

[0125] Step 201: In response to the partial discharge reference voltage signal being the positive polarity edge, a positive polarity edge reference graph corresponding to the partial discharge signal is determined with the positive polarity edge as a reference; and the insulation defect type corresponding to the variable frequency motor is determined by analyzing the spectrum of the positive polarity edge reference graph;

[0126] Step 202: In response to the partial discharge reference voltage signal being the negative polarity edge, taking the negative polarity edge as a reference, determining a negative polarity edge reference graph corresponding to the partial discharge signal; and determining the insulation defect type corresponding to the variable frequency motor by analyzing the spectrum of the negative polarity edge reference graph;

[0127] Step 203, in response to the partial discharge reference voltage signal being the positive polarity edge and the negative polarity edge, extracting from the partial discharge signal a first partial discharge electronic signal sampled at the positive polarity edge and a second partial discharge electronic signal sampled at the negative polarity edge; determining a positive polarity edge reference graph corresponding to the first partial discharge electronic signal with the positive polarity edge as a reference; determining a negative polarity edge reference graph corresponding to the second partial discharge electronic signal with the negative polarity edge as a reference; and determining the insulation defect type corresponding to the variable frequency motor by analyzing the spectrum of the positive polarity edge reference graph and / or the spectrum of the negative polarity edge reference graph.

[0128] In some optional embodiments of this embodiment, Fig.16 As shown, in step 201, by analyzing the spectrum of the positive polarity edge reference graph, determining the insulation defect type corresponding to the variable frequency motor includes:

[0129] Step 2011: Acquire a positive polarity preset defect discharge mode reference diagram, and determine whether the positive polarity edge reference diagram matches the positive polarity preset defect discharge mode reference diagram.

[0130] Step 2012: If a match is found, the insulation defect type corresponding to the variable frequency motor is determined based on the positive polarity preset defect discharge mode reference diagram.

[0131] Step 2013: If there is no match, determine the insulation defect type corresponding to the variable frequency motor based on the graph shape of the positive polarity edge reference graph.

[0132] In some optional embodiments of this embodiment, Fig.17 As shown, in step 202, by analyzing the spectrum of the negative polarity edge reference graph, determining the insulation defect type corresponding to the variable frequency motor includes:

[0133] Step 2021: Acquire a negative polarity preset defect discharge mode reference diagram, and determine whether the negative polarity edge reference diagram matches the negative polarity preset defect discharge mode reference diagram.

[0134] Step 2022: If a match is found, the insulation defect type corresponding to the variable frequency motor is determined based on the negative polarity preset defect discharge mode reference diagram.

[0135] Step 2023: If there is no match, determine the insulation defect type corresponding to the variable frequency motor based on the graph shape of the negative polarity edge reference graph.

[0136] In some optional embodiments of this embodiment, Fig.18 As shown, in step 203, by analyzing the spectrum of the positive polarity edge reference map and the spectrum of the negative polarity edge reference map, determining the insulation defect type corresponding to the variable frequency motor includes:

[0137] Step 2031 , obtaining a positive and negative polarity preset defect discharge mode reference diagram, and determining whether the positive polarity edge reference diagram and the negative polarity edge reference diagram match the positive and negative polarity preset defect discharge mode reference diagram.

[0138] Step 2032: If a match is found, the insulation defect type corresponding to the variable frequency motor is determined based on the positive and negative polarity preset defect discharge mode reference diagram.

[0139] Step 2033: If there is no match, determine the insulation defect type corresponding to the variable frequency motor based on the spectrum shape of the positive polarity edge reference graph and / or the spectrum shape of the negative polarity edge reference graph.

[0140] In some optional embodiments of this embodiment, Fig.19 As shown, in step 2033, based on the spectrum shape of the positive polarity edge reference graph and the spectrum shape of the negative polarity edge reference graph, determining the insulation defect type corresponding to the variable frequency motor includes:

[0141] Step 20331, determine whether the spectrum shape in the positive polarity edge reference diagram is consistent with the spectrum shape in the negative polarity edge reference diagram; Step 20332, if consistent, determine whether the partial discharge amplitude in the negative polarity edge reference diagram is greater than the partial discharge amplitude in the positive polarity edge reference diagram; Step 20333, if so, determine that the insulation defect type is a defect with polarity advantage.

[0142] Based on the same inventive concept, the embodiments of the present application also provide an insulation defect analysis device, which can be used to implement the method described in the above embodiments, as described in the following embodiments. Since the principle of the problem solved by the insulation defect analysis device is similar to that of the insulation defect analysis method, the implementation of the insulation defect analysis device can refer to the implementation of the insulation defect analysis method, and the repeated parts will not be repeated. As used below, the term "unit" or "module" can be a combination of software and / or hardware that implements a predetermined function. Although the system described in the following embodiments is preferably implemented in software, the implementation of hardware, or a combination of software and hardware, is also possible and conceived.

[0143] like Fig. 20 As shown, the insulation defect analysis device comprises:

[0144] An acquisition module 601 is configured to acquire a collected partial discharge signal and a partial discharge pulse reference voltage signal, wherein the partial discharge reference voltage signal includes a positive polarity edge and / or a negative polarity edge;

[0145] The insulation defect analysis module 602 is configured to determine an edge reference graph corresponding to the partial discharge signal with reference to the partial discharge reference voltage signal, and determine the insulation defect type corresponding to the variable frequency motor by analyzing the spectrum of the edge reference graph.

[0146] In some optional embodiments of this embodiment, Fig.21 As shown, the insulation defect analysis module 602 includes a first insulation defect analysis unit, a second insulation defect analysis unit and a third insulation defect analysis unit, wherein:

[0147] The first insulation defect analysis unit 6021 is configured to determine a positive polarity edge reference graph corresponding to the partial discharge signal in response to the partial discharge reference voltage signal being the positive polarity edge and taking the positive polarity edge as a reference; and determine the insulation defect type corresponding to the variable frequency motor by analyzing the spectrum of the positive polarity edge reference graph;

[0148] The second insulation defect analysis unit 6022 is configured to determine a negative polarity edge reference graph corresponding to the partial discharge signal in response to the partial discharge reference voltage signal being the negative polarity edge and taking the negative polarity edge as a reference; and determine the insulation defect type corresponding to the variable frequency motor by analyzing the spectrum of the negative polarity edge reference graph;

[0149] The third insulation defect analysis unit 6023 is configured to extract, in response to the partial discharge reference voltage signal being the positive polarity edge and the negative polarity edge, from the partial discharge signal, respectively a first partial discharge electronic signal sampled at the positive polarity edge and a second partial discharge electronic signal sampled at the negative polarity edge; determine a positive polarity edge reference graph corresponding to the first partial discharge electronic signal with the positive polarity edge as a reference; determine a negative polarity edge reference graph corresponding to the second partial discharge electronic signal with the negative polarity edge as a reference; and determine the insulation defect type corresponding to the variable frequency motor by analyzing the spectrum of the positive polarity edge reference graph and / or the spectrum of the negative polarity edge reference graph.

[0150] In some optional aspects of this embodiment, the first insulation defect analysis unit is further configured as follows:

[0151] Obtain a positive polarity preset defect discharge mode reference diagram, and determine whether the positive polarity edge reference diagram matches the positive polarity preset defect discharge mode reference diagram; if so, determine the insulation defect type corresponding to the variable frequency motor based on the positive polarity preset defect discharge mode reference diagram; if not, determine the insulation defect type corresponding to the variable frequency motor based on the spectrum shape of the positive polarity edge reference diagram;

[0152] In some optional aspects of this embodiment, the second insulation defect analysis unit is further configured as follows:

[0153] Obtain a negative polarity preset defect discharge mode reference diagram; determine whether the negative polarity edge reference diagram matches the negative polarity preset defect discharge mode reference diagram, and if so, determine the insulation defect type corresponding to the variable frequency motor based on the negative polarity preset defect discharge mode reference diagram; if not, determine the insulation defect type corresponding to the variable frequency motor based on the graph shape of the negative polarity edge reference diagram;

[0154] In some optional aspects of this embodiment, the third insulation defect analysis unit is further configured as follows:

[0155] Obtain a positive and negative polarity preset defect discharge mode reference diagram, and determine whether the positive polarity edge reference diagram and the negative polarity edge reference diagram match the positive and negative polarity preset defect discharge mode reference diagram; if they match, determine the insulation defect type corresponding to the variable frequency motor based on the positive and negative polarity preset defect discharge mode reference diagram; if they do not match, determine the insulation defect type corresponding to the variable frequency motor based on the spectrum shape of the positive polarity edge reference diagram and / or the spectrum shape of the negative polarity edge reference diagram.

[0156] In some optional aspects of this embodiment, the third insulation defect analysis unit is further configured as follows:

[0157] Determine whether the spectrum shape in the positive polarity edge reference diagram is consistent with the spectrum shape in the negative polarity edge reference diagram; if consistent, determine whether the partial discharge amplitude in the negative polarity edge reference diagram is greater than the partial discharge amplitude in the positive polarity edge reference diagram; if so, determine that the insulation defect type is a defect with polarity advantage.

[0158] It should be noted that the acquisition, storage, use and processing of data in the technical solution of this application are in compliance with the relevant provisions of laws and regulations.

[0159] According to an embodiment of the present disclosure, the present disclosure also provides an electronic device, a readable storage medium and a computer program product.

[0160] An electronic device comprises: at least one processor; and a memory connected to the at least one processor in communication; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can perform the steps of an insulation defect analysis method of the aforementioned embodiment.

[0161] A non-transitory computer-readable storage medium storing computer instructions, wherein the computer instructions are used to enable a computer to execute the steps of an insulation defect analysis method of the above embodiment.

[0162] A computer program product includes a computer program / instruction, which implements the steps of an insulation defect analysis method of the above embodiment when the computer program / instruction is executed by a processor.

[0163] Fig. 22A schematic block diagram of an example electronic device 900 that can be used to implement an embodiment of the present disclosure is shown. The electronic device is intended to represent various forms of digital computers, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device can also represent various forms of mobile devices, such as personal digital processing, cellular phones, smart phones, wearable devices, and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely examples and are not intended to limit the implementation of the present disclosure described and / or required herein.

[0164] like Fig. 22 As shown, the device 900 includes a computing unit 901, which can perform various appropriate actions and processes according to a computer program stored in a read-only memory (ROM) 902 or a computer program loaded from a storage unit 908 into a random access memory (RAM) 903. In the RAM 903, various programs and data required for the operation of the device 900 can also be stored. The computing unit 901, the ROM 902, and the RAM 903 are connected to each other via a bus 904. An input / output (I / O) interface 905 is also connected to the bus 904.

[0165] A number of components in the device 900 are connected to the I / O interface 905, including: an input unit 906, such as a keyboard, a mouse, etc.; an output unit 907, such as various types of displays, speakers, etc.; a storage unit 908, such as a disk, an optical disk, etc.; and a communication unit 909, such as a network card, a modem, a wireless communication transceiver, etc. The communication unit 909 allows the device 900 to exchange information / data with other devices through a computer network such as the Internet and / or various telecommunication networks.

[0166] The computing unit 901 may be a variety of general and / or special processing components with processing and computing capabilities. Some examples of the computing unit 901 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various special artificial intelligence (AI) computing chips, various computing units running machine learning model algorithms, a digital signal processor (DSP), and any appropriate processor, controller, microcontroller, etc. The computing unit 901 performs the various methods and processes described above, such as an insulation defect analysis method.

[0167] For example, in some embodiments, an insulation defect analysis method may be implemented as a computer software program, which is tangibly contained in a machine-readable medium, such as a storage unit 908. In some embodiments, part or all of the computer program may be loaded and / or installed on the device 900 via the ROM 902 and / or the communication unit 909. When the computer program is loaded into the RAM 903 and executed by the computing unit 901, one or more steps of the insulation defect analysis method described above may be performed. Alternatively, in other embodiments, the computing unit 901 may be configured to perform an insulation defect analysis method in any other appropriate manner (e.g., by means of firmware).

[0168] Various implementations of the systems and techniques described above herein can be implemented in digital electronic circuit systems, integrated circuit systems, field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), application specific standard products (ASSPs), systems on chips (SOCs), load programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various implementations can include: being implemented in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which can be a special purpose or general purpose programmable processor that can receive data and instructions from a storage system, at least one input device, and at least one output device, and transmit data and instructions to the storage system, the at least one input device, and the at least one output device.

[0169] The program code for implementing the method of the present disclosure may be written in any combination of one or more programming languages. These program codes may be provided to a processor or controller of a general-purpose computer, a special-purpose computer, or other programmable data processing device, so that the program code, when executed by the processor or controller, enables the functions / operations specified in the flow chart and / or block diagram to be implemented. The program code may be executed entirely on the machine, partially on the machine, partially on the machine and partially on a remote machine as a stand-alone software package, or entirely on a remote machine or server.

[0170] In the context of the present disclosure, a machine-readable medium may be a tangible medium that may contain or store a program for use by or in conjunction with an instruction execution system, device, or equipment. A machine-readable medium may be a machine-readable signal medium or a machine-readable storage medium. A machine-readable medium may include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, device, or equipment, or any suitable combination of the foregoing. A more specific example of a machine-readable storage medium may include an electrical connection based on one or more lines, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0171] To provide interaction with a user, the systems and techniques described herein can be implemented on a computer having: a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user; and a keyboard and pointing device (e.g., a mouse or trackball) through which the user can provide input to the computer. Other types of devices can also be used to provide interaction with the user; for example, the feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form (including acoustic input, voice input, or tactile input).

[0172] The systems and techniques described herein may be implemented in a computing system that includes back-end components (e.g., as a data server), or a computing system that includes middleware components (e.g., an application server), or a computing system that includes front-end components (e.g., a user computer with a graphical user interface or a web browser through which a user can interact with implementations of the systems and techniques described herein), or a computing system that includes any combination of such back-end components, middleware components, or front-end components. The components of the system may be interconnected by any form or medium of digital data communication (e.g., a communication network). Examples of communication networks include: a local area network (LAN), a wide area network (WAN), and the Internet.

[0173] A computer system may include a client and a server. The client and the server are generally remote from each other and usually interact through a communication network. The relationship of client and server is generated by computer programs running on respective computers and having a client-server relationship with each other. The server may be a cloud server, a server of a distributed system, or a server combined with a blockchain.

[0174] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps recorded in this disclosure can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of this disclosure can be achieved, and this document is not limited here.

[0175] The above specific implementations do not constitute a limitation on the protection scope of the present disclosure. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present disclosure shall be included in the protection scope of the present disclosure.

Claims

1. A partial discharge monitoring system for variable frequency motors, characterized in that: It includes a partial discharge coupler, a filter, a voltage measurement probe and a partial discharge signal acquisition and analysis device, wherein: The first end of the voltage measuring probe is electrically connected to the reference end, the second end of the voltage measuring probe is configured at the installation position of the partial discharge coupler, and the third end of the voltage measuring probe is electrically connected to the partial discharge signal acquisition and analysis device, and is used to measure the partial discharge reference voltage signal of the partial discharge monitoring system; The first end of the partial discharge coupler is electrically connected to the variable frequency motor, the second end of the partial discharge coupler is electrically connected to the filter, and the third end of the partial discharge coupler is electrically connected to the reference end, and is used to determine the monitoring signal of the variable frequency motor with the partial discharge reference voltage signal as a trigger, and transmit the monitoring signal to the filter; The filter is electrically connected to the partial discharge signal acquisition and analysis device, and is used to filter out interference signals in the monitoring signal to obtain a partial discharge signal; The partial discharge signal acquisition and analysis device is used to acquire the partial discharge signal and the partial discharge reference voltage signal, and determine the edge reference graph corresponding to the partial discharge signal with reference to the partial discharge reference voltage signal, and determine the insulation defect type corresponding to the variable frequency motor by analyzing the spectrum of the edge reference graph.

2. The partial discharge monitoring system according to claim 1, characterized in that: The lower cutoff frequency of the filter is configured to be greater than the upper cutoff frequency of the interference signal.

3. The partial discharge monitoring system according to claim 1, characterized in that: The installation position of the partial discharge coupler is related to the type of the variable frequency motor, wherein the types of the variable frequency motor include stator winding variable frequency power supply and rotor winding variable frequency power supply.

4. The partial discharge monitoring system according to claim 3, characterized in that: In response to the type of the variable frequency motor being the stator winding variable frequency power supply, the installation position of the partial discharge coupler is: Inside the stator winding lead terminal box or on the power supply cable close to the stator winding lead terminal box; wherein the position of the reference end is the grounding point; In response to the type of the variable frequency motor being the rotor winding variable frequency power supply, the installation position of the partial discharge coupler is: On a power supply cable between the slip ring and the frequency converter and close to the slip ring; wherein the end of the partial discharge coupler is electrically connected to the rotor shaft, and the position of the reference end is the rotor shaft.

5. The partial discharge monitoring system according to claim 1, characterized in that: The partial discharge reference voltage signal includes a positive polarity edge and / or a negative polarity edge, and the partial discharge signal acquisition and analysis device is further used for: In response to the partial discharge reference voltage signal being the positive polarity edge, a positive polarity edge reference graph corresponding to the partial discharge signal is determined with the positive polarity edge as a reference; and the insulation defect type corresponding to the variable frequency motor is determined by analyzing the spectrum of the positive polarity edge reference graph; In response to the partial discharge reference voltage signal being the negative polarity edge, a negative polarity edge reference graph corresponding to the partial discharge signal is determined with the negative polarity edge as a reference; and the insulation defect type corresponding to the variable frequency motor is determined by analyzing the spectrum of the negative polarity edge reference graph; In response to the partial discharge reference voltage signal being the positive polarity edge and the negative polarity edge, a first partial discharge electronic signal sampled at the positive polarity edge and a second partial discharge electronic signal sampled at the negative polarity edge are respectively extracted from the partial discharge signal; a positive polarity edge reference graph corresponding to the first partial discharge electronic signal is determined with the positive polarity edge as a reference; a negative polarity edge reference graph corresponding to the second partial discharge electronic signal is determined with the negative polarity edge as a reference; and the insulation defect type corresponding to the variable frequency motor is determined by analyzing the spectrum of the positive polarity edge reference graph and / or the spectrum of the negative polarity edge reference graph.

6. The partial discharge monitoring system according to claim 5, characterized in that: The step of determining the insulation defect type corresponding to the variable frequency motor by analyzing the spectrum of the positive polarity edge reference graph includes: Obtain a positive polarity preset defect discharge mode reference diagram, and determine whether the positive polarity edge reference diagram matches the positive polarity preset defect discharge mode reference diagram; if matched, determine the insulation defect type corresponding to the variable frequency motor based on the positive polarity preset defect discharge mode reference diagram; if not matched, determine the insulation defect type corresponding to the variable frequency motor based on the spectrum shape of the positive polarity edge reference diagram; The step of determining the insulation defect type corresponding to the variable frequency motor by analyzing the spectrum of the negative polarity edge reference graph includes: Obtain a negative polarity preset defect discharge mode reference diagram, and determine whether the negative polarity edge reference diagram matches the negative polarity preset defect discharge mode reference diagram; if matched, determine the insulation defect corresponding to the variable frequency motor based on the negative polarity preset defect discharge mode reference diagram; if not matched, determine the insulation defect type corresponding to the variable frequency motor based on the spectrum shape of the negative polarity edge reference diagram; The determining of the insulation defect type corresponding to the variable frequency motor by analyzing the spectrum of the positive polarity edge reference map and the spectrum of the negative polarity edge reference map includes: Obtain a positive and negative polarity preset defect discharge mode reference diagram, and determine whether the positive polarity edge reference diagram and the negative polarity edge reference diagram match the positive and negative polarity preset defect discharge mode reference diagram; if they match, determine the insulation defect type corresponding to the variable frequency motor based on the positive and negative polarity preset defect discharge mode reference diagram; if they do not match, determine the insulation defect type corresponding to the variable frequency motor based on the spectrum shape of the positive polarity edge reference diagram and / or the spectrum shape of the negative polarity edge reference diagram.

7. The partial discharge monitoring system according to claim 6, characterized in that: The determining of the insulation defect type corresponding to the variable frequency motor based on the spectrum shape of the positive polarity edge reference graph and the spectrum shape of the negative polarity edge reference graph includes: Determine whether the spectrum shape in the positive polarity edge reference diagram is consistent with the spectrum shape in the negative polarity edge reference diagram; if consistent, determine whether the partial discharge amplitude in the negative polarity edge reference diagram is greater than the partial discharge amplitude in the positive polarity edge reference diagram; if so, determine that the insulation defect type is a defect with polarity advantage.

8. An insulation defect analysis method based on the partial discharge monitoring system according to any one of claims 1 to 7, characterized in that: include: Acquire the collected partial discharge signal and partial discharge reference voltage signal, wherein the partial discharge reference voltage signal includes a positive polarity edge and / or a negative polarity edge; Taking the partial discharge reference voltage signal as a reference, an edge reference graph corresponding to the partial discharge signal is determined, and the insulation defect type corresponding to the variable frequency motor is determined by analyzing the spectrum of the edge reference graph.

9. The insulation defect analysis method according to claim 8, characterized in that: The method of determining an edge reference graph corresponding to the partial discharge signal by taking the partial discharge reference voltage signal as a reference, and determining the insulation defect type corresponding to the variable frequency motor by analyzing the spectrum of the edge reference graph, includes: In response to the partial discharge reference voltage signal being the positive polarity edge, a positive polarity edge reference graph corresponding to the partial discharge signal is determined with the positive polarity edge as a reference; and the insulation defect type corresponding to the variable frequency motor is determined by analyzing the spectrum of the positive polarity edge reference graph; In response to the partial discharge reference voltage signal being the negative polarity edge, a negative polarity edge reference graph corresponding to the partial discharge signal is determined with the negative polarity edge as a reference; and the insulation defect type corresponding to the variable frequency motor is determined by analyzing the spectrum of the negative polarity edge reference graph; In response to the partial discharge reference voltage signal being the positive polarity edge and the negative polarity edge, a first partial discharge electronic signal sampled at the positive polarity edge and a second partial discharge electronic signal sampled at the negative polarity edge are respectively extracted from the partial discharge signal; a positive polarity edge reference graph corresponding to the first partial discharge electronic signal is determined with the positive polarity edge as a reference; a negative polarity edge reference graph corresponding to the second partial discharge electronic signal is determined with the negative polarity edge as a reference; and the insulation defect type corresponding to the variable frequency motor is determined by analyzing the spectrum of the positive polarity edge reference graph and / or the spectrum of the negative polarity edge reference graph.

10. The insulation defect analysis method according to claim 9, characterized in that: The step of determining the insulation defect type corresponding to the variable frequency motor by analyzing the spectrum of the positive polarity edge reference graph includes: Obtain a positive polarity preset defect discharge mode reference diagram, and determine whether the positive polarity edge reference diagram matches the positive polarity preset defect discharge mode reference diagram; if so, determine the insulation defect type corresponding to the variable frequency motor based on the positive polarity preset defect discharge mode reference diagram; if not, determine the insulation defect type corresponding to the variable frequency motor based on the spectrum shape of the positive polarity edge reference diagram; The step of determining the insulation defect type corresponding to the variable frequency motor by analyzing the spectrum of the negative polarity edge reference graph includes: Obtain a negative polarity preset defect discharge mode reference diagram, and determine whether the negative polarity edge reference diagram matches the negative polarity preset defect discharge mode reference diagram; if matched, determine the insulation defect type corresponding to the variable frequency motor based on the negative polarity preset defect discharge mode reference diagram; if not matched, determine the insulation defect type corresponding to the variable frequency motor based on the spectrum shape of the negative polarity edge reference diagram; The determining of the insulation defect type corresponding to the variable frequency motor by analyzing the spectrum of the positive polarity edge reference map and the spectrum of the negative polarity edge reference map includes: Obtain a positive and negative polarity preset defect discharge mode reference diagram, and determine whether the positive polarity edge reference diagram and the negative polarity edge reference diagram match the positive and negative polarity preset defect discharge mode reference diagram; if they match, determine the insulation defect type corresponding to the variable frequency motor based on the positive and negative polarity preset defect discharge mode reference diagram; if they do not match, determine the insulation defect type corresponding to the variable frequency motor based on the spectrum shape of the positive polarity edge reference diagram and / or the spectrum shape of the negative polarity edge reference diagram.

11. The insulation defect analysis method according to claim 10, characterized in that: The determining of the insulation defect type corresponding to the variable frequency motor based on the spectrum shape of the positive polarity edge reference graph and the spectrum shape of the negative polarity edge reference graph includes: Determine whether the spectrum shape in the positive polarity edge reference diagram is consistent with the spectrum shape in the negative polarity edge reference diagram; if consistent, determine whether the partial discharge amplitude in the negative polarity edge reference diagram is greater than the partial discharge amplitude in the positive polarity edge reference diagram; if so, determine that the insulation defect type is a defect with polarity advantage.

12. An insulation defect analysis device, characterized in that: include: An acquisition module is configured to acquire the collected partial discharge signal and partial discharge pulse reference voltage signal, wherein the partial discharge reference voltage signal includes a positive polarity edge and / or a negative polarity edge; The insulation defect analysis module is configured to determine an edge reference graph corresponding to the partial discharge signal with reference to the partial discharge reference voltage signal, and determine the insulation defect type corresponding to the variable frequency motor by analyzing the spectrum of the edge reference graph.

13. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the insulation defect analysis method according to any one of claims 8 to 11 is implemented.

14. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the insulation defect analysis method according to any one of claims 8 to 11 is implemented.

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