An experimental platform for detecting the influence of vibration on the partial discharge characteristics of needle-plate electrodes

Abstract

The present invention discloses an experimental platform for detecting the influence of vibration on the partial discharge characteristics of a needle-plate electrode, comprising: a power supply unit for providing an adjustable test voltage; a model unit electrically connected to the power supply unit for testing the partial discharge characteristics of the needle-plate electrode under different electrode spacings, amplitudes, and vibration frequencies; a measurement unit electrically connected to the model unit for obtaining the partial discharge signals during the initial discharge process of the needle-plate electrode and the development characteristics of partial discharge under different conditions, and generating the influence laws of various vibration factors on the discharge of the needle-plate electrode. The present invention realizes the test of partial discharge characteristics under different electrode spacings, amplitudes, and vibration frequencies, obtains the partial discharge signals during the initial discharge process and the differences in the development characteristics of partial discharge under different conditions, and obtains the influence laws of various vibration factors on the discharge of the needle-plate electrode.

Description

Technical Field

[0001] The present invention relates to the technical field of power equipment fault diagnosis, and particularly to an experimental platform for detecting the influence of vibration on the partial discharge characteristics of a needle-plate electrode. Background Art

[0002] The healthy and stable operation of high-voltage electrical equipment is the fundamental guarantee for the reliable operation of the power system. During long-term operation, the equipment may be subjected to the interaction of electricity, heat, mechanical stress, etc., which may cause insulation degradation and generate partial discharge. Partial discharge is one of the most common insulation problems inside electrical equipment, seriously affecting the safe and stable operation of the equipment. Due to external excitation or internal electromagnetic force, etc., electrical equipment is not in a static state during actual operation, but is often in a motion state such as mechanical vibration. Therefore, in-depth study of the influence law of mechanical vibration on partial discharge characteristics is of great significance for clarifying the fault evolution mechanism of electrical equipment under service conditions and ensuring the safe operation of the equipment.

[0003] At present, the research on the influence of mechanical vibration mainly focuses on the change of equipment performance and the influence on partial discharge characteristics. In terms of equipment performance, the research on the influence of vibration on equipment mostly focuses on the change of mechanical performance and working characteristics, such as accelerating material degradation, causing equipment component loosening, poor contact of contacts, etc., and does not involve the influence of vibration on the partial discharge mechanism. In terms of the influence of vibration on partial discharge characteristics, the research mainly focuses on the influence of vibration leading phase and frequency, voltage magnitude on partial discharge behavior. Partial discharge is affected by many vibration conditions and the process is complex. Both vibration amplitude and frequency will affect the discharge process, and the vibration discharge processes under different electrode forms and dielectric types are also different.

[0004] In traditional research on the influence of vibration on the discharge process, the amplitude is generally small, and there is a lack of research on the vibration discharge characteristics under a large amplitude. The existing research on the influence and mechanism of vibration on partial discharge still needs to be further explored; therefore, there is an urgent need for an experimental platform for detecting the influence of vibration on the partial discharge characteristics of a needle-plate electrode to solve the problems existing in the prior art. Summary of the Invention

[0005] In order to solve the problems existing in the prior art, the purpose of the present invention is to provide an experimental platform for detecting the influence of vibration on the partial discharge characteristics of a needle-plate electrode, which is used to clarify the fault evolution mechanism of high-voltage electrical equipment under service conditions and ensure the safe operation of the equipment by studying the influence law of mechanical vibration in air on the partial discharge characteristics of the needle-plate electrode.

[0006] In order to achieve the above technical purpose, the present invention provides an experimental platform for detecting the influence of vibration on the partial discharge characteristics of a needle-plate electrode, including:

[0007] A power supply unit for providing an adjustable test voltage;

[0008] A model unit electrically connected to the power supply unit for testing the partial discharge characteristics of a needle-plate electrode at different electrode spacings, amplitudes, and vibration frequencies;

[0009] A measurement unit electrically connected to the model unit for acquiring the partial discharge signals of the needle-plate electrode during the initial discharge process and the development characteristics of partial discharge under different conditions, and generating the influence law of various vibration factors on the discharge of the needle-plate electrode.

[0010] Preferably, the power supply unit is composed of a power frequency test transformer, a protective resistor, a capacitive voltage divider, and a coupling capacitor;

[0011] The first end of the power frequency test transformer is electrically connected to the capacitive voltage divider and the coupling capacitor respectively through the protective resistor;

[0012] The second end of the power frequency test transformer is electrically connected to the capacitive voltage divider and the coupling capacitor.

[0013] Preferably, the capacitive voltage divider is composed of a first capacitor and a second capacitor connected in series;

[0014] The rated parameters of the power frequency test transformer are 10 kVA / 110 kV;

[0015] The resistance value of the protective resistor is 10 KΩ;

[0016] The series capacitance value of the first capacitor and the second capacitor is 1000 pF;

[0017] The capacitance value of the coupling capacitor is 1028 pF.

[0018] Preferably, the model unit is composed of a needle-plate electrode discharge model and a vibration platform;

[0019] The needle-plate electrode discharge model includes a cavity and a needle-plate electrode and an insulating bracket arranged in the cavity;

[0020] The vibration platform is composed of an exciter, a power amplifier, a signal generator, and an acceleration sensor;

[0021] The needle-plate electrode is rigidly connected to the ejector rod of the exciter;

[0022] The signal generator is electrically connected to the exciter through the power amplifier;

[0023] The acceleration sensor is used to collect the output amplitude and frequency of the needle-plate electrode.

[0024] Preferably, the needle-plate electrode consists of a tungsten needle electrode and a grounding electrode. Among them, the diameter of the needle neck of the tungsten needle electrode is 1.6 mm, the tip cone angle is 95°, the grounding electrode is a copper plate electrode, with a diameter of 48 mm and a thickness of 10 mm;

[0025] The adjustable range of the distance between the needle-plate electrodes is 0 - 30 mm.

[0026] Preferably, the acceleration sensor is an FP non-gold-plated acceleration sensor.

[0027] Preferably, the measurement unit is used to detect the partial discharge of the needle-plate electrode by the pulse current method;

[0028] The measurement unit includes a TWPD-2P digital partial discharge comprehensive analyzer, which is used to collect and analyze partial discharge signals;

[0029] The sampling rate of the TWPD-2P digital partial discharge comprehensive analyzer is 20 MHz, and the bandwidth is 10 kHz - 1 MHz.

[0030] Preferably, the experimental platform is used to obtain the partial discharge characteristics of the needle-plate electrode in air under vibration conditions by the step-up voltage method. Among them, the step-up voltage method includes the following steps:

[0031] Control the test voltage to slowly increase from 0 kV in steps of 1 kV, with a step-up time interval of 30 s, until the measured partial discharge charge reaches 100 pC. Record the voltage value at this time as the initial discharge voltage and keep the voltage constant, and obtain the two-dimensional scatter plot of the discharge signal within 90 s. Among them, 5 repeated tests are carried out under each test condition, including:

[0032] Under the condition of no vibration, the first partial discharge test is carried out with the needle-plate electrode spacing being 10 mm, 15 mm, 20 mm, 25 mm, and 30 mm in sequence,

[0033] Based on the electrode spacing of 20 mm and the vibration frequency of 15 Hz, the second partial discharge test is carried out with the amplitudes being 4 mm, 6 mm, 8 mm, 10 mm, and 12 mm in sequence,

[0034] Based on the two cases of electrode spacing of 10 mm and 20 mm, with an amplitude of 3 mm, the third partial discharge test is carried out with the frequencies being 25 Hz, 50 Hz, 75 Hz, 100 Hz, and 125 Hz in sequence;

[0035] According to the two-dimensional scatter plot, obtain the partial discharge characteristics, generate development characteristics, and analyze the influence law of various vibration factors on the discharge of the needle-plate electrode.

[0036] The present invention discloses the following technical effects:

[0037] The present invention realizes the partial discharge characteristic tests under different electrode spacings, amplitudes, and vibration frequencies, obtains the partial discharge signals during the initial discharge process and the differences in the development characteristics of partial discharges under different conditions, and obtains the laws of the influence of various vibration factors on the discharge of the needle-plate electrode. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0039] Figure 1 It is a structural diagram of an experimental platform for studying the influence of mechanical vibration in air on the partial discharge characteristics of a needle-plate electrode according to the present invention;

[0040] Figure 2 It is a schematic diagram of the needle-plate electrode model according to the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0041] In order to make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. Usually, the components of the embodiments of the present application described and illustrated herein can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the present application claimed, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present application.

[0042] As Figure 1-2 shown, the present invention provides an experimental platform for detecting the influence of vibration on the partial discharge characteristics of a needle-plate electrode, including:

[0043] A power supply unit for providing an adjustable test voltage;

[0044] A model unit electrically connected to the power supply unit for performing partial discharge characteristic tests on the needle-plate electrode under different electrode spacings, amplitudes, and vibration frequencies;

[0045] A measurement unit electrically connected to the model unit for obtaining the partial discharge signals of the needle-plate electrode during the initial discharge process and the development characteristics of partial discharges under different conditions, and generating the laws of the influence of various vibration factors on the discharge of the needle-plate electrode.

[0046] Further preferably, the power supply unit mentioned in the present invention is composed of a power frequency test transformer, a protection resistor, a capacitive voltage divider, and a coupling capacitor;

[0047] The first end of the power frequency test transformer is electrically connected to the capacitive voltage divider and the coupling capacitor respectively through the protection resistor;

[0048] The second end of the power frequency test transformer is electrically connected to the capacitive voltage divider and the coupling capacitor.

[0049] Further preferably, the capacitive voltage divider mentioned in the present invention is composed of a first capacitor and a second capacitor connected in series;

[0050] The rated parameters of the power frequency test transformer are 10 kVA / 110 kV;

[0051] The resistance value of the protection resistor is 10 KΩ;

[0052] The capacitance value after the first capacitor and the second capacitor are connected in series is 1000 pF;

[0053] The capacitance value of the coupling capacitor is 1028 pF.

[0054] Further preferably, the model unit mentioned in the present invention is composed of a needle-plate electrode discharge model and a vibration platform;

[0055] The needle-plate electrode discharge model includes a cavity and a needle-plate electrode and an insulating bracket arranged in the cavity;

[0056] The vibration platform is composed of an exciter, a power amplifier, a signal generator, and an acceleration sensor;

[0057] The needle-plate electrode is rigidly connected to the ejector rod of the exciter;

[0058] The signal generator is electrically connected to the exciter through the power amplifier;

[0059] The acceleration sensor is used to collect the output amplitude and frequency of the needle-plate electrode.

[0060] Further preferably, the needle-plate electrode mentioned in the present invention is composed of a tungsten needle electrode and a grounding electrode. Among them, the needle neck diameter of the tungsten needle electrode is 1.6 mm, the tip cone angle is 95°, the grounding electrode is a copper plate electrode, with a diameter of 48 mm and a thickness of 10 mm;

[0061] The adjustable range of the distance between the needle-plate electrodes is 0 - 30 mm.

[0062] Further preferably, the acceleration sensor mentioned in the present invention is an FP non-gilded acceleration sensor.

[0063] Further preferably, the measuring unit mentioned in the present invention is used to detect the partial discharge of the needle-plate electrode by the pulse current method;

[0064] The measuring unit includes a TWPD-2P digital partial discharge comprehensive analyzer, which is used to collect and analyze partial discharge signals;

[0065] The sampling rate of the TWPD-2P digital partial discharge comprehensive analyzer is 20 MHz, and the bandwidth is 10 kHz - 1 MHz.

[0066] Further preferably, the experimental platform mentioned in the present invention is used to obtain the partial discharge characteristics of the needle-plate electrode in air under vibration conditions through the step-up voltage method. Among them, the step-up voltage method includes the following steps:

[0067] Control the test voltage to slowly increase from 0 kV in steps of 1 kV, with a step-up time interval of 30 s, until the measured partial discharge charge reaches 100 pC. Record the voltage value at this time as the initial discharge voltage and keep the voltage constant, and obtain the two-dimensional scatter plot of the discharge signal within 90 s. Among them, 5 repeated tests are carried out based on each test condition, including:

[0068] Under the condition of no vibration, the first partial discharge test is carried out with the needle-plate electrode spacing being 10 mm, 15 mm, 20 mm, 25 mm, and 30 mm in sequence,

[0069] Based on the electrode spacing of 20 mm and the vibration frequency of 15 Hz, the second partial discharge test is carried out with the amplitudes being 4 mm, 6 mm, 8 mm, 10 mm, and 12 mm in sequence,

[0070] Based on the two cases of electrode spacing of 10 mm and 20 mm, with an amplitude of 3 mm, the third partial discharge test is carried out with the frequencies being 25 Hz, 50 Hz, 75 Hz, 100 Hz, and 125 Hz in sequence;

[0071] According to the two-dimensional scatter plot, obtain the partial discharge characteristics, generate the development characteristics, and analyze the influence law of various vibration factors on the discharge of the needle-plate electrode.

[0072] The present invention provides an experimental platform for studying the partial discharge characteristics of a needle-plate electrode under mechanical vibration in air, as Figure 1 and Figure 2 shown, which includes three parts: a power supply unit, a model unit, and a measuring unit.

[0073] The power supply unit includes a power frequency test transformer with rated parameters of 10 kVA / 110 kV; R is a protection resistor with a resistance value of 10 KΩ; C is a capacitive voltage divider (composed of two capacitors C1 and C2 in series) with a capacitance value of 1000 pF; Ck is a coupling capacitor with a capacitance value of 1028 pF. This unit provides an adjustable test voltage for the model unit.

[0074] The model unit consists of a defect model and a vibration platform. The defect model adopts a needle-plate electrode discharge model. The high-voltage electrode is a tungsten needle electrode with a needle neck diameter of 1.6 mm and a needle tip cone angle of 95°. The grounding electrode is a copper plate electrode with a diameter of 48 mm and a thickness of 10 mm. The adjustable range of the distance between the needle and plate electrodes is 0 - 30 mm. To avoid ablation of the needle tip by the discharge and affect the test results, the tungsten needle electrode is replaced after each test. After the needle and plate electrodes are stably installed on the insulating bracket and placed in the cavity, the plate electrode is rigidly connected to the ejector rod of the vibrator to ensure the synchronization of the electrode and the output of the vibrator. The vibration direction is the vertical direction. To avoid partial discharge in parts other than the electrode device, the edges of all parts are smoothed. The vibration platform consists of a vibrator, a power amplifier, and a signal generator. An FP non-gilded acceleration sensor is connected to the vibrating electrode to detect the actual output amplitude and frequency to ensure that the vibration frequency and amplitude of the electrode are consistent with the outputs of the signal generator and power amplifier of the vibration table.

[0075] The measurement unit uses the pulse current method to detect the partial discharge of the test sample. The partial discharge signal acquisition and analysis equipment is a TWPD-2P digital partial discharge comprehensive analyzer. The sampling rate of the equipment is 20 MHz, and the bandwidth is 10 kHz - 1 MHz.

[0076] Method embodiments:

[0077] The stepped voltage increase method is used to explore the partial discharge characteristics of the needle-plate electrode in air under vibration conditions. Before each test, check the wiring of the test platform. The test voltage starts to rise slowly from 0 kV in steps of 1 kV, and the voltage increase time interval is 30 s. When the measured partial discharge charge reaches 100 pC, it is considered that partial discharge starts. Record the voltage value at this time as the initial discharge voltage and keep the voltage constant. Record the two-dimensional scatter plot of the discharge signal within 90 s. In accordance with the above method, 5 repeated tests are carried out under each test condition.

[0078] This method conducts partial discharge tests on the needle-plate electrodes with distances of 10 mm, 15 mm, 20 mm, 25 mm, and 30 mm under non-vibration conditions.

[0079] This method conducts partial discharge tests on the needle-plate electrodes with an electrode distance of 20 mm, a vibration frequency of 15 Hz, and amplitudes of 4 mm, 6 mm, 8 mm, 10 mm, and 12 mm.

[0080] This method conducts partial discharge tests on the needle-plate electrodes with amplitudes of 3 mm and frequencies of 25 Hz, 50 Hz, 75 Hz, 100 Hz, and 125 Hz under two cases of electrode distances of 10 mm and 20 mm.

[0081] In the description of this specification, the descriptions referring to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc., mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0082] It should be noted that in the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word "comprising" does not exclude the presence of elements or steps not listed in the claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The present invention can be implemented by means of hardware including several different elements and by means of a suitably programmed computer. In the unit claims listing several devices, several of these devices may be embodied by the same item of hardware. The use of the words first, second, and third, etc. does not denote any order. These words may be interpreted as names.

[0083] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically defined.

Claims

1. An experimental platform for detecting the influence of vibration on the partial discharge characteristics of a needle-plate electrode, characterized in that, Including: A power supply unit for providing an adjustable test voltage; A model unit electrically connected to the power supply unit, used for testing the partial discharge characteristics of the needle-plate electrode at different electrode spacings, amplitudes, and vibration frequencies. The model unit consists of a needle-plate electrode discharge model and a vibration platform. The needle-plate electrode discharge model includes a cavity and a needle-plate electrode and an insulating bracket arranged in the cavity. The vibration platform consists of an exciter, a power amplifier, a signal generator, and an acceleration sensor. The needle-plate electrode is rigidly connected to the exciter push rod. The signal generator is electrically connected to the exciter through the power amplifier. The acceleration sensor is used to collect the output amplitude and frequency of the needle-plate electrode; A measurement unit electrically connected to the model unit, used to obtain the partial discharge signal of the needle-plate electrode during the initial discharge process and the development characteristics of partial discharge under different conditions, and generate the influence law of various vibration factors on the discharge of the needle-plate electrode; The power supply unit consists of a power frequency test transformer, a protection resistor, a capacitive voltage divider, and a coupling capacitor; The first end of the power frequency test transformer is electrically connected to the capacitive voltage divider and the coupling capacitor respectively through the protection resistor; The second end of the power frequency test transformer is electrically connected to the capacitive voltage divider and the coupling capacitor; The capacitive voltage divider is composed of a first capacitor and a second capacitor connected in series; The rated parameters of the power frequency test transformer are 10 kVA / 110 kV; The resistance value of the protection resistor is 10 KΩ; The capacitance value after the first capacitor and the second capacitor are connected in series is 1000 pF; The capacitance value of the coupling capacitor is 1028 pF; The needle-plate electrode consists of a tungsten needle electrode and a grounding electrode. Among them, the diameter of the needle neck of the tungsten needle electrode is 1.6 mm, the tip cone angle is 95°, and the grounding electrode is a copper plate electrode with a diameter of 48 mm and a thickness of 10 mm; The adjustable range of the distance between the needle-plate electrodes is 0 - 30 mm; The acceleration sensor is an FP non-gold-plated acceleration sensor; The measurement unit is used to detect the partial discharge of the needle-plate electrode by the pulse current method; The measurement unit includes a TWPD-2P digital partial discharge comprehensive analyzer for collecting and analyzing the partial discharge signal; The sampling rate of the TWPD-2P digital partial discharge comprehensive analyzer is 20 MHz, and the bandwidth is 10 kHz - 1 MHz; The experimental platform is used to obtain the partial discharge characteristics of the needle-plate electrode in air under vibration conditions by the step-up voltage method. The step-up voltage method includes the following steps: Control the test voltage to slowly increase from 0 kV in steps of 1 kV, the step-up time interval is 30 s, until the measured partial discharge charge reaches 100 pC, record the voltage value at this time as the initial discharge voltage and keep the voltage constant, and obtain a two-dimensional φ-q scatter plot of the discharge signal within 90 s. Among them, 5 repeated tests are carried out based on each test condition, including: The first partial discharge test was carried out with the needle-plate electrode spacing being 10 mm, 15 mm, 20 mm, 25 mm, and 30 mm in turn under the condition of no vibration. Based on the electrode spacing of 20 mm and the vibration frequency of 15 Hz, the second partial discharge test was carried out with the amplitudes being 4 mm, 6 mm, 8 mm, 10 mm, and 12 mm in turn. Based on the two cases of the electrode spacing being 10 mm and 20 mm, with the amplitude of 3 mm, the third partial discharge test was carried out with the frequencies being 25 Hz, 50 Hz, 75 Hz, 100 Hz, and 125 Hz in turn. According to the two-dimensional φ-q scatter plot, the partial discharge characteristics were obtained, the development characteristics were generated, and the influence laws of various vibration factors on the discharge of the needle-plate electrode were analyzed.

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