Resistive current monitoring device and method for zinc oxide arrester and fault diagnosis method

Abstract

The invention relates to the field of resistive current monitoring and diagnosis of zinc oxide lightning arresters, and discloses a resistive current monitoring device and method of a zinc oxide lightning arrester and a fault diagnosis method. Comprising a zinc oxide arrester, and a first ultrahigh-frequency partial discharge sensor, a second ultrahigh-frequency partial discharge sensor, an alternating-current voltage source, a first metal shielding shell, a metal guide plate, a magnetic field detector, a plurality of impedance regulators, a second metal shielding shell, a first current sensor, a high-frequency partial discharge sensor and a second current sensor which are arranged on the zinc oxide arrester, the single-chip microcomputer is used for obtaining signals collected by the sensors to calculate resistive current of the zinc oxide lightning arrester and a degradation value of a valve plate of the lightning arrester. By utilizing the device and the method provided by the invention, the resistive current of the zinc oxide arrester can be monitored in real time without introducing a reference signal from a voltage transformer, and meanwhile, the on-site automatic diagnosis and evaluation of the deterioration degree of the valve plate in the arrester are realized by eliminating the current interference on the umbrella skirt edge surface of the arrester.

Description

Technical Field

[0001] The invention relates to the technical field of resistive current monitoring and diagnosis of zinc oxide lightning arresters, and in particular to a resistive current monitoring device, method and fault diagnosis method of zinc oxide lightning arresters. Background Art

[0002] Zinc oxide arresters are currently the most effective means of limiting overvoltage protection and are widely used in substations to protect the insulation of electrical equipment from damage caused by lightning overvoltage. Zinc oxide arresters have excellent nonlinear volt-ampere characteristics. Under normal operating voltage, they are in a high-resistance state, and the current flowing through them is extremely small (microampere level). When encountering lightning overvoltage or operating overvoltage, their resistance instantly decreases to ground, thereby providing a leakage channel to protect power equipment.

[0003] Since the internal valve plate is subjected to the power frequency voltage for a long time, it will gradually deteriorate, causing the resistance characteristics to change and resulting in an increase in resistive current; the arrester has a poor structure, poor sealing, and damp internal components, which will also cause the resistive current to increase; at the same time, the presence of dirt on the surface of the arrester will generate surface current, which will also cause the resistive current to increase. The arrester with severe internal dampness and deterioration may explode under the impact of lightning, posing a safety hazard.

[0004] The current arrester monitoring device cannot monitor the resistive current, which is a characteristic of valve plate degradation and moisture, in real time. It can generally only monitor the full current (the sum of resistive current and capacitive current) indirectly, and the capacitive current usually accounts for more than 90%, which can easily lead to missed internal faults of the arrester. At present, the operation and maintenance personnel of the substation can only measure the resistive current of the zinc oxide arrester by regular live detection, but it is necessary to extract the voltage phase on the arrester through the corresponding voltage transformer secondary terminal to decompose the full current to obtain the resistive current. Chinese patent CN115932648B realizes real-time monitoring of the operating status of the arrester and early warning of faults by connecting the wireless processor module with the PT wireless synchronization module, and the current transformer monitors the grounding current of the arrester. However, the secondary terminal of the voltage transformer PT at the substation site is far away from the arrester, the electromagnetic field in space is complex, and the interference is serious when connected through the wireless synchronization module, and the measurement accuracy is limited. Chinese patent CN105954632B collects the leakage current and voltage parameters of the zinc oxide arrester, performs temperature interference correction and harmonic interference correction on the obtained resistive current, and the terminal processor processes and diagnoses according to the comprehensive data sent by the arrester. This method also requires the acquisition of the secondary terminal signal of the voltage transformer, which is inevitably affected by distance and space electromagnetic fields. At the same time, the influence of the surface current generated by the shed contamination on the arrester leakage current is not considered, and the fault cannot be diagnosed and evaluated on site.

[0005] In summary, the current online monitoring device for zinc oxide lightning arresters can only measure the full current, but cannot monitor the resistive current. The method in which the substation operation and maintenance personnel extract the voltage phase on the lightning arrester through the corresponding voltage transformer secondary terminal to decompose the full current to obtain the resistive current cannot detect the defects of the lightning arrester in time and is prone to lag. At the same time, the corresponding voltage phase signal needs to be extracted through the voltage transformer secondary terminal on site, which is far away, has serious interference, and has low detection accuracy, which seriously affects the efficiency of live detection. At the same time, it is impossible to eliminate the influence of the surface current generated by the umbrella skirt pollution on the lightning arrester leakage current, which is easy to misjudge and miss, causing safety hazards. Summary of the invention

[0006] To this end, the technical problem to be solved by the present invention is to overcome the existing technology of using the secondary terminals of the voltage transformer to extract the voltage phase on the lightning arrester to decompose and obtain the resistive current. Due to severe interference and the need to change the wiring for each measurement, the measurement accuracy is poor and the monitoring efficiency is low.

[0007] In order to solve the above technical problems, the present invention provides a resistive current monitoring device for a zinc oxide lightning arrester, wherein the zinc oxide lightning arrester comprises a lightning arrester core column, a lightning arrester valve plate, a lightning arrester grounding wire, a lightning arrester silicone rubber shed, a metal chassis, an insulating porcelain sheet, and a cement column, and the resistive current monitoring device comprises:

[0008] Partial discharge measurement module, including:

[0009] A first ultra-high frequency partial discharge sensor is disposed at a preset position on the outer surface of the arrester core column to collect ultra-high frequency electromagnetic wave signals of the arrester;

[0010] A second UHF partial discharge sensor is arranged on a side of the first UHF partial discharge sensor away from the arrester core column to collect space UHF electromagnetic wave signals;

[0011] An AC voltage source with its negative terminal grounded;

[0012] The magnetic field detection module is arranged in a grounded first metal shielding shell, the first metal shielding shell is supported by a grounded insulating rod, and is suspended outside the arrester core column and the first arrester silicone rubber shed. The magnetic field detection module includes a plurality of detection branches centered on the arrester core column, parallel to the arrester silicone rubber shed, and circumferentially arranged in the first metal shielding shell; each detection branch includes:

[0013] A metal guide plate is arranged in parallel below the silicone rubber shed of the arrester and is connected to the positive electrode of the AC voltage source;

[0014] A magnetic field detector is arranged in the area between the metal guide plate and the first arrester silicone rubber shed to collect regional magnetic field values;

[0015] A plurality of impedance adjusters are correspondingly arranged under the plurality of metal guide plates, electrically connected to the AC voltage source and the corresponding metal guide plates, and grounded through the guide plate grounding wire;

[0016] The current measurement module is arranged in a grounded second metal shielding shell and comprises:

[0017] A first current sensor, clamped outside the arrester grounding wire, collects the arrester grounding current;

[0018] A high-frequency partial discharge sensor is electrically connected to the arrester ground wire to collect partial discharge pulse current signals;

[0019] A second current sensor is clamped outside the arrester grounding wire and the guide plate grounding wire to collect the sum of the grounding currents;

[0020] The single chip microcomputer is communicatively connected with the partial discharge measurement module, the magnetic field detection module, the impedance regulator and the current measurement module to obtain the grounding current of the arrester and calculate the resistive current of the zinc oxide arrester; the regional magnetic field value, the sum of the grounding current, the ultra-high frequency electromagnetic wave signal of the arrester and the ultra-high frequency electromagnetic wave signal of the space are obtained to judge the fault degree of the zinc oxide arrester.

[0021] Preferably, the single chip microcomputer comprises:

[0022] A resistive current monitoring module is provided to obtain the grounding current of the arrester collected by the first current sensor within a preset time period to generate a first current waveform; perform Fourier decomposition on the first current waveform to obtain a third harmonic current waveform; based on the phase value and amplitude of the first current waveform when the phase of the third harmonic current is zero, obtain the resistive current of the zinc oxide arrester;

[0023] The fault diagnosis module generates a resistive current change curve based on the resistive current of the zinc oxide lightning arrester within a preset time period; if the curve growth rate of the resistive current change curve exceeds the preset growth rate, the AC voltage source is started, the loop impedance of multiple impedance regulators is adjusted, and the regional magnetic field values ​​collected by multiple magnetic field detectors are monitored in real time; when the multiple regional magnetic field values ​​are all lower than the preset magnetic field value, the sum of the grounding currents collected by the second current sensor within the preset time period is obtained to generate a second current waveform; the second current waveform is subjected to Fourier decomposition to obtain the third harmonic current waveform, and the fused resistive current superimposed by the lightning arrester grounding wire and the guide plate grounding wire is calculated; the ratio of the fused resistive current of the zinc oxide lightning arrester to the amplitude of the second current waveform is calculated: if the amplitude ratio is not greater than the preset ratio, it is determined that the arrester silicone rubber There is dirt on the rubber umbrella skirt; if the amplitude ratio is greater than the preset ratio, the AC voltage source is turned off, the maximum value of the partial discharge pulse current signal collected by the high-frequency partial discharge sensor is obtained, and the first state quantity is generated; the difference between the signals collected by the first ultra-high frequency partial discharge sensor and the second ultra-high frequency partial discharge sensor is obtained to produce the second state quantity; the ratio of the fused resistive current of the zinc oxide lightning arrester to the amplitude of the second current waveform is obtained to generate the third state quantity; based on the cumulative absorbed energy of the lightning arrester and the maximum cumulative absorbed energy designed at the factory, a fourth state quantity is generated; based on the operating years of the zinc oxide lightning arrester, a fifth state quantity is generated; based on the first state quantity, the second state quantity, the third state quantity, the fourth state quantity and the fifth state quantity, the degradation value of the lightning arrester valve plate is calculated to obtain the degree of failure of the zinc oxide lightning arrester.

[0024] An embodiment of the present invention provides a resistive current monitoring method for a zinc oxide lightning arrester, which is applied to the resistive current monitoring device for the zinc oxide lightning arrester as described above, and comprises:

[0025] Acquire the arrester grounding current collected by the first current sensor within a preset time period to generate a first current waveform;

[0026] Performing Fourier decomposition on the first current waveform to obtain a third harmonic current waveform;

[0027] The resistive current of the zinc oxide arrester is obtained based on the phase value and the amplitude of the first current waveform when the phase of the third harmonic current is zero.

[0028] Preferably, the resistive current of the zinc oxide arrester is expressed as:

[0029] I2=I m ×cosφ;

[0030] Where, I2 represents the resistive current of the zinc oxide arrester, I m represents the amplitude of the first current waveform, φ represents the phase difference between the arrester grounding current and voltage, and the expression is: α=θ-120°, β=θ-240°, θ represents the phase value of the first current waveform when the phase of the third harmonic current is zero, θ∈(0,360°).

[0031] An embodiment of the present invention provides a fault diagnosis method for a zinc oxide lightning arrester, which is applied to the resistive current monitoring device for the zinc oxide lightning arrester as described above, and comprises:

[0032] Based on the resistive current of the zinc oxide arrester within a preset time period, a resistive current variation curve is generated;

[0033] If the curve growth rate of the resistive current change curve exceeds the preset growth rate, the AC voltage source is started, the loop impedance of the plurality of impedance regulators is adjusted, and the regional magnetic field values ​​collected by the plurality of magnetic field detectors are monitored in real time;

[0034] When the magnetic field values ​​of the multiple regions are all lower than the preset magnetic field value, the sum of the ground currents collected by the second current sensor within the preset time period is obtained to generate a second current waveform;

[0035] Performing Fourier decomposition on the second current waveform to obtain a third harmonic current waveform, and calculating a fused resistive current superimposed on the arrester grounding wire and the guide plate grounding wire;

[0036] Calculate the ratio of the fused resistive current of the zinc oxide arrester to the amplitude of the second current waveform:

[0037] If the amplitude ratio is not greater than the preset ratio, it is determined that there is contamination on the silicone rubber shed of the arrester;

[0038] If the amplitude ratio is greater than the preset ratio, the AC voltage source is turned off, the maximum value of the partial discharge pulse current signal collected by the high-frequency partial discharge sensor is obtained, and a first state quantity is generated; the difference between the signals collected by the first ultra-high frequency partial discharge sensor and the second ultra-high frequency partial discharge sensor is obtained to produce a second state quantity; the ratio of the fused resistive current of the zinc oxide lightning arrester to the amplitude of the second current waveform is obtained to generate a third state quantity; based on the cumulative absorbed energy of the lightning arrester and the maximum cumulative absorbed energy designed at the factory, a fourth state quantity is generated; based on the operating years of the zinc oxide lightning arrester, a fifth state quantity is generated; based on the first state quantity, the second state quantity, the third state quantity, the fourth state quantity and the fifth state quantity, the degradation value of the lightning arrester valve plate is calculated to obtain the degree of failure of the zinc oxide lightning arrester.

[0039] Preferably, the first state quantity and the second state quantity include:

[0040] The first state quantity A is expressed as: , x represents the maximum value of the partial discharge pulse current signal collected by the high-frequency partial discharge sensor;

[0041] The second state quantity B is expressed as: y represents the difference between the signals collected by the first UHF partial discharge sensor and the signals collected by the second UHF partial discharge sensor.

[0042] Preferably, the third state quantity is expressed as:

[0043]

[0044] Wherein, C represents the third state quantity, and z represents the ratio of the fused resistive current of the zinc oxide arrester to the amplitude of the second current waveform.

[0045] Preferably, the fourth state quantity is expressed as:

[0046]

[0047] Among them, D represents the fourth state quantity; r represents the cumulative absorbed energy of the arrester, and the expression is t n Indicates the duration of lightning strike, n = 1, 2...N, N indicates the total number of lightning strikes, i n It represents the first current waveform of the arrester during a lightning strike; u represents the maximum cumulative absorbed energy of the arrester designed at the factory.

[0048] Preferably, the fifth state quantity is expressed as:

[0049]

[0050] Among them, E represents the fifth state quantity, and f represents the operating life of the lightning arrester.

[0051] Preferably, the calculating the degradation value of the arrester valve plate based on the first state quantity, the second state quantity, the third state quantity, the fourth state quantity and the fifth state quantity to obtain the fault degree of the zinc oxide arrester includes:

[0052] The degradation value G of the arrester valve is expressed as: G = C 3 (A 2 +B+D 3 )E 1 / 2 ;

[0053] Based on the degradation value of the arrester valve plate, the fault level of the zinc oxide arrester is obtained, which is expressed as:

[0054]

[0055] Among them, A, B, C, D and E represent the first state quantity, the second state quantity, the third state quantity, the fourth state quantity and the fifth state quantity respectively.

[0056] The above technical solution of the present invention has the following beneficial effects compared with the prior art:

[0057] The resistive current monitoring device and method of the zinc oxide lightning arrester described in the present invention calculates and obtains the resistive current of the zinc oxide lightning arrester by analyzing the lightning arrester grounding current collected by the first current sensor installed in the second metal shielding shell; through the resistive current monitoring device pre-arranged on the zinc oxide lightning arrester, the lightning arrester grounding current collected by the first current sensor can be directly obtained, and the waveform analysis is performed on it to calculate the resistive current, without the need for long-distance reading and the need to reconnect the secondary terminals of the voltage transformer during each measurement, the monitoring is convenient and efficient, and the resistive current obtained is highly accurate.

[0058] The fault diagnosis method of the zinc oxide lightning arrester described in the present invention is based on the partial discharge pulse current signal, the lightning arrester ultra-high frequency electromagnetic wave signal, the space ultra-high frequency electromagnetic wave signal, the fused resistive current, the second current waveform, the lightning arrester cumulative absorbed energy, the factory designed maximum cumulative absorbed energy and the operating life of the zinc oxide lightning arrester. Five state quantities are constructed to calculate the degradation value of the lightning arrester valve plate and obtain the fault degree of the zinc oxide lightning arrester, so as to replace the zinc oxide lightning arrester that needs to be replaced in time according to the fault degree, avoid the explosion of the severely degraded lightning arrester under the action of lightning strike, and ensure the safe and stable operation of the zinc oxide lightning arrester. Therefore, by using the resistive current monitoring device and method provided by the present invention, the resistive current of the zinc oxide lightning arrester can be monitored in real time without introducing a reference signal from the voltage transformer. At the same time, by eliminating the interference of the surface current of the lightning arrester skirt, the on-site automatic diagnosis and evaluation of the degradation degree of the valve plate inside the lightning arrester is realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below according to specific embodiments of the present invention in conjunction with the accompanying drawings, wherein

[0060] Figure 1 It is a structural schematic diagram of a resistive current monitoring device for a zinc oxide lightning arrester provided by the present invention;

[0061] Figure 2 is a top view of the magnetic field detection module provided by the present invention;

[0062] Figure 3 It is the equivalent circuit diagram of zinc oxide arrester;

[0063] Figure 4 It is a curve comparison diagram of the system sinusoidal fundamental voltage and third harmonic current of zinc oxide lightning arrester;

[0064] Figure 5 It is a graph of the relationship between the total current phase and the system sinusoidal fundamental voltage phase;

[0065] Figure 6 It is a flow chart of the steps of the fault diagnosis method of zinc oxide lightning arrester;

[0066] Explanation of the reference numerals in the accompanying drawings in the specification: 1. Lightning arrester grounding wire; 2. Metal chassis; 3. Insulating porcelain tile; 4. Cement column; 5. Lightning arrester valve plate; 6. Lightning arrester silicone rubber umbrella skirt; 7. First current sensor; 8. Second metal shielding shell; 9. First metal shielding shell; 10. High-frequency partial discharge sensor; 11. First UHF partial discharge sensor; 12. Second UHF partial discharge sensor; 13. Single-chip microcomputer; 14. Metal guide plate; 15. Impedance regulator; 16. Magnetic field detector; 17. AC voltage source; 18. Metal guide plate grounding lead; 19. Second current sensor; 20. Ground; 21. Grounding insulating rod; 22. Lightning arrester core column. DETAILED DESCRIPTION

[0067] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0068] Embodiment 1:

[0069] Reference Figure 1 As shown, a schematic diagram of the structure of the resistive current monitoring device of the zinc oxide lightning arrester provided by the present invention; the zinc oxide lightning arrester includes a lightning arrester core column, a lightning arrester valve plate, a lightning arrester grounding wire, a lightning arrester silicone rubber shed, a metal chassis, an insulating porcelain sheet, and a cement column; the resistive current monitoring device of this embodiment includes:

[0070] Partial discharge measurement module, including:

[0071] A first ultra-high frequency partial discharge sensor is disposed at a preset position on the outer surface of the arrester core column to collect ultra-high frequency electromagnetic wave signals of the arrester;

[0072] A second UHF partial discharge sensor is arranged on a side of the first UHF partial discharge sensor away from the arrester core column to collect space UHF electromagnetic wave signals;

[0073] An AC voltage source with its negative terminal grounded;

[0074] The magnetic field detection module is arranged in a grounded first metal shielding shell, the first metal shielding shell is supported by a grounded insulating rod, and is suspended outside the arrester core column and the first arrester silicone rubber shed. The magnetic field detection module includes a plurality of detection branches centered on the arrester core column, parallel to the arrester silicone rubber shed, and circumferentially arranged in the first metal shielding shell; each detection branch includes:

[0075] A metal deflector plate is arranged in parallel below the silicone rubber shed of the arrester and is connected to the positive electrode of the AC voltage source;

[0076] A magnetic field detector is arranged in the area between the metal guide plate and the first arrester silicone rubber shed to collect regional magnetic field values;

[0077] A plurality of impedance adjusters are correspondingly arranged under the plurality of metal guide plates, electrically connected to the AC voltage source and the corresponding metal guide plates, and grounded through the guide plate grounding wire;

[0078] The current measurement module is arranged in a grounded second metal shielding shell and comprises:

[0079] A first current sensor, clamped outside the arrester grounding wire, collects the arrester grounding current;

[0080] A high-frequency partial discharge sensor is electrically connected to the arrester ground wire to collect partial discharge pulse current signals;

[0081] A second current sensor is clamped outside the arrester grounding wire and the guide plate grounding wire to collect the sum of the grounding currents;

[0082] The single chip microcomputer is communicatively connected with the partial discharge measurement module, the magnetic field detection module, the impedance regulator and the current measurement module to obtain the grounding current of the arrester and calculate the resistive current of the zinc oxide arrester; the regional magnetic field value, the sum of the grounding current, the ultra-high frequency electromagnetic wave signal of the arrester and the ultra-high frequency electromagnetic wave signal of the space are obtained to judge the fault degree of the zinc oxide arrester.

[0083] In an embodiment of the present invention, the single chip microcomputer comprises:

[0084] A resistive current monitoring module is provided to obtain the grounding current of the arrester collected by the first current sensor within a preset time period to generate a first current waveform; perform Fourier decomposition on the first current waveform to obtain a third harmonic current waveform; based on the phase value and amplitude of the first current waveform when the phase of the third harmonic current is zero, obtain the resistive current of the zinc oxide arrester;

[0085] The fault diagnosis module generates a resistive current change curve based on the resistive current of the zinc oxide lightning arrester within a preset time period; if the curve growth rate of the resistive current change curve exceeds the preset growth rate, the AC voltage source is started, the loop impedance of multiple impedance regulators is adjusted, and the regional magnetic field values ​​collected by multiple magnetic field detectors are monitored in real time; when the multiple regional magnetic field values ​​are all lower than the preset magnetic field value, the sum of the grounding currents collected by the second current sensor within the preset time period is obtained to generate a second current waveform; the second current waveform is subjected to Fourier decomposition to obtain the third harmonic current waveform, and the fused resistive current superimposed by the lightning arrester grounding wire and the guide plate grounding wire is calculated; the ratio of the fused resistive current of the zinc oxide lightning arrester to the amplitude of the second current waveform is calculated: if the amplitude ratio is not greater than the preset ratio, it is determined that the arrester silicone rubber There is dirt on the rubber umbrella skirt; if the amplitude ratio is greater than the preset ratio, the AC voltage source is turned off, the maximum value of the partial discharge pulse current signal collected by the high-frequency partial discharge sensor is obtained, and the first state quantity is generated; the difference between the signals collected by the first ultra-high frequency partial discharge sensor and the second ultra-high frequency partial discharge sensor is obtained to produce the second state quantity; the ratio of the fused resistive current of the zinc oxide lightning arrester to the amplitude of the second current waveform is obtained to generate the third state quantity; based on the cumulative absorbed energy of the lightning arrester and the maximum cumulative absorbed energy designed at the factory, a fourth state quantity is generated; based on the operating years of the zinc oxide lightning arrester, a fifth state quantity is generated; based on the first state quantity, the second state quantity, the third state quantity, the fourth state quantity and the fifth state quantity, the degradation value of the lightning arrester valve plate is calculated to obtain the degree of failure of the zinc oxide lightning arrester.

[0086] Specifically, refer to Figure 1 The resistive current monitoring device of the zinc oxide lightning arrester of the embodiment of the present invention, the zinc oxide lightning arrester body includes: a lightning arrester valve plate 5, a silicone rubber umbrella skirt 6, a lightning arrester grounding wire 1, a metal chassis 2, an insulating ceramic plate 3 and a cement column 4; the insulating ceramic plate 3 is installed under the metal chassis 2 to play an insulating role, and the metal chassis 2 is connected to the lightning arrester grounding wire 1 to ensure that the leakage current of the lightning arrester valve plate and the surface current of the lightning arrester silicone rubber umbrella skirt are grounded through the lightning arrester grounding wire. The cement column 4 is below the insulating ceramic plate 3 and plays a supporting role. The device added in the embodiment of the present invention includes:

[0087] ① The first UHF partial discharge sensor 11 is closely attached to the outer surface of the arrester core column 22, and the second UHF partial discharge sensor 12 is spatially close to the first UHF partial discharge sensor 11, but is not attached to the outer surface of the arrester core column 22, and is used to measure the spatial UHF electromagnetic wave interference at the position measured by the first UHF partial discharge sensor 11;

[0088] ② The first metal shielding shell 9 is suspended and installed outside the arrester core column and the silicone rubber shed and grounded, and is supported and fixed by the grounding insulating rod 21 to shield the interference of the space magnetic field on the shed surface current measurement;

[0089] The eight metal guide plates 14 are placed in a circular shape with equal angles and with the arrester core column 22 as the center of the circle, parallel to the arrester silicone rubber shed 6;

[0090] The magnetic field detector 16 is placed between the metal guide plate 14 and the arrester silicone rubber shed 6 to detect the magnetic field in the space between the metal guide plate 14 and the arrester silicone rubber shed 6;

[0091] The AC voltage source 17 is electrically connected to the metal guide plate 14 and the metal guide plate grounding lead 18 to adjust the loop current through the impedance regulator;

[0092] The magnetic field detector 16 transmits the magnetic field value to the single chip microcomputer 13 in real time, and the single chip microcomputer controls the impedance regulator 15 to adjust the loop impedance;

[0093] ③ The first current sensor 7 and the high-frequency partial discharge sensor 10 are installed outside the arrester grounding wire 1 to monitor the current waveform and high-frequency partial discharge pulse current signal flowing through the arrester grounding wire in real time;

[0094] The second metal shielding shell 8 is installed outside the first current sensor 7, the second current sensor 19 and the high-frequency partial discharge sensor 10 and is grounded to avoid the influence of the leakage magnetic field in the substation space on the measurement through electromagnetic shielding;

[0095] The second current sensor 19 is installed outside the metal guide plate grounding lead 18 and the arrester grounding wire 1 to monitor the sum of the currents of the metal guide plate grounding lead and the arrester grounding wire;

[0096] The measurement results of the first current sensor 7 and the second current sensor 19 are transmitted to the single chip microcomputer for calculation and analysis.

[0097] ④ The metal chassis 2 is connected to the arrester valve plate 5 and the arrester silicone rubber shed 6 at the same time, and is grounded through the arrester grounding wire 1.

[0098] Reference Figure 2 As shown in FIG. , it is a top view of the magnetic field detection module; Figure 2As shown, eight metal guide plates 14 are arranged in an equiangular ring in space, each metal guide plate 14 is parallel to the surface of the arrester silicone rubber shed 6, and eight magnetic field detectors 16 are placed in parallel between the metal guide plates 14 and the arrester silicone rubber shed 6. When there is dirt on the surface of the arrester's silicone rubber shed, there is a surface current on the surface. Since the first metal shielding shell 9 shields the electromagnetic field in space, and the internal leakage current of the arrester valve plate is basically perpendicular to the magnetic field detector, it cannot affect the magnetic field detector 16. Only the surface current of the arrester's silicone rubber shed 6 and the metal guide plate 14 can affect the magnetic field at the magnetic field detector. Therefore, the impedance regulator is adjusted by the single-chip microcomputer until the detection values ​​of the eight magnetic field detectors 16 are all lower than 0.2A / m. The magnetic field generated in space by the surface current of the arrester's silicone rubber shed 6 and the current of the eight metal guide plates 14 cancel each other out, that is, the surface current of the arrester's silicone rubber shed 6 and the current of the eight metal guide plates 14 are equal in magnitude and opposite in direction. Since the second current sensor 19 is installed outside the metal guide plate grounding lead and the arrester grounding wire to monitor the sum of the currents of the metal guide plate grounding lead and the arrester grounding wire, the surface current of the arrester's silicone rubber shed can be eliminated through detection by the second current sensor 19, and the internal leakage current of the arrester valve plate can be obtained.

[0099] Embodiment 2:

[0100] Based on the above embodiment, in an embodiment of the present invention, a resistive current monitoring method of a zinc oxide lightning arrester includes:

[0101] S101: Acquire the arrester grounding current (ie, the total current) collected by the first current sensor within a preset time period, and generate a first current waveform;

[0102] S102: Perform Fourier decomposition on the first current waveform to obtain a third harmonic current waveform;

[0103] S103: Based on the phase value and amplitude of the first current waveform when the phase of the third harmonic current is zero, the resistive current of the zinc oxide arrester is obtained, which is expressed as:

[0104] I2=I m ×cosφ;

[0105] Where, I2 represents the resistive current of the zinc oxide arrester, I m represents the amplitude of the first current waveform, φ represents the phase difference between the arrester grounding current and voltage, and the expression is: α=θ-120°, β=θ-240°, θ represents the phase value of the first current waveform when the phase of the third harmonic current is zero, θ∈(0,360°).

[0106] Reference Figure 3As shown in the figure, it is the equivalent circuit diagram of zinc oxide arrester. Due to the nonlinearity of valve plate resistance, zinc oxide arrester is in high resistance state at low voltage level, and its resistance drops rapidly to low resistance state at high voltage level. Therefore, it can be equivalent to a circuit of capacitor and nonlinear resistor in parallel, where i R is the resistive current component generated, i C is the capacitive current component, i x is the total current of the lightning arrester. Figure 4 As shown, it is a curve comparison diagram of the system sinusoidal fundamental voltage and third harmonic current of zinc oxide lightning arrester; refer to Figure 5 As shown, it is a relationship diagram between the phase of the total current and the phase of the system sinusoidal fundamental voltage; usually, the system sinusoidal fundamental voltage will generate the third harmonic through the nonlinear resistor valve plate of the lightning arrester, and there is a certain relationship between the phases of the two, that is, when the phase of the third harmonic is 0, the phase of the system sinusoidal fundamental voltage is 0, 120°, and 240°. Since the system sinusoidal fundamental voltage is still a sinusoidal fundamental wave through the capacitor and will not generate the third harmonic, the third harmonic in the total current is generated by the system sinusoidal fundamental voltage passing through the nonlinear resistor valve plate of the lightning arrester. The third harmonic is extracted from the total current waveform through Fourier decomposition. When the third harmonic phase is 0, the total current phase is recorded, and the system sinusoidal fundamental voltage phase may be 0, 120°, and 240°. Usually, the phase difference between the total current phase and the system sinusoidal fundamental voltage is close to 90°, so as to determine the phase of the system sinusoidal fundamental voltage, and obtain the resistive current by decomposing the total current into components with the same phase as the system sinusoidal fundamental voltage.

[0107] The resistive current monitoring device and method for a zinc oxide lightning arrester described in the present invention calculate and obtain the resistive current of the zinc oxide lightning arrester by analyzing the lightning arrester grounding current collected by a first current sensor installed in a second metal shielding shell; through a resistive current monitoring device pre-arranged on the zinc oxide lightning arrester, real-time monitoring of the resistive current of the zinc oxide lightning arrester can be achieved without introducing a reference signal from a voltage transformer, and the lightning arrester grounding current collected by the first current sensor can be directly obtained, and a waveform analysis is performed on it to calculate the resistive current, without the need for long-distance reading or replacement of wiring for each measurement, and the monitoring is convenient and efficient, and the resistive current obtained is highly accurate.

[0108] Embodiment 3:

[0109] Based on the above embodiment, the embodiment of the present invention judges the fault degree of the zinc oxide lightning arrester based on the monitored resistive current, referring to Figure 6 As shown, it is a flow chart of the steps of the fault diagnosis method of zinc oxide lightning arrester, and the specific steps include:

[0110] S201: generating a resistive current variation curve based on the resistive current of the zinc oxide arrester within a preset time period;

[0111] S202: if the curve growth rate of the resistive current change curve exceeds the preset growth rate, starting the AC voltage source, adjusting the loop impedance of the plurality of impedance regulators, and monitoring the regional magnetic field values ​​collected by the plurality of magnetic field detectors in real time;

[0112] S203: When the magnetic field values ​​of the multiple regions are all lower than the preset magnetic field value, obtaining the sum of the ground currents collected by the second current sensor within the preset time period to generate a second current waveform;

[0113] S204: Perform Fourier decomposition on the second current waveform to obtain a third harmonic current waveform, and calculate a fused resistive current superimposed on the arrester grounding wire and the guide plate grounding wire;

[0114] S205: Calculate the ratio of the fused resistive current of the zinc oxide arrester to the amplitude of the second current waveform:

[0115] S205-1: If the amplitude ratio is not greater than the preset ratio, it is determined that the arrester silicone rubber shed

[0116] There is filth;

[0117] S205-2: If the amplitude ratio is greater than the preset ratio, turn off the AC voltage source, obtain the maximum value of the partial discharge pulse current signal collected by the high-frequency partial discharge sensor, and generate a first state quantity; obtain the difference between the signals collected by the first ultra-high frequency partial discharge sensor and the second ultra-high frequency partial discharge sensor, and produce a second state quantity; obtain the ratio of the fused resistive current of the zinc oxide lightning arrester to the amplitude of the second current waveform, and generate a third state quantity; based on the cumulative absorbed energy of the lightning arrester and the maximum cumulative absorbed energy of the factory design, generate a fourth state quantity; based on the operating years of the zinc oxide lightning arrester, generate a fifth state quantity; based on the first state quantity, the second state quantity, the third state quantity, the fourth state quantity and the fifth state quantity, calculate the degradation value of the lightning arrester valve plate and obtain the degree of failure of the zinc oxide lightning arrester.

[0118] Specifically, the five state quantities of the embodiment of the present invention are respectively expressed as:

[0119] The first state quantity A is expressed as: , x represents the maximum value of the partial discharge pulse current signal collected by the high-frequency partial discharge sensor;

[0120] The second state quantity B is expressed as: y represents the difference between the signals collected by the first UHF partial discharge sensor and the signals collected by the second UHF partial discharge sensor.

[0121] The third state quantity C is expressed as: z represents the ratio of the fused resistive current of the zinc oxide arrester to the amplitude of the second current waveform;

[0122] The fourth state quantity D is expressed as: r represents the cumulative energy absorbed by the arrester, which can be expressed as t n Indicates the duration of lightning strike, n = 1, 2...N, N indicates the total number of lightning strikes, i n It represents the first current waveform of the arrester during lightning strike; u represents the maximum cumulative absorption energy of the arrester designed at the factory;

[0123] The fifth state quantity E is expressed as: f represents the operating life of the arrester.

[0124] Specifically, based on the first state quantity, the second state quantity, the third state quantity, the fourth state quantity and the fifth state quantity, the degradation value of the arrester valve plate is calculated to obtain the fault degree of the zinc oxide arrester, including:

[0125] The degradation value G of the arrester valve is expressed as: G = C 3 (A 2 +B+D 3 )E 1 / 2 ;

[0126] Based on the degradation value of the arrester valve plate, the fault level of the zinc oxide arrester is obtained, which is expressed as:

[0127]

[0128] Among them, A, B, C, D and E represent the first state quantity, the second state quantity, the third state quantity, the fourth state quantity and the fifth state quantity respectively.

[0129] If dirt is detected on the silicone rubber shed of the arrester, it can be rinsed with pure water under voltage. If the degradation value G of the arrester valve plate is ≥120, the arrester valve plate is judged to be in a state of severe degradation and complete degradation. At this time, the arrester may explode under the impact of lightning and it is necessary to immediately shut down the power for replacement.

[0130] The resistive current monitoring device of the zinc oxide lightning arrester according to the embodiment of the present invention monitors the resistive current of the zinc oxide lightning arrester in real time; first, the resistive current is calculated in real time by monitoring the full current waveform; when the resistive current growth rate is greater than 10%, the diagnostic process is automatically started; first, the surface current of the rubber shed of the lightning arrester is simulated by an AC voltage source, a metal guide plate and an impedance regulator; when the detection values ​​of 8 magnetic field detectors are all lower than 0.2A / m, the surface current of the silicon rubber shed of the lightning arrester is equal to the current of the metal guide plate in magnitude but opposite in direction; after excluding the surface current, when the ratio of the resistive current to the full current is lower than 20%, it is determined that there is contamination in the silicon rubber shed of the lightning arrester, generating a surface current and causing the resistive current to be abnormal. It often increases; when the ratio of resistive current to total current is higher than 20%, the fault diagnosis method of zinc oxide lightning arrester described in the present invention is based on partial discharge pulse current signal, lightning arrester ultra-high frequency electromagnetic wave signal, space ultra-high frequency electromagnetic wave signal, fused resistive current, second current waveform, lightning arrester cumulative absorbed energy, factory designed maximum cumulative absorbed energy and operating life of zinc oxide lightning arrester. Five state quantities are constructed to calculate the degradation value of the lightning arrester valve plate and obtain the fault degree of the zinc oxide lightning arrester, so as to replace the zinc oxide lightning arrester that needs to be replaced in time according to the fault degree, avoid the explosion of the severely degraded lightning arrester under the action of lightning strike, and ensure the safe and stable operation of the zinc oxide lightning arrester.

[0131] The resistive current monitoring device and method of the zinc oxide lightning arrester described in the present invention calculates and obtains the resistive current of the zinc oxide lightning arrester by analyzing the lightning arrester grounding current collected by the first current sensor installed in the second metal shielding shell; through the resistive current monitoring device pre-installed on the zinc oxide lightning arrester, the lightning arrester grounding current collected by the first current sensor can be directly obtained, and the waveform analysis is performed on it to calculate the resistive current, without the need for long-distance reading and the need to change the wiring for each measurement, the monitoring is convenient and efficient, and the resistive current obtained is highly accurate. The fault diagnosis method for zinc oxide lightning arrester described in the present invention constructs five state quantities based on the partial discharge pulse current signal, the lightning arrester ultra-high frequency electromagnetic wave signal, the space ultra-high frequency electromagnetic wave signal, the fused resistive current, the second current waveform, the cumulative absorbed energy of the lightning arrester, the factory designed maximum cumulative absorbed energy and the operating life of the zinc oxide lightning arrester to calculate the degradation value of the lightning arrester valve plate and obtain the fault degree of the zinc oxide lightning arrester, so as to replace the zinc oxide lightning arrester that needs to be replaced in time according to the fault degree, avoid the explosion of the severely degraded lightning arrester under the action of lightning strike, and ensure the safe and stable operation of the zinc oxide lightning arrester.

[0132] Therefore, by using the resistive current monitoring device and method provided by the present invention, real-time monitoring of the resistive current of the zinc oxide lightning arrester can be achieved without introducing a reference signal from the voltage transformer. At the same time, by eliminating the interference of the surface current of the lightning arrester skirt, on-site automatic diagnosis and evaluation of the degree of deterioration of the valve plate inside the lightning arrester can be achieved.

[0133] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0134] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0135] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0136] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0137] Obviously, the above embodiments are merely examples for the purpose of clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the present invention.

Claims

1. A resistive current monitoring device for a zinc oxide lightning arrester, the zinc oxide lightning arrester comprising a lightning arrester core column, a lightning arrester valve plate, a lightning arrester grounding wire, a lightning arrester silicone rubber shed, a metal chassis, an insulating ceramic sheet, and a cement column, characterized in that: The resistive current monitoring device comprises: Partial discharge measurement module, including: A first ultra-high frequency partial discharge sensor is disposed at a preset position on the outer surface of the arrester core column to collect ultra-high frequency electromagnetic wave signals of the arrester; A second UHF partial discharge sensor is arranged on a side of the first UHF partial discharge sensor away from the arrester core column to collect space UHF electromagnetic wave signals; An AC voltage source with its negative terminal grounded; The magnetic field detection module is arranged in a grounded first metal shielding shell, the first metal shielding shell is supported by a grounded insulating rod, and is suspended outside the arrester core column and the first arrester silicone rubber shed. The magnetic field detection module includes a plurality of detection branches centered on the arrester core column, parallel to the arrester silicone rubber shed, and circumferentially arranged in the first metal shielding shell; each detection branch includes: A metal guide plate is arranged in parallel below the silicone rubber shed of the arrester and is connected to the positive electrode of the AC voltage source; A magnetic field detector is arranged in the area between the metal guide plate and the first arrester silicone rubber shed to collect regional magnetic field values; A plurality of impedance adjusters are correspondingly arranged under the plurality of metal guide plates, electrically connected to the AC voltage source and the corresponding metal guide plates, and grounded through the guide plate grounding wire; The current measurement module is arranged in a grounded second metal shielding shell and comprises: A first current sensor, clamped outside the arrester grounding wire, collects the arrester grounding current; A high-frequency partial discharge sensor is electrically connected to the arrester ground wire to collect partial discharge pulse current signals; A second current sensor is clamped outside the arrester grounding wire and the guide plate grounding wire to collect the sum of the grounding currents; The single chip microcomputer is communicatively connected with the partial discharge measurement module, the magnetic field detection module, the impedance regulator and the current measurement module to obtain the grounding current of the arrester and calculate the resistive current of the zinc oxide arrester; the regional magnetic field value, the sum of the grounding current, the ultra-high frequency electromagnetic wave signal of the arrester and the ultra-high frequency electromagnetic wave signal of the space are obtained to judge the fault degree of the zinc oxide arrester.

2. The resistive current monitoring device of the zinc oxide lightning arrester according to claim 1, characterized in that: The single chip microcomputer comprises: A resistive current monitoring module is provided to obtain the grounding current of the arrester collected by the first current sensor within a preset time period to generate a first current waveform; perform Fourier decomposition on the first current waveform to obtain a third harmonic current waveform; based on the phase value and amplitude of the first current waveform when the phase of the third harmonic current is zero, obtain the resistive current of the zinc oxide arrester; The fault diagnosis module generates a resistive current change curve based on the resistive current of the zinc oxide lightning arrester within a preset time period; if the curve growth rate of the resistive current change curve exceeds the preset growth rate, the AC voltage source is started, the loop impedance of multiple impedance regulators is adjusted, and the regional magnetic field values ​​collected by multiple magnetic field detectors are monitored in real time; when the multiple regional magnetic field values ​​are all lower than the preset magnetic field value, the sum of the grounding currents collected by the second current sensor within the preset time period is obtained to generate a second current waveform; the second current waveform is subjected to Fourier decomposition to obtain the third harmonic current waveform, and the fused resistive current superimposed by the lightning arrester grounding wire and the guide plate grounding wire is calculated; the ratio of the fused resistive current of the zinc oxide lightning arrester to the amplitude of the second current waveform is calculated: if the amplitude ratio is not greater than the preset ratio, it is determined that the arrester silicone rubber There is dirt on the rubber umbrella skirt; if the amplitude ratio is greater than the preset ratio, the AC voltage source is turned off, the maximum value of the partial discharge pulse current signal collected by the high-frequency partial discharge sensor is obtained, and the first state quantity is generated; the difference between the signals collected by the first ultra-high frequency partial discharge sensor and the second ultra-high frequency partial discharge sensor is obtained to produce the second state quantity; the ratio of the fused resistive current of the zinc oxide lightning arrester to the amplitude of the second current waveform is obtained to generate the third state quantity; based on the cumulative absorbed energy of the lightning arrester and the maximum cumulative absorbed energy designed at the factory, a fourth state quantity is generated; based on the operating years of the zinc oxide lightning arrester, a fifth state quantity is generated; based on the first state quantity, the second state quantity, the third state quantity, the fourth state quantity and the fifth state quantity, the degradation value of the lightning arrester valve plate is calculated to obtain the degree of failure of the zinc oxide lightning arrester.

3. A resistive current monitoring method for a zinc oxide lightning arrester, applied to a resistive current monitoring device for a zinc oxide lightning arrester as claimed in any one of claims 1 to 2, characterized in that: include: Acquire the arrester grounding current collected by the first current sensor within a preset time period to generate a first current waveform; Performing Fourier decomposition on the first current waveform to obtain a third harmonic current waveform; The resistive current of the zinc oxide arrester is obtained based on the phase value and the amplitude of the first current waveform when the phase of the third harmonic current is zero.

4. The resistive current monitoring method of a zinc oxide lightning arrester according to claim 3, characterized in that: The resistive current of the zinc oxide arrester is expressed as: I2=I m ×cosφ; Where, I2 represents the resistive current of the zinc oxide arrester, I m represents the amplitude of the first current waveform, φ represents the phase difference between the arrester grounding current and voltage, and the expression is: α=θ-120°, β=θ-240°, θ represents the phase value of the first current waveform when the phase of the third harmonic current is zero, θ∈(0,360°).

5. A fault diagnosis method for a zinc oxide lightning arrester, applied to the resistive current monitoring device for a zinc oxide lightning arrester as claimed in any one of claims 1 to 2, characterized in that: include: Based on the resistive current of the zinc oxide arrester within a preset time period, a resistive current variation curve is generated; If the curve growth rate of the resistive current change curve exceeds the preset growth rate, the AC voltage source is started, the loop impedance of the plurality of impedance regulators is adjusted, and the regional magnetic field values ​​collected by the plurality of magnetic field detectors are monitored in real time; When the magnetic field values ​​of the multiple regions are all lower than the preset magnetic field value, the sum of the ground currents collected by the second current sensor within the preset time period is obtained to generate a second current waveform; Performing Fourier decomposition on the second current waveform to obtain a third harmonic current waveform, and calculating a fused resistive current superimposed on the arrester grounding wire and the guide plate grounding wire; Calculate the ratio of the fused resistive current of the zinc oxide arrester to the amplitude of the second current waveform: If the amplitude ratio is not greater than the preset ratio, it is determined that there is contamination on the silicone rubber shed of the arrester; If the amplitude ratio is greater than the preset ratio, the AC voltage source is turned off, the maximum value of the partial discharge pulse current signal collected by the high-frequency partial discharge sensor is obtained, and the first state quantity is generated; the difference between the signals collected by the first ultra-high frequency partial discharge sensor and the second ultra-high frequency partial discharge sensor is obtained to produce the second state quantity; the ratio of the fused resistive current of the zinc oxide arrester to the amplitude of the second current waveform is obtained to generate the third state quantity; Based on the cumulative absorbed energy of the arrester and the factory designed maximum cumulative absorbed energy, a fourth state quantity is generated; Based on the operating years of the zinc oxide arrester, a fifth state quantity is generated; Based on the first state quantity, the second state quantity, the third state quantity, the fourth state quantity and the fifth state quantity, the degradation value of the arrester valve plate is calculated to obtain the fault degree of the zinc oxide arrester.

6. The fault diagnosis method for zinc oxide lightning arrester according to claim 5, characterized in that: The first state quantity and the second state quantity include: The first state quantity A is expressed as: , x represents the maximum value of the partial discharge pulse current signal collected by the high-frequency partial discharge sensor; The second state quantity B is expressed as: y represents the difference between the signals collected by the first UHF partial discharge sensor and the signals collected by the second UHF partial discharge sensor.

7. The fault diagnosis method for zinc oxide lightning arrester according to claim 5, characterized in that: The third state quantity is expressed as: Wherein, C represents the third state quantity, and z represents the ratio of the fused resistive current of the zinc oxide arrester to the amplitude of the second current waveform.

8. The fault diagnosis method for zinc oxide lightning arrester according to claim 5, characterized in that: The fourth state quantity is expressed as: Among them, D represents the fourth state quantity; r represents the cumulative absorbed energy of the arrester, and the expression is t n Indicates the duration of lightning strike, n = 1, 2...N, N indicates the total number of lightning strikes, i n It represents the first current waveform of the arrester during a lightning strike; u represents the maximum cumulative absorbed energy of the arrester designed at the factory.

9. The fault diagnosis method for zinc oxide lightning arrester according to claim 5, characterized in that: The fifth state quantity is expressed as: Among them, e represents the fifth state quantity, and f represents the operating life of the lightning arrester.

10. The fault diagnosis method of zinc oxide lightning arrester according to claim 5, characterized in that: The method of calculating the degradation value of the arrester valve plate based on the first state quantity, the second state quantity, the third state quantity, the fourth state quantity and the fifth state quantity to obtain the fault degree of the zinc oxide arrester includes: The degradation value G of the arrester valve is expressed as: G = C 3 (A 2 +B+D 3 )E 1 / 2 ; Based on the degradation value of the arrester valve plate, the fault level of the zinc oxide arrester is obtained, which is expressed as: Among them, A, B, C, D and E represent the first state quantity, the second state quantity, the third state quantity, the fourth state quantity and the fifth state quantity respectively.

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