A zinc oxide valve plate analysis device and data processing method in a zinc oxide lightning arrester

Abstract

The present invention discloses a device for analyzing zinc oxide valve plates in zinc oxide lightning arresters and a data processing method. The device includes a device housing and a housing cover mounted on the housing opening of the device housing; a fixed electrode plate is fixed to the bottom of the device housing, and the fixed electrode plate is connected to a plurality of fixed electrode plate pressure rods; a movable electrode plate insulating layer is provided above each fixed electrode plate pressure rod in the device housing, a movable electrode plate is fixed to the bottom of the movable electrode plate insulating layer, and the movable electrode plate is connected to the movable electrode plate pressure rod; and a high-voltage tester is also included, which is electrically connected to the fixed electrode plate and the movable electrode plate. In the method, voltage and current data are obtained by multiple pressure measurements, and then the least squares method is used to obtain fitting parameters. The fitting parameters are compared with the corresponding parameters of normal and abnormal zinc oxide valve plates to achieve judgment.

Description

Technical Field

[0001] The present invention relates to the field of arrester fault analysis devices in power transmission and transformation equipment of power systems, in particular to a zinc oxide valve plate analysis device in a zinc oxide arrester and a data processing method. Background Art

[0002] Lightning arresters release energy from lightning or power system operational overvoltages, protecting electrical equipment from transient overvoltage hazards. Lightning arresters consist of a main body, an insulating base, and leads. Zinc oxide valve discs are typically used as the primary component within the arrester. During actual use, zinc oxide valve discs can occasionally burn out or even explode, impacting the safety of equipment operation. When a single-phase zinc oxide arrester fails, the arrester on that phase is generally already damaged, and the operating status of the remaining phases or other adjacent zinc oxide arresters remains uncertain. On-site analysis of the zinc oxide arresters is necessary to quickly determine potential failure points and predict the service life of arresters from the same batch.

[0003] When a zinc oxide lightning arrester fails in the 10kV and 35kV circuits of a 110kV substation, the zinc oxide lightning arrester and other zinc oxide lightning arresters from the same batch that are still working under the same operating conditions can be disassembled and the zinc oxide valve plates inside the zinc oxide lightning arrester removed for testing. Testing and analysis of the zinc oxide valve plates can be used to determine whether other zinc oxide lightning arresters from the same batch, under the same operating conditions, have potential faults. Summary of the Invention

[0004] The present invention provides a device for analyzing zinc oxide valve plates in zinc oxide lightning arresters and a data processing method, which are applied to perform on-site fault analysis of zinc oxide lightning arresters in 10kV and 35kV circuits in a 110kV substation, thereby determining the possibility of faults in zinc oxide lightning arresters in the same batch and discovering zinc oxide lightning arresters that have already failed. After replacing zinc oxide lightning arresters that have failed or are likely to fail, the operation of the power grid can be made safer and more stable.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] A zinc oxide valve plate analysis device in a zinc oxide lightning arrester comprises a device housing (1) and a housing cover (2) mounted on the top shell opening of the device housing (1); a fixed electrode plate (10) is fixed at the bottom of the device housing (1), and the fixed electrode plate (10) is connected to a plurality of fixed electrode plate pressure rods (9) extending upward; a movable electrode plate insulating layer (5) is also provided above each fixed electrode plate pressure rod (9) in the device housing (1), a movable electrode plate (6) is fixed at the bottom of the movable electrode plate insulating layer (5), and the movable electrode plate (6) is connected to a plurality of movable electrode plate pressure rods (7) extending downward; the zinc oxide valve plate (8) to be tested is placed on the upper end of each fixed electrode plate pressure rod (9), and the housing cover (2) applies force to the movable electrode plate insulating layer (5), thereby causing the lower end of each movable electrode plate pressure rod (7) to press on the zinc oxide valve plate (8) to be tested;

[0007] It also includes a high-voltage tester (13), which is electrically connected to the fixed electrode plate (10) and the movable electrode plate (6) respectively.

[0008] Furthermore, the housing cover (2) is connected to the movable electrode plate insulating layer (5) via a plurality of springs, whereby the housing cover (2) applies force to the movable electrode plate insulating layer (5) via the springs.

[0009] Furthermore, the lower end of the fixed electrode plate pressing rod (9) is threadedly connected to the fixed electrode plate (10), and the upper end of the movable electrode plate pressing rod (7) is threadedly connected to the movable electrode plate (6).

[0010] Furthermore, the upper end of each fixed electrode plate pressure rod (9) is in full contact with the zinc oxide valve plate (8) to be tested, and the lower end of each movable electrode plate pressure rod (7) is in full contact with the zinc oxide valve plate (8) to be tested.

[0011] Furthermore, a conductive paste is provided at the contact point between the upper end of each fixed electrode plate pressure rod (9) and the zinc oxide valve plate (8) to be tested, and a conductive paste is provided at the contact point between the lower end of each movable electrode plate pressure rod (7) and the zinc oxide valve plate (8) to be tested.

[0012] A data processing method for the zinc oxide valve plate analysis device in the zinc oxide lightning arrester comprises the following steps:

[0013] Step 1: The high-voltage tester (13) applies a voltage to the zinc oxide valve plate (8) to be tested between the fixed electrode plate (10) and the movable electrode plate (6). The measurement is started when the applied voltage is lower than 20% of the value obtained by dividing the overall working voltage of the zinc oxide lightning arrester by the number of valve plates. The applied voltage is such that the working current in the circuit formed by the high-voltage tester (13), the fixed electrode plate (10), the fixed electrode plate pressure rod (9), the zinc oxide valve plate to be tested (8), the movable electrode plate pressure rod (7), and the movable electrode plate (6) is within the range of 0.5 mA to 1.5 mA.

[0014] Step 2: The high voltage tester (13) is instructed to collect voltage and current data in the circuit multiple times;

[0015] Step 3: Perform least squares fitting on the voltage and current data collected by the high-voltage tester (13) to obtain the intercept and slope of the fitting, and compare the intercept and slope obtained by fitting with the corresponding data of the normal zinc oxide valve piece and the corresponding data of the abnormal zinc oxide valve piece, thereby evaluating the performance of the zinc oxide valve piece to be tested.

[0016] Furthermore, in step 1, the voltage is applied in a unidirectional and slow manner.

[0017] Furthermore, the number of collection times in step 2 is no less than 8 times.

[0018] Furthermore, in step 3, a correlation coefficient is obtained by least square fitting. When the correlation coefficient is less than 0.90, the corresponding multiple collected voltage and current data are invalid.

[0019] The technical solution adopted by the present invention is to provide a device for analyzing zinc oxide valve plates in zinc oxide lightning arresters and a data processing method. The device is used to measure zinc oxide valve plates removed from disassembled zinc oxide lightning arresters on site to obtain raw measurement data, and the data processing method is used to perform least squares data processing on the raw measurement data.

[0020] The beneficial effect of the present invention is that the causes of failure of zinc oxide lightning arresters of the same type and the same batch are very similar. Therefore, when a single zinc oxide lightning arrester fails, the zinc oxide valve plate analysis device and data processing method in the zinc oxide lightning arrester proposed by the present invention can perform performance analysis on similar zinc oxide lightning arresters of the same type and the same batch, and confirm whether the remaining zinc oxide lightning arresters have common problems, so as to avoid the recurrence of failure of zinc oxide lightning arrester equipment of the same type and the same batch. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Shown is a schematic diagram of a zinc oxide valve plate analysis device in a zinc oxide lightning arrester.

[0022] Figure 2The figure shows a plan view of the contact surface between the movable electrode plate, the fixed electrode plate and the pressure rod in a zinc oxide valve plate analysis device in a zinc oxide lightning arrester; specifically, the lower surface of the movable electrode plate and the upper surface of the fixed electrode plate.

[0023] Figure 3 The figure shows a schematic diagram of the main wiring structure of a zinc oxide valve plate analysis device in a zinc oxide lightning arrester.

[0024] Figure 4 Shown is a diagram of the original measurement data of a zinc oxide valve plate analysis device in a zinc oxide lightning arrester.

[0025] Figure 5 The figure shows the fitting diagram of zinc oxide valve plate data after least squares data processing. DETAILED DESCRIPTION

[0026] The present invention will be further described below with reference to the accompanying drawings and examples.

[0027] like Figure 1 、 Figure 2 、 Figure 3 The figure shows a schematic diagram of a zinc oxide valve plate analysis device in a zinc oxide lightning arrester according to the present embodiment. The device is used to analyze zinc oxide valve plates in zinc oxide lightning arresters. The device includes a high-voltage tester 13, a device housing 1, and a housing cover 2 that is installed on the top shell opening of the device housing 1. A fixed electrode plate 10 is fixed to the bottom of the device housing 1, and a plurality of conductive fixed electrode plate pressure rods 9 extending vertically upward are connected to the top of the fixed electrode plate 10. A movable electrode plate insulating layer 5 is also provided above each fixed electrode plate pressure rod 9 in the device housing 1, and a movable electrode plate 6 is fixed to the bottom of the movable electrode plate insulating layer 5, and a plurality of conductive movable electrode plate pressure rods 7 extending vertically downward are connected to the bottom of the movable electrode plate 6. Several cylindrical grooves are provided on the top of the movable electrode plate insulating layer 5, and a spring 4 is placed in each cylindrical groove. The lower end of the spring 4 contacts the bottom of the cylindrical groove but is not fixed. The upper end of the spring 4 passes through the notch of the cylindrical groove and contacts the bottom of the outer shell cover 2 but is not fixed. In this way, the spring 4 is assembled between the movable electrode plate insulating layer 5 and the outer shell cover 2, and the spring 4 can be removed and replaced.

[0028] A fixed insulating layer 3 is further provided in the device housing 1 and surrounds the fixed electrode plate 10 , the fixed electrode plate pressure rod 9 , the movable electrode plate pressure rod 7 , the movable electrode plate 6 , and the movable electrode plate insulating layer 5 .

[0029] The zinc oxide valve plate 8 to be tested is placed on the upper end of each fixed electrode plate pressure rod 9, and is supported on the bottom surface of the zinc oxide valve plate 8 to be tested by each fixed electrode plate pressure rod 9, and the zinc oxide valve plate 8 to be tested is pressed by the lower end of each movable electrode plate pressure rod 7, and the outer shell cover 2 applies force to the movable electrode plate insulating layer 5 through each spring 4, so that the lower end of each movable electrode plate pressure rod 7 is pressed tightly against the top surface of the zinc oxide valve plate 8 to be tested.

[0030] The housing cover 2 is connected to the movable electrode plate insulating layer 5 via a plurality of springs, whereby the housing cover 2 applies a force to the movable electrode plate insulating layer 5 via the springs.

[0031] A high-voltage anode terminal 11 is installed through the middle of the movable electrode plate's insulating layer 5. Its lower end is connected to the movable electrode plate 6, and its upper end protrudes through the housing cover 2. High-voltage cathode terminals 12 are connected to the sides of the fixed electrode plate 10, extending from the corresponding side of the device housing 1. A high-voltage tester 13 is connected to the protruding ends of the high-voltage anode terminal 11 and the high-voltage cathode terminal 12, respectively, thereby establishing an electrical connection between the high-voltage tester 13 and the fixed electrode plate 10 and the movable electrode plate 6.

[0032] In this embodiment, the zinc oxide valve plate 8 to be tested comes from a disassembled zinc oxide lightning arrester.

[0033] In this embodiment, the bottom surface of the movable electrode plate 6 and the top surface of the fixed electrode plate 10 are as follows: Figure 2 As shown, a number of threaded holes are respectively provided on the bottom surface of the movable electrode plate 6 and the top surface of the fixed electrode plate 10. The upper end of the movable electrode plate pressure rod 7 is fixedly connected to the bottom surface of the movable electrode plate 6 by a threaded connection, and the lower end of the fixed electrode plate pressure rod 9 is fixedly connected to the top surface of the fixed electrode plate 10 by a threaded connection.

[0034] The specific number of movable electrode plate pressure rods 7 and fixed electrode plate pressure rods 9 needs to be determined according to the diameter of the zinc oxide valve disc 8 to be tested. Specifically, take out the zinc oxide valve disc 8 to be tested and measure its diameter. The number of movable electrode plate pressure rods 7 and fixed electrode plate pressure rods 9 is determined based on the diameter. It is required to ensure that the lower ends of all movable electrode plate pressure rods 7 and the upper ends of fixed electrode plate pressure rods 9 are all pressed onto the corresponding surfaces of the zinc oxide valve disc 8 to be tested, that is, the lower ends of each movable electrode plate pressure rod 7 are all in contact with the upper surface of the zinc oxide valve disc 8 to be tested, and the upper ends of each fixed electrode plate pressure rod 9 are all in contact with the lower surface of the zinc oxide valve disc 8 to be tested. If the edge of a movable electrode plate pressure rod 7 or a fixed electrode plate pressure rod 9 exceeds the surface of the zinc oxide valve disc, the exceeding pressure rod must be rotated and removed.

[0035] In this embodiment, the zinc oxide valve disc analysis device in a zinc oxide lightning arrester includes at least three sets of springs 4 to ensure that the movable electrode pressure rod 7 can be fully pressed onto the zinc oxide valve disc 8 to be tested. Different spring types 4 can be selected to correspond to the different thicknesses of the zinc oxide valve disc 8 to be tested. Before the measurement begins, the corresponding spring 4 type must be selected to accommodate the different thicknesses of the zinc oxide valve disc 8 to be tested.

[0036] During measurement in this embodiment, the upper and lower surfaces of the zinc oxide valve disc 8 to be tested are coated with conductive paste and then placed evenly on top of each fixed electrode plate pressure rod 9. The movable electrode plate pressure rod 7 is then pressed against the upper surface of the zinc oxide valve disc 8 to be tested. The selected spring 4 is then placed into the hole in the movable electrode plate insulation layer 5, and the housing cover 2 is placed on the device housing 1 and tightened.

[0037] In this embodiment, the positive and negative electrodes of the high-voltage tester 13 are connected to the high-voltage anode terminal 11 and the high-voltage cathode terminal 12, respectively. The high-voltage tester 13 has the ability to measure, display, and record voltage and current. All personnel and objects that may cause discharge are removed from the vicinity of the zinc oxide valve plate analysis device in the zinc oxide lightning arrester in preparation for pressure measurement. During measurement, the voltage causes the high-voltage tester 13, the high-voltage anode terminal 11, the movable electrode plate 6, the movable electrode plate pressure rod 7, the zinc oxide valve plate to be tested 8, the fixed electrode plate pressure rod 9, the fixed electrode plate 10, and the high-voltage cathode terminal 12 to form a circuit.

[0038] This embodiment also discloses a data processing method based on a zinc oxide valve plate analysis device in a zinc oxide lightning arrester, comprising the following steps:

[0039] Step 1: Use a unidirectional slow voltage application method to allow the high-voltage tester 13 to apply voltage to the zinc oxide valve plate 8 to be tested between the fixed electrode plate 10 and the movable electrode plate 6. Start measurement when the applied voltage is lower than 20% of the value obtained by dividing the overall working voltage of the zinc oxide lightning arrester by the number of valve plates, and the applied voltage makes the working current in the circuit formed by the high-voltage tester 13, the fixed electrode plate 10, the fixed electrode plate pressure rod 9, the zinc oxide valve plate 8 to be tested, the movable electrode plate pressure rod 7, and the movable electrode plate 6 within the range of 0.5mA-1.5mA.

[0040] Step 2: Instruct the high-voltage tester 13 to collect voltage and current data in the circuit multiple times, with the number of collection times being no less than 8 times.

[0041] Step 3: Perform a least squares fit on the voltage and current data collected by the high-voltage tester 13 to obtain the fitted intercept a, slope b, and correlation coefficient r. When the correlation coefficient r is less than 0.90, the corresponding multiple collected voltage and current data are invalid. When the correlation coefficient r is greater than or equal to 0.90, the fitted intercept a and slope b are compared with the corresponding data (i.e., intercept and slope) of the normal zinc oxide valve disc and the corresponding data (i.e., intercept and slope) of the abnormal zinc oxide valve disc, respectively, to evaluate the performance of the zinc oxide valve disc to be tested.

[0042] In this embodiment, the pressure test is performed using a unidirectional, slow voltage application method. The applied voltage maintains the operating current in the circuit within the range of 0.5mA-1.5mA. To reduce measurement errors, the voltage of a single zinc oxide valve disc (8) under test is only applied until the full measurement is complete; repeated application and reduction of voltage is not permitted. Because measurement errors are unavoidable, multi-point measurement is employed.

[0043] Figure 4 This is a graph of the original measurement data of a zinc oxide valve plate analysis device in a zinc oxide lightning arrester. In fact, due to the existence of measurement deviations, the current single set of 1mA data used to evaluate the performance of zinc oxide lightning arresters and zinc oxide valve plates is not objective. It is necessary to quantify a certain amount of data near 1mA to reduce measurement errors, so that the performance evaluation of zinc oxide valve plates will be more objective. For the full-range working voltage of the zinc oxide lightning arrester, the current-voltage relationship is not linear. This is the basis for the working of the zinc oxide lightning arrester, but in a small range, such as when the current is within 0.5mA-1.5mA, the voltage-current relationship is approximately linear, which can be used as a method for processing raw data. Therefore, this embodiment is for Figure 4 The least squares fitting is performed on the original data, and the calculation formula is as follows:

[0044]

[0045] Where: x i To measure the current, y i is the measured voltage, n is the number of data samples (n is not less than 8), r is the correlation coefficient, a is the intercept, and b is the slope.

[0046] Figure 5The figure shows the fitting diagram of the zinc oxide valve disc data after least squares data processing. The data evaluation criteria consist of slope b, intercept a, and correlation coefficient r. The zinc oxide valve disc is evaluated based on these three data. If the conventional requirements for the least squares correlation coefficient are followed, it cannot meet the actual needs of testing the performance of the zinc oxide valve disc. According to actual work experience, the number of sampling data points must not be less than 8, and the correlation coefficient r must not be less than 0.90, otherwise the data set is invalid. The fitting data a and b are used to evaluate the performance of the zinc oxide valve disc to be tested. In fact, at the work site, the zinc oxide valve discs removed from the faulty zinc oxide lightning arrester must contain faulty zinc oxide valve discs, and the zinc oxide valve discs removed from the normal zinc oxide lightning arrester must contain normal zinc oxide valve discs. Therefore, the data after the least squares fitting method can be used to directly compare with the corresponding data of normal zinc oxide valve discs and abnormal zinc oxide valve discs to directly evaluate the performance of the zinc oxide valve discs. The overall performance of the zinc oxide lightning arrester can then be evaluated based on the performance of the zinc oxide valve discs.

[0047] The preferred embodiments of the present invention are described in detail above with reference to the accompanying drawings. The embodiments described in the present invention are merely descriptions of the preferred embodiments of the present invention and do not limit the concept and scope of the present invention. The various specific technical features described in the above specific embodiments can be combined in any suitable manner unless there is any contradiction. Such combinations should also be regarded as the contents disclosed in this disclosure as long as they do not violate the concept of the present invention. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0048] The present invention is not limited to the specific details of the above-mentioned embodiments. Within the scope of the technical concept of the present invention and without departing from the design concept of the present invention, various modifications and improvements made to the technical solution of the present invention by those skilled in the art should fall within the scope of protection of the present invention. The technical contents for which protection is sought in the present invention have been fully recorded in the claims.

Claims

1. A data processing method based on a zinc oxide valve plate analysis device in a zinc oxide lightning arrester, characterized in that: The zinc oxide valve plate analysis device in the zinc oxide lightning arrester comprises a device housing (1) and a housing cover (2) which is mounted on the top shell opening of the device housing (1); a fixed electrode plate (10) is fixed at the bottom of the device housing (1), and the fixed electrode plate (10) is connected to a plurality of fixed electrode plate pressure rods (9) extending upward; a movable electrode plate insulating layer (5) is also provided above each fixed electrode plate pressure rod (9) in the device housing (1), a movable electrode plate (6) is fixed at the bottom of the movable electrode plate insulating layer (5), and the movable electrode plate (6) is connected to a plurality of movable electrode plate pressure rods (7) extending downward; the zinc oxide valve plate (8) to be tested is placed on the upper end of each fixed electrode plate pressure rod (9), and the housing cover (2) applies force to the movable electrode plate insulating layer (5), thereby causing the lower end of each movable electrode plate pressure rod (7) to press on the zinc oxide valve plate (8) to be tested; and a high-voltage tester (13) is also included, and the high-voltage tester (13) is electrically connected to the fixed electrode plate (10) and the movable electrode plate (6) respectively; The data processing method based on the zinc oxide valve plate analysis device in the zinc oxide lightning arrester comprises the following steps: Step 1: The high-voltage tester (13) applies a voltage to the zinc oxide valve plate (8) to be tested between the fixed electrode plate (10) and the movable electrode plate (6), and the measurement is started when the applied voltage is lower than 20% of the value obtained by dividing the overall working voltage of the zinc oxide lightning arrester by the number of valve plates, and the applied voltage makes the working current in the circuit formed by the high-voltage tester (13), the fixed electrode plate (10), the fixed electrode plate pressure rod (9), the zinc oxide valve plate to be tested (8), the movable electrode plate pressure rod (7), and the movable electrode plate (6) within the range of 0.5 mA to 1.5 mA; Step 2: The high-voltage tester (13) collects voltage and current data in the circuit multiple times; Step 3: Perform least squares fitting on the voltage and current data collected by the high-voltage tester (13) to obtain the intercept and slope of the fitting, and compare the intercept and slope obtained by fitting with the corresponding data of the normal zinc oxide valve piece and the corresponding data of the abnormal zinc oxide valve piece, respectively, to evaluate the performance of the zinc oxide valve piece to be tested.

2. The data processing method of the zinc oxide valve plate analysis device in the zinc oxide arrester according to claim 1, characterized in that: The housing cover (2) is connected to the movable electrode plate insulating layer (5) via a plurality of springs, whereby the housing cover (2) applies a force to the movable electrode plate insulating layer (5) via the springs.

3. The data processing method of the zinc oxide valve plate analysis device in the zinc oxide arrester according to claim 1, characterized in that: The lower end of the fixed electrode plate pressing rod (9) is threadedly connected to the fixed electrode plate (10), and the upper end of the movable electrode plate pressing rod (7) is threadedly connected to the movable electrode plate (6).

4. The data processing method of the zinc oxide valve plate analysis device in the zinc oxide lightning arrester according to claim 1, characterized in that: The upper end of each fixed electrode plate pressing rod (9) is in full contact with the zinc oxide valve plate (8) to be tested, and the lower end of each movable electrode plate pressing rod (7) is in full contact with the zinc oxide valve plate (8) to be tested.

5. The data processing method of the zinc oxide valve plate analysis device in the zinc oxide arrester according to claim 1, characterized in that: Conductive paste is provided at the contact point between the upper end of each fixed electrode plate pressure rod (9) and the zinc oxide valve plate (8) to be tested, and conductive paste is provided at the contact point between the lower end of each movable electrode plate pressure rod (7) and the zinc oxide valve plate (8) to be tested.

6. The data processing method of the zinc oxide valve plate analysis device in the zinc oxide lightning arrester according to claim 1, characterized in that: When applying voltage in step 1, a unidirectional slow voltage application method is adopted.

7. The data processing method for the zinc oxide valve plate analysis device in the zinc oxide lightning arrester according to claim 1, characterized in that: The number of collection times in step 2 is no less than 8 times.

8. The data processing method for the zinc oxide valve plate analysis device in the zinc oxide arrester according to claim 1, characterized in that: In step 3, a correlation coefficient is obtained by least square fitting. When the correlation coefficient is less than 0.90, the corresponding multiple collected voltage and current data are invalid.

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