A smart bipolar surge arrester DC high-voltage leakage current tester

Abstract

This invention relates to the field of leakage current testing technology, and discloses an intelligent bipolar surge arrester DC high-voltage leakage current tester, comprising an intelligent control module, a DC high-voltage module, a first current sampling module, a second current sampling module, and a current limiting module. The DC high-voltage module has a first output terminal and a second output terminal. The first output terminal is connected to a first circuit, and the second output terminal is connected to a second circuit. The first current sampling module is installed on the first circuit and is electrically connected to the upper and lower surge arresters connected in parallel. The second circuit is equipped with a control switch, a series current limiting module, and the second current sampling module, which is electrically connected to the lower surge arrester. The control switch is communicatively connected to the intelligent control module. This invention can complete the leakage current test of the upper and lower surge arresters without removing the leads, improving the efficiency of the test and reducing power outage time.

Description

Technical Field

[0001] This invention relates to the field of leakage current testing technology, and in particular to an intelligent bipolar surge arrester DC high-voltage leakage current tester. Background Technology

[0002] The leakage current of a surge arrester is the total current flowing through the arrester during operation at its normal rated voltage. It includes resistive current (the harmful component) and capacitive current (the normal component). The resistive current is generated by the nonlinear resistance characteristics of the varistor plates. This resistive current increases as the nonlinear characteristics of the varistor plates degrade with aging or moisture, making it a key monitoring point. The capacitive current is generated by the equivalent capacitance of the surge arrester and is usually stable, independent of the condition of the varistor plates. The leakage current of a surge arrester reflects its insulation condition and is an important means of determining the quality of a surge arrester under operating voltage.

[0003] U 1mA The voltage is the reference value applied across the surge arrester when the leakage current is 1mA during leakage current testing; it is also called the initial operating voltage. This voltage is used to verify the quality of the metal oxide resistor or surge arrester and serves as the reference value for all subsequent leakage current test results at 0.75 times the DC 1mA voltage during operation.

[0004] 0.75U 1mA Voltage is one of the important parameters for determining the characteristics of a surge arrester. Its magnitude is 0.75 times the initial operating voltage, expressed as 0.75U. 1mA The leakage current at this voltage should not exceed 50 μA.

[0005] On the volt-ampere characteristic curve of a zinc oxide surge arrester, the 1mA reference voltage and the leakage current at 0.75 times that voltage actually reflect the location of the inflection point of the characteristic curve. These are two important parameters for determining the characteristics of the surge arrester, and they can directly reflect whether the surge arrester has deteriorated or become damp. According to current regulations, surge arresters must be periodically tested with a DC 1mA reference voltage (initial operating voltage U). 1mA ) and 0.75U 1mA Test the leakage current to check if the surge arrester's varistor is damp and determine if its operating performance meets the requirements.

[0006] Currently, during field testing, the lead of the upper section surge arrester 60 must be grounded. The testing principle of the two-meter method is as follows: Figure 1 As shown. Figure 1 In the diagram, (a) is a two-meter method for testing the leakage current of a surge arrester, which includes an upper surge arrester 60, a lower surge arrester 70, a surge arrester base 100, and two ammeters. μA(a) shows a DC high-voltage generator 200, and (b) is a schematic diagram of a surge arrester. The surge arrester includes a subway tower support 300, an upper surge arrester 60, a lower surge arrester 70, a connecting flange 400, and an equalizing ring 500. The lower surge arrester 70 is installed at the upper end of the subway tower support 300, and the upper surge arrester 60 is connected to the lower surge arrester 70 via the connecting flange 400. An equalizing ring 500 is installed at the upper end of the upper surge arrester 60. The circuit diagram for the three-meter method for testing the leakage current of a surge arrester is shown below. Figure 2 As shown, compared with the two-meter method for testing the leakage current of a surge arrester, this three-meter method for testing the leakage current of a surge arrester specifically has one more ammeter. μA The extra ammeter μA Connect and ground the upper surge arrester 60. The two-meter and three-meter methods are simple and easy to implement, but they are only suitable when the volt-ampere characteristics of the upper and lower surge arresters are exactly the same; otherwise, the error will be large. In actual operation, the volt-ampere characteristics of the upper and lower surge arresters are unlikely to be exactly the same. Therefore, the high-voltage lead of the upper surge arrester 60 must be removed, its upper end grounded, and the 0.75U of each surge arrester measured separately. 1mA Leakage current is used to determine whether the current is within acceptable limits.

[0007] As the voltage level of surge arresters increases, their length and induced voltage also increase. Furthermore, some surge arresters use tubular wiring, requiring the use of lifting vehicles, cranes, and other equipment to remove the high-voltage leads, resulting in long installation and removal times and a large workload. The lack of a ground wire as a protective measure poses certain safety risks to maintenance personnel. To improve testing efficiency, reduce power outage time, and save manpower and resources, existing technology CN103293409A discloses a DC testing method and platform for surge arresters based on voltage compensation. This solution is commonly used in power maintenance sites. Figure 2 Based on the circuit shown, add a variable polarity DC high-voltage generator. During the experiment, repeatedly adjust the two DC high-voltage generators, read the data displayed on the two microammeters, and calculate the leakage current of the upper and lower surge arresters until the leakage current of both surge arresters reaches 1mA. Then, set the initial operating voltage U... 1mA Reduced to 0.75U 1mA The test showed that each surge arrester had a voltage of 0.75U. 1mA Measure the leakage current to determine whether the upper and lower surge arresters are qualified, and complete the experimental task.

[0008] The existing DC testing methods and platforms for surge arresters based on voltage compensation have the following four drawbacks:

[0009] Disadvantage 1: In the DC test procedure for surge arresters, the leads must be disconnected to complete the DC leakage current test if any of the following three situations occur:

[0010] 1) When the DC high voltage generator outputs a negative 5kV voltage, the leakage current of the lower surge arrester exceeds the leakage current of the upper surge arrester;

[0011] 2) When the DC high voltage generator outputs a negative 5kV voltage, the leakage current of the lower surge arrester does not exceed the leakage current of the upper surge arrester. However, when the negative voltage output of DC high voltage generator 1 is further increased, the leakage current of the lower surge arrester reaches 1mA before the leakage current of the upper surge arrester.

[0012] 3) When the DC high voltage generator outputs a positive 5kV voltage, the leakage current of the lower surge arrester is less than 1mA.

[0013] Disadvantage 2: The debugging process is time-consuming and complex. When conducting leakage current tests on-site, the DC test method and test platform for surge arresters based on voltage compensation require manually adjusting the output voltage of two DC high-voltage generators, reading the microammeter data, and calculating the leakage current values ​​of the upper and lower surge arresters. The debugging process can only be completed when the leakage current values ​​of the upper and lower surge arresters are both 1mA.

[0014] Disadvantage 3: This approach significantly increases the cost of testing equipment, wasting resources. When testing the DC high-voltage leakage current of two series-connected surge arresters on a pole using a voltage-compensated DC testing method and platform, two DC high-voltage generators need to operate simultaneously. One of these generators is a specially designed generator with adjustable output polarity; meeting these testing conditions will further increase the cost of this specially designed generator.

[0015] Disadvantage 4: Variable polarity voltage multiplier rectifier circuits are difficult to translate into actual products. While the principle of the variable polarity voltage multiplier rectifier circuit based on the DC test method and test platform for voltage-compensated surge arresters is feasible, its application in actual production presents certain difficulties. Currently, the high-voltage units used in the field are unipolar voltage multiplier rectifier circuits (also known as voltage multiplier barrels). For user safety, manufacturers use insulating materials to completely solidify this circuit within a barrel. In this variable polarity voltage multiplier rectifier circuit, the polarity switching switch must be capable of interrupting high voltages of tens to hundreds of kilovolts, resulting in a large size and weight. If the operating handles of these switches are encapsulated on the surface of the high-voltage barrel, users will face the risk of electric shock during operation. Even if these switches are encapsulated separately, this risk still exists. Summary of the Invention

[0016] The purpose of this invention is to provide an intelligent DC high-voltage leakage current tester for bipolar surge arresters, which can automatically or semi-automatically complete functions such as voltage regulation, data processing, test result display, and printing output. Using this invention can improve work efficiency, save material and financial resources for surge arrester testing, and reduce on-site operational risks and labor intensity. It truly achieves leakage current testing without removing the high-voltage leads. Specifically, the objectives of this invention include:

[0017] (1) In response to the above-mentioned disadvantages 1) and 2), this invention proposes a current limiting method to complete the leakage current test of the upper section surge arrester without removing the lead wire.

[0018] (2) In response to the above-mentioned disadvantage 1 mentioned in point 3), the present invention proposes the injection current method to complete the leakage current test of the next section of the surge arrester without removing the lead wire.

[0019] (3) In view of the above-mentioned disadvantage 2, the intelligent bipolar surge arrester DC high voltage leakage current tester designed in this invention can automatically or semi-automatically complete the test function, realizing the design goal of simple operation and high work efficiency.

[0020] (4) In view of the above-mentioned disadvantage 3, the present invention proposes a DC high voltage leakage current tester with positive and negative outputs, which replaces the two independent DC high voltage generators in the "DC test method and test platform for surge arresters based on voltage compensation", which greatly reduces the cost of test equipment.

[0021] (5) To address the problems mentioned in Disadvantage 4 above, this invention primarily uses negative polarity output and secondarily uses positive polarity output. Positive polarity output is only activated when using the current injection method, and the positive polarity output does not require polarity change. This avoids the risk of induced overvoltage when switching DC high voltage polarity switches.

[0022] To achieve the above objectives, the following technical solution is adopted:

[0023] An intelligent bipolar surge arrester DC high-voltage leakage current tester includes an intelligent control module, a DC high-voltage module, a first current sampling module, a second current sampling module, and a current limiting module; wherein:

[0024] Both the first current sampling module and the second current sampling module are communicatively connected to the intelligent control module, and the intelligent control module is communicatively connected to the DC high voltage module.

[0025] The DC high voltage module has a first output terminal and a second output terminal. The first output terminal is connected to a first circuit, and the second output terminal is connected to a second circuit. A first current sampling module is provided on the first circuit. The first current sampling module is electrically connected to the upper and lower surge arresters connected in parallel. A control switch, a series current limiting module, and a second current sampling module are provided on the second circuit. The second current sampling module is electrically connected to the lower surge arrester. The control switch is communicatively connected to the intelligent control module.

[0026] The current limiting module includes multiple current limiting resistors and multiple current limiting switches. The multiple current limiting resistors are connected in series, and each current limiting resistor is connected in parallel with a current limiting switch. All multiple current limiting switches are communicatively connected to the intelligent control module.

[0027] Furthermore, the control switch includes a first switch node, a second switch node, a third switch node, and a switch assembly; wherein, the first switch node is connected to the current limiting module, the second switch node is connected to the ground terminal, the third switch node is connected to the second output terminal, and the switch assembly is rotatably disposed on the first switch node. During the rotation of the switch assembly around the first switch node, the first switch node can be connected to the second switch node or the first switch node can be connected to the third switch node.

[0028] Furthermore, it also includes a display controller, which is communicatively connected to the intelligent control module.

[0029] Furthermore, it also includes a test data printing component, which is communicatively connected to the intelligent control module.

[0030] Furthermore, the intelligent control module is configured as follows:

[0031] The control switch is turned off, the voltage output from the first output terminal is gradually increased, and the first current value collected by the first current sampling module and the second current value collected by the second current sampling module are acquired in real time.

[0032] When the second current value reaches the first current threshold before the difference between the first and second current values ​​reaches the first current threshold, the first workflow is executed.

[0033] When the difference between the first current value and the second current value reaches the first current threshold before the second current value, the second workflow is executed.

[0034] Furthermore, the first workflow includes:

[0035] Control the first output terminal to stop boosting voltage, and obtain the first voltage value output by the first output terminal at the current moment;

[0036] The voltage output from the first output terminal is controlled to gradually decrease until it reaches the set first voltage threshold. The current value collected by the second current sampling module at this time is obtained and saved as the leakage current value of the next arrester. Wherein, the first voltage threshold is n times the first voltage value, and n is a real number from 0 to 1.

[0037] The voltage output from the first output terminal is controlled to gradually increase from a set first voltage threshold. When the difference between the first current value and the second current value reaches the first current threshold, the first output terminal is controlled to stop increasing the voltage, and the second voltage value output by the first output terminal at the current moment is obtained.

[0038] The voltage output from the first output terminal is controlled to gradually decrease until it reaches the set second voltage threshold. The difference between the current value collected by the first current sampling module and the current value collected by the second current sampling module is obtained and saved as the leakage current value of the surge arrester in the previous section. The second voltage threshold is n times the second voltage value.

[0039] Furthermore, the intelligent control module is further configured as follows:

[0040] During the process of gradually increasing the voltage output from the first output terminal, the number of current-limiting resistors connected in the current-limiting module is controlled so that the first current value is always less than the set second current threshold.

[0041] Furthermore, the intelligent control module is further configured to control the number of current-limiting resistors connected in the current-limiting module in the following manner, so that the first current value is always less than the set second current threshold:

[0042] When the first current value is greater than or equal to the set second current threshold, the control switch is turned on, and the number of connected current-limiting resistors is adjusted by adjusting the on / off state of the current-limiting switch until the second current value is less than the set third current threshold.

[0043] Furthermore, the second workflow includes:

[0044] Control the first output terminal to stop boosting voltage, and obtain the third voltage value output by the first output terminal at the current moment;

[0045] The voltage output from the first output terminal is controlled to gradually decrease until it reaches the set third voltage threshold. The difference between the current value collected by the first current sampling module and the current value collected by the second current sampling module is obtained at this time and saved as the leakage current value of the surge arrester in the previous section. The third voltage threshold is n times the third voltage value, where n is a real number from 0 to 1.

[0046] The voltage output from the first output terminal is controlled to rise back to the third voltage value and remain unchanged. The voltage output from the second output terminal is controlled to gradually rise until the second current value reaches the first current threshold and the voltage rise stops. The fourth voltage value output from the second output terminal at this time is obtained. At the same time, the first output terminal is controlled to decrease to the third voltage threshold and the second output terminal is controlled to decrease to the fourth voltage threshold. The second current value at this time is obtained and saved as the leakage current value of the surge arrester in the next section. The fourth voltage threshold is n times the fourth voltage.

[0047] Furthermore, the tester includes two testing modes during testing: automatic mode and semi-automatic mode.

[0048] In automatic mode, the tester completes all tests according to the preset procedure, automatically saves the test results and supports printing output;

[0049] In semi-automatic mode, when the second current value reaches the first current threshold, the difference between the first current value and the second current value reaches the first current threshold, or the leakage current value test of the upper section surge arrester or the leakage current value test of the lower section surge arrester is completed, the display controller issues an audible prompt and pauses the process, and resumes the process after receiving an instruction to continue the operation; wherein, the first current value and the second current value are the current values ​​collected by the first current sampling module and the second current sampling module, respectively.

[0050] The beneficial effects of this invention are reflected in:

[0051] This invention provides an intelligent bipolar surge arrester DC high-voltage leakage current tester with two output ports, positive and negative, whose output voltages are adjustable to meet the leakage current testing needs of single-section and series-connected double-section surge arresters. Its advantages are particularly prominent for testing 220kV pole-mounted series surge arresters. The specific advantages of this invention are as follows:

[0052] (1) The leakage current test of the upper and lower sections of the surge arrester was completed without removing the lead wires, which improved the efficiency of the test work, reduced the power outage time, saved manpower and material resources, and provided safety guarantee for on-site operators.

[0053] (2) This test instrument is not a simple combination of two DC high-voltage generators, but rather utilizes EDA technology to design and optimize modules such as the control module, DC high-voltage module, and wireless communication module. The circuit structure is simple and the performance is stable. Compared with existing solutions, the test equipment of this invention has a low cost, is easy to use, and has good prospects for widespread application.

[0054] (3) The present invention has two working modes: automatic and semi-automatic. It is user-friendly and easy to operate.

[0055] In summary, the intelligent bipolar surge arrester DC high-voltage leakage current tester developed in this invention provides a novel testing device and experimental scheme for leakage current testing of 220kV and above surge arresters. A particularly significant advantage is that it eliminates the need to remove the high-voltage leads of the upper surge arrester. This saves time on lead disconnection and reconnection, reduces the level of operational risk and the danger of electric shock, providing strong protection for safe production and favorable conditions for successfully completing tests on 220kV and above zinc oxide surge arresters. Attached Figure Description

[0056] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0057] Figure 1 The diagram shows the principle of leakage current testing for surge arresters using the two-meter method in the prior art; where (a) is the leakage current testing circuit for surge arresters using the two-meter method, and (b) is a schematic diagram of the surge arrester.

[0058] Figure 2 This is a schematic diagram of the leakage current test principle of the three-meter method for surge arresters in the existing technology.

[0059] Figure 3 This is a schematic diagram of the structure of an intelligent bipolar surge arrester DC high-voltage leakage current tester provided in an embodiment of the present invention;

[0060] Figure 4 A test flowchart of an intelligent bipolar surge arrester DC high-voltage leakage current tester provided for an embodiment of the present invention;

[0061] Figure 5 This is a schematic diagram of the first workflow executed by the intelligent control module according to an embodiment of the present invention;

[0062] Figure 6 This is a schematic diagram of the second workflow executed by the intelligent control module according to an embodiment of the present invention;

[0063] Figure 7 The flowchart illustrates the operation of an intelligent bipolar surge arrester DC high-voltage leakage current tester provided in this embodiment of the invention.

[0064] Explanation of reference numerals in the attached figures:

[0065] 10. Intelligent control module; 20. DC high voltage module; 30. First current sampling module; 40. Second current sampling module; 50. Current limiting module; 501. Current limiting switch; 60. Upper surge arrester; 70. Lower surge arrester; 80. Control switch; 801. First switch node; 802. Second switch node; 803. Third switch node; 804. Switch assembly; 90. Display controller; 110. Test data printing assembly; R. Current limiting resistor; 100. Surge arrester base; 200. DC high voltage generator; 300. Connection to subway tower bracket; 400. Connection flange; 500. Equalizing ring; μA 1. Ammeter. Detailed Implementation

[0066] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, unless otherwise specified, the following embodiments and features described therein can be combined with each other.

[0067] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples.

[0068] For metal oxide surge arresters, the DC reference voltage corresponding to the DC reference current, whether tested as a whole or in sections, should not be lower than the value specified in the existing document "AC Gapless Metal Oxide Surge Arresters" GB 11032, and should comply with the product technical specifications. The allowable deviation between the measured value and the manufacturer's measured value should be ±5%. Currently, DC high-voltage generators are commonly used to test the leakage current of two surge arresters connected in series. However, commercially available DC high-voltage generators only have one voltage output port. When testing the leakage current of two surge arresters connected in series in the field, it is often necessary to disconnect the high-voltage lead of the upper surge arrester to complete the test. To address the characteristics of on-site installation and testing requirements of two-section surge arresters, this invention provides an intelligent bipolar surge arrester DC high-voltage leakage current tester that automatically or semi-automatically completes the DC high-voltage leakage current test of two-section surge arresters without altering the on-site installation structure.

[0069] like Figure 3As shown, the intelligent bipolar surge arrester DC high-voltage leakage current tester includes an intelligent control module 10, a DC high-voltage module 20, a first current sampling module 30, a second current sampling module 40, and a current limiting module 50. The first current sampling module 30 and the second current sampling module 40 are both communicatively connected to the intelligent control module 10, and the intelligent control module 10 is communicatively connected to the DC high-voltage module 20. The DC high-voltage module 20 has a first output terminal E1 and a second output terminal E2. The first output terminal E1 is connected to a first circuit, and the second output terminal E2 is connected to a second circuit. A first current sampling module is installed on the first circuit. The sampling module 30 is electrically connected to the upper surge arrester 60 and the lower surge arrester 70 connected in parallel. The second circuit is equipped with a control switch 80, a current limiting module 50 and a second current sampling module 40 connected in series. The second current sampling module 40 is electrically connected to the lower surge arrester 70. The control switch 80 is communicatively connected to the intelligent control module 10. The current limiting module 50 includes multiple current limiting resistors R and multiple current limiting switches 501. The multiple current limiting resistors are connected in series, and each current limiting resistor R is connected in parallel with a current limiting switch 501. The multiple current limiting switches 501 are all communicatively connected to the intelligent control module 10.

[0070] It should be noted that the first output terminal E1 and the second output terminal E2 can be used individually or in series. Figure 1 The first output terminal E1 and the second output terminal E2 shown are in the state when they are used in series.

[0071] In some embodiments, the control switch 80 includes a first switch node 801, a second switch node 802, a third switch node 803, and a switch assembly 804; wherein, the first switch node 801 is connected to the current limiting module 50, the second switch node 802 is connected to the ground terminal, the third switch node 803 is connected to the second output terminal E2, and the switch assembly 804 is rotatably disposed on the first switch node 801. During the rotation of the switch assembly 804 around the first switch node 801, the first switch node 801 and the second switch node 802 or the first switch node 801 and the third switch node 803 can be connected.

[0072] The core function of the control switch 80 is to change the circuit path of the first switch node 801 connected to the current limiting module 50 by physically rotating the switch assembly 804, thereby switching between grounding mode and injection current mode in the circuit of the next section surge arrester 70.

[0073] Grounding Mode (First Switch Node 801 and Second Switch Node 802 Connected): When the switch assembly 804 rotates to connect the first switch node 801 and the second switch node 802, the test circuit of the lower surge arrester 70 is directly guided to the grounding terminal after passing through the current limiting module 50. This mode is the default or initial state of the tester and is suitable for the current limiting method and the initial stage of the test process. In this mode, the leakage current of the lower surge arrester 70 is entirely provided by the first output terminal E1 and measured by the second current sampling module 40. When a current limiting resistor needs to be applied, the intelligent control module 10 achieves this by controlling the current limiting switch 501 in the current limiting module 50, while the control switch 80 always remains in this grounding mode to ensure circuit continuity.

[0074] Current injection mode (first switch node 801 and third switch node 803 connected): When the switch assembly 804 rotates to connect the first switch node 801 and the third switch node 803, the test circuit of the lower surge arrester 70 is no longer directly grounded, but instead connected to the second output terminal E2 (positive polarity) of the DC high voltage module 20. This mode is designed for the current injection method. When the test process enters the current injection method stage, the intelligent control module 10 issues a command to drive the switch assembly 804 to switch from the grounding mode to the current injection mode. This switch causes the auxiliary power supply E2 to be connected in series in the lower surge arrester circuit. The current output by E2 and the current provided by E1 work together to act on the lower surge arrester 70, so that even if the voltage of E1 remains unchanged, the total current flowing through the lower surge arrester 70 (monitored by the second current sampling module 40) can reach the test condition of 1mA by adjusting the voltage of E2.

[0075] In some embodiments, the intelligent bipolar surge arrester DC high voltage leakage current tester further includes a display controller 90, which is communicatively connected to the intelligent control module 10.

[0076] The display controller 90 receives real-time test data from the intelligent control module 10. This includes, but is not limited to: the output voltage of the DC high-voltage module 20, the current value collected by the first current sampling module 30 and the second current sampling module 40, the current test mode (automatic / semi-automatic), and the current step of the test process. After the test is completed, the final test result is clearly displayed on the screen of the display controller 90. The display controller 90 typically integrates an input unit, such as a touch screen or physical buttons. The operator issues commands to the tester through it. When the user selects automatic or semi-automatic mode through the display controller 90, or clicks "Start Test," these commands are immediately sent to the intelligent control module 10 via the communication link. The intelligent control module 10 then starts or adjusts the corresponding test process according to the received commands.

[0077] In semi-automatic mode, the intelligent control module 10 pauses the process at critical points (such as when the current of the next surge arrester reaches 1mA, or when a voltage reduction to 0.75 times is required for reading) and sends a prompt message to the display controller 90. The display controller 90 then alerts the operator with sound and light, and displays guiding information such as "The next surge arrester has met the test conditions; please confirm the 0.75 times voltage reduction test." After the operator confirms, they can issue a confirmation or continue command through the display controller 90. Only after receiving this command will the intelligent control module 10 execute the next step of the process, thus achieving precise human-machine collaborative control.

[0078] In some embodiments, the intelligent bipolar surge arrester DC high voltage leakage current tester further includes a test data printing component 110, which is communicatively connected to the intelligent control module 10.

[0079] In some embodiments, such as Figure 4 As shown, the intelligent control module 10 is configured to execute the following test process, including steps S401-S403.

[0080] S401: Set the control switch 80 to the closed state, control the voltage output of the first output terminal E1 to gradually increase, and acquire the first current value A1 collected by the first current sampling module 30 and the second current value A2 collected by the second current sampling module 40 in real time.

[0081] S402: When the second current value A2 reaches the first current threshold before the difference between the first current value A1 and the second current value A2, the first working process is executed.

[0082] In this embodiment, the first current threshold is set to 1mA. The first working process in this embodiment is defined as the current limiting method, which refers to the current limiting method used when testing the upper surge arrester 60 to prevent the starting operating voltage U of the lower surge arrester 70 from being too low. 1mA Excessive current will cause the leakage current of the lower surge arrester 70 to fall into the saturation region of its volt-ampere characteristic, resulting in a leakage current far exceeding 1mA and causing overload damage to the test equipment. To test the leakage current of the lower surge arrester 70, a resistor of appropriate value is connected in series in this circuit to control the current in this circuit to not exceed 1mA, thus completing the test of the upper surge arrester 60. This method is called the current limiting method.

[0083] In some embodiments, such as Figure 5 As shown, the first workflow includes the following steps S501-S505:

[0084] S501: Controls the first output terminal E1 to stop boosting and obtains the first voltage value output by the first output terminal E1 at the current moment.

[0085] In this embodiment, as the voltage at the first output terminal E1 increases, the second current value A2 reaches the first current threshold before the difference between the first current value A1 and the second current value A2. This is the basis for executing step S501, i.e., a prerequisite for the intelligent control module 10 to execute the first working process. Based on this, it is assumed that the next section surge arrester 70 first meets the test conditions. At this time, the output voltage at the first output terminal E1 stops increasing, and the first voltage value is U. E1（A2=1mA） .

[0086] S502: Control the voltage output of the first output terminal E1 to gradually decrease until it reaches the set first voltage threshold, obtain the current value collected by the second current sampling module 40 at this time, and save it as the leakage current value of the next section surge arrester 70; wherein, the first voltage threshold is n times the first voltage value, and n is a real number from 0 to 1.

[0087] For example, in this embodiment, n=0.75. The first output terminal E1 starts to step down, and when the output voltage U of the first output terminal E1... E1 The voltage drops to the first threshold voltage of 0.75U. E1（A2=1mA） Save 0.75U at that time. E1（A2=1mA） Under the condition, the current value A2 collected by the second current sampling module 40 is the leakage current value of the next section surge arrester 70.

[0088] S503: Control the voltage output of the first output terminal E1 to gradually increase from the set first voltage threshold. When the difference between the first current value A1 and the second current value A2 reaches the first current threshold, control the first output terminal E1 to stop increasing the voltage and obtain the second voltage value output by the first output terminal E1 at the current moment.

[0089] After completing the leakage current test of the next-stage surge arrester 70 in step S502, the first output terminal E1 switches from buck to boost mode. When the difference between the first current value A1 and the second current value A2 reaches the first current threshold of 1mA, the leakage current test conditions of the previous-stage surge arrester 60 are met, and the second voltage value U is recorded. E1（A1-A2=1mA） .

[0090] S504: Control the voltage output of the first output terminal E1 to gradually decrease until it reaches the set second voltage threshold, obtain the difference between the current value collected by the first current sampling module 30 and the current value collected by the second current sampling module 40 at this time, and save it as the leakage current value of the surge arrester 60 in the previous section; wherein, the second voltage threshold is n times the second voltage value.

[0091] In this embodiment, similar to step S502, after determining the second voltage value U... E1（A1-A2=1mA） Then, the voltage output from the first output terminal E1 gradually decreases until the output voltage U of the first output terminal E1 is reduced. E1 The voltage drops to the second threshold of 0.75U. E1（A1-A2=1mA）When the difference between A1 and A2 is obtained, this difference is the leakage current value of the surge arrester 60 in the previous section.

[0092] Based on the above steps S501-S504, the current-limiting resistor method was used to test the leakage current of the upper and lower surge arresters.

[0093] S403: When the difference between the first current value A1 and the second current value A2 reaches the first current threshold before the second current value A2, the second working process is executed.

[0094] The second working process is defined in this embodiment as the current injection method. The current injection method refers to ensuring that the leakage current of the upper surge arrester 60 does not exceed 1mA while simultaneously achieving the 1mA leakage current test condition for the lower surge arrester 70. Another voltage source is connected in series in the test circuit of the lower surge arrester to provide the required current to the circuit, making the circuit current reach 1mA. This method is called the current injection method.

[0095] In some embodiments, such as Figure 6 As shown, the second workflow includes the following steps S601-S603:

[0096] S601: Controls the first output terminal E1 to stop boosting and obtains the third voltage value output by the first output terminal E1 at the current moment.

[0097] As the voltage at the first output terminal E1 increases, when the difference between the first current value A1 and the second current value A2 reaches 1mA before the second current value A2, meaning the leakage current of the upper surge arrester 60 reaches the test condition first, the second working process is executed. In step S601, the voltage boost at the first output terminal E1 is stopped, and the third voltage value U of the output of the first output terminal E1 is obtained. E1（A1-A2=1mA） .

[0098] S602: Control the voltage output of the first output terminal E1 to gradually decrease until it reaches the set third voltage threshold. Obtain the difference between the current value collected by the first current sampling module 30 and the current value collected by the second current sampling module 40 at this time, and save it as the leakage current value of the surge arrester 60 in the previous section. Wherein, the third voltage threshold is n times the third voltage value, and n is a real number from 0 to 1.

[0099] Based on the third voltage value U determined in step S601 E1（A1-A2=1mA） The voltage output from the first output terminal E1 is gradually reduced until it reaches the third voltage threshold of 0.75U. E1（A1-A2=1mA） Save the output voltage at the first output terminal E1 as the third voltage threshold of 0.75U. E1A1-A2=1mA） The difference between the first current value A1 and the second current value A2 is the leakage current value of the upper surge arrester 60.

[0100] S603: Control the voltage output of the first output terminal E1 to rise back to the third voltage value and remain unchanged, control the voltage output of the second output terminal E2 to gradually rise until the second current value reaches the first current threshold and stop the voltage rise, obtain the fourth voltage value output by the second output terminal E2 at this time, and simultaneously control the first output terminal E1 to decrease to the third voltage threshold and the second output terminal E2 to decrease to the fourth voltage threshold, obtain the second current value at this time, and save it as the leakage current value of the next section surge arrester 70; wherein, the fourth voltage threshold is n times the fourth voltage.

[0101] In step S603, the output voltage at the first output terminal E1 rises back to the third voltage value U. E1（A1-A2=1mA） The purpose of this operation is to ensure that the leakage current of the upper surge arrester 60 does not exceed 1mA, while also allowing the lower surge arrester 70 to obtain the maximum E1 output voltage.

[0102] Under the condition that the output voltage of the first output terminal E1 cannot be increased, in order to make the second current value A2 reach 1mA (i.e., the leakage current of the lower surge arrester 70 reaches 1mA), the intelligent control module 10 connects the second output terminal E2 to the leakage current test circuit of the lower surge arrester, injecting current into the circuit. At this time, the second current value A2 is determined by I... E1 with I E2 It consists of two parts. E1 Provided by the first output terminal E1, with no change in value; I E2 The second current value A2 is provided by the second output terminal E2, and its magnitude is determined by the voltage output of the second output terminal E2. Therefore, the magnitude of the second current value A2 is determined by the second output terminal E2. Increase the output voltage of the second output terminal E2 and monitor the second current value A2. When the second current value A2 reaches 1mA, it indicates that the leakage current of the next section surge arrester 70 has reached 1mA, and the fourth voltage value U output by the second output terminal E2 is determined. E2（A1-A2=1mA） At the same time, reduce the output voltage of the first output terminal E1 and the second output terminal E2, that is, reduce the third voltage value U. E1（A1-A2=1mA） and the fourth voltage value U E2（A1-A2=1mA） The voltage was reduced to the third voltage threshold of 0.75U. E1（A1-A2=1mA） and the fourth voltage threshold of 0.75U E2（A1-A2=1mA） Save the second current value A2 at this time, which is the leakage current value of the next section surge arrester 70.

[0103] The steps S601-S603 above constitute the entire process of completing the leakage current test of the upper and lower sections of the surge arrester using the injection current method.

[0104] In some embodiments, the intelligent control module 10 is further configured to perform the following current limiting protection process: during the process of gradually increasing the voltage output of the first output terminal E1, the number of current limiting resistors connected in the current limiting module 50 is controlled so that the first current value is always less than the set second current threshold.

[0105] In some embodiments, the intelligent control module 10 is further configured to control the number of current-limiting resistors connected in the current-limiting module 50 in such a way that the first current value is always less than the set second current threshold: when the first current value is greater than or equal to the set second current threshold, the control switch 80 is turned on, and the number of current-limiting resistors connected is adjusted by adjusting the on / off state of the current-limiting switch until the second current value is less than the set third current threshold.

[0106] In this embodiment, the second current threshold is set to 3mA to ensure that the tester operates within its load capacity range, i.e., the output current is less than 3mA. When the first output terminal E1 re-enters the boost mode, the intelligent control module 10 selects an appropriate current-limiting resistor R from the current-limiting module 50 and connects it to the leakage current test circuit of the next arrester, reducing the current in that circuit to approximately 0.5mA. After the tester starts, the switch of the current-limiting module 50 is closed, and the next arrester 70 is essentially directly grounded. When current limiting is required, the control module calculates and selects a switch to open, connecting the current-limiting resistor to reduce the current in that branch. During the voltage rise at the output terminal E1, if the current approaches 1mA again, the control module will continue to connect the current-limiting resistor to ensure that the current in that circuit does not exceed 1mA.

[0107] In some embodiments, the intelligent bipolar surge arrester DC high-voltage leakage current tester has automatic and semi-automatic operating modes. After the tester is started, the automatic or semi-automatic test mode can be selected via the display controller 90 (touch screen).

[0108] Automatic Mode: When in automatic mode, the tester will complete the leakage current test of both the upper and lower surge arrester sections according to the preset workflow. The test results are displayed on the display controller 90 and saved for review and printing purposes. The workflow ends after manually selecting whether to print or not.

[0109] Semi-automatic mode: When the intelligent control module 10 detects that the difference between A2 or A1 and A2 is 1mA, the control module will issue an audible prompt and display the surge arrester information with a current of 1mA on the display controller 90, and the preset workflow will pause; when manually selecting 0.75U... 1mA After output, 0.75U 1mA The leakage current value under the given conditions is saved and displayed on the smart terminal, and the preset workflow is paused again. The workflow ends when manual selection to print or not print is made. During semi-automatic testing, the display controller 90 displays real-time test step prompts and results. When data archiving is required, the test results can be printed using the mini printer on the tester.

[0110] In some embodiments, a workflow of the intelligent bipolar surge arrester DC high-voltage leakage current tester is as follows: Figure 7 As shown, this workflow can be pre-configured in the intelligent control module 10 in the form of software or a module and executed by the intelligent control module 10, specifically including the following steps:

[0111] Step 1: The voltage E1 in the DC high voltage module increases, and A1 and A2 are obtained; where A1 is the first current value collected in real time by the first current sampling module, and A2 is the second current value collected in real time by the second current sampling module.

[0112] Step 2: Determine if condition A1 < 3mA is true. If true (Y), proceed to step 3. If false (N), end the process.

[0113] Step 3: Determine if condition A2=1mA is true. If true, proceed to step 4. If false, proceed to step 6.

[0114] Step 4: Stop boosting E1, the voltage drops to 75% of the current value, save the value of A2, connect the current limiting resistor R, boost E1, and determine whether the condition A1-A2=1mA is true. If it is true, proceed to step 5. If it is not true, continue to boost E1.

[0115] Step 5: Stop boosting E1, reduce the output voltage of E1 to 75% of the current value, save the A1-A2 values, and determine whether to print the test results based on the manually input instructions. If yes, print the output and end the process; otherwise, end the process.

[0116] Step 6: Determine if the condition A1-A2=1mA is true. If not, let E1 continue to increase the voltage and return to step 2. If true, proceed to step 7.

[0117] Step 7: Stop boosting E1, reduce the voltage to 75% of the current value, save the A1-A2 value, restore the output voltage of E1 to the voltage when A1-A2=1mA, keep it unchanged, boost E2, and determine whether the condition A2=1mA is true. If it is not true, continue to boost E2. If it is true, proceed to step 8.

[0118] Step 8: E2 stops boosting, the output voltages of E1 and E2 drop to 75% of the current value, save the A2 value, and determine whether to print the test results based on the manually input instructions. If yes, print the output and end the process; otherwise, end the process.

[0119] In some embodiments, the two current sampling modules may consist of current sensors or wireless microammeters. The intelligent control module 10 obtains the leakage current parameters of the upper and lower surge arresters via wired or wireless communication, thereby enabling control over... Figure 7 This demonstrates precise control over the entire testing process.

[0120] The testing instrument proposed in this invention was compared with the traditional method of removing the upper high-voltage lead and replacing it with a grounding wire. The test was conducted on a 220kV surge arrester with 16 units. 1mA Voltage, I 0.75U1mA The test results were compared and the average time was calculated, as shown in Table 1.

[0121] Table 1. Test U using the present invention and the traditional lead removal grounding method 1mA I 0.75U1mA and average time

[0122]

[0123] The above embodiments are only used to illustrate the present invention and are not intended to limit the present invention. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions also fall within the scope of the present invention, and the patent protection scope of the present invention should be defined by the claims.

Claims

1. An intelligent bipolar surge arrester DC high-voltage leakage current tester, characterized in that, It includes an intelligent control module, a DC high-voltage module, a first current sampling module, a second current sampling module, and a current limiting module; among which: Both the first current sampling module and the second current sampling module are communicatively connected to the intelligent control module, and the intelligent control module is communicatively connected to the DC high voltage module. The DC high voltage module has a first output terminal and a second output terminal. The first output terminal is connected to a first circuit, and the second output terminal is connected to a second circuit. A first current sampling module is provided on the first circuit. The first current sampling module is electrically connected to the upper and lower surge arresters connected in parallel. A control switch, a series current limiting module, and a second current sampling module are provided on the second circuit. The second current sampling module is electrically connected to the lower surge arrester. The control switch is communicatively connected to the intelligent control module. The current limiting module includes multiple current limiting resistors and multiple current limiting switches. The multiple current limiting resistors are connected in series, and each current limiting resistor is connected in parallel with a current limiting switch. The multiple current limiting switches are all communicatively connected to the intelligent control module. The control switch includes a first switch node, a second switch node, a third switch node, and a switch assembly; wherein, the first switch node is connected to the current limiting module, the second switch node is connected to the ground terminal, the third switch node is connected to the second output terminal, and the switch assembly is rotatably mounted on the first switch node. During the rotation of the switch assembly around the first switch node, the first switch node can be connected to the second switch node or the first switch node can be connected to the third switch node. The intelligent control module is configured as follows: The control switch is turned off, the voltage output from the first output terminal is gradually increased, and the first current value collected by the first current sampling module and the second current value collected by the second current sampling module are acquired in real time. When the second current value reaches the first current threshold before the difference between the first and second current values ​​reaches the first current threshold, the first workflow is executed. When the difference between the first current value and the second current value reaches the first current threshold before the second current value, the second workflow is executed. The first workflow includes: Control the first output terminal to stop boosting voltage, and obtain the first voltage value output by the first output terminal at the current moment; The voltage output from the first output terminal is controlled to gradually decrease until it reaches the set first voltage threshold. The current value collected by the second current sampling module at this time is obtained and saved as the leakage current value of the next arrester. Wherein, the first voltage threshold is n times the first voltage value, and n is a real number from 0 to 1. The voltage output from the first output terminal is controlled to gradually increase from a set first voltage threshold. When the difference between the first current value and the second current value reaches the first current threshold, the first output terminal is controlled to stop increasing the voltage, and the second voltage value output by the first output terminal at the current moment is obtained. The voltage output from the first output terminal is controlled to gradually decrease until it reaches the set second voltage threshold. The difference between the current value collected by the first current sampling module and the current value collected by the second current sampling module is obtained at this time and saved as the leakage current value of the surge arrester in the previous section. Wherein, the second voltage threshold is n times the second voltage value. The second workflow includes: Control the first output terminal to stop boosting voltage, and obtain the third voltage value output by the first output terminal at the current moment; The voltage output from the first output terminal is controlled to gradually decrease until it reaches the set third voltage threshold. The difference between the current value collected by the first current sampling module and the current value collected by the second current sampling module is obtained at this time and saved as the leakage current value of the surge arrester in the previous section. The third voltage threshold is n times the third voltage value, where n is a real number from 0 to 1. The voltage output from the first output terminal is controlled to rise back to the third voltage value and remain unchanged. The voltage output from the second output terminal is controlled to gradually rise until the second current value reaches the first current threshold and the voltage rise stops. The fourth voltage value output from the second output terminal at this time is obtained. At the same time, the first output terminal is controlled to decrease to the third voltage threshold and the second output terminal is controlled to decrease to the fourth voltage threshold. The second current value at this time is obtained and saved as the leakage current value of the surge arrester in the next section. The fourth voltage threshold is n times the fourth voltage.

2. The intelligent bipolar surge arrester DC high-voltage leakage current tester according to claim 1, characterized in that, It also includes a display controller, which is communicatively connected to the intelligent control module.

3. The intelligent bipolar surge arrester DC high-voltage leakage current tester according to claim 1, characterized in that, It also includes a test data printing component, which is communicatively connected to the intelligent control module.

4. The intelligent bipolar surge arrester DC high-voltage leakage current tester according to claim 1, characterized in that, The intelligent control module is further configured as follows: During the process of gradually increasing the voltage output from the first output terminal, the number of current-limiting resistors connected in the current-limiting module is controlled so that the first current value is always less than the set second current threshold.

5. The intelligent bipolar surge arrester DC high-voltage leakage current tester according to claim 4, characterized in that, The intelligent control module is further configured to control the number of current-limiting resistors connected in the current-limiting module in the following manner, so that the first current value is always less than the set second current threshold: When the first current value is greater than or equal to the set second current threshold, the control switch is turned on, and the number of connected current-limiting resistors is adjusted by adjusting the on / off state of the current-limiting switch until the second current value is less than the set third current threshold.

6. The intelligent bipolar surge arrester DC high-voltage leakage current tester according to claim 2, characterized in that, The tester includes two testing modes: automatic mode and semi-automatic mode. In automatic mode, the tester completes all tests according to the preset procedure, automatically saves the test results and supports printing output; In semi-automatic mode, when the second current value reaches the first current threshold, the difference between the first current value and the second current value reaches the first current threshold, or the leakage current value test of the upper section surge arrester or the leakage current value test of the lower section surge arrester is completed, the display controller issues an audible prompt and pauses the process, and resumes the process after receiving an instruction to continue the operation; wherein, the first current value and the second current value are the current values ​​collected by the first current sampling module and the second current sampling module, respectively.

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