Microammeter and lightning arrester leakage current test device and method

Abstract

The invention discloses a microammeter and lightning arrester leakage current test device and method, the microammeter and lightning arrester leakage current test device comprises a first current sampling module, a second current sampling module, a converter module and an access module, the first current sampling module comprises a first resistor and a first digital potentiometer, and the second current sampling module comprises a second resistor and a second digital potentiometer; one end of the first resistor is connected with one end of the first digital potentiometer, and one end of the second resistor is connected with one end of the second digital potentiometer; the converter module comprises an analog-to-digital converter and a single-chip microcomputer, the other ends of the first digital potentiometer, the second digital potentiometer, the first resistor and the second resistor are respectively connected with the differential input end of the analog-to-digital converter, the output end of the analog-to-digital converter is connected with one end of the single-chip microcomputer, and the other end of the single-chip microcomputer is connected with the access module. By designing dual-channel sampling, two paths of test current data can be transmitted to a control box for test measurement control, and the accuracy of a measurement result is improved.

Description

Technical Field

[0001] The invention relates to the technical field of microammeters, and in particular to a microammeter, a lightning arrester leakage current test device and a method. Background Art

[0002] At present, the conventional test method of removing the high-voltage lead is still used for the DC reference voltage and leakage current test of 220kV lightning arresters on site. The height of 220kV lightning arrester equipment is relatively high, and the high-voltage lead is thick. Each pre-test removal requires a lift or a large escalator. This test method has the following disadvantages: large workload and long time; repeated disassembly and assembly of the lead wires can easily cause hidden dangers such as lead damage and poor contact of screws; the work is relatively dangerous. Therefore, the double-meter method is currently used to improve the leakage current test method of multi-section lightning arresters. The improved method is that the lightning arrester with two or more series structures can be tested without removing the high-voltage lead wires. In the typical wiring diagram, the DC high-voltage output end is connected in series with a microammeter, and the low-voltage end is directly connected to the microammeter or connected in series with a current-limiting resistor and then connected to the microammeter for grounding. In order to achieve the simultaneous measurement of the DC 1mA voltage and 0.75U1mA of the upper and lower lightning arresters, it is necessary to achieve accurate sampling of the voltage and current signals during the test.

[0003] At present, the microammeters used in China are all independently sampled, and one microammeter measures one current. It is impossible to send the current data of two microammeters to the same control box for calculation and control. Therefore, manual reading and calculation are generally used in the test. Manual reading will bring the following problems: at least 3 people are required to read, the work efficiency is low, and because multiple people read, simultaneity will cause deviations; at the current inflection point of the lightning arrester, the current is too sensitive to voltage changes, which increases the difficulty of manual adjustment and also causes errors; due to the high difficulty of adjustment, 1mA work takes a long time, and at this time the DC high-voltage generator is in a high voltage and high current (relative to capacity) state. If it is in this state for too long, it will cause great damage to the test equipment. Summary of the invention

[0004] In order to solve the above technical problems, the embodiments of the present invention provide a microammeter, a lightning arrester leakage current test device and a method to solve the problems of large errors and low work efficiency due to manual readings in the lightning arrester leakage current test.

[0005] A first aspect of an embodiment of the present invention provides a microammeter, comprising a first current sampling module, a second current sampling module, a converter module and an access module, wherein:

[0006] The first current sampling module includes a first resistor and a first digital potentiometer, and the second current sampling module includes a second resistor and a second digital potentiometer;

[0007] One end of the first resistor is connected to one end of the first digital potentiometer, and one end of the second resistor is connected to one end of the second digital potentiometer;

[0008] The converter module includes an analog-to-digital converter and a single-chip microcomputer, the analog-to-digital converter includes a first differential input terminal and a second differential input terminal, the other end of the first digital potentiometer and the other end of the second digital potentiometer are respectively connected to the first differential input terminal, and the other ends of the first resistor and the second resistor are respectively connected to the second differential input terminal;

[0009] The output end of the analog-to-digital converter is connected to one end of the single-chip microcomputer, and the other end of the single-chip microcomputer is connected to the access module.

[0010] In a first possible implementation manner of this embodiment, the first resistor is connected in series with the first digital potentiometer, and the second resistor is connected in series with the second digital potentiometer.

[0011] In a first possible implementation manner of this embodiment, the first differential input terminal is a positive input terminal, and the second differential input terminal is a negative input terminal.

[0012] A second aspect of an embodiment of the present invention provides a lightning arrester leakage current test device, the device comprising a control module, a DC high voltage generating module, a plurality of lightning arresters and a microammeter, wherein:

[0013] The microammeter is the microammeter according to the first aspect of the embodiment of the present invention;

[0014] The control module is connected to the DC high voltage generating module, and the DC high voltage generating module is connected to the single chip microcomputer in the microammeter;

[0015] The plurality of lightning arresters include a first lightning arrester and a second lightning arrester, and input ends of the first lightning arrester and the second lightning arrester are respectively connected to the DC high voltage generating module;

[0016] The DC high voltage generating module is connected to the microammeter.

[0017] In a possible implementation manner of the second aspect, the negative terminal of the first lightning arrester is grounded, and the negative terminal of the second lightning arrester is connected in series with the first resistor and the second digital potentiometer of the microammeter and then grounded.

[0018] In a possible implementation of the second aspect, the DC high voltage generating module is connected to the microammeter, including:

[0019] The control module is connected to the DC high voltage generating module via wireless Bluetooth and is used to communicate with the DC high voltage generating module.

[0020] In a possible implementation manner of the second aspect, the control module is communicatively connected to the single-chip microcomputer in the microammeter via an optical fiber.

[0021] A third aspect of an embodiment of the present invention provides a lightning arrester leakage current test method, the method comprising:

[0022] Based on the preset control logic, the DC high voltage generating module is controlled to output DC high voltage;

[0023] Collecting currents obtained at the first sampling point and the second sampling point to obtain a first current and a second current, and obtaining a third current according to the first current and the second current;

[0024] The third current, the second current and the first current are sent to the control box, so that the control box updates the control strategy according to the third current, the second current and the first current, and controls the DC high voltage transmission module according to the updated control strategy.

[0025] In a possible implementation of the third aspect, based on a preset control logic, controlling the DC high voltage generating module to output the DC high voltage includes:

[0026] The resistance adjustment information is sent to the single chip microcomputer, so that the single chip microcomputer adjusts the resistance of the digital potentiometer at the first sampling point or the second sampling point.

[0027] In a possible implementation manner of the third aspect, obtaining the third current according to the first current and the second current includes:

[0028] Based on the difference between the first current and the second current, a third current is obtained, wherein the expression of the third current is:

[0029] x=I xI 1

[0030] In the formula, x represents the third current, Ix represents the first current, and I1 represents the second current.

[0031] Compared with the prior art, the beneficial effects of the present invention are:

[0032] The microammeter provided by the embodiment of the present invention includes a first current sampling module, a second current sampling module, a converter module and an access module, wherein the first current sampling module includes a first resistor and a first digital potentiometer, and the second current sampling module includes a second resistor and a second digital potentiometer; one end of the first resistor is connected to one end of the first digital potentiometer, and one end of the second resistor is connected to one end of the second digital potentiometer; the converter module includes an analog-to-digital converter and a single-chip microcomputer, the analog-to-digital converter includes a first differential input terminal and a second differential input terminal, the other end of the first digital potentiometer and the other end of the second digital potentiometer are respectively connected to the first differential input terminal, the other ends of the first resistor and the second resistor are respectively connected to the second differential input terminal, the output end of the analog-to-digital converter is connected to one end of the single-chip microcomputer, and the single-chip microcomputer and the other end are connected to the access module. By designing dual-channel sampling, two-way test current data can be transmitted to the control box to perform test measurement control and improve the accuracy of the measurement results. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 A schematic diagram of the system topology in the microammeter provided by the present invention;

[0034] Figure 2 A test device topology diagram of a lightning arrester leakage current test device provided by the present invention;

[0035] Figure 3 The present invention provides a flow chart of the arrester leakage current test method. DETAILED DESCRIPTION

[0036] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] It should be understood that the step numbers used in this document are only for convenience of description and are not intended to limit the order in which the steps are executed.

[0038] It should be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0039] The terms “include” and “comprising” indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0040] The term "and / or" means and includes any and all possible combinations of one or more of the associated listed items.

[0041] See also Figure 1 , a certain embodiment of the present invention provides a microammeter, such as Figure 1 As shown, it includes a first current sampling module, a second current sampling module, a converter module and an access module, wherein:

[0042] The first current sampling module includes a first resistor and a first digital potentiometer, and the second current sampling module includes a second resistor and a second digital potentiometer;

[0043] One end of the first resistor is connected to one end of the first digital potentiometer, and one end of the second resistor is connected to one end of the second digital potentiometer;

[0044] The converter module includes an analog-to-digital converter and a single-chip microcomputer, the analog-to-digital converter includes a first differential input terminal and a second differential input terminal, the other end of the first digital potentiometer and the other end of the second digital potentiometer are respectively connected to the first differential input terminal, and the other ends of the first resistor and the second resistor are respectively connected to the second differential input terminal;

[0045] The output end of the analog-to-digital converter is connected to one end of the single-chip microcomputer, and the other end of the single-chip microcomputer is connected to the access module.

[0046] In this embodiment, if Figure 1 As shown, Figure 1 The circuit structure diagram of a dual-input channel microammeter is shown in FIG. 1 , which includes a sampling resistor 1, a sampling resistor 2, multiple digital potentiometers, a single-chip microcomputer, a differential input AD, and an optical fiber communication interface. One end of the sampling resistor 1 is connected to a digital potentiometer, one end of the sampling resistor 2 is connected to a digital potentiometer, and the other ends of the sampling resistor 1 and the sampling resistor 2 are connected to the differential input AD. The other end of the digital potentiometer connected to the sampling resistor 1 is connected to the differential input AD, and the other end of the digital potentiometer connected to the sampling resistor 2 is connected to the differential input AD. The differential input AD is connected to the single-chip microcomputer, and the single-chip microcomputer is connected to the optical fiber communication interface.

[0047] It should be noted that the current sampling module is composed of a standard resistor and a digital potentiometer in series. According to Ohm's law, the voltage is proportional to the current. The voltage across the resistor and the potentiometer after they are connected in series reflects the magnitude of the current. By measuring the voltage, the magnitude of the current can be calculated based on the size of the resistor.

[0048] It should be noted that the access module refers to an optical fiber communication interface, which is used to connect to an external DC high voltage generating module to achieve bidirectional data transmission.

[0049] In one embodiment, the first resistor is connected in series with the first digital potentiometer, and the second resistor is connected in series with the second digital potentiometer.

[0050] In this embodiment, the sampling resistor 1 is connected in series with a digital potentiometer, and the sampling resistor 2 is connected in series with a digital potentiometer.

[0051] In one embodiment, the first differential input terminal is a positive input terminal, and the second differential input terminal is a negative input terminal.

[0052] In this embodiment, sampling resistor 1 and sampling resistor 2 are respectively connected to the differential input terminal, which is the two input pins AIN(+) and AIN(-) of the A / D integrated circuit. By selecting a suitable sampling resistor, the sampling voltage is just within the analog voltage input range of the A / D integrated circuit, and can be directly connected to the A / D integrated circuit chip.

[0053] See also Figure 2 A certain embodiment of the present invention provides a topological diagram of a lightning arrester leakage current test device, including a control module, a DC high voltage generating module, a plurality of lightning arresters and a microammeter, wherein:

[0054] The microammeter is a microammeter provided by one of the embodiments;

[0055] The control module is connected to the DC high voltage generating module, and the DC high voltage generating module is connected to the single chip microcomputer in the microammeter;

[0056] The plurality of lightning arresters include a first lightning arrester and a second lightning arrester, and input ends of the first lightning arrester and the second lightning arrester are respectively connected to the DC high voltage generating module;

[0057] The DC high voltage generating module is connected to the microammeter.

[0058] In this embodiment, Figure 2 It is a test device topology diagram of a dual-channel microammeter connected to a lightning arrester leakage current test device, wherein a DC high voltage generation module generates the DC high voltage required for the lightning arrester leakage current test, and the DC high voltage is connected in series with a sampling resistor 1 and a digital potentiometer and then loaded on the high voltage input end of two lightning arresters, and the negative end of the lightning arrester 2 is connected in series with a sampling resistor 2 and a digital potentiometer. The microammeter is a microammeter provided in one of the embodiments;

[0059] The remote control box contains test operation control software, which communicates with the DC high voltage generating module via wireless Bluetooth. The DC high voltage generating module and the microammeter realize two-way data transmission via optical fiber.

[0060] In one embodiment, the negative terminal of the first lightning arrester is grounded, and the negative terminal of the second lightning arrester is connected in series with the first resistor and the second digital potentiometer of the microammeter and then grounded.

[0061] In this embodiment, the negative terminal of the arrester 1 is grounded, and the negative terminal of the arrester 2 is connected in series with the sampling resistor 2 and the digital potentiometer to ground.

[0062] In one embodiment, the DC high voltage generating module is connected to the microammeter, including:

[0063] The control module is connected to the DC high voltage generating module via wireless Bluetooth and is used to communicate with the DC high voltage generating module.

[0064] In one embodiment, the control module is communicatively connected to the single chip microcomputer in the microammeter via an optical fiber.

[0065] In this embodiment, the remote control box contains test operation control software, which communicates with the DC high voltage generating module via wireless Bluetooth.

[0066] The microammeter also has a fiber optic communication interface to transmit the test data to the DC high voltage generating module, which can be monitored and remotely calibrated through the upper remote control box of the DC high voltage generating module.

[0067] See also Figure 3 , a certain embodiment of the present invention provides a flow chart of a lightning arrester leakage current test method, comprising:

[0068] Based on the preset control logic, the DC high voltage generating module is controlled to output DC high voltage;

[0069] Collecting currents obtained at the first sampling point and the second sampling point to obtain a first current and a second current, and obtaining a third current according to the first current and the second current;

[0070] The third current, the second current and the first current are sent to the control box, so that the control box updates the control strategy according to the third current, the second current and the first current, and controls the DC high voltage transmission module according to the updated control strategy.

[0071] In this embodiment, the control software in the remote control box controls the DC high voltage generating module through Bluetooth communication, thereby controlling and managing the entire test process, and realizing automatic voltage step-up and step-down operation of the test process according to the given control logic. At the same time, the control software also has the functions of parameter setting, data recording, data query, data printing, etc. Specifically, based on the preset control logic, the DC high voltage generating module is controlled to output DC high voltage, and then the digital signal converted by the A / D chip is read by the single-chip microcomputer at each sampling point, and the output current of the DC high voltage generating module is calculated, and the current flowing through the arrester 2 is calculated, thereby the current flowing through the arrester 1 can be calculated.

[0072] It should be noted that the first sampling point is the output current Ix of the DC high voltage generating module, and the second sampling point is the current I1 of the arrester 2. The first current refers to the output current Ix of the DC high voltage generating module, and the second current refers to the current I1 of the arrester 2. The third current refers to the current of the arrester 1.

[0073] In one embodiment, based on a preset control logic, controlling the DC high voltage generating module to output DC high voltage includes:

[0074] The resistance adjustment information is sent to the single chip microcomputer, so that the single chip microcomputer adjusts the resistance of the digital potentiometer at the first sampling point or the second sampling point.

[0075] In one embodiment, obtaining the third current according to the first current and the second current includes:

[0076] Based on the difference between the first current and the second current, a third current is obtained, wherein the expression of the third current is:

[0077] x=I xI 1

[0078] In the formula, x represents the third current, Ix represents the first current, and I1 represents the second current.

[0079] In this embodiment, the remote control box communicates with the micro-amperemeter microcontroller through optical fiber. The remote control box sends the digital potentiometer resistance adjustment information to the microcontroller according to the calibration requirements, and the microcontroller adjusts the digital potentiometer resistance according to the information. The resistance adjustment information is to increase the resistance value or decrease the resistance value.

[0080] After the single chip microcomputer reads the current at each sampling point, it obtains the output current I x of the DC high voltage generating module and the current I 1 flowing through the arrester 2. From this, it can be calculated that the current flowing through the arrester 1 is I xI 1.

[0081] The present invention provides a microammeter, a lightning arrester leakage current test device and a method, which implement dual-channel sampling, measure and calculate the dual-channel leakage current through a group of A / D sampling (dual-channel differential analog signal input) and a single-chip microcomputer, and the calculation result is transmitted to the control box by a group of optical fibers of the microammeter to carry out measurement and control of the test. According to a given control logic, automatic step-up and step-down operations are realized during the test, which can effectively reduce the deviation caused by manual readings, reduce the difficulty of adjustment, and reduce damage to the test equipment.

[0082] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0083] The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. It is particularly pointed out that for those skilled in the art, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the scope of protection of the present invention.

Claims

1. A microammeter, characterized in that: It includes a first current sampling module, a second current sampling module, a converter module and an access module, wherein: The first current sampling module includes a first resistor and a first digital potentiometer, and the second current sampling module includes a second resistor and a second digital potentiometer; One end of the first resistor is connected to one end of the first digital potentiometer, and one end of the second resistor is connected to one end of the second digital potentiometer; The converter module includes an analog-to-digital converter and a single-chip microcomputer, the analog-to-digital converter includes a first differential input terminal and a second differential input terminal, the other end of the first digital potentiometer and the other end of the second digital potentiometer are respectively connected to the first differential input terminal, and the other ends of the first resistor and the second resistor are respectively connected to the second differential input terminal; The output end of the analog-to-digital converter is connected to one end of the single-chip microcomputer, and the other end of the single-chip microcomputer is connected to the access module.

2. The microammeter according to claim 1, characterized in that: Also includes: The first resistor is connected in series with the first digital potentiometer, and the second resistor is connected in series with the second digital potentiometer.

3. The microammeter according to claim 1, characterized in that: The first differential input terminal is a positive input terminal, and the second differential input terminal is a negative input terminal.

4. A lightning arrester leakage current test device, characterized in that: It includes a control module, a DC high voltage generation module, multiple lightning arresters and microammeters, among which: The microammeter is a microammeter as claimed in any one of claims 1 to 3; The control module is connected to the DC high voltage generating module, and the DC high voltage generating module is connected to the single chip microcomputer in the microammeter; The plurality of lightning arresters include a first lightning arrester and a second lightning arrester, and input ends of the first lightning arrester and the second lightning arrester are respectively connected to the DC high voltage generating module; The DC high voltage generating module is connected to the microammeter.

5. The arrester leakage current test device according to claim 4, characterized in that: include: The negative end of the first lightning arrester is grounded, and the negative end of the second lightning arrester is connected in series with the first resistor and the second digital potentiometer of the microammeter and then grounded.

6. The arrester leakage current test device according to claim 4, characterized in that: The DC high voltage generating module is connected to the microammeter and includes: The control module is connected to the DC high voltage generating module via wireless Bluetooth and is used to communicate with the DC high voltage generating module.

7. The arrester leakage current test device according to claim 4, characterized in that: Also includes: The control module is connected to the single chip microcomputer in the microammeter for communication via an optical fiber.

8. A lightning arrester leakage current test method, characterized in that: The lightning arrester leakage current test device described in claims 3 to 6 above is implemented, comprising: Based on the preset control logic, the DC high voltage generating module is controlled to output DC high voltage; Collecting currents obtained at the first sampling point and the second sampling point to obtain a first current and a second current, and obtaining a third current according to the first current and the second current; The third current, the second current and the first current are sent to the control box, so that the control box updates the control strategy according to the third current, the second current and the first current, and controls the DC high voltage transmission module according to the updated control strategy.

9. The lightning arrester leakage current test method according to claim 8, characterized in that: The method of controlling the DC high voltage generating module to output DC high voltage based on the preset control logic includes: The resistance adjustment information is sent to the single chip microcomputer, so that the single chip microcomputer adjusts the resistance of the digital potentiometer at the first sampling point or the second sampling point.

10. The lightning arrester leakage current test method according to claim 8, characterized in that: The obtaining a third current according to the first current and the second current includes: A third current is obtained based on the difference between the first current and the second current, wherein the expression of the third current is: x=Ix-I 1 Wherein, x represents the third current, Ix represents the first current, and I1 represents the second current.

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