Pre-failure short circuit testing device of gapless metal oxide arrester

Abstract

The utility model relates to a pre-failure short circuit testing device for a gapless metal oxide arrester, which is characterized in that voltage is continuously applied to a to-be-tested arrester, and voltage at two ends of the arrester and current flowing through the arrester are monitored at the same time until the to-be-tested arrester reaches a pre-failure testing device. Through the testing device with a simple structure, the testing requirement of lightning arrester pre-failure short circuit in the international standard IEC 60099-4 is met; meanwhile, one testing device can meet the requirements of to-be-tested lightning arresters of different specifications.

Description

Technical Field

[0001] The utility model relates to the field of lightning protection, and particularly to a pre-failure short-circuit test device for a gapless metal oxide lightning arrester. Background Art

[0002] A lightning arrester is an electrical device that can release lightning or also release the energy of switching overvoltages in a power system, protect electrical equipment from transient overvoltages (lightning overvoltages, switching overvoltages, power frequency transient overvoltages), and does not cause a system ground short circuit.

[0003] With the increasing requirements for the quality of lightning protection projects, the operating status of lightning arresters is very important for the reliable operation of power systems and ensuring personnel safety. The pre-failure short-circuit test of lightning arresters is an important link in testing the performance of lightning arresters.

[0004] The international standard "IEC 60099-4" defines the indicators for the pre-failure short-circuit test of lightning arresters, corresponding to the minimum and maximum rated voltages for various types and designs of open-circuit or short-circuit failure lightning arresters. Content of the Utility Model

[0005] The purpose of the utility model is to provide a pre-failure short-circuit test device for a gapless metal oxide lightning arrester.

[0006] The device includes: a lightning arrester under test, a voltage probe, a current coil, a voltage and current collector, a shunt resistance switch, a programmable power supply, a processor, and a step-up coil T1. The programmable power supply outputs a preset voltage value, and the step-up coil T1 connected to it steps up the voltage. The two paths of the step-up coil T1 are respectively connected to the shunt resistance switch and the current coil. The two ends of the lightning arrester under test are respectively connected to the output ends of the shunt resistance switch and the current coil. The voltage probe is connected to the two ends of the lightning arrester under test to detect the real-time voltage at both ends of the lightning arrester under test. The two ends of the voltage and current collector are respectively connected to the voltage probe and the current coil to collect the voltage value and current value of the voltage probe and the current coil. The voltage and current collector is connected to the processor, and the processor controls and adjusts the output voltage of the programmable power supply.

[0007] Wherein, further, the shunt resistance switch includes a first resistor R1 and a first gear of a first switch K1; a second resistor R2 and a second gear of a second switch K2; and a third resistor R3 and a third gear of a third switch K3.

[0008] Wherein, further, the shunt resistance switch includes a first resistor R1 and a first gear of a first switch K1; a second resistor R2 and a second gear of a second switch K2; a third resistor R3 and a third gear of a third switch K3; a fourth resistor R4 and a fourth gear of a fourth switch K4; and an nth resistor Rn and an nth gear of an nth switch Kn.

[0009] Among them, further, the shunt resistance switch is a sliding resistor RS.

[0010] Among them, further, the current flowing through the arrester under test is maintained within the range of 10 - 30 A.

[0011] Among them, further, the processor includes a host computer and an ARM controller. The host computer is communicatively connected to the ARM controller through a serial interface, and the voltage and current collector is communicatively connected to the host computer through a network communication interface to obtain the voltage value and current value of the arrester.

[0012] Among them, further, the ARM controller communicates with the controlled program power supply through the SPI module.

[0013] Among them, further, an overcurrent protector is provided at the input end of the controlled program power supply.

[0014] The advantages of the present utility model are as follows: The test device with a simple structure meets the test requirements for the pre-failure short circuit of arresters in the international standard "IEC 60099-4"; at the same time, one test device can meet arresters under test of different specifications. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic structural diagram of the first embodiment of the pre-failure short circuit test device for a gapless metal oxide arrester of the present utility model;

[0016] Figure 2 It is a schematic structural diagram of the second embodiment of the pre-failure short circuit test device for a gapless metal oxide arrester of the present utility model;

[0017] Figure 3 It is a schematic structural diagram of the third embodiment of the pre-failure short circuit test device for a gapless metal oxide arrester of the present utility model;

[0018] Figure 4 It is a schematic structural diagram of the processor 26 of the pre-failure short circuit test device for a gapless metal oxide arrester of the present utility model;

[0019] Figure 5 It is a flowchart for testing of the pre-failure short circuit test device for a gapless metal oxide arrester of the present utility model;

[0020] Figure 6 It is a two-dimensional current-voltage curve graph of the test of the pre-failure short circuit test device for a gapless metal oxide arrester of the present utility model.

[0021] In the figure: 10... arrester under test, 21... voltage probe, 22... current coil, 23... voltage and current collector, 24... shunt resistance switch, 25... programmable power supply, 26... processor, 261... host computer, 262... ARM controller, 27... overcurrent protector. Specific embodiments

[0022] Please refer to Figure 1 In the first embodiment, the test device 20 includes: an arrester under test 10, a voltage probe 21, a current coil 22, a voltage and current collector 23, a shunt resistance switch 24, a programmable power supply 25, a processor 26, an overcurrent protector 27, and a step-up coil T1.

[0023] Among them, the programmable power supply 25 is a power supply that can change output current, voltage, power and other parameters through a specific programming interface. The programmable power supply realizes precise control and adjustment of multiple parameters such as output current, voltage and power through technologies such as microprocessors, digital signal processors, analog circuits, and in combination with advanced control algorithms and software. The programmable power supply is divided into two control modes: open-loop control and closed-loop control.

[0024] The voltage output by the programmable power supply 25 is stepped up through the step-up coil T1. The output end of the step-up coil T1 is connected to the shunt resistance switch 24; the other output end is connected to the current coil 22. The two ends of the arrester under test 10 are respectively connected to the output ends of the shunt resistance switch 24 and the current coil 22. At the same time, the voltage probe 21 is also connected to the output ends of the shunt resistance switch 24 and the current coil 22 to detect the real-time voltage at both ends of the arrester under test 10. The two ends of the voltage and current collector 23 are respectively connected to the voltage probe 21 and the current coil 22. The output end of the voltage and current collector 23 is connected to the processor 26. After the processor 26 analyzes and compares the collected voltage and current data, the output voltage of the programmable power supply 25 is adjusted.

[0025] In order to meet the test requirements of arresters under test 10 of different models, the shunt resistance switch 24 needs to provide different resistances for classification, so as to meet the current and voltage requirements of the arrester under test 10 for the pre-failure short-circuit test specified in the international standard "IEC 60099-4". Different models have different preset voltage and current values, such as Figure 1 As shown: The shunt resistance switch 24 includes a first resistor R1, the first gear of the first switch K1; a second resistor R2, the second gear of the second switch K2; and a third resistor R3, the third gear of the third switch K3, and can be switched to different resistance gears according to needs.

[0026] Such as Figure 2As shown in the figure: To meet the requirements of more models of arresters 10 to be tested, in this embodiment, the shunt resistance switch 24 may include the first gear of the first resistor R1 and the first switch K1; the second gear of the second resistor R2 and the second switch K2; the third gear of the third resistor R3 and the third switch K3; and the fourth resistor R4 and the fourth switch K4, and so on until the nth resistor Rn and the nth switch Kn are set according to requirements. In this way, different gears of shunt resistors can be freely selected according to the different shunt requirements of arresters 10 of different models to be tested.

[0027] As Figure 3 shown in the figure: To better and more precisely divide the gears of the shunt resistance switch 24, the shunt resistance switch 24 may be a sliding resistor RS, which can be adjusted according to different requirements by the sliding resistor RS.

[0028] As Figure 4 shown in the figure: In the above test device 20, the processor 26 may be composed of a host computer 261 connected to an ARM controller 262 through a serial interface. Among them, the ARM (Advanced RISC Machines) processor 262 is the first RISC microprocessor designed by Acorn Computers Limited for the market.

[0029] The overcurrent protector 27 is connected to the zero line of this test device 20 to protect the entire circuit when the current of the entire test device 20 suddenly increases.

[0030] The working principle of this device 20 is as follows: For communication, human-machine interaction is realized in a serial manner; the host computer 261 sends instructions for the shunt resistance switch 24 to the ARM controller 262 according to the set voltage. The ARM controller 262 executes the switching of the corresponding shunt resistance switch 24 according to the received instructions for the shunt resistance switch 24. The host computer 261 sends a start instruction and a preset voltage value to the ARM controller 262. The ARM controller 262 controls the program-controlled power supply 25 to start and output the preset voltage according to the received start instruction and output voltage value. The host computer 261 sends a stop instruction to the ARM controller 262. The ARM controller 262 controls the program-controlled power supply 25 to stop voltage output and stop the test according to the received stop instruction; the voltage and current collector 23 communicates with the host computer 261 through a network communication interface to obtain the real-time voltage value and current value of the arrester 10 to be tested. At the same time, the host computer 262 will make a voltage-current-time curve from the real-time voltage value and current value obtained during the test, and analyze whether the arrester 10 to be tested is qualified through the voltage-current-time curve.

[0031] This utility model only needs to be able to collect the voltage value across the arrester 10 to be tested and the current value flowing through the arrester 10 to be tested in real time. The test device can be designed in various deformed ways, which will not be elaborated here.

[0032] Figure 5 Flow chart of the test method using the present utility model is as follows Figure 5 shown: It includes: Step S1, according to the preset voltage value output by the programmable power supply 25 of the voltage across the arrester 10 to be tested and the gear of the shunt resistance switch 24; wherein, the gear of the shunt resistance switch 24 is determined according to the preset voltage value; Step S2, through Figure 3 the present test device 20 shown, collect the real-time voltage and current values across the arrester 10 to be tested; Step S3, compare the real-time voltage value across the arrester 10 to be tested with the standard voltage value of the arrester 10 to be tested. If they are not equal, adjust the preset voltage value output by the programmable power supply 25; if they are equal, within the preset time, continuously collect the real-time voltage and current values across the arrester 10 to be tested and output them to the processor 26; Step S4, the processor 26 generates a two-dimensional voltage and current curve graph according to time, voltage and current. Step S5, compare the two-dimensional voltage and current curve graph with the standard two-dimensional voltage and current curve graph. If they are consistent, it is judged as qualified; if they are inconsistent, it is judged as a qualified product.

[0033] Among them, in Step S5, the two-dimensional voltage and current curve graph can be collected through an oscilloscope. If there is a current burst exceeding the preset value within the preset time, it is judged as: unqualified; if the current value is stable, it is judged as: qualified product.

[0034] Among them, in Step S3, if the real-time voltage value across the arrester 10 to be tested is different from the standard voltage value of the arrester 10 to be tested, adjust the preset voltage value output by the programmable power supply 25 so that the real-time voltage across the arrester 10 to be tested approaches the standard voltage value.

[0035] Specifically, in Step S3, if the real-time voltage across the arrester 10 to be tested is higher than the standard voltage value of the arrester 10 to be tested, adjust the voltage value output by the programmable power supply 25 to be lower than the preset voltage value; if the real-time voltage value across the arrester 10 to be tested is lower than the standard voltage value of the arrester 10 to be tested, adjust the voltage value output by the programmable power supply 25 to be higher than the preset voltage value.

[0036] The process of this test device is illustrated by the following example: First, for the surge arrester 10 under test, through the calculation of applying a voltage of 1.15Uc across the surge arrester under test as specified in the "IEC 60099-4" standard. In this embodiment, the Uc of the surge arrester 10 under test is 6000. Thus, the voltage across the surge arrester 10 under test is 6900V. The resistance of the shunt resistance switch 24 is between 100 ohms and 5000 ohms. The step-up ratio of the step-up circuit T1 is 1:20. The preset voltage value of the programmable power supply 25 is: 345V. The "IEC60099-4" standard stipulates that the test time and the data acquisition time are: 3 - 5 minutes. This embodiment is set to 4 minutes. When the voltage-current collector 23 collects the information that the real-time voltage value of the voltage probe 21 is lower than 6900V, it is processed by the processor 26, and a voltage of 355V is sent to the programmable power supply 25 to supply voltage to the step-up circuit T1 for step-up. When the information that the voltage value of the voltage probe 21 across the surge arrester 10 under test collected in real time is higher than 6900V is processed by the processor 26, a voltage of 335V is sent to the programmable power supply 25 to supply voltage to the step-up circuit T1 for step-up. After 10 seconds of adjustment in this embodiment, it stabilizes near 6900V.

[0037] Within the set test time of 4 minutes, the output two-dimensional voltage and current curve graphs are as Figure 4 shown: The voltage across the stable voltage probe 21 is 6900V. The resistance of the shunt resistance switch 24 for shunt selection is 2500 ohms, and the current value of the current coil 22 has been stably output at 2 - 3 milliamperes. At 58 seconds, the current of the current coil 22 suddenly increases, as Figure 6 shown: The voltage across both ends of the surge arrester 10 under test is adjusted for the first 10 seconds to a stable 6900V. During the detection process, at 58 seconds, as Figure 6 shown: The current passing through the current coil 22 suddenly surges sharply, and the surge arrester 10 under test is a non-conforming product.

[0038] The advantages of the present utility model are: The test device meets the test requirements for the pre-failure short circuit of surge arresters in the international standard "IEC 60099-4"; at the same time, the test device can meet different specifications of surge arresters under test.

[0039] Various modifications to these embodiments will be obvious to those skilled in the art. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present utility model. Therefore, the present utility model will not be limited to these embodiments shown herein, but rather will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A pre-failure short-circuit test device for a gapless metal oxide arrester, characterized in that: include: A lightning arrester to be tested, a voltage probe, a current coil, a voltage and current collector, a shunt resistor switch, a programmable power supply, a processor and a booster coil T1. The programmable power supply outputs a preset voltage value and boosts the voltage of the booster coil T1 connected thereto. Two paths of the booster coil T1 are respectively connected to the shunt resistor switch and the current coil. The two ends of the lightning arrester to be tested are respectively connected to the output ends of the shunt resistor switch and the current coil. The voltage probe is connected to the two ends of the lightning arrester to detect the real-time voltage at the two ends of the lightning arrester to be tested. The two ends of the voltage and current collector are respectively connected to the voltage probe and the current coil to collect the voltage and current values ​​of the voltage probe and the current coil. The voltage and current collector is connected to the processor, and the processor controls and adjusts the output voltage of the programmable power supply.

2. The pre-failure short-circuit test device for gapless metal oxide arrester according to claim 1, characterized in that: The shunt resistor switch includes a first resistor R1 and a first level of a first switch K1; a second resistor R2 and a second level of a second switch K2; and a third resistor R3 and a third level of a third switch K3.

3. The pre-failure short-circuit test device for gapless metal oxide arrester according to claim 1, characterized in that: The shunt resistor switch includes a first resistor R1 and a first gear of a first switch K1; a second resistor R2 and a second gear of a second switch K2; a third resistor R3 and a third gear of a third switch K3; a fourth resistor R4 and a fourth gear of a fourth switch K4; and an nth resistor Rn and an nth gear of an nth switch Kn.

4. The pre-failure short-circuit test device for gapless metal oxide arrester according to claim 1, characterized in that: The shunt resistor switch is a sliding resistor RS.

5. The pre-failure short-circuit test device for gapless metal oxide arrester according to claim 1, characterized in that: The current flowing through the arrester under test is kept within the range of 10-30A.

6. The pre-failure short-circuit test device for gapless metal oxide arrester according to claim 1, characterized in that: The processor comprises a host computer and an ARM controller, the host computer is connected to the ARM controller through a serial interface, and the voltage and current collector is connected to the host computer through a network communication interface to obtain the voltage value and current value of the arrester.

7. The pre-failure short-circuit test device for a gapless metal oxide arrester according to claim 6, characterized in that: The ARM controller is communicatively connected with the program-controlled power supply via the SPI module.

8. The pre-failure short-circuit test device for gapless metal oxide arrester according to claim 1, characterized in that: An overcurrent protector is provided at the input end of the programmable power supply.

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