CN118130858A - Withstand voltage test discharge breakdown protection device - Google Patents
Withstand voltage test discharge breakdown protection device Download PDFInfo
- Publication number
- CN118130858A CN118130858A CN202410301651.8A CN202410301651A CN118130858A CN 118130858 A CN118130858 A CN 118130858A CN 202410301651 A CN202410301651 A CN 202410301651A CN 118130858 A CN118130858 A CN 118130858A
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- current
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- transformer
- relay
- normally open
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- 238000012360 testing method Methods 0.000 title claims abstract description 29
- 230000015556 catabolic process Effects 0.000 title claims abstract description 25
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims abstract description 32
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 29
- 239000010703 silicon Substances 0.000 claims abstract description 29
- 238000000034 method Methods 0.000 abstract description 8
- 238000001514 detection method Methods 0.000 abstract description 3
- 230000002633 protecting effect Effects 0.000 abstract 1
- 230000009471 action Effects 0.000 description 8
- 238000009413 insulation Methods 0.000 description 6
- 238000007599 discharging Methods 0.000 description 3
- 230000008569 process Effects 0.000 description 3
- 230000004044 response Effects 0.000 description 3
- 230000007547 defect Effects 0.000 description 2
- 230000003449 preventive effect Effects 0.000 description 2
- 230000008439 repair process Effects 0.000 description 2
- 238000013142 basic testing Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000003990 capacitor Substances 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R1/00—Details of instruments or arrangements of the types included in groups G01R5/00 - G01R13/00 and G01R31/00
- G01R1/36—Overload-protection arrangements or circuits for electric measuring instruments
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/12—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing
- G01R31/14—Circuits therefor, e.g. for generating test voltages, sensing circuits
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Testing Relating To Insulation (AREA)
Abstract
The invention relates to the technical field of high-voltage electric voltage withstand test equipment, in particular to a discharge breakdown protection device for a voltage withstand test. The overcurrent protection method of the voltage-withstanding device adopts the mode that a detection element is connected in series with the ground wire end at the high voltage side of the step-up transformer, the discharge breakdown condition of a high-voltage loop is directly detected, the method that the overcurrent of the traditional voltage-withstanding test is detected through the input end of the step-up transformer is abandoned, meanwhile, an electronic circuit and a silicon controlled rectifier are adopted as a switch for protecting action to break down, the fact that after the overcurrent is broken down by equipment, the power is cut off in the shortest time and at an alternating current zero crossing point, and the equipment to be tested is furthest protected from being damaged and expanded due to continuous long-time discharge after the voltage-withstanding breakdown is avoided.
Description
Technical Field
The invention relates to the technical field of electronics, in particular to a discharge breakdown protection device for a withstand voltage test.
Background
The preventive power frequency alternating current withstand voltage test in the power system is the most direct method for identifying the insulation strength of the electrical equipment, and the insulation defect can be truly and effectively found, so that the power frequency alternating current withstand voltage test is the most basic test item in the preventive test items of the power system; however, when the tested equipment is subjected to discharge breakdown, arc heating effect is continuously generated at the breakdown point, so that the damage degree of the breakdown point is increased continuously along with the extension of time, and the shorter the power-off time is, the smaller the damage of the tested equipment is, and the lower the later repair cost is. The traditional power frequency withstand voltage test equipment adopts the method that the output current of a transformer is detected at the output end of an autotransformer, when a test sample tested at the side of a step-up transformer is in discharge breakdown short circuit, the output current of the autotransformer also exceeds an allowable value, and a relay protection device for detecting the output current of the autotransformer sends an action instruction at the moment to trip the action of a contactor, and the autotransformer is powered off and the step-up transformer is powered off; the protection device has the following defects: 1. the protection device adopts the traditional relay protection device, the action response time is about 100ms, and the tested equipment still receives the burning loss of breakdown discharge current in the time of 100ms, so that the burning loss of the insulation weak part of the tested equipment is serious, and the repair cost is increased; 2. because the traditional protection tripping power-off adopts the direct power-off of the main contact of the contactor, and the current of the transformer is suddenly changed to zero, reverse potential which is multiple times generated at the output end of the transformer is generated, and the tested equipment and the step-up transformer are damaged further.
Disclosure of Invention
Aiming at the technical problems, the invention provides a discharge breakdown protection device for a voltage withstand test, which is used for solving the problems that the prior protection device has long power-off time after breakdown and is easy to generate reverse potential after power-off and serious damage to tested equipment is caused during the voltage withstand test.
In order to achieve the above purpose, the technical scheme of the invention is as follows:
a withstand voltage test discharge breakdown protection device comprising: the device comprises an operation control box, a pair of contactor normally open contacts, a boosting transformer, a first current limiting resistor, a tested device, a boosting transformer output grounding terminal and a second current limiting resistor, wherein the operation control box is connected with the L end and the N end of a power supply;
The device also comprises a first silicon controlled rectifier, a second silicon controlled rectifier and a direct current stabilized voltage supply, wherein one end of the first silicon controlled rectifier and one end of the second silicon controlled rectifier are connected in reverse parallel and then connected with the output end of the autotransformer, the other end of the first silicon controlled rectifier and one end of the second silicon controlled rectifier are connected with the input end of the step-up transformer, and the first silicon controlled rectifier control electrode and the second silicon controlled rectifier control electrode are correspondingly connected with a first normally-closed contact and a second normally-closed contact of the optocoupler relay;
The grounding end of the tested equipment is connected in series with the primary side of the current transformer, the secondary side of the current transformer is connected with the alternating current side of the single-phase bridge rectifier, the positive electrode of the single-phase bridge rectifier is connected with the cathode of the voltage-stabilizing diode, the negative electrode of the single-phase bridge rectifier is connected with the anode of the voltage-stabilizing diode, the positive electrode and the negative electrode of the single-phase bridge rectifier are also connected with the adjustable resistor, the positive electrode of the single-phase bridge rectifier is connected with the anode of the normally open contact input side light-emitting diode of the optocoupler relay through the second current limiting resistor, the cathode of the normally open contact input side light-emitting diode of the optocoupler relay is connected with the anode of the normally closed contact input side light-emitting diode of the optocoupler relay, and the cathode of the normally closed contact input side light-emitting diode of the optocoupler relay is connected with the negative electrode of the single-phase bridge rectifier;
The input end of the direct current stabilized power supply is connected with the output ends of a pair of normally open contacts of the contactor, the positive electrode of the direct current stabilized power supply is connected with the first normally open contact of the opto-coupler relay in series, the second normally open contact of the opto-coupler relay is connected with the micro-relay, the micro-relay is connected with the negative electrode of the direct current stabilized power supply, the second normally open contact of the opto-coupler relay is connected with the positive electrode of the diode, the negative electrode of the diode is connected with the positive electrode of the rectifier bridge, and the normally closed contact of the micro-relay is connected with the coil branch of the contactor of the operation control box in series.
Compared with the prior art, the invention has the beneficial effects that: a current transformer is connected in series to the output ground terminal of the step-up transformer to isolate the value of the high-voltage side current, so that the insulation current and the capacitor discharge current of the tested equipment can be directly and effectively detected for monitoring; in the withstand voltage test process of the tested equipment, the rapid response of the over-fixed value of the partial discharge current and the insulation breakdown current occurs, and the corresponding response time of the action is less than 2ms; in the withstand voltage test process, partial discharge and insulation breakdown occur, and when the test power supply is disconnected in the protection action, the characteristic of zero crossing shutoff of the current of the silicon controlled rectifier is utilized, so that the damage of reverse overvoltage generated by the step-up transformer to equipment is avoided when the power supply is disconnected by the traditional switch.
Drawings
FIG. 1 is a schematic circuit diagram of the present invention;
FIG. 2 is a graph showing a waveform of leakage current after a device under test is subjected to a high voltage in a conventional manner;
Fig. 3 is a graph showing discharge breakdown waveform detection in the withstand voltage test after using the present invention.
Description of the drawings:
1. A normally open contact of the contactor; 2. an autotransformer; 3. a step-up transformer; 4. a first current limiting resistor; 5. operating a control box; 6. a device under test; 7. a first silicon controlled rectifier; 8. a second silicon controlled rectifier; 9. a current transformer; 10. a DC stabilized power supply; 11. a single phase bridge rectifier; 12. zener diode, 13: optocoupler relay, 14: the adjustable resistor, 15, second current limiting resistor; 16. a diode; 17. a micro relay; 18. normally closed contacts of the micro-relay; 19. a first thyristor control electrode; 20. a second thyristor control electrode; 21. a first normally open contact; 22. a second normally open contact; 23. a first normally closed contact; 24. and a second normally-closed contact.
Detailed Description
The objects, technical solutions and advantages of the present invention will become more apparent by the following detailed description of the present invention with reference to the accompanying drawings. It should be understood that the description is only illustrative and is not intended to limit the scope of the invention. In addition, in the following description, descriptions of well-known structures and techniques are omitted so as not to unnecessarily obscure the present invention.
A withstand voltage test discharge breakdown protection device comprising: the device comprises an operation control box 5, wherein the operation control box 5 is connected with an L end and an N end of a power supply, one ends of a pair of normally open contacts 1 of a contactor controlled by the operation control box 5 are respectively connected with the L end and the N end of the power supply, the other ends of the normally open contacts 1 of the pair of contactors are connected with the input end of an autotransformer 2, the output end of the autotransformer 2 is connected with the input end of a step-up transformer 3, one end of a high-voltage output end of the step-up transformer 3 is connected with one end of a first current limiting resistor 4, the other end of the first current limiting resistor 4 is connected with a tested device 6, and meanwhile, the other ends of the tested device 6 and an output grounding end of the step-up transformer 3 are connected and then connected to the ground;
The direct-current power supply comprises a first silicon controlled rectifier 7, a second silicon controlled rectifier 8 and a direct-current stabilized power supply 10, wherein one end of the first silicon controlled rectifier 7 and one end of the second silicon controlled rectifier 8 are connected in reverse parallel and then connected with the output end of an autotransformer 2, the other end of the first silicon controlled rectifier is connected with the input end of a step-up transformer 3, and a first silicon controlled rectifier control electrode 19 and a second silicon controlled rectifier control electrode 20 are correspondingly connected with a first normally-closed contact 23 and a second normally-closed contact 24 of an optocoupler relay 13;
The grounding end of the tested device 6 is connected in series with the primary side of the current transformer 9, the secondary side of the current transformer 9 is connected with the alternating-current side of the single-phase bridge rectifier 11, the positive electrode of the single-phase bridge rectifier 11 is connected with the cathode of the zener diode 12, the negative electrode of the single-phase bridge rectifier 11 is connected with the anode of the zener diode 12, the positive electrode and the negative electrode of the single-phase bridge rectifier 11 are also connected with the adjustable resistor 14, the positive electrode of the single-phase bridge rectifier 11 is connected with the anode of the normally open contact input side light emitting diode of the optocoupler relay 13 through the second current limiting resistor 15, the cathode of the normally open contact input side light emitting diode of the optocoupler relay 13 is connected with the anode of the normally closed contact input side light emitting diode of the optocoupler relay 13, and the cathode of the normally closed contact input side light emitting diode of the optocoupler relay 13 is connected with the negative electrode of the single-phase bridge rectifier 11;
The input end of the direct current stabilized power supply 10 is connected with the output ends of a pair of normally open contacts 1 of the contactor, the positive pole of the direct current stabilized power supply 10 is connected with a first normally open contact 21 of an optocoupler relay 13 in series, a second normally open contact 22 of the optocoupler relay 13 is connected with a micro relay 17, the micro relay 17 is connected with the negative pole of the direct current stabilized power supply 10, the second normally open contact 22 of the optocoupler relay 13 is connected with the anode of a diode 16, the cathode of the diode 16 is connected with the positive pole of a rectifier bridge, and the normally closed contact of the micro relay 17 is connected with a contactor coil branch of the operation control box 5 in series.
The withstand voltage test device regulates the voltage of the autotransformer 2, and boosts the voltage to a preset value through the boosting transformer 3, so as to carry out a withstand voltage test on the tested equipment 6; in the test process, if the tested device 6 is discharged and broken down, the secondary side of the current transformer 9 connected in series in the loop of the tested device 6 has the condition of current surge, the surge current passes through the single-phase bridge rectifier 11 to be rectified into current direct current, and the current direct current flows through the adjustable resistor 14, the second current limiting resistor 15 and the two light emitting diodes 16 of the optocoupler relay 13 and is connected in parallel with the voltage stabilizing diode 12 between the positive electrode and the negative electrode of the single-phase bridge rectifier 11, so that the voltage rise caused by the current can be stabilized, protected and limited; when two light emitting diodes of the optocoupler relay 13 emit light, pins of a first normally-closed contact 23 and a second normally-closed contact 24 of the optocoupler relay 13 are disconnected, so that a power supply of the step-up transformer 3 is disconnected when a current zero crossing point is cut off, a quick power-off protection function is achieved, meanwhile, pins of a first normally-open contact 21 and a second normally-open contact 22 of the optocoupler relay 13 are short-circuited and closed, a continuous working power supply is improved for the optocoupler relay 13, continuous disconnection of the pins of the first normally-closed contact 23 and the second normally-closed contact 24 of the optocoupler relay 13 is guaranteed, coils of the micro-relay 17 are powered on, and the micro-relay normally-closed contact 18 is disconnected to operate a control circuit in the control box 5, so that the normally-open contact 1 of the contactor is released to be disconnected, and reliable power-off of the withstand voltage test device is completed.
As shown in fig. 2, a waveform line a is a leakage current waveform line of the tested device 6 after being subjected to high voltage; the waveform line B in the figure is a voltage waveform line that the test device 6 receives. From the graph, when the amplitude of the waveform line a suddenly increases (the leakage current suddenly increases), that is, when the sample is broken down, the voltage of the step-up transformer is simultaneously pulled down, and the protection trip power-off (that is, the applied voltage is reset to zero and the discharge current is reset to zero) is performed after the breakdown discharge time of nearly 100ms, that is, the tested device 6 bears the breakdown discharge damage of nearly 100 ms.
As shown in fig. 3, a discharge breakdown waveform detection chart of a withstand voltage test after the device of the invention is additionally arranged is shown; it can be seen from the graph that when the amplitude of the waveform line a suddenly increases (the tested device 6 is not completely broken down, the discharge current does not reach the preset action value of the adjustable resistor, and the discharge current does not reach the protection fixed value, so that the newly-installed protection device of the device does not act, after the lapse of approximately 5ms, the discharge current is suddenly increased, the newly-increased protection is started, the control electrodes of the first silicon controlled rectifier 7 and the second silicon controlled rectifier 8 at the input end of the step-up transformer are disconnected, so that when the power frequency current passes through the zero point, the silicon controlled rectifier is not freewheeling, and is turned off and cut off, the tested device 6 can be seen to pass through 5ms discharge (because the discharge current does not reach the preset action value of the newly-added device), and when the occurrence of the complete breakdown current reaches the preset value, the step-up transformer is powered off when the breakdown leakage current is less than 8ms, namely the tested device 6 bears the breakdown discharge damage of approximately 8+5 ms. If the action current adjusting potentiometer 14 of the newly added protection device is adjusted ideally in the test, the protection device is started at the initial stage of discharging the tested device 6, the tested device 6 only receives 5ms discharging impact, and the power frequency discharging current can cross the zero point, so that the problem that the subsequent tested device 6 is broken down is possibly avoided.
The foregoing description of the preferred embodiments of the invention is not intended to limit the invention to the precise form disclosed, and any such modifications, equivalents, and alternatives falling within the spirit and scope of the invention are intended to be included within the scope of the invention.
Claims (1)
1. A withstand voltage test discharge breakdown protection device comprising: the device comprises an operation control box (5), wherein the operation control box (5) is connected with the L end and the N end of a power supply, one ends of a pair of normally open contacts (1) of the contactor controlled by the operation control box (5) are respectively connected with the L end and the N end of the power supply, the other ends of the normally open contacts (1) of the pair of the contactor are connected with the input end of an autotransformer (2), the output end of the autotransformer (2) is connected with the input end of a step-up transformer (3), one end of a high-voltage output end of the step-up transformer (3) is connected with one end of a first current-limiting resistor (4), the other end of the first current-limiting resistor (4) is connected with a tested device (6), and the other end of the tested device (6) is connected with the output grounding end of the step-up transformer (3) simultaneously and then connected with the ground, and the device is characterized in that: the direct-current power supply comprises a first controllable silicon (7), a second controllable silicon (8) and a direct-current stabilized power supply (10), wherein one end of the first controllable silicon (7) and one end of the second controllable silicon (8) are connected in reverse parallel and then connected with the output end of an autotransformer (2), the other end of the first controllable silicon is connected with the input end of a step-up transformer (3), and a first normally-closed contact (23) and a second normally-closed contact (24) of an optocoupler relay (13) are correspondingly connected with a first controllable silicon control electrode (19) and a second controllable silicon control electrode (20);
The grounding end of the tested device (6) is connected in series with the primary side of the current transformer (9), the secondary side of the current transformer (9) is connected with the alternating-current side of the single-phase bridge rectifier (11), the positive electrode of the single-phase bridge rectifier (11) is connected with the cathode of the voltage-stabilizing diode (12), the negative electrode of the single-phase bridge rectifier (11) is connected with the anode of the voltage-stabilizing diode (12), the positive electrode and the negative electrode of the single-phase bridge rectifier (11) are also connected with the adjustable resistor (14), the positive electrode of the single-phase bridge rectifier (11) is connected with the anode of the normally open contact input side light-emitting diode (16) of the optocoupler relay (13) through the second current limiting resistor (15), the cathode of the normally open contact input side light-emitting diode (16) of the optocoupler relay (13) is connected with the anode of the normally closed contact input side light-emitting diode (16), and the cathode of the normally closed contact input side light-emitting diode (16) of the optocoupler relay (13) is connected with the negative electrode of the single-phase bridge rectifier (11);
The input end of the direct current stabilized power supply (10) is connected with the output ends of a pair of normally open contacts (1) of the contactor, the positive electrode of the direct current stabilized power supply (10) is connected with a first normally open contact (21) of an optocoupler relay (13) in series, a second normally open contact (22) of the optocoupler relay (13) is connected with a micro relay (17), the micro relay (17) is connected with the negative electrode of the direct current stabilized power supply (10), the second normally open contact (22) of the optocoupler relay (13) is connected with the positive electrode of a diode (16), the negative electrode of the diode (16) is connected with the positive electrode of a rectifier bridge, and the normally closed contact (18) of the micro relay is connected with a contactor coil branch of an operation control box (5) in series.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410301651.8A CN118130858A (en) | 2024-03-16 | 2024-03-16 | Withstand voltage test discharge breakdown protection device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410301651.8A CN118130858A (en) | 2024-03-16 | 2024-03-16 | Withstand voltage test discharge breakdown protection device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN118130858A true CN118130858A (en) | 2024-06-04 |
Family
ID=91243100
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202410301651.8A Pending CN118130858A (en) | 2024-03-16 | 2024-03-16 | Withstand voltage test discharge breakdown protection device |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN118130858A (en) |
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2024
- 2024-03-16 CN CN202410301651.8A patent/CN118130858A/en active Pending
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