CN114895116A

CN114895116A - Capacitor discharge test device

Info

Publication number: CN114895116A
Application number: CN202210321732.5A
Authority: CN
Inventors: 徐德勤; 罗景华; 潘荣臻
Original assignee: Ningbo Tianan Electric Technology Co ltd
Current assignee: Ningbo Tianan Electric Technology Co ltd
Priority date: 2022-03-30
Filing date: 2022-03-30
Publication date: 2022-08-12

Abstract

The invention discloses a capacitor discharge test device, which belongs to the technical field of low-voltage complete switch equipment industry and solves the problem of low efficiency of manual test and test of a capacitor, and the technical scheme is characterized by comprising a PC (personal computer), a voltage regulating module, a boosting module, a rectifying module, a current limiting module, a switch module, a measurement and control module, a display module and a timing module, wherein the PC is used for data communication and data display; the voltage regulating module is connected with alternating current power supply input and supplies power, the output of the voltage regulating module sequentially passes through the boosting module, the rectifying module, the current limiting module and the switch module, the measurement and control module is connected to the switch module and used for regulating and controlling a direct current output value, current signal data and voltage signal data are measured, the timing module is used for providing timing data, the display module is used for displaying a state signal, the measurement and control module is also connected with the communication interface module, the communication interface module is used for being in communication connection with a PC and transmitting data, and the effect of an automatic high-efficiency test is achieved.

Description

Capacitor discharge test device

Technical Field

The invention relates to the field of low-voltage complete switch equipment industry, in particular to a capacitor discharge test device.

Background

The 10.20.5 item in the standardized design scheme (2020 edition) of low-voltage switch cabinets made by the national grid company requires discharge tests on reactive compensation capacitors used in national grid standard low-voltage cabinets, and the specific requirements are as follows: the discharge test is carried out on capacitors with different capacities, the capacitors are charged to a rated voltage peak value by a direct current method, then a discharge device is switched on, a discharge facility of the device ensures that the time from the rated voltage peak value to 50V is not more than 3min after the capacitors are powered off, and the test is met after 5 times of continuous measurement.

The rated voltage of the capacitor used in the low-voltage reactive power compensation cabinet is generally AC400 to AC550V, and the peak voltage of the capacitor is about 1.414 times of the rated voltage, namely the peak voltage of the common capacitor is 566V to 778V.

The conventional discharge test method is to charge a capacitor using a direct current power supply having an output voltage of about DC800V, measure a voltage across the capacitor using a voltage measuring meter, and stop charging when a peak voltage of the capacitor is reached. And (3) starting timing by using a stopwatch, starting discharging of the capacitor due to the fact that a discharging device is arranged in the capacitor, measuring the end voltage of the capacitor by using a voltage measuring meter, stopping timing by using the stopwatch when the voltage is discharged to 50V, reading the discharging time, continuously performing 5 times, and judging that the discharging time is less than 3 minutes after 5 times, wherein the test is qualified.

From the above, the conventional test method is completed manually, and is relatively complex, the test efficiency is low, and the waveform data of the discharge test cannot be recorded.

Disclosure of Invention

The invention aims to overcome the defects in the prior art, at least solves the technical problems in the related technology to a certain extent, and provides a capacitor discharge test device which has the advantages of automation of discharge test, process record storage, display of voltage waveform of a capacitor end in the discharge process and improvement of test precision and efficiency of products.

In order to solve the technical problems, the technical scheme of the invention is as follows: a capacitor discharge test device comprises a PC (personal computer) which is used for data communication and data display, and further comprises a voltage regulating module, a boosting module, a rectifying module, a current limiting module, a switch module, a measurement and control module, a display module and a timing module;

the voltage regulation module is connected AC power supply input and is carried out power supply, and the output of voltage regulation module is through module, rectifier module, current limiting module and the switch module of stepping up in proper order, and the scope of exporting DC power supply at switch module's output is 0-1000V adjustable, observe and control module connection is on switch module and is used for regulation and control direct current output value, measurement current signal data, measurement voltage signal data, the timing module is used for providing timing data, display module is used for showing status signal, and communication interface module is still connected to observe and control module, and communication interface module is used for carrying out data transfer with PC communication connection.

Preferably, the voltage regulating module adopts an autotransformer, the input is AC220V, the output is AC0-250V, and the amplitude of the final DC output voltage is controlled by the voltage regulating module to be matched with the peak voltage of the tested capacitor.

Preferably, the boosting module uses an isolation transformer to further boost the output voltage of the voltage regulating module by multiple times.

Preferably, the rectifier module rectifies the alternating current into direct current, and a bridge rectifier structure is adopted.

Preferably, the current limiting module limits current by using a resistor, and when the dc output voltage is the peak voltage of the capacitor, the current limiting resistor can limit the on-rush current of the capacitor to be below 2A.

Preferably, the switch module is controlled by the control module and is responsible for switching on and switching off the direct current output circuit, when the switch module is switched on, the direct current power supply charges the capacitor, the voltage of the end of the capacitor is gradually increased, and when the switch module is switched off, the capacitor automatically discharges, and the voltage of the end of the capacitor is gradually decreased.

Preferably, the measurement and control module is responsible for measuring and transmitting the voltage value of the capacitor end, is responsible for connecting and disconnecting the direct current charging circuit, is responsible for starting the timing module to time, is responsible for communicating with the PC to transmit data, and is responsible for displaying signals by the display module.

Preferably, a charging stop threshold and a discharging stop threshold of the capacitor are arranged on the measurement and control module, and the measurement and control module performs on-off control of the switch module according to the set thresholds;

when the voltage of the capacitor terminal reaches a charging stop threshold value, a threshold relay in the measurement and control module acts, the switch module cuts off a charging loop, and the capacitor starts to discharge;

when the voltage of the capacitor end is just lower than the threshold value, the threshold relay is reset, and the timing module is started to start timing;

when the voltage of the capacitor end reaches a discharge stop threshold, a threshold relay acts to stop the timing module to time;

the timing module measures the discharge time of the capacitor terminal voltage as it falls from the nominal peak voltage to 50V.

Preferably, still include the workstation, the slip table power supply container places, be provided with the slip table that removes on the workstation, be provided with the magnet on the slip table, be provided with interval control module on the condenser discharge test device, interval control module includes infrared distance sensor, comparison module, drive module and the electromagnet assembly that the induction magnet is close to the distance, infrared distance sensor connects comparison module, and drive module is connected to comparison module's output, and electromagnet assembly is connected to drive module, and wherein, comparison module judges when the magnet is close to the distance and is less than the threshold value, triggers drive module work, and drive module switches on the electromagnet coil, and electromagnet coil produces and pushes away the slip table to the repulsion of magnet opposition.

Preferably, the threshold value for comparison in the comparison module is set by a potentiometer adjustment.

Compared with the background technology, the technical effects of the invention are mainly reflected in the following aspects: compared with the traditional test method, the scheme realizes the automation of the discharge test process of the capacitor and improves the test efficiency. According to the scheme, the measured data is digitized, the timing module is started and stopped automatically, manual operation errors are eliminated, and the precision of test data is improved. The scheme realizes the visual display of the discharge voltage waveform and the recording of the waveform data, and realizes the traceability of test data.

Drawings

FIG. 1 is a block diagram of a circuit block according to one embodiment;

FIG. 2 is a schematic front view of the embodiment;

FIG. 3 is a schematic diagram of a backside structure of the embodiment;

FIG. 4 is a schematic circuit diagram of a second exemplary embodiment of an intermediate distance control module;

FIG. 5 is a schematic diagram showing a mode of use in the second embodiment.

Reference numerals: 101. a PC machine; 102. a voltage regulating module; 103. a boost module; 104. a rectification module; 105. a current limiting module; 106. a switch module; 107. a measurement and control module; 108. a display module; 109. a timing module; 110. a communication interface module; 300. a work table; 400. a sliding table; 500. a magnet; 600. a spacing control module; 601. an infrared distance sensor; 602. a comparison module; 603. a drive module; 604. an electromagnet assembly.

Detailed Description

The following detailed description of the embodiments of the present invention is provided in order to make the technical solution of the present invention easier to understand and understand.

Example (b):

a capacitor discharge test device is shown in figure 1 and comprises a PC (personal computer) 101, wherein the PC 101 is used for data communication and data display, and further comprises a voltage regulating module 102, a boosting module 103, a rectifying module 104, a current limiting module 105, a switch module 106, a measurement and control module 107, a display module 108 and a timing module 109.

The voltage regulating module 102 is connected with the input of an alternating current power supply and supplies power, the output of the voltage regulating module 102 sequentially passes through the boosting module 103, the rectifying module 104, the current limiting module 105 and the switch module 106, and the range of outputting the direct current power supply at the output end of the switch module 106 is adjustable within 0-1000V. The measurement and control module 107 is connected to the switch module 106 and is used for regulating and controlling a direct current output value, measuring current signal data and measuring voltage signal data, the timing module 109 is used for providing timing data, the display module 108 is used for displaying a state signal, the measurement and control module 107 is further connected with the communication interface module 110, and the communication interface module 110 is used for being in communication connection with the PC 101 and transmitting data.

Specifically, the voltage regulating module 102 is an autotransformer, the input is AC220V, the output is AC0-250V, and the amplitude of the final dc output voltage is controlled by the voltage regulating module 102 to match the peak voltage of the capacitor under test. The pressure regulating mode can be manual pressure regulation. The boost module 103 further boosts the output voltage of the voltage regulation module 102 by 3 times using an isolation transformer. The utility model has the advantages of play the effect of keeping apart the commercial power, ensure safety. The rectifier module 104 rectifies the ac power into dc power, and adopts a bridge rectifier structure. The current limiting module 105 limits current using a resistor, which limits the on inrush current to the capacitor to below 2A when the dc output voltage is the capacitor peak voltage, preventing impact damage to the capacitor and the device. The switch module 106 is controlled by the measurement and control module 107 and is responsible for switching on and off the direct current output circuit, when the direct current output circuit is switched on, the direct current power supply charges the capacitor, the voltage of the end of the capacitor is gradually increased, when the direct current output circuit is switched off, the capacitor automatically discharges, and the voltage of the end of the capacitor is gradually decreased. The measurement and control module 107 is responsible for measuring and transmitting the voltage value of the capacitor end, for connecting and disconnecting the direct current charging circuit, for starting the timing module 109 to time, for communicating with the PC 101 to transmit data, and for displaying signals by the display module 108. The timing module 109 enables in-situ timing and display of capacitor discharge time.

The discharge test device completes the functions of direct-current power generation, capacitor charge and discharge control, capacitor end voltage measurement, timing display and the like. The PC 101 is connected with the discharge test device by using an MODBUS protocol through a serial port or a USB port of the PC 101, so that the functions of accurate measurement of discharge time, discharge waveform display and discharge test data record storage are realized.

A charging stop threshold and a discharging stop threshold of the capacitor are set on the measurement and control module 107, and the measurement and control module 107 performs on-off control of the switch module 106 according to the set thresholds; when the voltage of the capacitor terminal reaches the charging stop threshold, a threshold relay in the measurement and control module 107 acts, the switch module 106 cuts off the charging loop, and the capacitor starts to discharge; when the voltage of the capacitor end is just lower than the threshold value, the threshold relay is reset, and the timing module 109 is started to start timing; when the voltage of the capacitor end reaches the discharge stop threshold, the threshold relay acts to stop the timing module 109 to time; the timing module 109 meters the discharge time of the capacitor terminal voltage as it falls from the nominal peak voltage to 50V.

The PC 101 end is provided with an MODBUS communication module, a human-computer interaction interface, a discharge waveform display module 108, a database recording module and the like. And the MODBUS communication module is responsible for program communication with the discharge test device, transmits the charge and discharge threshold data to the test device and reads the voltage value of the capacitor end from the test device.

And the human-computer interaction interface completes the setting of the charging and discharging threshold value, displays the instant capacitor end voltage value read from the discharging test device and displays accurate real-time discharging time. The interface also provides the function of automatically calculating the rated peak voltage of the capacitor with different rated voltages, and is convenient for testers to use.

The discharge waveform display module 108 is responsible for drawing a start end voltage real-time value polygonal line waveform chart when the voltage of the capacitor end is reduced to a rated peak voltage, the abscissa is discharge time, the ordinate is a voltage value, and sampling is carried out for 5 times per second.

And the database recording module is used for recording all voltage amplitudes and time values in the waveform drawing process into a database for storage, judging by using a test result, backtracking data, redrawing the discharge voltage waveform and the like.

Working process

Before the discharge test is started, firstly, the internal connecting wire of the tested capacitor is removed, and the direct current power supply output end of the discharge test device is connected with the capacitor connecting terminal by using a special test connecting wire. The PC 101 is connected with the communication interface terminal of the discharge test device through a serial port by using a shielding twisted pair, and the PC 101 without the serial port can be connected with the discharge test device through a USB interface by using USB-to-serial port equipment.

And adjusting the handle of the voltage regulator of the discharge test device to the minimum position, and switching on the power supply of the test device. The control terminal of the dedicated PC 101 is started, the capacitor rated peak voltage is calculated from the capacitor rated voltage, and the peak voltage is set as the charge stop threshold voltage by the control terminal of the PC 101. The discharge stop threshold voltage was set to 50V.

The control end of the PC 101 is well provided with relevant test information, the number of continuous tests is set to be 5, and a 'test starting' button is clicked to start the test.

And operating a starting button of the discharge test device to switch on the charging loop. And operating a voltage regulating handle of the discharge test device to slowly increase the voltage, and when the charging voltage is higher than a set charging stop threshold value, actuating a threshold relay to control the switch module 106 to disconnect the charging loop, and stopping rotating the voltage regulating handle.

The capacitor enters a free discharge state and the terminal voltage begins to drop. When the terminal voltage just drops below the charging stop threshold, the threshold relay returns and controls the timing module 109 to start timing.

When the voltage of the capacitor end is just reduced to be below 50V, the discharging stops the action of the threshold relay, and the timing module 109 stops timing. The first test was completed. At this time, the time displayed by the timing module 109 is the discharge test result time.

When the next test is needed, only the starting button of the discharge test device is operated, and the voltage regulating handle is not needed to be operated, so that the test can be automatically completed. Until all 5 trials were completed.

The control end of the PC 101 records the discharge time of each time and displays an instantaneous discharge waveform chart.

After the test, the test result was judged by 5 discharge times.

Because the voltage sampling period of the measurement and control module 107 is less than 0.2 second, the maximum error of the starting timing and the ending timing is respectively 0.2 second, the maximum error of the discharge time timing is 0.4 second, and the discharge time of a capacitor generally exceeds 120 seconds, the measurement precision is higher than 0.3%, and the measurement precision is very high.

The method steps of operation are further understood in conjunction with fig. 2 and 3:

firstly, capacitor wiring.

1. And connecting the three-phase capacitors. Any two of three binding posts of the three-phase power capacitor are connected, the 9 th direct current output positive pole of the testing device is connected with the two binding posts connected with the capacitor, and the 10 th direct current output negative pole of the testing device is connected with the third binding post independent of the capacitor.

2. The single-phase capacitor is wired. And connecting the direct current output positive pole of the 9 th end of the test device with the first capacitor wiring terminal, and connecting the direct current output negative pole of the 10 th end of the test device with the second capacitor wiring terminal.

And secondly, resetting the voltage regulator. In order to prevent the initial voltage output from being too high, the handle of the voltage regulator 2 of the test device is turned to the bottom anticlockwise, and the voltage regulator is arranged at 0 position.

And thirdly, switching on a main power supply. The test device power switch 1 is closed, the main power supply is switched on, and the test device indicator lamp 6 and the instruments 7 and 8 are lighted.

And fourthly, setting overvoltage and undervoltage alarm values of a voltmeter 8 of the testing device. The over-voltage and under-voltage alarm values of the voltmeter are set according to one of the following two methods.

1. The peak voltage is calculated. And multiplying the rated voltage of the capacitor by 1.414, and rounding to obtain the peak voltage of the capacitor. According to the method of the specification of the measurement and control device, setting the overvoltage alarm value of the measurement and control device as the peak voltage of the capacitor; the under-voltage alarm value is set to 50V.

2. And an output line for switching the serial port of the notebook computer to 485 is connected with the 5 th and 6 th terminals of the secondary wiring terminal 12 of the testing device. The PC 101 operates to select a capacitor of a corresponding capacity and rated voltage to automatically complete the peak voltage calculation. And then, setting a button, and setting the overvoltage and undervoltage alarm values of the measurement and control device to be the peak voltage of the capacitor and 50V.

And fifthly, switching on a test loop power supply. And a closing button 4 of the test device is pressed to connect a power supply of the test loop, and the output loop of the test device outputs direct-current voltage.

And sixthly, adjusting the voltage output value to the test loop to automatically cut off. While observing the display value of the voltmeter 8 of the test device, the handle of the voltage regulator 2 of the test device is slowly rotated clockwise until the test loop acts, the red light 5 of the test device is turned off, and the green light 6 is turned on. This is when the test device timing module 1097 starts timing.

And seventhly, reading the time value of the timing module 109. When the voltage of the capacitor end is reduced to below 50V, the test device measuring and control device 8 performs under-voltage alarm action, and the timing module 109 stops timing. The value of the timing module 109 is read and the value is in seconds. This value is the capacitor discharge time.

And eighthly, switching on a test loop and starting the next discharge test. And pressing a switching-on button 4 of the test device to switch on the test loop, starting to recharge the capacitor by the test device according to the current not greater than 2A, and automatically actuating the test loop when the peak voltage of the capacitor is reached.

And ninthly, repeating the seventh step and the eighth step until 5 tests are completed. And (5) waiting for several minutes, and disconnecting the power switch 1 of the testing device after the reading of the voltmeter is less than 10V, removing the connecting wire and finishing the capacitor discharge test.

And (6) qualification judgment. If the discharge time value of the capacitor is not more than 180 seconds in 5 times of tests. The test is passed, and the capacitor is qualified.

The second embodiment:

referring to fig. 4 and 5, the present solution includes a workbench 300, a groove is formed on a horizontal surface of the workbench 300, a sliding table 400 is disposed in the groove, the sliding table 400 is used for placing a power supply container, and the sliding table 400 can move in the groove. The worktable 300 is provided with a movable sliding table 400, the sliding table 400 is provided with a magnet 500, and the capacitor discharge test device is provided with an interval control module 600. The distance control module 600 includes an infrared distance sensor 601 for sensing the approaching distance of the magnet 500, a comparison module 602, a driving module 603, and an electromagnet assembly 604. The infrared distance sensor 601 is connected with the comparison module 602, the output end of the comparison module 602 is connected with the driving module 603, and the driving module 603 is connected with the electromagnet assembly 604. When the comparison module 602 determines that the approaching distance of the magnet 500 is smaller than the threshold, the driving module 603 is triggered to operate, the driving module 603 turns on the electromagnet coil, and the electromagnet coil generates a repulsive force opposite to the magnet 500 to push the sliding table 400 away. The threshold for comparison in the comparison module 602 is set by potentiometer adjustment.

The comparing module 602 includes a comparator LM1 and a potentiometer Rp, one end of the potentiometer Rp is connected to the voltage V, the other end of the potentiometer Rp is grounded, and the adjusting end of the potentiometer Rp can output a voltage threshold, which can be adjusted and set. When the voltage signal of the infrared distance sensor 601 is greater than the threshold value, the comparator LM1 outputs a high level. The driving module 603 comprises a triode T, resistors R10, R11, R12 and a photoelectric coupler U1, the base of the triode T is connected with the output of the comparator LM1, the collector of the triode T is connected with the voltage Vcc, the emitter of the triode T is connected with one end of the resistor R10 and one end of the resistor R11, the other end of the resistor R10 is connected with the anode of the photoelectric coupler U1, the other end of the resistor R11 is connected with the cathode and the grounding end of the photoelectric coupler U1, the 12V voltage is connected with the collector of the photoelectric coupler through the resistor R12, the emitter of the photoelectric coupler U1 is grounded through an electromagnet coil, therefore, when the sliding table 400 is close to the base, the infrared distance sensor 601 outputs a sensing signal, when the trigger distance is sensed, the comparator LM1 outputs a high level, thereby driving the transistor T to conduct, the photocoupler U1 is operated to make the electromagnet assembly 604 generate magnetic force, and the sliding platform 400 is moved away by the same pole repelling force.

Therefore, in the working process, the capacitors to be tested can be prevented from being close to each other in operation, and the working safety and reliability degree is improved.

The above are only typical examples of the present invention, and besides, the present invention may have other embodiments, and all the technical solutions formed by equivalent substitutions or equivalent changes are within the scope of the present invention as claimed.

Claims

1. A capacitor discharge test device comprises a PC (101), wherein the PC (101) is used for data communication and data display, and is characterized in that: the device also comprises a voltage regulating module (102), a boosting module (103), a rectifying module (104), a current limiting module (105), a switch module (106), a measurement and control module (107), a display module (108) and a timing module (109);

the voltage regulation module (102) is connected AC power supply input and is carried out power supply, and the output of voltage regulation module (102) is in proper order through boost module (103), rectifier module (104), current limiting module (105) and switch module (106), and the scope of output DC power supply at switch module (106) is 0-1000V adjustable, observe and control module (107) and connect on switch module (106) and be used for regulating and control the DC output value, measure current signal data, measurement voltage signal data, timing module (109) are used for providing timing data, display module (108) are used for showing status signal, observe and control module (107) and still connect communication interface module (110), and communication interface module (110) are used for and carry out data transfer with PC (101) communication connection.

2. A capacitor discharge test apparatus as claimed in claim 1, wherein: the voltage regulating module (102) adopts an autotransformer, the input is AC220V, the output is AC0-250V, and the amplitude of the final direct current output voltage is controlled by the voltage regulating module (102) to be matched with the peak voltage of the tested capacitor.

3. A capacitor discharge test apparatus as claimed in claim 1, wherein: the boosting module (103) uses an isolation transformer to further boost the output voltage of the voltage regulating module (102) by multiple times.

4. A capacitor discharge test apparatus as claimed in claim 1, wherein: the rectifying module (104) rectifies alternating current into direct current and adopts a bridge rectifying structure.

5. A capacitor discharge test apparatus as claimed in claim 1, wherein: the current limiting module (105) limits current by adopting a resistor, and when the direct current output voltage is the peak voltage of the capacitor, the current limiting resistor can limit the on-rush current of the capacitor to be below 2A.

6. A capacitor discharge test apparatus as claimed in claim 1, wherein: the switch module (106) is controlled by the measurement and control module (107) and is responsible for switching on and switching off the direct current output loop, when the direct current output loop is switched on, the direct current power supply charges the capacitor, the voltage of the end of the capacitor is gradually increased, when the direct current output loop is switched off, the capacitor automatically discharges, and the voltage of the end of the capacitor is gradually reduced.

7. A capacitor discharge test apparatus as claimed in claim 1, wherein: the measurement and control module (107) is responsible for measuring and transmitting the voltage value of the capacitor end, is responsible for connecting and disconnecting the direct current charging circuit, is responsible for starting the timing module (109) to time, is responsible for communicating with the PC (101) to carry out data transmission, and is responsible for displaying signals by the display module (108).

8. A capacitor discharge test apparatus as claimed in claim 1, wherein: a charging stop threshold and a discharging stop threshold of a capacitor are arranged on the measurement and control module (107), and the measurement and control module (107) controls the switch-on and switch-off of the switch module (106) according to the set thresholds;

when the voltage of the capacitor terminal reaches a charging stop threshold value, a threshold relay in the measurement and control module (107) acts, the switch module (106) cuts off a charging loop, and the capacitor starts to discharge;

when the end voltage of the capacitor is just lower than the threshold value, the threshold value relay resets, and the timing module (109) is started to start timing;

when the voltage of the capacitor end reaches a discharging stop threshold value, a threshold relay acts and a timing module (109) stops timing;

a timing module (109) measures the discharge time for the capacitor terminal voltage to drop from a nominal peak voltage to 50V.

9. A capacitor discharge test apparatus as claimed in claim 1, wherein: still include workstation (300), be provided with slip table (400) of removal on workstation (300), slip table (400) supply container places, be provided with magnet (500) on slip table (400), be provided with interval control module (600) on the condenser discharge test device, interval control module (600) include infrared distance sensor (601), comparison module (602), drive module (603) and electromagnet assembly (604) that induction magnet (500) are close to the distance, infrared distance sensor (601) are connected comparison module (602), and drive module (603) are connected to the output of comparison module (602), and electromagnet assembly (604) is connected to drive module (603), and wherein, when comparison module (602) judge that magnet (500) are close to the distance and are less than the threshold value, trigger drive module (603) and work, and electromagnet coil is put through to drive module (603), the electromagnet coil generates a repulsive force to the magnet (500) in opposite phase to push the sliding table (400) open.

10. A capacitor discharge test apparatus as claimed in claim 1, wherein: the threshold value for comparison in the comparison module (602) is set by potentiometer adjustment.