Partial discharge calibration pulse generator

Abstract

The partial discharge calibration pulse generator comprises an upper shell and a lower shell which are assembled, a circuit board is arranged in the upper shell, and a liquid crystal display screen, an operation key, a charging port, a positive terminal and a negative terminal which are respectively corresponding to through holes in the upper shell are arranged on one side, facing the upper shell, of the circuit board. The circuit board is further provided with a control mechanism used for controlling calibration of the partial discharge detector, the output end of the operation key is connected with the input end of the control mechanism, and the output end of the control mechanism is connected with the input end of the liquid crystal display screen, the input end of the positive terminal and the input end of the negative terminal. And a battery for storing electric energy is arranged in the lower shell. The partial discharge calibration pulse generator provided by the utility model has the advantages of multiple gears and high precision, and can meet the requirement of high-precision discharge detection.

Description

Technical Field

[0001] The utility model relates to the technical field of pulse generators, and more specifically to a partial discharge calibration pulse generator. Background Art

[0002] The partial discharge signal can directly reflect the condition of the insulation system of high-voltage power equipment. The partial discharge test determines the insulation performance and the status of the power equipment by measuring partial discharge parameters such as apparent discharge amount and discharge phase. The accuracy of these values ​​is closely related to the performance of the partial discharge calibration pulse generator.

[0003] The partial discharge calibration pulse generator is a device for calibrating the partial discharge detector. The purpose of calibration is to determine the scale factor of the apparent charge measurement and verify that the partial discharge detector can correctly measure the specified partial discharge value. Before the test, the partial discharge calibration pulse generator outputs a fixed amount of electricity to the two ends of the test piece to simulate the response of the partial discharge detector when the test piece discharges at this amount of electricity. At this time, the scale factor is adjusted to determine the range of the partial discharge detector so that the apparent discharge of the test piece at the rated voltage can be measured during the test. The calibration pulse generator currently used for partial discharge measurement has a single output frequency, and the discharge range of its output calibration signal is 1-1000pC. The accuracy of the calibrator is about 5%, which cannot meet the accuracy of partial discharge measurement. Utility Model Content

[0004] The technical problem to be solved by the utility model is to provide a partial discharge calibration pulse generator to solve the problem of low measurement accuracy of the existing pulse generator.

[0005] In order to solve the above technical problems, the technical solutions adopted by the present utility model are as follows.

[0006] A partial discharge calibration pulse generator comprises an upper shell and a lower shell which are matched with each other. A circuit board is arranged inside the upper shell. A liquid crystal display screen for displaying inspection information, an operation button for controlling the operation of the pulse generator, a charging port for charging, and a positive electrode terminal and a negative electrode terminal for outputting a bipolar pulse signal are arranged on the side of the circuit board facing the upper shell, which correspond to the through holes on the upper shell respectively. A control mechanism for controlling the calibration of a partial discharge detector is also arranged on the circuit board. The output end of the operation button is connected to the input end of the control mechanism. The output end of the control mechanism is respectively connected to the input end of the liquid crystal display screen, the positive electrode terminal and the negative electrode terminal. A battery for storing electric energy is arranged inside the lower shell. The input end of the battery is connected to the charging port, and the output end of the battery is connected to the input end of the control mechanism.

[0007] To further optimize the technical solution, the control mechanism includes a power management module connected to the battery for providing a stable working power supply, a main controller that sends a standard square wave signal according to an operation button, a square wave processing module that amplifies the amplitude of the square wave signal, a gear control module for dividing the square wave signal into a plurality of gear voltages, a gear switching module for selecting one of the plurality of gears, a voltage amplification module for following and amplifying the square wave signal, a gear selection module for selecting a corresponding square wave signal, and a calibration capacitor for converting the selected standard square wave signal into a standard bipolar pulse signal. The power input end of the power management module is connected to the battery output end, and the power management module and the operation button are connected to each other. The output end of the button is respectively connected to the input end of the main controller, the output end of the main controller is respectively connected to the input end of the square wave processing module and the liquid crystal display, the output end of the square wave processing module is connected to the input end of the gear control module, the output end of the gear control module is connected to the input end of the gear switching module, the output end of the gear switching module is connected to the input end of the voltage amplification module, the output end of the voltage amplification module is connected to the input end of the gear selection module, the output end of the gear selection module is connected to the input end of the calibration capacitor, the output end of the calibration capacitor outputs a bipolar pulse signal to the positive terminal, the negative terminal is grounded, and the positive terminal and the negative terminal provide a calibration bipolar pulse signal to the partial discharge detector through a wiring harness.

[0008] To further optimize the technical solution, the control mechanism also includes a battery power collection module for collecting battery power, the input end of the battery power collection module is connected to the output end of the power management module, and the output end of the battery power collection module is connected to the input end of the main controller.

[0009] To further optimize the technical solution, the voltage amplification module includes a voltage amplification module 1 for following the square wave signal and a voltage amplification module 2 for amplifying the square wave signal by 5 times, the input ends of the voltage amplification module 1 and the voltage amplification module 2 are respectively connected to the output end of the gear switching module, and the output ends of the voltage amplification module 1 and the voltage amplification module 2 are respectively connected to the input end of the gear selection module.

[0010] To further optimize the technical solution, the operation buttons include a battery button for powering on the control mechanism, a gear button for adjusting the output gear, a frequency button for adjusting the output frequency, and a switch button for controlling the power on and off of the pulse generator. The output ends of the battery button, the gear button, and the frequency button are respectively connected to the input ends of the main controller, and the output end of the switch button is connected to the input end of the power management module.

[0011] To further optimize the technical solution, the battery is arranged on the lower shell through a battery box cover.

[0012] To further optimize the technical solution, the battery is a rechargeable 16.8V lithium battery.

[0013] Due to the adoption of the above technical scheme, the technical progress achieved by the present invention is as follows.

[0014] The utility model provides a local discharge calibration pulse generator with multiple gears and high precision, which can meet the needs of high-precision discharge detection. The precision of the pulse voltage is greatly improved through the gear control module, and the rise time of the calibration pulse can be controlled to be less than 40ns through the voltage amplification module, thereby improving the calibration rate. In addition, the output frequency of the utility model is adjustable within the range of 50-1000Hz, and the pulse output gear covers the calibration range of 10pC-2000pC, with a wide range of applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a structural schematic diagram of the utility model;

[0016] Figure 2 It is a structural schematic diagram of the upper shell of the utility model;

[0017] Figure 3 It is a structural schematic diagram of the lower shell of the utility model;

[0018] Figure 4 This is a schematic diagram of the structure of the battery box cover of the utility model;

[0019] Figure 5 It is an exploded view of the utility model;

[0020] Figure 6 This is a principle block diagram of the control mechanism of the utility model;

[0021] Figure 7 This is a circuit diagram of the main controller of the utility model;

[0022] Figure 8 This is a circuit diagram of the square wave processing module of the utility model;

[0023] Fig. 9 This is a circuit diagram of the gear control module of the utility model;

[0024] Fig.10 This is a circuit diagram of the gear shift module of the utility model;

[0025] Fig.11 This is a circuit diagram of the voltage amplification module 1 of the utility model;

[0026] Fig.12 This is a circuit diagram of the voltage amplification module 2 of the utility model;

[0027] Fig.13 This is a circuit diagram of the gear selection module of the utility model.

[0028] Among them: 1. Upper shell, 2. Circuit board, 3. LCD screen, 4. Lower shell, 5. Battery, 6. Battery box cover, 7. Battery button, 8. Shift button, 9. Frequency button, 10. Switch button, 11. Charging port, 12. Type C port, 13. Positive terminal, 14. Negative terminal. DETAILED DESCRIPTION

[0029] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0030] A partial discharge calibration pulse generator, combined with Figures 1 to 5 As shown, it includes an upper shell 1, a lower shell 4 and a circuit board 2. The upper shell 1 and the lower shell 4 are matched and fixedly connected by screws.

[0031] The circuit board 2 is fixed in the upper shell 1 by screws. The side of the circuit board 2 facing the upper shell 1 is provided with a liquid crystal display 3, an operation button, a charging port 11, a Type C port 12, a positive terminal 13 and a negative terminal 14. The upper shell 1 is provided with through holes corresponding to the liquid crystal display, the operation button, the charging port, the Type C port 12, the positive terminal 13 and the negative terminal 14. The liquid crystal display is used to display the verification information, the operation button is used to control the operation of the pulse generator, the charging port is used to charge the pulse generator, the Type C port is used to download the program, and it is convenient for the control software of the utility model to upgrade. The positive terminal and the negative terminal are used to output bipolar pulse signals. A control mechanism is also provided on the circuit board to control the verification of the partial discharge detector. The output end of the operation button is connected to the input end of the control mechanism. The output end of the control mechanism is respectively connected to the input end of the liquid crystal display, the positive terminal and the negative terminal, and the control mechanism is electrically connected to the Type C port.

[0032] A square wave access terminal is provided between the positive terminal and the negative terminal for calibrating the pulse generator.

[0033] A battery 5 is disposed inside the lower housing 4 for storing electric energy to power the pulse generator. The input end of the battery is connected to the charging port 11 , and the output end of the battery is connected to the power input end of the control mechanism.

[0034] The battery 5 is arranged on the lower housing 4 through the battery box cover 6, and the battery box cover 6 is fixed to the lower housing by bolts.

[0035] The operation buttons include a battery button 7, a gear button 8, a frequency button 9 and a switch button 10. The output ends of the battery button, the gear button and the frequency button are respectively connected to the input end of the main controller, and the output end of the switch button is connected to the input end of the power management module. The battery button is used to power on the control mechanism, the gear button is used to adjust the output gear, the frequency button is used to adjust the output frequency, and the switch button is used to control the pulse generator to turn on and off.

[0036] The principle block diagram of the control mechanism is as follows Figure 6 As shown, it includes a power management module, a battery power acquisition module, a main controller, a square wave processing module, a gear control module, a gear switching module, a voltage amplification module, a gear selection module and a calibration capacitor. The input end of the battery power acquisition module is connected to the output end of the power management module, the output ends of the power management module, the battery power acquisition module and the operation button are respectively connected to the input end of the main controller, the output end of the main controller is respectively connected to the input end of the square wave processing module and the liquid crystal display screen, the output end of the square wave processing module is connected to the input end of the gear control module, the output end of the gear control module is connected to the input end of the gear switching module, the output end of the gear switching module is connected to the input end of the voltage amplification module, the output end of the voltage amplification module is connected to the input end of the gear selection module, the output end of the gear selection module is connected to the input end of the calibration capacitor, the output end of the calibration capacitor outputs a bipolar pulse signal to the positive terminal, the negative terminal is grounded, and the positive terminal and the negative terminal provide a calibration bipolar pulse signal to the partial discharge detector through a wiring harness.

[0037] The power management module is connected to the battery 5, which is a rechargeable 16.8V lithium battery. The power management module provides a stable working power supply. The power management module can control the device to automatically shut down after a period of inactivity, and has the characteristics of low energy consumption.

[0038] The battery power acquisition module is used to collect the battery power and send the collected information to the main controller. The main controller sends the power information to the LCD screen, which displays the power information on the LCD screen.

[0039] The main controller outputs a standard square wave signal of a predetermined frequency and voltage according to the operation button, and transmits the data to the LCD screen 3, and sends the square wave processing signal FANGBO to the square wave processing module. The circuit diagram of the main controller in the utility model is as follows: Figure 7 shown.

[0040] The square wave processing module is used to amplify the amplitude of the square wave signal FANGBO sent by the main controller. The circuit diagram of the square wave processing module is as follows: Figure 8 As shown, the ADA4891-1 conditioning chip is used to receive the square wave signal FANGBO sent by the main controller and amplify the 3.3V standard square wave into a 4V standard square wave.

[0041] The gear control module is used to divide the amplified 4V standard square wave into multiple gear voltages. The standard square wave is divided into six square wave signals of 100mV, 200mV, 500mV, 1V, 2V, and 4V through high-precision resistors. The circuit diagram of the gear control module is as follows Fig. 9 As shown, the corresponding output signals are 10pC, 20pC, 50pC, 100pC, 200pC, 500pC, 1000pC, and 2000pC respectively.

[0042] The gear switching module selects one of the six square wave signals and outputs it to the voltage amplifier module. The gear switching module is composed of a relay group. The 10pC, 20pC, 50pC, 100pC, 200pC, 500pC, 1000pC, and 2000pC signals output by the gear control module enter the relay group and output 10-200pC-in and 500-2000pC-in signals to the voltage amplifier module respectively. The specific circuit diagram is as follows: Fig.10 shown.

[0043] The voltage amplification module includes a voltage amplification module 1 and a voltage amplification module 2. The input ends of the voltage amplification module 1 and the voltage amplification module 2 are respectively connected to the output end of the gear switching module, that is, the 10-200pC-in signal output by the gear switching module is sent to the voltage amplification module 1, and the 500-2000pC-in signal output by the gear switching module is sent to the voltage amplification module 2; the output ends of the voltage amplification module 1 and the voltage amplification module 2 are respectively connected to the input end of the gear selection module, that is, the 10-200pC-out signal output by the voltage amplification module 1 and the 500-2000pC-out signal output by the voltage amplification module 2 are sent to the gear selection module.

[0044] The voltage amplifier module 1 uses a voltage amplifier follower circuit to enhance the signal output of 100mV, 200mV, 500mV, 1V, and 2V square wave signals. The circuit diagram of the voltage amplifier module 1 is as follows: Fig.11 As shown, the ADA4891 signal conditioning chip is used to output 10pC, 20pC, 50pC, 100pC, and 200pC power levels under the command of the main controller. The ADA4891 is powered by 0-5V and follows the square wave signal to ensure high-precision output of small power signals.

[0045] The voltage amplifier module 2 amplifies the 1V, 2V, and 4V square wave signals by 5 times through the current-type operational amplifier to achieve 5V, 10V, and 20V square wave signal outputs. The circuit diagram of the voltage amplifier module 2 is shown in FIG. Fig.12As shown, the THS3490 signal conditioning chip is used to output 500pC, 1000pC, and 2000pC power levels under the command of the main controller. The high-voltage, high-bandwidth current-type operational amplifier THS3490 is used to provide ±15V power supply, and the square wave signal is amplified 5 times to ensure that a 20V high voltage can be output.

[0046] The gear selection module receives 10-200pC-out signal and 500-2000pC-out signal, and then selects and outputs according to the instruction of the main controller. Its circuit diagram is as follows Fig.13 As shown, the final output signal is selected by the relay to the calibration capacitor.

[0047] The calibration capacitor converts the selected standard square wave signal into a standard bipolar pulse signal. The calibration capacitor adopts 100pF. The pulse signal output by the calibration capacitor is output through the positive terminal and the negative terminal.

[0048] When the utility model is working, the switch button is pressed to supply power to the power management module, and the power management module outputs a 3.3V voltage to the input end of the main controller. A command is issued to the main controller by operating the button, and a standard square wave is obtained after processing by the main controller. The standard square wave is output to the input end of the square wave processing module through the GPIO port of the main controller. The square wave processing module amplifies the 3.3V standard square wave into a 4V standard square wave through the signal conditioning chip ADA4891-1, and then outputs the 4V standard square wave to the gear control module. The gear control module divides the 4V standard square wave through high-precision resistors to generate voltages for each gear. The gear control module outputs the processed voltages of each gear to the gear switching module. The gear switching module selects the power gear to be output and switches it to the voltage amplification module 1 or the voltage amplification module 2. Voltage amplifier module 1 uses the signal conditioning chip ADA4891 to output 10pC, 20pC, 50pC, 100pC, and 200pC power levels. ADA4891 uses 0-5V power supply to follow the square wave signal to ensure high-precision output of small power signals. Voltage amplifier module 2 uses the signal conditioning chip THS3490 to output 500pC, 1000pC, and 2000pC power levels. The high-voltage, high-bandwidth current amplifier THS3490 is used to provide ±15V power supply, and the square wave signal is amplified 5 times to ensure that a 20V high voltage can be output. The corresponding square wave signal is selected by the gear selection module, and the standard square wave signal is converted into a standard bipolar pulse signal through a calibrated capacitor.

[0049] Press the frequency button to output the corresponding frequency. The frequency is adjustable from 50-1000Hz in 50Hz steps.

[0050] Press the gear button to output the corresponding gear. The power is divided into eight gears: 10pC, 20pC, 50pC, 100pC, 200pC, 500pC, 1000pC and 2000pC.

[0051] When the battery button is pressed, the power management module connects the working power supply to the ADC channel of the main controller after resistor voltage division. The main controller obtains the battery voltage through sampling and calculation and displays the battery voltage on the LCD screen. When the battery voltage is low, the leftmost end of the LCD screen displays L, indicating that the battery power is low and needs to be charged in time.

[0052] When the utility model calibrates the partial discharge detector without applying pressure, the positive terminal and the negative terminal output are connected to the high voltage end and the ground end of the coupling capacitor, and the coupling capacitor, the impedance, and the partial discharge instrument are connected to build a test circuit. Through the frequency button and the gear button, the appropriate frequency and gear are selected according to the partial discharge detector to be calibrated. After the selection is completed, the switch button is pressed to output a standard bipolar pulse signal. The bipolar pulse signal is transmitted to the partial discharge detector to be tested through the coupling capacitor and the impedance, and the corresponding discharge amount is calibrated at the end of the partial discharge detector, thereby realizing the calibration of the partial discharge detector.

Claims

1. A partial discharge calibration pulse generator, characterized in that: The invention comprises an upper shell (1) and a lower shell (4) which are matched with each other. A circuit board (2) is arranged inside the upper shell (1). A liquid crystal display screen (3) for displaying inspection information, an operation button for controlling the operation of a pulse generator, a charging port (11) for charging, and a positive electrode terminal (13) and a negative electrode terminal (14) for outputting a bipolar pulse signal are arranged on the side of the circuit board (2) facing the upper shell (1). The circuit board is also provided with a control mechanism for controlling the calibration of a partial discharge detector. The output end of the operation button is connected to the input end of the control mechanism. The output end of the control mechanism is respectively connected to the input end of the liquid crystal display screen, the positive electrode terminal and the negative electrode terminal. A battery (5) for storing electric energy is arranged inside the lower shell (4). The input end of the battery is connected to the charging port, and the output end of the battery is connected to the input end of the control mechanism.

2. A partial discharge calibration pulse generator according to claim 1, characterized in that: The control mechanism comprises a power management module connected to the battery (5) for providing a stable working power supply, a main controller that sends a standard square wave signal according to an operation button, a square wave processing module that amplifies the amplitude of the square wave signal, a gear control module that divides the square wave signal into a plurality of gear voltages, a gear switching module that selects one of the plurality of gears, a voltage amplification module that follows and amplifies the square wave signal, a gear selection module that selects a corresponding square wave signal, and a calibration capacitor that converts the selected standard square wave signal into a standard bipolar pulse signal. The power input end of the power management module is connected to the battery output end, and the power management module and the operation button are connected to each other. The output ends are respectively connected to the input ends of the main controller, the output ends of the main controller are respectively connected to the input ends of the square wave processing module and the liquid crystal display, the output end of the square wave processing module is connected to the input end of the gear control module, the output end of the gear control module is connected to the input end of the gear switching module, the output end of the gear switching module is connected to the input end of the voltage amplification module, the output end of the voltage amplification module is connected to the input end of the gear selection module, the output end of the gear selection module is connected to the input end of the calibration capacitor, the output end of the calibration capacitor outputs a bipolar pulse signal to the positive terminal, the negative terminal is grounded, and the positive terminal and the negative terminal provide a calibration bipolar pulse signal to the partial discharge detector through a wiring harness.

3. A partial discharge calibration pulse generator according to claim 2, characterized in that: The control mechanism also includes a battery power collection module for collecting battery power, the input end of the battery power collection module is connected to the output end of the power management module, and the output end of the battery power collection module is connected to the input end of the main controller.

4. A partial discharge calibration pulse generator according to claim 2, characterized in that: The voltage amplification module includes a voltage amplification module 1 for following the square wave signal and a voltage amplification module 2 for amplifying the square wave signal by 5 times, the input ends of the voltage amplification module 1 and the voltage amplification module 2 are respectively connected to the output end of the gear switching module, and the output ends of the voltage amplification module 1 and the voltage amplification module 2 are respectively connected to the input end of the gear selection module.

5. A partial discharge calibration pulse generator according to claim 2, characterized in that: The operation buttons include a battery button (7) for powering on the control mechanism, a gear button (8) for adjusting the output gear, a frequency button (9) for adjusting the output frequency, and a switch button (10) for controlling the on / off of the pulse generator, wherein the output ends of the battery button, the gear button, and the frequency button are respectively connected to the input ends of the main controller, and the output end of the switch button is connected to the input end of the power management module.

6. A partial discharge calibration pulse generator according to claim 1, characterized in that: The battery (5) is arranged on the lower housing (4) via a battery box cover (6).

7. A partial discharge calibration pulse generator according to claim 1, characterized in that: The battery (5) is a rechargeable 16.8V lithium battery.

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