CN204832431U - High voltage DC tests integrated device - Google Patents

Abstract

The utility model relates to an integrated device for direct current high voltage testing, which comprises a control unit for inputting commercial power and processing it to output an alternating current signal, a boosting unit for boosting and rectifying the alternating current signal into a high voltage direct current signal for output, the control unit and the boosting The unit is integrated into one. The control unit includes a rectification circuit, a first filter circuit, a pulse width modulation power switch, an inverter circuit, a control circuit, a given circuit, and a negative feedback circuit. The given circuit and the negative feedback circuit are respectively connected to the control circuit. The boost unit includes a frequency conversion circuit, an intermediate frequency transformer, a voltage doubler rectifier circuit, and a second filter circuit. The integrated device for direct current high voltage testing of the utility model integrates a control unit and a booster unit, thereby providing support for direct current high voltage experiments, which is less subject to external interference and has higher safety.

Description

DC high voltage test integrated device

technical field

The utility model relates to a direct current high voltage test integration device used for conducting direct current high voltage insulation tests on electric equipment.

Background technique

Power equipment usually needs to conduct insulation tests under DC high voltage, such as measuring its DC characteristic parameters, withstand voltage level, leakage current, etc.; some high-voltage test equipment also requires DC high voltage as a power supply, so the DC high-voltage test device is used for high-voltage tests. One of the important equipment. Traditional DC high-voltage test devices are composed of two independent units: the control part (composed of low-voltage electronic components) and the booster device (composed of intermediate frequency transformers, silicon stacks, and capacitor voltage doubler rectifiers). The output cable socket of the control part is connected with the cable socket of the booster device through an external special cable, and the cable should not have short circuit, open circuit, or poor contact. The boost device is then assembled with the current limiting resistor and the microammeter, and finally connected to the equipment under test through a special test lead. Both the control part and the booster device should be reliably grounded with special ground wires to form a test circuit. For the traditional DC high-voltage test device, the control part and the booster device adopt a split design, and the connecting cable is prone to failures such as outer layer insulation wear, internal disconnection, and poor contact of the interface, resulting in safety hazards, low output voltage accuracy, or even failure. Output high voltage and other issues. The leakage current of the equipment under test is tested by an external microammeter, and the wiring of the instrument will directly affect the test circuit, resulting in errors or even invalid test data. Moreover, the components of the entire device are cumbersome to assemble and the wiring is complicated, and it is very easy to introduce space electric field interference, resulting in test data errors, and the device's anti-interference ability and safety are poor.

Contents of the invention

The purpose of the utility model is to provide a DC high-voltage test integrated device capable of performing DC high-voltage tests, which is less affected by external influences, and has high anti-interference ability and safety.

For achieving the above object, the technical scheme that the utility model adopts is:

An integrated device for direct current high voltage testing, used for conducting insulation tests on electrical equipment under direct current high voltage, which includes a control unit that connects to the mains and processes it to output an alternating signal, and boosts and rectifies the alternating current signal into a high voltage A step-up unit for DC signal output, the control unit is integrated with the step-up unit.

The output end of the step-up unit is connected with a high-voltage shielded cable and connected with the electric device under test.

The control unit and the boost unit are integrated in a vertical and horizontal case, and the case has a shielding structure and a grounding structure.

The control unit includes a rectifier circuit for inputting commercial power and rectifying it into direct current, a first filter circuit for filtering the direct current, a pulse width modulation power switch connected to the first filter circuit, and The pulse width modulation power switch is connected to output the inverter circuit of the AC signal, the control circuit for controlling the pulse width modulation power switch, the given circuit for setting the required DC high voltage, and the negative feedback The negative feedback circuit of the high-voltage direct current signal, the given circuit and the negative feedback circuit are respectively connected with the control circuit.

The rectifier circuit is a bridge rectifier circuit; the filter circuit includes an electrolytic capacitor; the pulse width modulation power switch includes a MOS power tube.

The control unit also includes a protection circuit for protection according to the outputted high-voltage direct current signal, and the protection circuit is connected with the control circuit.

The step-up unit includes a frequency conversion circuit, an intermediate frequency transformer connected to the frequency conversion circuit, a voltage doubler rectifier circuit connected to the intermediate frequency transformer, and a second filtering circuit connected to the voltage doubler rectifier circuit. circuit.

The voltage doubler rectifier circuit includes a high voltage silicon stack; the second filter circuit includes a high voltage capacitor.

The output terminal of the second filtering circuit is connected with a current limiting resistor.

The integrated device for direct current high voltage testing also includes a measuring meter integrated with the boost unit.

Due to the application of the above technical solutions, the utility model has the following advantages compared with the prior art: the integrated device for direct current high voltage testing of the present utility model integrates the control unit and the boost unit, thereby providing support for the direct current high voltage experiment, which is affected by the outside world Less distraction and higher security.

Description of drawings

Accompanying drawing 1 is a functional block diagram of the utility model.

Detailed ways

Below in conjunction with embodiment the utility model is further described.

Embodiment 1: An integrated DC high-voltage test device for conducting insulation tests under DC high voltage on electric equipment (including measuring electric equipment parameters or providing power for high-voltage test equipment), including an integrated control unit and a booster The pressure unit is integrated in an international general-purpose vertical and horizontal chassis, which has a shielding structure and a grounding structure. The entire high-voltage component is fixed in a specific chassis by foaming technology. The chassis adopts shielding and reliable grounding measures, which improves the test accuracy and ensures the safety of the test personnel.

The control unit is used for inputting the mains and processing it to output an AC signal, and the booster unit is used for boosting and rectifying the AC signal into a high-voltage DC signal for output.

The control unit includes a rectifier circuit for inputting commercial power and rectifying it into DC, a first filter circuit for filtering DC, a pulse width modulation power switch connected to the first filter circuit, and a pulse width modulation power switch connected to output The inverter circuit of the AC signal, the control circuit of the control pulse width modulation power switch, the given circuit used to give the required DC high voltage, the negative feedback circuit of the negative feedback high-voltage DC signal, the given circuit and the negative feedback circuit are respectively connected with the control circuit is connected. The rectifier circuit is a bridge rectifier circuit; the filter circuit includes an electrolytic capacitor; the pulse width adjustment power switch includes a MOS power tube, the inverter circuit is a MOS bridge inverter circuit, and a dial switch can be used for a given circuit. The control unit may also include a protection circuit for protection according to the output high-voltage direct current signal, and the protection circuit is connected with the control circuit. In addition, the control unit can also be provided with a display screen for displaying the given DC high voltage information and the information of the actual output high voltage DC signal.

The boost unit includes a frequency conversion circuit, an intermediate frequency transformer connected to the frequency conversion circuit, a voltage doubler rectifier circuit connected to the intermediate frequency transformer, and a second filter circuit connected to the voltage doubler rectifier circuit. Wherein, the voltage doubler rectifier circuit includes a high-voltage silicon stack; the second filter circuit includes a high-voltage capacitor. The output end of the step-up unit, that is, the output end of the second filter circuit can be connected to the electric equipment under test by connecting a high-voltage shielded cable after passing through a current-limiting resistor. The high-voltage shielded cable adopts silicone rubber insulated high-voltage shielded soft wire, and its insulation to the ground can withstand high voltage above the rated working voltage, has good shielding performance, good anti-interference performance, and can be directly connected to the equipment under test by dragging the ground.

The DC high-voltage test integrated device also includes a measuring meter integrated with the boost unit, including an ammeter part and a voltmeter part, both of which are digital display measuring meters, and the output high-voltage DC signal can pass through the measuring meter and communicate with the protection circuit connected.

The above-mentioned intermediate frequency transformer is poured with epoxy resin, with high frequency and small volume, which greatly reduces the weight of the device. The high-voltage capacitor is made of polyethylene film material, which has good insulation performance and high withstand voltage. The high-voltage silicon stack adopts a single series package of small silicon particles, which effectively eliminates the influence of the leakage current flowing on the surface of the silicon stack on the test results, and has good reliability.

The principle of the main circuit of this device is: input 220V mains, pass through the bridge rectifier circuit, convert AC into DC; and then filter through the electrolytic capacitor, control the MOS power tube to input the DC to the bridge inverter circuit, and obtain the AC signal . After the DC signal is frequency converted, it outputs an intermediate frequency sine wave AC voltage to increase the voltage of the intermediate frequency transformer, and then passes through a high-voltage silicon stack to rectify and output DC high voltage. At the same time, it is filtered by a high-voltage capacitor to obtain a very stable DC voltage. This device adopts a measurement module composed of high-value resistors and microampere-level currents that meet engineering test requirements for independent voltage measurement.

This device has the following characteristics:

(1) This device adopts an intermediate frequency voltage doubling circuit, applies PWM pulse width modulation technology and high-power IGBT devices, and the voltage can be adjusted from 0V. According to the theory of electromagnetic compatibility, special shielding, isolation and grounding measures are adopted to make the DC high voltage The test is high-quality, portable, and can withstand abnormal flashover and discharge under rated voltage without damage. It has high-voltage overvoltage, high-voltage overcurrent protection, and power supply side overvoltage and overcurrent protection.

(2) This device adopts large voltage feedback, so the output voltage stability is greatly improved, and the voltage drift is very small. High voltage overvoltage setting adopts digital dial switch, which can directly display the setting voltage value and has high setting accuracy. A high-precision 0.75U _DC1mA function button is added, which brings great convenience to the measurement of metal oxide arresters; the output voltage adjustment adopts a single multi-turn potentiometer, which has high adjustment accuracy and simple operation.

The present invention integrates the control part, the booster device, the current-limiting resistor, and the measuring meter, without connecting the control part with the booster device and external components through connecting cables, and only needs to connect the high-voltage output cable to the device under test. Can. After this improvement, this device can effectively eliminate the potential safety hazards caused by the failure of the connecting cable, the low accuracy of the output voltage or even the failure to output high voltage, and the data error caused by the space electric field interference caused by cumbersome wiring. The entire test device is small in size, Light weight, easy to work on site.

The beneficial effect of this device is:

(1) Using large voltage feedback, the output voltage has high stability, and the ripple coefficient is less than or equal to 1%. Full-scale smooth voltage regulation, good voltage regulation fineness, regulation accuracy ≤0.5%, stability ≤1%, voltage error ±1% (reading ±0.2kV), current error ±(1%±1 digit). The boost potentiometer boosts the voltage from zero, and has a voltage scale indication. 0.75U _DC1mA function button, convenient for metal oxide arrester characteristic test, accuracy ± (1% reading ± 0.2kV). The overvoltage protection is set by the dial code, which is clear at a glance, and the error is ±1%.

(2) The high-voltage output cable adopts double-shielded cables, the high-voltage shield and the ground shield are independent of each other, and its insulation to the ground can withstand high voltages above the rated working voltage, and has good shielding and anti-interference performance, and the application of the ground shield improves operational safety .

(3) Through integrated development, it can effectively eliminate the hidden dangers of cumbersome wiring to the surrounding electrified areas, greatly improve the operation safety, and reduce the data error caused by the space electric field interference caused by it, and reduce the number of operators by simplifying the wiring. Significantly improve production efficiency.

The use process of the above-mentioned device is as follows:

(1) The integrity of the device should be checked before use.

(2) The protective grounding wire, the working grounding wire and the grounding wire of the resistive discharger should be separately connected to the grounding bar of the equipment under test (that is, one-point grounding). Wire.

(3) Put the power switch in the off position and check that the voltage regulating potentiometer should be at zero. The overvoltage protection setting value is generally 1.1 times the test voltage.

(4) No-load boost to verify whether the overvoltage protection setting is sensitive.

(5) Turn on the power switch, at this time the green light is on, indicating that the power is on.

(6) Press the red button, and the red light will be on, indicating that the high voltage is connected.

(7) Gently adjust the voltage regulating potentiometer in the clockwise direction, and the output terminal will increase the voltage from zero. After rising to the required working voltage, record the reading of the ammeter according to the specified time, and check whether the control box and the high-voltage output line are abnormal. sound.

(8) Press the yellow button, and the voltage should drop to 75% of the above-mentioned required test voltage, so as to verify whether the function of 0.75U _DC1mA is normal.

(9) To lower the voltage, return the voltage regulating potentiometer to zero, then press the green button to cut off the high voltage and turn off the power switch.

(10) Conduct leakage current and DC withstand voltage tests on the equipment under test. After the inspection test is carried out to confirm that there is no abnormality in the measuring device, the relevant test can be started. Connect the equipment under test, ground wire, etc., and turn on the power after checking.

(11) Boost to the required voltage or reference current. The boosting speed should be 3-5kV test voltage per second. When boosting the voltage of the equipment under test with large capacitance, it is also necessary to monitor the charging current of the ammeter not to exceed the maximum operating current of the test device. For small capacitance devices under test, such as metal oxide arresters, first increase to 90% of the required voltage (current), then slowly and carefully increase to the required voltage (current), and then read the voltage (current) from the digital display meter value. If you need to measure 0.75U _DC1mA on the metal oxide arrester, first increase to U _DC1mA voltage value, and then press the yellow button, then the voltage will drop to 75% of the original, and keep this state, you can read the current at this time . After the measurement is completed, the voltage regulating potentiometer returns to zero counterclockwise and press the green button. Press the red button when you need to boost again.

(12) After the test is completed, reduce the voltage, return the voltage regulating potentiometer to zero, press the green button, and turn off the power.

(13) For small-capacitance devices under test such as metal oxide arresters, the discharge time through the piezoresistor is generally very fast. For cables and other large-capacity devices under test, the voltage of the device under test should be self-discharged to below 20% of the test voltage, and then discharged through the supporting resistive discharger. After the equipment under test is fully discharged and the grounding wire is hung, the removal of the high-voltage lead wire and the replacement of the wiring are allowed.

(14) Operation after protection action. In the process of use, if the red light is off, the green light is on, and the voltage drops, it is the relevant protection action. At this time, the power switch should be turned off, and the indicator lights on the panel will not light up. Return the voltage regulating potentiometer to the zero position, and after one minute, the low-voltage capacitor in the standby mode is fully discharged before turning on the power switch again, re-conduct the no-load test and find out the situation, then the boost test can be performed again.

The invention overcomes the problems existing in the prior art, and is a new generation of portable DC high-voltage test integrated device developed in combination with field practice.

The above-mentioned embodiments are only to illustrate the technical concept and characteristics of the present utility model, and its purpose is to enable those familiar with this technology to understand the content of the present utility model and implement it accordingly, and not to limit the protection scope of the present utility model. All equivalent changes or modifications made according to the spirit of the utility model shall fall within the protection scope of the utility model.

Claims (10)

1. a high direct voltage Test integration device, for carrying out the Insulation Test under high direct voltage to power equipment, it is characterized in that: it comprise pass into civil power and it is processed and the control module of output AC signal, by described AC signal boosting rectification be high-voltage dc signal export boosting unit, described control module and described boosting unit become one.

2. high direct voltage Test integration device according to claim 1, is characterized in that: the output terminal of described boosting unit connects high-tension shielding cable and is connected with the power equipment described in tested.

3. high direct voltage Test integration device according to claim 1 and 2, is characterized in that: described control module and described boosting unit are integrated in the cabinet of horizontal-vertical double-purpose, and described cabinet has shielding construction and ground structure.

4. high direct voltage Test integration device according to claim 1, it is characterized in that: described control module comprises input civil power and is rectified into the rectification circuit of direct current, described direct current is carried out to the first filtering circuit of filtering, the pulse width modulated power switch be connected with the first described filtering circuit, be connected with described pulse width modulated power switch and export the inverter circuit of described AC signal, the control circuit of the pulse width modulated power switch described in control, for the given circuit of given required high direct voltage, the negative-feedback circuit of the high-voltage dc signal described in negative feedback, described given circuit is connected with described control circuit respectively with described negative-feedback circuit.

5. high direct voltage Test integration device according to claim 4, is characterized in that: described rectification circuit is bridge rectifier circuit; Described filtering circuit comprises electrochemical capacitor; Described pulse width modulated power switch comprises MOS power tube.

6. the high direct voltage Test integration device according to claim 4 or 5; it is characterized in that: the described control module high-voltage dc signal also comprised according to output carries out the protection circuit protected, and described protection circuit is connected with described control circuit.

7. high direct voltage Test integration device according to claim 1, is characterized in that: described boosting unit comprises frequency changer circuit, the I.F.T. be connected with described frequency changer circuit, the voltage doubling rectifing circuit be connected with described I.F.T., the second filtering circuit of being connected with described voltage doubling rectifing circuit.

8. high direct voltage Test integration device according to claim 7, is characterized in that: described voltage doubling rectifing circuit comprises high voltage silicon rectifier stack; The second described filtering circuit comprises high-voltage capacitance.

9. the high direct voltage Test integration device according to claim 7 or 8, is characterized in that: the output terminal of the second described filtering circuit is connected with current-limiting resistance.

10. high direct voltage Test integration device according to claim 1, is characterized in that: it also comprises the meter mutually integrated with described boosting unit.