CN204241525U - A kind of 10kV square-wave voltage generator of coaxial configuration - Google Patents

Abstract

The utility model provides a 10kV square wave voltage generator with a coaxial structure, including a high-voltage DC power supply, an energy storage capacitor, a gas spark switch, a gas storage tank and a square wave voltage measuring capacitor arranged in a metal shielding box Voltage divider; the high-voltage DC power supply is connected to the energy storage capacitor, the gas spark switch is connected to the measured voltage divider; the gas spark switch is connected to the energy storage capacitor; the axes of the gas spark switch and the energy storage capacitor are both set in a metal shielding box At the same position; the high-voltage DC power supply charges the energy storage capacitor. When the charging voltage rises to the breakdown voltage of the gas spark switch, the gas spark switch breaks down and outputs a rising-edge square wave voltage to the measured voltage divider. Compared with the prior art, the utility model provides a 10kV square wave voltage generator with a coaxial structure, which has stable performance, strong load capacity, strong operability, strong anti-electromagnetic interference ability, and the capacitor voltage divider can be directly Conduct square wave response test to judge its dynamic response performance.

Description

A 10kV Square Wave Voltage Generator with Coaxial Structure

technical field

The utility model relates to a square wave voltage generator, in particular to a 10kV square wave voltage generator with a coaxial structure.

Background technique

In the power system, in order to test the ability of electrical equipment to withstand lightning impulse overvoltage, it is necessary to perform an impulse voltage withstand test before leaving the factory, so it is necessary to be equipped with an impulse voltage generator and supporting impulse voltage divider measuring equipment for the test The equipment undergoes other performance tests such as factory withstand voltage. Since the wave front time of the lightning impulse waveform is only on the order of μs, the impulse voltage divider needs to have better dynamic response characteristics to ensure the accuracy of the amplitude and time measurement of the impulse voltage divider. At present, the method of judging the dynamic characteristics of the impact voltage divider mainly adopts the square wave voltage response test of the impact voltage divider, and extracts the dynamic response characteristic parameters of the impact voltage divider by analyzing the square wave response waveform of the voltage divider. In the square wave response test of the impact voltage divider, the square wave voltage source is required to have high amplitude, wide pulse width and ns-level rising edge.

Currently commonly used square wave voltage generators include square wave generators based on mercury switches, square wave voltage generators that use pulse forming line loops or Marx loops and steep switches (usually including gas switches and MOSFET switches), etc. . The advantages of the square wave generator based on the mercury switch are: easy to use, good repetition frequency characteristics, and the rise time of the square wave can reach ns level, but due to the limited withstand voltage of the mercury switch, the ordinary mercury switch can only generate ) V low-voltage square wave, and with the improvement of the current impulse test voltage level, the voltage division ratio of the impulse voltage divider is increasing continuously. The signal is quite weak, susceptible to surrounding electromagnetic interference, and has a poor signal-to-noise ratio, which is not conducive to analysis and calculation. For a pulse generator that adopts a pulse forming line or a Marx circuit and is designed by the steepening switch principle, although the rise time of the output square wave can be very short (several ns or even ps level), and the amplitude can reach tens of kilovolts, but its output pulse width is limited by the length of the pulse forming line, usually only a few hundred ns. Since the stabilization time of the impact resistance voltage divider is generally about 200ns, and the stabilization time of the weak damping voltage divider is longer, the exact stabilization time of the voltage divider cannot be calculated if the pulse width is too small.

To sum up, it is necessary to provide a square wave generator capable of high voltage level, strong load capacity, short rise time, and wide pulse width, so that it is difficult to accurately and reliably analyze the square wave response characteristics of the voltage divider.

Contents of the invention

In order to meet the needs of the prior art, the utility model provides a 10kV square wave voltage generator with a coaxial structure. The voltage generator includes a high-voltage DC power supply, and an energy storage capacitor and a gas A spark switch, a gas storage tank, and a capacitor voltage divider; the high-voltage DC power supply is connected to an energy storage capacitor, and the gas spark switch is connected to a measured voltage divider; the gas spark switch is connected to an energy storage capacitor;

The axis of the gas spark switch and the axis of the energy storage capacitor are both arranged at the same position of the metal shielding box;

The high-voltage DC power supply charges the energy storage capacitor, and when the charging voltage rises to the breakdown voltage of the gas spark switch, the gas spark switch breaks down and outputs a rising-edge square wave voltage to the measured voltage divider;

The capacitive voltage divider is used to measure the square wave voltage.

Preferably, a charging lead terminal is provided on the outside of the metal shielding box; one branch at one end of the energy storage capacitor is connected to the gas spark switch, and the other branch is connected to a high-voltage DC power supply through the charging lead terminal; The other end of the energy storage capacitor is connected to a grounding switch;

Preferably, a matching resistor is provided between the energy storage capacitor and the gas spark switch to match the refracted voltage and reflected voltage generated on the electrodes when the gas spark switch breaks down, thereby reducing the output of the voltage generator. Overshoot of wave voltage;

A DC charging resistor is provided between the energy storage capacitor and the high-voltage DC power supply, which is used to protect the energy storage capacitor at the moment when the high-voltage DC power supply starts charging;

Preferably, the energy storage capacitor includes four parallel polypropylene film capacitors, and the polypropylene film capacitors are sequentially connected to form a ring structure; the capacitance of each polypropylene film capacitor is 1 μF;

Preferably, the discharge gap of the gas spark switch is a ball electrode gap; the gap distance of the ball electrode gap is changed by adjusting the distance adjustment knob on the gas spark switch;

Preferably, the gas spark switch is filled with nitrogen of 2.5-4 atmospheres; nitrogen of 4.5 atmospheres is stored in the gas storage tank;

The air pressure sensor detects the air pressure in the gas spark switch, and when the air pressure is less than a preset value, adjusts the opening of the pressure stabilizing valve between the gas spark switch and the gas storage tank, and the gas storage tank inflates the gas spark switch;

Preferably, the breakdown voltage of the gas spark switch is changed by adjusting the gap distance and the air pressure of the ball electrode gap in the gas spark switch, thereby adjusting the square wave voltage amplitude output to the measured voltage divider after the gas spark switch breaks down and pulse width;

Preferably, the capacitive voltage divider is arranged directly above the gas spark switch, including chip capacitors arranged on the disk and connected in parallel according to the squirrel-cage structure;

The high-voltage arm capacitance of the capacitive voltage divider is the inductive capacitance between the disc and the metal connecting column in the gas spark switch, and the low-voltage arm capacitance is the patch capacitance;

The voltage division ratio of the high-voltage arm voltage and the low-voltage arm voltage in the capacitor voltage divider is 1000:1;

Preferably, the output terminal of the capacitive voltage divider is connected to a digital oscilloscope for measuring the output waveform of the voltage generator.

Compared with the closest prior art, the excellent effect of the utility model is:

1. In the technical solution of the utility model, the energy storage capacitor adopts four parallel polypropylene film capacitors, and the energy storage capacitor and the gas spark switch are coaxially arranged in a metal shielding box, and the structure is compact;

2. In the technical solution of the utility model, the gas spark switch is used as a discharge switch, which can generate a square wave signal with adjustable amplitude, a maximum voltage of 10kV, a pulse width greater than 1μs, a rise time of less than 5ns, small overshoot, and repeatable waveform output ;

3. In the technical solution of the present invention, the self-contained capacitive voltage divider in the voltage square wave source has a compact structure and fast response, and is used to measure the output square wave voltage of the square wave voltage generator. The axis cable is output to the oscilloscope for observing the waveform;

4. The utility model provides a 10kV square wave voltage generator with a coaxial structure, which has stable performance, strong load capacity, strong operability, and strong anti-electromagnetic interference ability. The capacitor voltage divider can directly perform square wave voltage waveform Measurement;

5. The utility model provides a 10kV square wave voltage generator with a coaxial structure. The connected load can be various voltage levels and various voltage division ratios. The impact resistance divider and the weak damping capacitor divider can It is of great scientific research and engineering value to carry out the research on the square wave response test of the impulse voltage measuring equipment and the steep wave measuring equipment and its traceability.

Description of drawings

Below in conjunction with accompanying drawing, the utility model is further described.

Fig. 1: A structural diagram of a 10kV square wave voltage generator with a coaxial structure in the embodiment of the utility model;

Figure 2: A perspective view of a 10kV square wave voltage generator with a coaxial structure in an embodiment of the utility model;

Fig. 3: a perspective view of the energy storage capacitor in the embodiment of the utility model;

Figure 4: A side view of the energy storage capacitor in the embodiment of the utility model;

Fig. 5: A working principle diagram of a 10kV square wave voltage generator with a coaxial structure in the embodiment of the utility model;

Among them, 1-energy storage capacitor; 2-gas spark switch; 3-capacitor voltage divider; 4-ball electrode gap; 5-matching resistor; 6-charging lead terminal; 7-square wave voltage generator output; 8- Gas storage tank; 9- metal shielding box shell; 10- grounding switch; 11- barometer; 12- output connector of capacitor voltage divider; 13- grounding switch button; 14- polypropylene film capacitor; 15- polypropylene film capacitor ; 16-polypropylene film capacitor; 17-polypropylene film capacitor.

Detailed ways

Embodiments of the present invention are described in detail below, examples of which are shown in the drawings, wherein the same or similar reference numerals represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the figures are exemplary and are intended to explain the present invention, but should not be construed as limiting the present invention.

The utility model provides a 10kV square wave voltage generator with a coaxial structure, which is composed of a high-voltage DC source, an energy storage capacitor 1, a gas spark switch 2, a gas storage tank 8 and a capacitor voltage divider 3. The square wave voltage generator has a compact overall structure and adopts a coaxial structure arrangement; one end of the energy storage capacitor 1 is connected to an electrode of the gas spark switch 2 after passing through a matching resistor 5, and the other end of the gas spark switch 2 is a square wave voltage The output terminal 7 of the generator is connected to the load voltage divider.

As shown in Figures 1 and 2, a 10kV square wave voltage generator with a coaxial structure in this embodiment includes a high-voltage DC power supply, and an energy storage capacitor 1, a gas spark switch 2, and a gas storage capacitor arranged in a metal shielding box. tank 8 and capacitive divider 3;

The high-voltage DC power supply is connected to the energy storage capacitor 1, and the gas spark switch 2 is connected to the voltage divider under test;

The gas spark switch 2 is connected to the energy storage capacitor 1, and the axis of the gas spark switch and the capacitor voltage divider are both arranged at the same position of the metal shielding box, that is, coaxial connection, so as to ensure a compact structure of the square wave voltage generator.

The high-voltage DC power supply charges the energy storage capacitor 1. When the charging voltage rises to the breakdown voltage of the gas spark switch 2, the gas spark switch 2 breaks down and outputs a rising-edge square wave voltage to the voltage divider under test.

1. Energy storage capacitor Ca;

(1) Connection relationship:

The outer side of the metal shielding box is provided with a charging lead terminal 6; one branch at one end of the energy storage capacitor 1 is connected to the gas spark switch 2, and the other branch is connected to the high-voltage DC power supply through the charging lead terminal 6; the other end of the energy storage capacitor 1 is connected to the gas spark switch 2. Grounding switch 10 is connected.

As shown in Figure 5, a matching resistor Rb is provided between the energy storage capacitor 1 and the gas spark switch 2 to match the refraction voltage and reflected voltage generated on the electrodes when the gas spark switch 2 breaks down, thereby reducing the output of the voltage generator Overshoot of square wave voltage;

A DC charging resistor Ra is provided between the energy storage capacitor 1 and the high-voltage DC power supply, which is used to protect the energy storage capacitor at the moment when the high-voltage DC power supply starts charging to prevent excessive current.

(2) Internal structure:

As shown in Figures 3 and 4, the energy storage capacitor 1 includes four parallel-connected polypropylene film capacitors 14-17, and the polypropylene film capacitors are connected to form a ring structure; the capacitance of each polypropylene film capacitor is 1 μF.

2. Gas spark switch;

The discharge gap of the gas spark switch 2 is the ball electrode gap 4; the gap distance of the ball electrode gap 4 can be changed by adjusting the distance adjustment knob on the gas spark switch 2.

The gas spark switch 2 is filled with nitrogen of 2.5-4 atmospheric pressure; the nitrogen of 4.5 atmospheric pressure is stored in the gas storage tank 8; When setting the value, adjust the opening of the pressure stabilizing valve between the gas spark switch 2 and the gas storage tank 8, and the gas storage tank 8 inflates the gas spark switch 2. After the air pressure reaches the preset value, readjust the opening of the pressure stabilizing valve , the gas storage tank 8 stops charging the gas spark switch 2.

3. Capacitive voltage divider;

Used to measure the square wave voltage output by a gas spark switch.

The capacitive voltage divider 3 is arranged directly above the gas spark switch 2, including chip capacitors arranged on the disc connected in parallel according to the squirrel cage structure; The inductive capacitor between the metal connections, the low-voltage arm capacitor is a chip capacitor;

The voltage division ratio of the high voltage arm voltage and the low voltage arm voltage in the capacitor voltage divider 3 is 1000:1.

The output terminal 12 of the capacitive voltage divider 3 is connected with a digital oscilloscope for measuring the output waveform of the voltage generator.

4. Working principle:

As shown in Figure 5, by adjusting the gap distance of the ball electrode gap 4 in the gas spark switch 2 and the size of the air pressure, the breakdown voltage of the gas spark switch 2 is changed, thereby adjusting the breakdown voltage of the gas spark switch 2 to the measured voltage divider Output square wave voltage amplitude and pulse width.

In this embodiment, the maximum amplitude of the square wave voltage output by the voltage generator is 10 kV, the minimum pulse width is 1 μs, and the maximum overshoot is 5%.

5. The working process of the 10kV square wave voltage generator used for the performance check of the impact voltage divider provided by the utility model is:

(1) Set the gap distance and air pressure of the ball electrode gap 4 in the gas spark switch 2 according to the square wave voltage amplitude required for the performance check of the measured voltage divider.

(2) According to the experimental data table, the breakdown voltage corresponding to the gap distance and air pressure in step (1) can be found.

(3) Set the charging voltage value of the high-voltage DC power supply to the energy storage capacitor 1 to ensure that the voltage value is slightly higher than the breakdown voltage obtained in step (2).

(4) After the gas spark switch 2 breaks down and discharges, read the square wave voltage waveform in the oscilloscope connected to the capacitor voltage divider, and analyze the square wave voltage waveform, and extract the dynamics of the load voltage divider according to the square wave voltage waveform parameters Response characteristic parameters.

The square wave voltage waveform is a rising edge square wave waveform. It adopts the principle of capacitor discharge square wave generation to form a square wave with a pulse width of 2 μs. The pulse width is much longer than the response stabilization time of the tested voltage divider. The response of the rising edge of the square wave will not interfere with its response to the falling edge, and the output waveform after the falling edge of the square wave can be stabilized at zero potential for a long time, without interference to the response of the voltage divider under test.

The capacitor voltage divider and the gas spark switch are compactly arranged together, and its voltage division ratio is about 1000:1. It is connected to a digital oscilloscope through a coaxial cable for direct observation of the square wave voltage waveform. After a discharge is completed, the residual charge on the energy storage capacitor is released through the grounding switch of the square wave voltage generator to ensure the safety of people and equipment.

The square wave voltage generator provided by the utility model has a strong load capacity, and can be connected to a measured voltage divider with a resistance of >2kΩ, or a weakly damped capacitor voltage divider with a capacitance value of about 400pF. Ensure that the rising edge of the square wave voltage output by the square wave voltage generator is <5ns. At the same time, the components in the square wave voltage generator are all high-voltage components, have good withstand voltage characteristics and long life, and are suitable for on-site and laboratory tests. Except for the high-voltage DC power supply, all other components are integrated in the metal shielding box. The high-voltage DC power supply is connected to the energy storage capacitor through the charging lead terminal on the metal shielding box, and the output voltage of the high-voltage DC power supply can be connected during use.

Finally, it should be noted that the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in this application, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the scope of protection of this application.

Claims (9)

1. a 10kV square-wave voltage generator for coaxial configuration, it is characterized in that, described voltage generator comprises high-voltage DC power supply, and is arranged on storage capacitor, gas spark switch, gas-holder and the capacitive divider in a metal shielding box; Described high-voltage DC power supply is connected with storage capacitor, and described gas spark switch is connected with tested voltage divider; Described gas spark switch is connected with storage capacitor;

The axis of described gas spark switch and the axis of described storage capacitor are all arranged on the same position of metal shielding box;

Described high-voltage DC power supply charges to storage capacitor, and when charging voltage rises to the voltage breakdown of gas spark switch, gas spark switch punctures the square-wave voltage exporting rising edge formula to tested voltage divider;

Described capacitive divider, for measuring described square-wave voltage.

2. voltage generator as claimed in claim 1, it is characterized in that, the outside of described metal shielding box is provided with charging lead terminal; A branch road of described storage capacitor one end is connected with described gas spark switch, and another branch road is connected with high-voltage DC power supply by described charging lead terminal; The described storage capacitor other end is connected with grounding switch.

3. voltage generator as claimed in claim 1, it is characterized in that, build-out resistor is provided with between described storage capacitor and described gas spark switch, for mating the refraction voltage and reflected voltage that produce on electrode when gas spark switch punctures, thus reduce the overshoot that described voltage generator exports square-wave voltage;

Be provided with DC charging resistance between described storage capacitor and described high-voltage DC power supply, start the transient protection storage capacitor charged for high-voltage DC power supply.

4. voltage generator as claimed in claim 1, it is characterized in that, described storage capacitor comprises four polypropylene screen capacitors in parallel, and described polypropylene screen capacitor connects the annular framework of rear composition successively; The electric capacity of each polypropylene screen capacitor is 1 μ F.

5. voltage generator as claimed in claim 1, it is characterized in that, the discharging gap of described gas spark switch is ball electrode gap; The clearance distance of described ball electrode gap is changed by the roll adjustment knob on adjustments of gas spark switch.

6. voltage generator as claimed in claim 1, is characterized in that, is filled with 2.5-4 atmospheric nitrogen in described gas spark switch; 4.5 atmospheric nitrogen are had in described gas-holder;

Baroceptor detects the air pressure in gas spark switch, and when described air pressure is less than preset value, adjust the aperture of the pressure maintaining valve between described gas spark switch and gas-holder, gas-holder is inflated to gas spark switch.

7. the voltage generator as described in claim 5 or 6, it is characterized in that, by the clearance distance of ball electrode gap and the size of air pressure in adjustment gas spark switch, change the voltage breakdown of gas spark switch, thus adjustment gas spark switch punctures square-wave voltage amplitude and the pulsewidth of backward tested voltage divider output.

8. voltage generator as claimed in claim 1, it is characterized in that, described capacitive divider is arranged on directly over described gas spark switch, comprises the patch capacitor be connected in parallel according to cage-shaped structure be arranged on disk;

The high voltage arm capacitor of described capacitive divider is the inductance capacitance in described disk and gas spark switch between metal joint pin, and low-voltage arm electric capacity is described patch capacitor;

The intrinsic standoff ratio of described capacitive divider mesohigh arm voltage and low-voltage arm voltage is 1000:1.

9. voltage generator as claimed in claim 1, it is characterized in that, the output terminal of described capacitive divider is connected with digital oscilloscope, for measuring the output waveform of described voltage generator.