Design ideas of impulse voltage generator

Author： GOZ Electric Time：2014-05-02 11:34:28 Read：12

    The design of the impulse voltage generator can be divided into two parts. The first is the design of the impulse voltage generator itself, including the selection of impulse capacitor, calculation of wave front resistance and wave tail resistance, selection of charging resistor and protection resistor, Selection of wave front resistor and wave tail resistor wire, selection of high-voltage test transformer, selection of high-voltage silicon stack, selection of ball gap diameter, etc. The second is the design of the impulse voltage measurement circuit. In this design, the impulse voltage divider adopts a two-stage structure, including the selection of primary voltage divider and secondary voltage divider.

     A lot of approximations are made during the design process, which inevitably leads to design errors. The reasons are as follows: on the one hand, the influence of the parasitic inductance of each link is ignored; secondly, the design of the impact voltage divider, the two-stage Although the voltage dividing structure has a higher voltage dividing ratio and better response characteristics, it also inevitably introduces calculation errors; the other is the selection of components. Due to limited reference materials, for some components, especially the voltage dividing The capacitors, resistors and cables in the device can only be selected within a small range, and it is impossible to achieve complete matching and appropriateness. More references should be made during actual design.

     This design process involves a lot of knowledge and standards in high-voltage engineering. Through this design, I have a deeper understanding of the working principle of the impulse voltage generator. The successful completion of this design would of course be inseparable from the careful guidance of the teacher and the enthusiastic help of the students.

Impulse voltage generator design instructions

1. The high-efficiency lightning impulse voltage generator consists of six stages, with a rated voltage of 660kv and outputs a standard lightning impulse voltage waveform.

2. Select domestic high-voltage pulse capacitors as impact capacitors. Please refer to the relevant parameter table of the design process for the following specific parameters.

3. The impulse voltage generator adopts a high-efficiency circuit, which enables the discharge circuit to have high utilization efficiency.

4. The wave head resistance and wave tail resistance of the impulse voltage generator are made of constantan wire of appropriate specifications (that is, they must meet the temperature rise and voltage withstand requirements at the same time).

5. In order to ensure that the impulse voltage generator has a suitable charging time (not too large or too small), ensure the uniformity of charging of capacitors at all levels, make the ball gap actions at all levels more reliable, and ensure the utilization coefficient of the discharge circuit If it is not too low, select a charging resistor; in order to protect the rectifier device and voltage equalization, use a protective resistor.

6. The charging time of the impulse voltage generator is estimated to be 15 seconds, which is moderate and appropriate.

7. After estimating the capacity and voltage, determine the choice of domestic test transformer.

8. After estimating the reverse peak voltage and rated setting current, determine the selected model of high-voltage silicon stack.

9. Check the ball gap discharge voltmeter to easily determine that the copper ball meets the discharge requirement at the gap distance.

10. In order to obtain a higher voltage dividing ratio and good transient response characteristics, the impulse voltage dividing system of the impulse voltage generator adopts a two-stage structure. Please refer to the design process for the specific voltage dividing system structure and low-voltage test circuit.

11. To prevent interference, low-voltage circuits and measuring instruments must be well shielded.