The Design And Research Of High Voltage Pulse Coaxial Capacitance Divider

With the rapid development of high voltage engineering in power system, so it raises harsh stander to the requirements measurement technology of nanosecond pulse signal. The nanosecond high voltage pulse changes rapidly, its rising time is very short, just from sub-nanosecond to nanosecond. The amplitude of the pulse usually reaches dozens of kV, so it is very high. The electromagnetic interruption of it is also severe, electronic equipment of the substation secondary side is seriously impacted, in severe cases may cause the system to arrest. In the actual measurement system, the voltage level of the digital oscilloscope and other measuring instruments can not reach too high a voltage level of measurement requirements, to measure a high-frequency and high-voltage pulse signal, it is necessary to introduce in the measurement system enables fast pulse signal distortion attenuation equipment. The divider is a device which can convert the high voltage pulse into the low one with certain proportion so as to measure it with the oscilloscope. In the measurement of pulsed high-voltage system, divider plays an irreplaceable role.According to the basic working principle of the voltage divider, the divider is divided into resistive, capacitive, resistive and capacitive forms. Capacitive divider is mainly applied to the pulsed high voltage of high frequency, wide frequency response band width. In this paper, the operating characteristics of the capacitive divider, applicable environment, with the frequency change of the amplitude frequency characteristics are analyzed. For the transient voltage in the measurement of substation switching operation, and to measure electromagnetic pulse generator transient pulse signal, double shielded cable structure of the coaxial capacitive divider is proposed. The basic working principle of the coaxial capacitive divider, the advantage of the characteristics of the coaxial structure are analyzed, coaxial voltage divider is modeled, the theory model ratio of the voltage divider is calculated, divider internal electric displacement vector cloud images is simulated with the electromagnetic finite element simulation software ANSYS. Coaxial capacitive divider is designed. According to the design parameters, capacitive divider for laboratory is produced and experimental platform is set up based on the divider. Actual working conditions of coaxial capacitive divider, the influence to ratio of divider for earth stray capacitance and the characteristics of amplitude and frequency for the actual work of capacitive divider are researched. According to the actual experimental results, the method and attention for improving the performance of capacitive divider are put forward. The combination of simulation and experimental results are analyzed and summarized, and can provide reference measurements for the design and production of the nanosecond pulse high-voltage capacitive voltage divider.