Design Of A High-voltage Signal Generator Based On Flashover Fault Detection

It is very important to locate cable faults and fix them, after power cables break down. High voltage signal generator is an important part of cable tester. This paper is researching the detection of the cable flashover fault, and designing a high voltage generator based on demands for the three pulse methods.The high voltage generator is mainly composed of rectifier filter, voltage regulator, DC chopper circuit, inverter, high-frequency transformers, voltage doubler rectifyier circuit and pulse generating circuit. The power frequency AC will be transformed into the low voltage direct current(DC) through a rectifier, filter and voltage regulator, and then the direct current will be regulated through the DC chopper. This article uses BTS device achieve chopper function, and modulation PWM wave that is to change the duty cycle to achieve high-performance adjustable DC.Inverter circuit, in the form of the full bridge inverter circuit, transforms the adjustable dc inverter into a high frequency ac square wave signal. The high frequency alternating current generated will create the dc high voltage through the high-frequency transformer booster and doubler rectifier. This paper will introduce the selection of inverter circuit, voltage doubler rectifyier circuit and analyzes the production of high-frequency transformers in detail.Low voltage nanosecond pulse is created through pulse generating circuit. The direct voltage after doubling rectifying current as input pulse, through high speed switching MOS tube and capacitor charging and discharging effect, finally get the nanosecond pulse.It contains some calculation of various parameters in the selected main circuits, including input rectifier filter circuit, voltage regulator circuit, inverter circuit, high frequency transformer, voltage doubler rectifyier circuit and pulse generator, and hardwaresthe in the whole system have been selected in it. At last, it introduces a large number of simulation urinalysis and some tests to the whole system. The results of simulation analysises and experiment waveforms are given in it, which proves the rationality of theoretical urinalysis and the design.