Design of Primary Converter for Electronic Voltage Transformers Based on Capacitive Divider

The primary converter of the electronic voltage transformer(CEVT) based on the capacitive divider is described.The principle and the system constituted of CEVT are expatiated.The secondary resistive divider of the transducer affects the phase error of CEVT but no affection on the divider coefficient.The A/D converter is the critical component for designing the primary side circuit.It analyzes A/D converter and its driver circuit in detail,which uses ADS8325 as A/D converter and provides excellent performances,such as high resolution,low temperature coefficient and low power consumption.It realizes the single optical fiber data transmitting through imitating asynchronous transmitting with synchronous clock rate.The temperature tests show that the temperature characteristic is within ±0.2% with the range-40(°C)～+40(°C).The type tests of the CEVT show that the linearity characteristic is within ±0.2%.