Design of 10 kV Wide Frequency DC Voltage Transformer
The resistance-capacitance matching(RCM)relationship of 10 kV DC voltage transformer(DCVT)based on the principle of resistance capacitance voltage division(RCVD)is not easy to meet under actual working conditions,making its bandwidth unable to meet the requirements.According to the the equivalent circuit and parameters of 10 kV DCVT based on the principle of RCVD under actual operating conditions,the frequency characteristic transfer function is established,and the influencing factors of DC volt-age divider ratio and frequency characteristic are analyzed.The quantitative effect of the initial accuracy of the resistor on the DC voltage divider ratio and the degree of influence of the initial accuracy of the capacitor and stray capacitance on frequency characteristic are obtained.A method of parallel connection of the resistance capacitance matching unit(RCMU)in the low-voltage arm of RCVD is proposed,which combines the selection of resistance-capacitance parameters of the main body of RCVD,and the DC voltage divider ratio can be calibrated through the adjustable resistor in RCMU,and the frequency characteristics of the DCVT can be compensated through the adjustable capacitor in RCMU.Finally,a prototype experiment is conducted,and the results show that the matching resistance calibrates the DC voltage division ratio from 10 000:5.015 to the design value 10 000:5,and the matching capacitance reduces the amplitude error of 10 kV DC voltage transformer from 14%to nearly 1%within the bandwidth of 50 Hz to 3 kHz.
DC voltage transformerresistance capacitance voltage dividerresistance capacitance matchingfrequency characteristics
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