How to Conduct the Test on the Linearity of Impulse Voltage Divider?

Abstract: In the process of tracing the impulse voltage measuring system, low-voltage DC source or impulse voltage calibrator is utilized to measure the scale factor of voltage divider. Therefore, the effect of linearity of voltage divider on uncertainty of measuring system must be taken into account. Given that the national standard has not been established, an experimental method is put forward in the paper for measuring the linearity of voltage divider. The resistor divider R200S is made use of to obtain the linearity of impulse voltage generator; DC divider is adopted to measure the charge voltage of generator and the ratio of HCR600 indication value to charge voltage; then the linearity of amended generator is obtained. The results show that the linearity of HCR600 decreases from +0.4% to﹣0.8%; the maximum difference between positive polarity and negative polarity is 0.14%; the linearity of negative polarity is superior to that of positive polarity. Moreover, the linearity of 500kV resistor divider with known linearity is used to be compared with that of HCR600. The results show that two curves match basically, and the maximum difference is 0.15% at the same voltage. That means that this method can be used to correctly measure the linearity of measuring divider. In addition, this method can also be applicable to verify the test during the establishment of national standards. If the generator equipment meets some requirements, the method can also be used to calibrate the UHV impulse equipment.

Key words: linearity, impulse voltage generator, impulse voltage divider, efficiency deviation, comparison calibration; scale factor, charge voltage