Analysis of Amplitude Measurement Error Deriving from Divider in Steep-Front Impulse Voltage Measurement

摘要

Steep-front impulse voltage test is one of the main methods to evaluate the quality of cap and pin insulators. However, there is no standard steep-front impulse wave source to calibrate steep-front impulse voltage of the measurement system. The standard lightning impulse voltage is usually used to as calibration wave source. In this paper, three resistance dividers of steep-front impulse voltage measurement system are calibrated by standard lightning wave source. It was found that the ratio variety of divider is less than 3% which meets the standard. However, two resistance dividers parallel measurement of the same steep-front voltage signal still produce a measurement error of magnitude of 10%. The error source is analyzed in the paper which revealed that the square-wave response of the divider will have a large impact on the measurement error of the steep-front voltage, but have little effect on the lightning impulse voltage. Therefore, using a standard lightning voltage source to calibrate the resistance divider of the steep-front impulse measurement system will result in greater error. Finally, the mathematical method of error correction is proposed, and the measurement error caused by the square wave response can be reduced by the deconvolution calculation.