Due to the variety of cross-sectional areas in 10 kV distribution network lines, when the non-contact voltage device measures the voltage of different line diameters, the line-electrode coupling capacitance becomes time-varying. This variation complicates the determination of the voltage dividing ratio, making it difficult to accurately invert the line voltage. In this paper, under the condition that the outer copper electrode is not grounded, the self-calibration method of dual-probe coupling capacitance based on the capacitanceswitching array is proposed. This method eliminates the influence of line-diameter variation on the measurement results by casting the capacitance between the inner and outer copper electrodes of the dual-probe. Additionally, the sensitivity formula of each measured voltage is derived to quantify the effect of measurement errors on the inverted line voltage, and the optimized probe parameters are used to realize the adaptive measurement of the distribution network line diameter. Finally, the simulation circuit is designed and the experimental platform is constructed to complete the calibration of the sensor parameters and perform the adaptive testing of different line diameters. The experimental results show that when the cross-sectional area of the 10 kV distribution line changes from 70 mm 2 to 150 mm 2 , the maximum relative error between the line voltage inverted by the sensor and the real line voltage is 2. 685% , which meets the standard of electronic voltage transformer. This in turn can validates the effectiveness of the proposed method.