To realize fast and accurate ultra-high insulation resistance measurement existing slow decay time-varying nonlinear background current, a method based on nonlinear error suppression algorithm is proposed. Firstly, the electrometer output signal is detected with the group period T and alternating test voltage. And then signal matrix relatively to the error background current in adjacent n + 2 groups characterized by n-order polynomial is constructed. Finally, the measurement result excluding background error is achieved by error suppression algorithm. The experiment results show that the transition time caused by the natural attenuation, which is tens of minutes to hours, is shorten to several minutes, while improving the measurement accuracy under the condition of test current from 10 pA down to 0. 1 pA, and insulation resistance measuring range can be effectively extended to 1016 Ω scale.%针对在超高绝缘电阻测量时,因存在衰减缓慢的时变非线性背景电流而难以快速准确测量的难题,提出一种基于非线性误差抑制算法的超高阻测量方法.首先分组交替改变测试电压极性,测量相应静电计输出信号,再根据非线性误差电流特点,采用n次多项式表示相邻n+2个分组的背景电流,构建连续n+2个分组测量的输出电压矩阵,最后通过误差抑制算法得到不合背景电流项的测量结果.实验结果表明,采用非线性误差电流抑制算法可将由固有衰减时间引起的测量过渡时间从长达数十分钟至数小时缩短到数分钟,同时提高了在10 ～0.1 pA极微电流条件下的超高阻测量精度,绝缘电阻测量量程可有效扩展到1016 Ω量级.
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