静电电位非接触式测量的偏差和修正

Deviation and Modification of Non⁃Contact Measurement of Electrostatic Voltage

非接触式静电电位测试仪是一种不接触待测体,通过静电感应间接测量导体或绝缘体表面电位的仪器。在现有规范下,非接触式静电电位测试仪的测试结果具有相当大的不确定性,难以给出绝对或正确的测试值。本文基于变电容式电场传感器,分析了非接触式静电电位测试仪准确测试带电体表面电位的条件,通过试验确定了测试和标定过程对带电体静电状态及表面电位测试结果的影响方式,以及非接触式电位测量中存在的偏差,并提出相应的修正方法。指出在非接触式电位测试中,应该考虑带电体尺寸的有限性、测试探头和测试距离对带电体静电特性的影响、绝缘体带电均匀性及表面电位等效表征等问题。

A non-contact electrostatic voltmeter is an instrument that indirectly measures the surface poten⁃tial of conductors or insulators by electrostatic induction without contacting the charged body.Under the current standards,the measurement of a non-contact electrostatic voltmeter has considerable uncertainty and it is difficult to give the absolute electrostatic voltage.In this paper,the conditions for a non-contact electrostatic voltmeter based on the variable capacitance electric field sensor to precisely measure the sur⁃face potential of the charged body are clarified.The influence of the operating process on electrostatic state and measured surface potential of the charged body as well as the deviation of measurement are con⁃firmed by experiments.It is suggested that when measuring the surface potential by using the noncontacting electrostatic voltmeters,one should consider the limited dimension of the charged body,the influence of the field sensor and the measuring distance on the electrostatic state of the charged body,the surface charge distribution and the equivalent characterization of the surface potential of insulators.