Grounding resistance measuring instrument controlled by a microcomputer and a bias magnetic regulator

The author has successfully developed a grounding resistance measuring instrument controlled by a microcomputer. The instrument can regulate the measuring loop current precisely by the bias magnetic theory of double iron cores and adopt a flexible software to eliminate the error. Tests have shown that the measuring error is less than 0.5%. The instrument thus satisfies precisely the IEC stipulations for measuring grounding resistance of electrical equipment.