RATIO ERROR SELF CALIBRATION SYSTEM FOR MINIATURE CURRENT TRANSFORMER

摘要

A ratio error self calibration system for a miniature current transformer comprises a 10-segment single disc miniature sensing diverter, a 5A/0.5A miniature current comparator, three multi-ratio miniature current comparators, a power supply current transformer, a test current source, an error measurement apparatus, a zeroing impedance casing and a galvanometer, wherein 5A/0.5A to 0.001A ratio values are led out employing a reference current method self calibration line and a current comparator cascade single-disc induction diverter ratio expansion line. The ratio error self calibration system for a miniature current transformer is characterized in that the current ratio measuring ranges are divided into three segments as following: 5A/0.5 A to 0.1A, 5A/0.05A to 0.01A and 5A/0.005A to 0.001A, which are covered respectively by three multi-ratio miniature current comparators. The advantages are provided as following: the number of self calibration operation steps is small, the measuring range expansion efficiency is high, and value reproducibility is good.