Study on Precision Selection of Instrument Transformer and its Calibration for Automatic Test System

Abstract

System accuracy is an important assessment indicator for automatic test system, which is influenced by many factors such as instrument, person, and environment. The paper takes a set of automatic motor testing system for an example, the mathematic relationship between the system accuracy and the precision of instrument transformers was analyzed, which also provides a theoretical reference for the precision selection of instrument transformer when the system accuracy was known. Some improved measures such as the selection of measuring point and the calibration of transformer ratio and phase angle are put forward. Testing results verified its simplicity and efficiency, besides the novelty above, the paper also provides a new idea to improve the system accuracy of constructed test platforms without increasing the cost for exchanging a matched transformer.