Title :
A calibrating device for large direct current instruments up to 320 kiloampere-turns
Author :
Zhu, Mingjun ; Xu, Ken
Author_Institution :
Dept. of Electr. Eng., Huazhong Univ. of Sci. & Technol., Hubei, China
fDate :
6/1/1998 12:00:00 AM
Abstract :
A device for calibrating large dc instruments ranging up to 320 kA has been designed. The calibrating coil simulates the actual busbar and its turns can readily be changed to meet various required measurement ranges. The calibrating coil is arranged in the shape of a cross so that we can determine the influence of the external magnetic field. The accuracies are 6×10-6 when a differential current measuring method is adopted and 200×10-6 when a differential voltage measuring method is adopted. The stability of the power supply is 0.02% per hour. The error due to the current fluctuation is very small and thus can be neglected
Keywords :
calibration; coils; current comparators; current transformers; electric current measurement; 320 kA; busbar simulation; calibrating coil; calibrating device; cross shape coil; differential current measuring method; differential voltage measuring method; external magnetic field influence; large direct current instruments; power supply stability; required measurement ranges; standard comparator; Bars; Calibration; Coils; Current measurement; Instruments; Magnetic field measurement; Power supplies; Power system stability; Shape; Switches;
Journal_Title :
Instrumentation and Measurement, IEEE Transactions on
