The Design Of An Intelligent Current Transformer Calibrator Based On MSP430

With the growing of the power grid size and the developing of the concernedtechnology, the requirements and the difficulty in the measurements of the power grid aremore and more complicated. Though, the calibration of the power transformer is one ofthe most important parts of the measurements of the power grid, it takes too much timeand labor to finish the calibration of the power transformer with the traditional electriccalibrator, because we have to do so much work of zero modulation artificially. It’s notonly inefficient, but also inaccurate.This paper mainly deals with the invention of a high-accuracy digital powertransformer calibrator which is designed basing on the theory of orthogonal decompositionfor deviation signal. Using the calibrator designed here, We can not only calibrate thephase deviation and ratio deviation of a power current transformer, but also measure theload of a power current transformer. The designed calibrator is a high-accuracy measuringsystem with SCM MSP430as its core. The paper not only explains the designing principleand the methods used in the realization of the system, but also investigate the methods toexpand the function of the calibrator so that it can be used for calibration of power voltagetransformers and admittance measuring.The paper is mainly divided into five parts. Chapter one explains the source of thepower current transformers’ deviation and the development of the calibration theory forcurrent transformers. In chapter two, the theory of orthogonal decomposition for deviationsignal is explained in detail. Chapter three introduces the hardware of the calibratingsystem and its designing methods. Chapter four introduces the software of the calibratingsystem and the analysis of the deviation of the outcome we achieve. In chapter five, weexpand the function of the calibrator so that we can use the system to calibrate the powervoltage transformer and measure the impedance.