On-line Calibration of Voltage Transformers Using Synchrophasor Measurements

Un-calibrated instrument transformers present at the inputs of phasor measurement units (PMUs) can significantly degrade their outputs. This also causes problems in downstream applications that use PMU data. This paper presents a method for calibrating voltage transformers online using synchrophasor measurements. The proposed approach aims to find the optimal locations where good quality measurements must be added so as to bring the calibration error of all the measurements below a pre-defined threshold. The IEEE-118 bus system, the IEEE-300 bus system, and a 2383 bus Polish system have been used as the test systems for this analysis. The advantage of the proposed approach is its effectiveness and robustness.