A Novel and Simple Method for VT and CT Calibration

The calibration of measurement transformers represents a classical task in the practice of electrical measurements. The great part of the commercial instruments expressly designed for this purpose founds their working principle on a scheme based on an idea of Kusters and Moore. Though they can assure a very high accuracy, the need to employ a high-performance electromagnetic circuit makes them very expensive and not suitable for measurements at frequencies higher than 50 or 60 Hz. For this reason, this kind of instruments cannot be employed for calibration of the new generation of current and voltage transducers, like electronic measurement transformers, which employment is growing in all the applications where wide bandwidth is required. In this paper a new method for the calibration of measurement transformers is proposed. It is based on a simple and cost-effective hardware that can be easily implemented. In spite of its simplicity, the tests developed on a prototype have clearly point out that proper uncertainty of the proposed method is in the same order of that of a state-of-art commercial instruments.