Accuracy Performance of Power Voltage Transformers

摘要

Power Voltage Transformers, a novel concept in power systems worldwide, are units that incorporate features of both power and instrument transformers. Their primary purpose is power delivery. However, as they are still mainly specified according to standards for instrument transformers, their users sometimes expect simultaneous accuracy performance inherent to conventional voltage transformers. Due to a very large disproportion between the rated value of the burden on the power winding and the burden on the metering winding, achieving required accuracy classes is, at the very least, challenging both from design and testing perspective, and sometimes even impossible. The idea of this paper is to aggregate extensive experience the authors have with the topic of accuracy performance of Power Voltage Transformer units, and provide examples, guidelines and recommendations on how accuracy performance should be incorporated into upcoming dedicated Power Voltage Transformer standards, and engineering practice. All conclusions and observations within this paper will be corroborated with the results of measurements performed on actual units, calculations or both.