Converter-based Intelligent Transformer for Enhanced Grid Monitoring and Control

Abstract

The electric grid is rapidly evolving by incorporating advanced equipment that bears a variety of smart features in addition to their traditional functionalities. The power transformers are the most significant equipment in the substation and have been traditionally performing voltage conversion and isolation. However, the modern grid dynamics demand a variety of smart control features at strategic locations of the grid for which the most appropriate candidate are the transformers. Accordingly, the idea of solid-state transformers (SST) was conceived but they are still far from integration into grid due to their poor lifetime and reliability concerns. Also, the investment on existing infrastructure demands introduction of smart features into already installed traditional transformers. This paper proposes a converter-based intelligent transformer configuration that utilizes conventional transformers and introduces smart features into them through a power electronics-based module integrated between neutral and substation ground. The device introduces a variety of advanced features in traditional transformers that include voltage regulation, voltage balancing, harmonics isolation, supporting voltage ride through (VRT) capabilities of distributed energy resources (DERs) and avoiding grid collapse due to certain natural or man-made disturbances, such as, solar storms and high-altitude nuclear explosions. The proposed scheme is evaluated utilizing Typhoon hardware-in-the-loop (HIL-604) real-time simulator for a modified IEEE-9 bus benchmark system. The results verify the promising performance of the proposed scheme to enhance grid reliability, resiliency and power quality.