Experience from Testing Digital T&D Equipment by Benjamin Baum

Digitalization is omnipresent these days and new technologies are arising rapidly. By contrast, while some digitalization exists in power generation, transport and distribution, it tends to be treated highly conservatively. Nevertheless, driven by the need to integrate volatile energy sources while also increasing efficiency and reliability, digital T&D equipment has been finding its way into substations. Items range from conventional instrument transformers featuring an additional A/D converter to new wireless, miniaturized temperature sensors. In parallel there is a trend to reduce footprint of substations and one possibility to achieve this is merging components. Part of this miniaturization is only possible with availability of digital equipment. While digital technologies have already been used for years on a station level, what has changed is expansion towards the process/bay level where instrument transformers, circuit breakers and protection relays are located. With such new digital equipment and operational methodologies, new dielectric stresses can be experienced, leading to need for a different approach when testing and evaluating such components. This presentation reviews the type of digital equipment that has been tested in recent years. Special attention is given to traditional test procedures, such as lightning impulse, that have become more severe due to requirements from the digital side. Finally, projects are presented that demonstrate how digitalization provides both new opportunities and new challenges for insulating technologies.