A new protection and monitoring system for dry type transformers based on innovative sensor technologies

In this contribution a new protection and monitoring system for dry type transformers is introduced, which consists of three parts and is based on innovative sensor technologies. The first part protects the device against overheating using an optical fibre sensor, which signals an alarm when a local overheating appears. In this case a second unit allows the identification of interturn short circuits in the coils by determining and analyzing the transfer function. The third part, which operates independently from the two others, monitors the partial discharge activity and provides the capability for a localization of partial discharge sources. The developed monitoring system operates online, is efficient and cost-effective and can be easily installed at almost all categories of dry type transformers.