The implementation of continuous online Dissolved Gas Analysis (DGA) monitoring for all transmission and distribution substations

San Diego Gas & Electric (SDG&E) has committed to the construction of a comprehensive Transmission and Distribution Substation Condition Based Maintenance (CBM) project. The ultimate objective of this project is to extend the useful life and make greater utilization of its Transmission and Distribution Substation Assets. The transformer is the most expensive and critical asset in the substation and continuous online Dissolved Gas Analysis (DGA) provides the greatest insight into transformer condition, providing the basis for the desired asset optimization. With the advent of modern technology, a range of online DGA applications are available and this paper will investigate how SDGE selected the appropriate level of DGA monitoring for each transformer in its T&D substation fleet.