Design of transformer load monitoring systems by utilizing smart meter data

In this paper, an innovative transformer load monitoring system by utilizing smart meter data has been designed to determine the daily power profile of distribution transformers. A two-stage load estimator algorithm that combines customer load pattern from smart meters and state estimation (SE) theory is developed to provide the secondary output power of distribution transformers in the low voltage network at a sound accuracy with customer smart meter measurements. The estimated results that could reflect true transformer loading within 15 min intervals then are used for transformer load management. A data visualization based human machine interface is also designed to allow operators to intuitively monitor the loading levels of distribution transformers. Test results of a practical distribution feeder with 12 transformers in Taipower are presented. The methodology proposed in this paper can effectively assist electric utilities for the evaluation of loading factors of distribution transformers to prevent the burn out of transformers caused by overloading problem. The operation efficiency of distribution systems can also be enhanced by loading balance of distribution transformers.