The energy losses discovery in the grid requires intensive data exchange between the transmission/distribution systems operators and retail electricity companies. Since these companies are using various billing and dispatching systems, they have unaligned master data and different structure of the transactional data, which cannot easily be matched. Ontology-driven data exchange is a solution which offers tools for data transformation, validation and merge. We present the model and the system built for the transmission system operators in order to enable their data exchange with the distribution systems operators and retail electricity companies. We will discuss our approach to the construction of an ontology-driven automated system for the energy losses discovery, which is focused on binding heterogenous data and unifying its processing with the ontology-based rules.