The Common Information Model (CIM) - IEC 61970, a well-known industry standard data model, is used to describe networked physical assets in an electrical power grid. Whereas this data model can be used to represent most detailed description of grid assets, currently it has limited application in power system network modeling. This is due to a couple of reasons. Firstly, many applications only require a simplified, mathematically abstracted network model and secondly, the CIM represents only a snapshot of grid state and therefore cannot accommodate time-series data from SCADA/PMU measurements. Furthermore, the legacy software developed for applications like powerflow consume data in proprietary formats, none of which is essentially CIM. As a first step in developing a new interoperable power grid data model to satisfy grid-analytic requirements, we have investigated and used CIM as one of the data ingestion sources. In this paper, we present our work of data ingestion, abstraction and translation from CIM to Bus-Branch Model (BBM) as a part of an overall system design and implementation for grid analytics and data interoperability.