The increasing share of distributed and renewable generation units and demand response resources in distribution grids necessitates improvement of its supervision, monitoring and control schemes for reliable operation. Thereby distribution grids have to be made more intelligent using innovative methods, solutions and automation. It is therefore expected to have more smart meters, switches and sensors installed under its operation domain. So a large volume of information has to be managed to integrate the grid-derived processes into utility systems and practices which is expensive and unrealistic. Further, the application of these data is diverse and processed at different rates. So, the main challenge for the distribution system operator is to achieve efficient operation and control of such active grids with accurate information about the state of the grid by making use of the existing infrastructures to a large extent and then install minimum of possible metering and automation devices for reducing the overall costs. This project develops innovative methods and techniques not only for accurately estimating performance of the distribution grids but also for providing alternatives to control, protect and operate the system assets to ensure safe and reliable electricity to all consumers and maximise utilisation of local renewable energy.