Reducing the cost of distributed energy resources (DERs) such as renewables, storage,electric vehicles and smart loads is driving their increased connection to distributionsystems. Extracting maximum benefits from DERs require liberalising distribution sys-tems by allowing: (1) a distribution transactive energy market (DTEM) operated by alocal distribution operator (LDO) and (2) peer-to-peer (P2P), peer-to-LDO (P2LDO) andTransmission-to-LDO (T2LDO) type transactions. A DTEM will bring several benefitssuch as: (1) enhanced economic opportunity for DERs, making them more profitable and(2) increased social welfare benefiting both buyers and sellers. To achieve this objective, wedevelop a comprehensive three-phase DTEM platform that provides maximum economicopportunities for DERs and maximises social welfare that benefits all market participants,while considering P2P, P2LDO and T2LDO transactions, for both energy and ancillaryservices. Interaction between bulk electricity market independent system operator (ISO)and LDO controlled DTEM is presented. The DTEM model is implemented as a practi-cal mixed-integer linear programming formulation that includes a network reconfigurationfeature. The DTEM model is studied on three-phase 5-bus and 34-bus systems, demon-strating its effectiveness to settle energy and ancillary service transactions, while obtainingdistribution locational marginal prices. Results show that P2P transactions, when allowed,increase social welfare and increases profitability of DER
