The utility model discloses a smart metering case system, including terminal equipment, routing module, smart metering case, electric energy meter and collection module, terminal equipment passes through TTL level serial ports with the routing module and links to each other, and the collection module of routing module and smart metering case passes through the power line and links to each other, and the collection module of smart metering case receives that the laggard line store of platform district's information that terminal equipment sent and self are through zero cross detection circuit smart metering 0 place circuit phase information and preserve. The problem of affiliated platform district and phase place dynamic identification 's the function of RS485 electric energy meter, support for management such as platform district distribution transformer's branch phase load, phase separating line loss provide information, the examination provides the assurance with the line loss for the fine -grained management in platform district, effective help platform distinguish the pointed discovery of managers and is solved.