In all kinds of measurement equipment the most important things are uncertainty, stability and immunity of measurement and ability to sense possible faults in the measured quantities. Three phase energy meter with capability of measuring an additional current and zero current respectively, was developed in a company named Strip's d. o. o. Main application of the meter is in electric switchboards, where it is used for sub-metering of electrical energy. The meter is installed behind the fuse or current breakers on the three phase or single phase load side. The meter is a component of a bigger system, which provides storage for measured characteristics of power grid and displays diagnostics of data received from meters added to the system.
The present diploma thesis describes the development of the three phase energy meter, including description of design, structure of product and mathematical calculations required for measurements. Main principle of operation and data transition is presented as well. According to given functional and technical requirements, there are also presented tests of product and corresponding results. Some problems that occurred during the development of the product and data transition are pointed out.