This study describes a practical demonstration of low- and medium-voltage network monitoring through information exchange between metering, supervisory control and data acquisition and network information systems. The goal of the project is to increase observability of the network for operators and provide more information for network planners. Practical experiences and recommendations for secondary substation retrofitting are provided based on 18 installations of remote terminal units, fault locators and line sensors in 10/0.4 kV secondary substations.