Development of Medium Voltage DC (MVDC) distribution systems require using proper protection schemes whereas due to the behavior of dc fault current, the conventional fault detection methods for ac distribution systems cannot provide a selective protection for these networks. In this paper, a differential based protection method using Ethernet communication has been implemented for a radial MVDC distribution system with integrated PV and WT. This method must be fast enough to detect the faults before involving the main converters and separate only the faulty feeder in order to increase the reliability of the power system. The experimental validation is performed by using Hardware-in-the-Loop (HIL) approach and communication based on the IEC61850 protocol. A real time simulator (OPAL-RT) and a development board (DK60) are used to evaluate the method and to calculate the time delay of this fault detection algorithm.