A real-time co-simulation of a simplified power system was succesfully performed through interconnecting laboratories of Politecnico di Torino in Italy and Shanghai Jiao Tong University in China. This is a direct connection between the two Opal-RT simulators using UDP/IP. This is a bidirectional communication and both simulators could receive data concurrently. The simple test case consists of a MV feeder of a distribution system running on PoliTo's simulator, and a set of load and generation profiles as an outcome of a prosumer behavior model on Jiao Tong's simulator. PoliTo's simulator sends voltage and current (as well as total active and reactive power injected to the feeder) measurements to Jiao Tong's; while Jiao Tong's simulator sends a set of P, Q values for all substations to PoliTo. The communication report time was set to 5 seconds (in order to update loads and generators, and also retrieve measurements) just to stress latency and reliability of the connection. It was also tested with 1 second rate. However for this kind of slow transients, ranges of minutes are also sufficient. Both models run with 250 microsecond time-step in EMT using eMEGAsim configuration