The failure detection of substation equipment causing the system blackout is the main problem in electrical transmission due to the delayed data transmission network. The communication among electrical power substation is an essential part of the protection system in electrical power transmission for providing a reliable network. So far, the Indonesian electric utility entrusted the third parties to provide the communication network. However, this pathway has the drawback in data transmission, for instance data delayed, because it is not directly integrated with the system. Thus, in this study, we proposed a novel built-in method that allowed the user to conduct a real-time monitoring on the entire system. We implemented two stages; the first stage was to deploy the primary multiplexer to provide 2 Mbps loop network, while the second stage was to develop the independent network by installing the synchronous digital hierarchy (SDH) network to replace the existing one. Based on G.703 channel test, we found that the proposed network was capable of replacing the third parties network, confirmed by direct testing using network monitoring system.