To plan and protect networks from possible failures, network analysis is being done. According to the results of short circuits by the analysis of the network, adjustments are made to the parameters of relay protection. The configuration and selection of relay protection is then determined based on the network itself. The most common protection used at high voltage is distant protection. It is easy to adjust and does not require large conversions of connection at the measuring point and is very efficient and fast. The area of protection of zone I is very fast about 80% of the transmission line that it protects from the transmission line. The polygonal characteristic is most effective due to the application of numerical relays, which have a very high accuracy of measuring and issuing orders for switching off. The analysis in the paper compared the stepping values of the failure impedance of the three-pole short circuit on each transmission water on the polygonal characteristic with and without added resistance at the fault site. When analyzing with added resistance at the fault site, protection manages to protect transmission lines, however, very fast communication schemes are needed to make protection more efficient because in some places zone I does not reach 80% of water protection. The analysis of the protection of transmission protection on the example from the graduate thesis was intended to show that adjusting the protection in the standard short circuit is very effective, however with the added resistance at the fault site, but with additional adjustment for these cases of failures, the safety, reliability, and integrity of each network can be improved.