In the ring distribution network, differential relays, which rely on communication between the protection relays, are used for the underground cable protection. To guarantee cable protection when communication is failed, an auxiliary protection by using directional overcurrent. The use of ring circuits in 6 – 35 kV distributed electrical networks can improve the reliability of power sup-ply. An increase in the load power and the share of distributed generation and renewable energy sources causes the redistribution of the power flow during the operation of an electrical. This solution is based on Recommendation ITU-T G. 1344, which defines the protection switching protocol and mechanisms for Ethernet ring network topologies which will be described in detail in this document. Further, the duration of the voltage. A Ring Main Unit (RMU) is a compact medium voltage (MV) switchgear assembly used to create reliable, sectionalized distribution networks. In order to protect technical infrastructures, systems, machines and networks against cyber threats, it is necessary to implement – and continuously maintain – a holistic.
