Abstract

The development of today's technology, the availability of electrical energy must be met very well. Because we already know that almost all human activities require electrical energy. In an electric power system, this energy is produced by a generator driven by a prime mover so that it can produce electrical energy. The propulsion can come from water, steam, geothermal and others. So from that initial mover we can call it PLTA (Hydroelectric Power Plant), PLTU (Steam Power Plant), PLTP (Geothermal Power Plant), and others. From the generator, the electrical energy is sent through the transmission network after it is connected to the distribution network, from the distribution network the energy is distributed to consumers. To meet the reliability of the availability and distribution of electrical energy, the need for an adequate protection system is absolutely necessary. The function of the protection system equipment is to identify disturbances and separate the disturbed network part from other parts that are still in normal condition and at the same time secure this part from damage that can cause greater losses. Overcurrent relay is a safety relay that works because of the amount of current and is installed on a high voltage network, medium voltage is also on the power transformer safety. This relay serves to secure electrical equipment due to phase disturbances.