Short-circuit protection in Off-Grid system

Renewable sources of electric energy belong to key areas in research and development in recent years. This course leads to the design and development of autonomous power units, which are subject to specific requirements, so-called Off-Grid systems, designed as power supply for energy self-sufficient houses. The specific requirements for Off-Grid systems are: independent of external power supply, maximum efficiency of using the renewable sources, stable generation - consumption balance and opportunities of energy storage. Generally, in most cases, there are mentioned only the benefits and proactive development direction of these concepts, but as usually as with every product, there is no longer mention about the issues related to operations in long time term. The goal of this paper is to point out the operation issues of the Off-Grid systems with specific requirements, especially with regard to the protection methods and abnormal operating conditions such as a short circuit in the isolated network of Off-Grid power system.