Protection verification and designing while establishing collective prosumer?s low-voltage electrical installation. A case study

IEC 60364-8-2 introduces many safety issues concerning a new concept of integration of electricity consumers and local power generation and energy storage, i.e., prosumer's low-voltage electrical installations. A collective type of them is several consumer installations connected to the same public distribution system and sharing one common set of local power supplies and energy storage unit. The transition to island mode raises technical challenges related to ensuring the protection selectivity and the effectiveness of protection against electric shock. They result from the expected short-circuit currents, much smaller compared to other modes. In this paper, the first approach for protection verification and design concerning collective prosumers' electrical installation to be established based on an existing low-voltage distribution system in each area (group of prosumers) is proposed. It includes the following: calculation of short-circuit currents while operating in island mode, selection of the currents relying on the current limit of an energy storage unit, verification of the protection devices, and design of the additional protection. The case study confirms the approach allows for the investigation of the common protection devices in terms of meeting both the safety and selectivity requirements. Otherwise, advanced protection schemes and strategies should be considered to meet the same safety requirements.