scope:

NVN-IEC/TS 62257-9-2 which is a technical specification, specifies the general requirements for the design and the implementation of microgrids used in decentralized rural electrification to ensure the safety of persons and property and their satisfactory operation according to the scheduled use. This part of IEC 62257 applies to microgrids for decentralized rural electrification purposes. The microgrids covered by this part of IEC 62257 are low voltage a.c., three-phase or singlephase, with rated capacity less than or equal to 100 kVA. They are powered by a single micropower plant and do not include voltage transformation. The rated capacity is at the electrical output of the micropower plant, that is, the upstream terminals of the main switch between the micropower plant and the microgrid. The voltage levels covered under this specification are voltages of the 240 V 1-Ø/415 V 3-Ø, the 230 V 1-Ø/400 V 3-Ø, the 220 V 1-Ø/380 V 3-Ø, and the 120 V 1-Ø/208 V 3-Ø systems at 60 Hz or 50 Hz; or obeyed by local code. This part of IEC 62257 specifies microgrids made of overhead lines because of technical and economical reasons in the context of decentralized rural electrification. In particular cases, underground cables can be used. The requirements cover microgrids with radial architecture.