Optimal interconnection device between DNO and small scale DERs of customer

This paper presents an interconnection device between DNO and small scale DERs of customers. It can link DERs more economically and improve the power quality for customers owing to prevent power failure by independent operation in case of power failure in DNO network and trade the electricity with DNO. In addition it can send information on the condition of the customer electricity network. So DNO can operate their distribution network efficiently. For the customer it can connect DERs efficiently and reduce installation spaces. In this device each power converter of DER connected to DC link and one bidirectional inverter wired to DC link. A static transfer switch (STS) was installed so that customers can prevent power failure by islanding operation during the DNO network failure. An intelligent electronic device (IED) was installed so that power and information can be exchanged with DNO or nearby customers and the protection control can be done to satisfy all the current standards for DERs.