DNP3 Implementation in a High DER Penetration Distribution System

With more distributed energy resources (DERs) being added on the grid to curb green house emissions, smart devices on the edge like inverters need to communicate with apps as well as centralized devices owned by local utilities to report pertinent data such as voltages and currents. In addition, central controllers also need to be able to send commands to inverters to help maintain the grid and sustain safe operating conditions. In this paper, 766 inverters based on a real distribution feeder are modeled in OPAL-RT and voltages, currents, real and reactive power measurements are sent to an SEL Real Time Automation Controller (RTAC) via DNP3, a supervisory control and data acquisition (SCADA) protocol. Voltage violations of ±5% (under 0.95 or over 1.05 per unit) are also modeled which need to be mitigated by sending commands to the inverters through the RTAC. The model was tested and validated first using Modbus which has read/write limitations not allowing an immediate holistic view of the system. As such, DNP3 was implemented which has no such limitations to prove the versatility of the model as well as validate the use of RTAC in an environment with a high penetration rate of DERs and their coordinated control. This paper will describe how the feeder model was created before diving into the intricacies of using SCADA protocols in OPAL-RT, connecting an RTAC to the OPAL-RT, and constructing a DNP3 map. Results will include seeing appropriate data in the RTAC’s acSELerator program as well as voltage measurement changes due to inverter commands being sent from the RTAC.