Design and Implementation of an Automatic Synchronizing and Protection Relay through Power-Hardware-in-the-Loop (PHIL) Simulation

This paper focuses on the design and implementation of an automatic synchronizing and protection relay. The relay automates the synchronization process of a Distributed Energy Resource (DER) to the Main Grid. The proposed design utilizes cost-effective data acquisition using Arduino in combination with LabVIEW software to implement the multipurpose synchronizing relay. The proposed synchronizing relay is capable of synchronizing a Distributed Generator (DG) to the power grid from black-start and fulfills the requirements imposed by the utility. The relay is implemented through voltage and frequency control of an actual lab-scale synchronous generator. In the synchronization process, frequency synchronization is completed using speed control of the stepper motor acting as the prime mover and voltage synchronization is accomplished using Excitation Control module through Power-Hardware-in-the-Loop (PHIL) simulation. In grid-connected mode, active and reactive power controls and protection schemes for the synchronous generator have also been implemented. The proposed multifunction relay has been deployed and tested on a lab-scale testbed to validate the proposed design and functionality.