A HARDWARE-IN-THE-LOOP EXPERIMENTAL TESTBED FOR THE EVALUATION OF POWER GRID STABILITY AND SECURITY

Abstract

This research presents the development of a hardware-in-the-loop testbed for a three-bus power grid interfaced with a simulated networked control system (NCS) for investigation of cyberattacks and their possible impacts on the power grid. The three-bus grid consists of two generator buses, configured as slack bus (constant voltage and angle) and PV bus (constant power and constant voltage), and a load bus (PQ bus). The synchronous generators are driven by dynamometers serving as prime movers, and the field circuits controlled by insulated gate bipolar junction transistors (IGBT). The load bus is comprised of resistors, capacitors, and inductors that are connected to the generator buses through transmission lines. The simulated NCS is implemented on an Opal-RT platform, which is a PC/FPGA based real-time simulator that can integrate hardware with software based simulations, commonly referred to as hardware-in-the-loop (HIL). In general, HIL setups have the advantage that physical elements under test interact in real time with a simulated model of a large scale system and provide a better insight of performance of both the physical system and the controller. In this HIL experimental setup, the data acquisition unit (DAQ), and the controller are both implemented on the Opal-RT platform. A baseline for the behavior of the three-bus system is first established by operating the generator under various load conditions for which the controller maintains the desired terminal voltage. Then various types of cyberattacks were initiated on the system that include bias attack, data attack, and Denial-of-Service (DoS) attacks. The closed loop generator control system maintained the stability of the system as well as the required bus voltages within a certain tolerance. With no attack prevention mechanism in place, the developed experimental platform provides a facility to observe and evaluate the impacts of various cyberattacks on a real physical microgrid.