Effects of Communication Delays in Electric Grid

Communication delay occurs in electric power grid for various reasons, thus affects the performance of the control systems and can cause power loss. This paper analyzes the causes and effects of such communication delays in electric grid system. For the analysis, a simulated power network consisting of several generators is considered, where braking resistors (BR) are used for transient stability control of the grid. The switching of the BR is implemented by a fuzzy logic controller. The possible causes of communication delay are addressed. Also, it is described how much delay a system can tolerate for proper functioning, and what cyber threats or adversary can do to cause further delay. A balanced (3LG: three-phase-to-ground) fault at different points on the transmission lines is considered. Simulation results show that although the fuzzy logic-controlled braking resistor is effective in improving the transient stability, the communication delay associated with the (online calculation of the Total Kinetic Energy Deviation, TKED) input to the fuzzy controller has an influence on the transient stability performance. Keywords-Braking resistor, commnication delay; cyber threats; electric grid, fuzzy logic controller, total kinetic energy deviation.