In this paper, a backup protection scheme is presented. The proposed scheme uses the concept of a cognitive radio-based wireless sensor network to implement a protection scheme without the need for conventional electric wires and/or optical fiber between current and voltage transducers, control panels, and circuit breakers. The proposed scheme uses unlicensed spectrum channels by applying spectrum sensing and frequency allocation algorithms that are used in cognitive radio based systems. The importance of the proposed scheme comes from its cost effectiveness compared to the Ethernet communication both wired and wireless if the data transfer and message exchange is done using cognitive radio_based communication for relatively long distances. The proposed scheme utilizes cognitive radio-based communication network to convey analog and digital signals within a substation. In this way, it saves the cost of the copper wires and/or optical fiber that would be used to transmit digital and analog signals. Further, it does not require the expensive spectrum licenses that would have been purchased if Ethernet long-distance wireless communications are utilized. To assess the benefits/challenges related to the application of cognitive radio_based communication, a detailed and realistic modeling of both power systems and cognitive radio_based communication systems is performed simultaneously. The proposed scheme is simulated using MATLAB/Simulink and performance of the proposed scheme was investigated under different communication scenarios.

In this paper, the particle swarm optimization (PSO) technique is used to optimally allocate phasor measurement units (PMUs) within standard test systems and a real-world power system. PMUs are allocated at system substations in a manner that ensures complete system observability while minimizing installation costs. This study considers IEEE 14-, 30-, and 57-bus standard test systems, along with the Jordanian national high-voltage grid. The optimal allocation was performed separately on the 132 kV and 400 kV buses of the Jordanian grid. Additionally, a novel technique for further minimization of measurement units, considering electric grid planning, is investigated. The results demonstrate that the proposed approach successfully reduces the required number of PMUs while maintaining full system observability. For instance, the IEEE 14-bus system achieved complete observability with only four PMUs, while the IEEE 30-bus and 57-bus systems required ten and seventeen PMUs, respectively. For the Jordanian transmission network, the 400 kV system required only three PMUs, and the 132 kV system required twenty-six PMUs. Furthermore, it was found that integrating power system planning and grid expansion strategies into the PMU placement problem may further reduce installation costs. The results emphasize the effectiveness of the proposed approach in enhancing situational awareness, improving state estimation accuracy, and facilitating reliable protection, control, and monitoring schemes. This study concludes that an optimal PMU allocation strategy shall be incorporated into power system planning studies to maximize cost efficiency while ensuring full observability.